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NFIP Floodplain Management Requirements – FEMA 480
BID #: FEMA 480
ISSUED: 2/1/2005
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Executive Summary
This document is a FEMA study guide and desk reference designed for local officials responsible for administering and enforcing floodplain management regulations, specifically concerning the National Flood Insurance Program (NFIP). It offers guidance on understanding and implementing floodplain management ordinances, interpreting flood maps and studies, and handling various floodplain-related issues. The guide also aims to broaden the understanding of floodplain management strategies that can be applied at the local level and help prepare for the Certified Floodplain Manager designation. The original date was February 2005.
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--- Document: NFIP Floodplain Management Requirements – FEMA 480 Document ---
National Flood Insurance Program (NFIP)
Floodplain Management Requirements
A Study Guide and Desk Reference for Local Offi cials
FEMA 480
February 2005
This study guide and desk reference can serve two purposes.
First, it can be used as a study guide to enhance the knowledge
and skills of local officials responsible for administering and
enforcing local floodplain management regulations. It is also
intended to broaden their understanding of floodplain
management strategies that can be applied at the local level.
Local officials and others can use the study guide to help them
study for the exam for the Association of State Floodplain
Manager's (ASFPM) Certified Floodplain Manager designation.
Secondly, the study guide can be used as a desk reference that
you can refer to when specific issues arise as you implement
your floodplain management ordinance. Guidance is included on
how to handle many of the issues and information provided that
will help you explain the requirements to citizens of your
community.
While any interested person may use this study guide and desk
reference, it is written specifically for the local official who is
responsible for administering his or her community's floodplain
management regulations.
a home
National Flood Insurance Program (NFIP)
Floodplain Management
Requirements
A Study Guide and Desk Reference for Local Officials
FEMA 480
February 2005
Use the arrow keys to turn pages
National Flood Insurance Program (NFIP) Floodplain Management
Requirements: A Study Guide and Desk Reference for Local
Officials
TABLE OF CONTENTS
Unit O: Orientation
A. Introduction.............................................................................................. O-3
Study guide objectives ............................................................................ O-4
B. Study guide materials............................................................................... O-5
Notebook................................................................................................. O-5
Flood insurance study and maps............................................................. O-6
Learning Checks ..................................................................................... O-6
C. Using the Study Guide ............................................................................. O-7
Where to get help.................................................................................... O-7
D. Acknowledgments.................................................................................... O-8
Illustrations ............................................................................................. O-8
Unit 1: Floods and Floodplain Management
Introduction.............................................................................................. 1-4
A. Floods and Floodplains ............................................................................. 1-5
Riverine Flooding .................................................................................... 1-6
Overbank flooding .............................................................................. 1-7
Flash flooding ..................................................................................... 1-8
Riverine erosion .................................................................................. 1-8
Coastal flooding....................................................................................... 1-9
Coastal storms ..................................................................................... 1-9
Coastal erosion.................................................................................. 1-10
Tsunamis................................................................................................ 1-11
Lake flooding .................................................................................... 1-11
Shallow Flooding................................................................................... 1-11
Sheet flow ......................................................................................... 1-11
Ponding ............................................................................................. 1-12
Urban drainage.................................................................................. 1-12
Special Flood Hazards ........................................................................... 1-12
Closed basin lakes............................................................................. 1-13
Uncertain flow paths ......................................................................... 1-13
Dam breaks ....................................................................................... 1-14
Ice jams ............................................................................................. 1-15
Mudflow............................................................................................ 1-15
Natural and beneficial floodplain functions........................................... 1-16
Natural flood and erosion control ..................................................... 1-17
Biologic resources and functions ...................................................... 1-17
Societal resources and functions ....................................................... 1-17
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B. Floodplain Development......................................................................... 1-19
Floodplain Development Dynamics ...................................................... 1-19
Riverine floodplains.......................................................................... 1-19
Watersheds ........................................................................................ 1-20
Coasts ................................................................................................ 1-21
Flood Damage........................................................................................ 1-22
Hydrodynamic forces........................................................................ 1-22
Debris impact .................................................................................... 1-24
Hydrostatic forces ............................................................................. 1-25
Soaking.............................................................................................. 1-25
Sediment and contaminants............................................................... 1-26
Safety and Health Hazards..................................................................... 1-27
C. Floodplain Management.......................................................................... 1-28
Evolution................................................................................................ 1-28
The Unified National Program for Floodplain Management................. 1-29
Strategies and tools ........................................................................... 1-30
Floodplain Management Strategies........................................................ 1-30
Strategy 1: Modify human susceptibility to flood damage............... 1-30
Strategy 2: Modify the impact of flooding ....................................... 1-31
Strategy 3: Modify flooding itself..................................................... 1-31
Strategy 4: Preserve and restore natural resources ........................... 1-32
Unit 2: The National Flood Insurance Program
A. History....................................................................................................... 2-3
B. How the NFIP Works................................................................................ 2-6
Mapping ................................................................................................... 2-6
Insurance.................................................................................................. 2-7
Regulations .............................................................................................. 2-8
C. Roles and Responsibilities ........................................................................ 2-9
The community role................................................................................. 2-9
The state role............................................................................................ 2-9
The federal role...................................................................................... 2-10
D. Community Participation ........................................................................ 2-12
Joining the NFIP .................................................................................... 2-12
Compliance ............................................................................................ 2-13
Probation ........................................................................................... 2-14
Suspension ........................................................................................ 2-14
Sanctions for non-participation.............................................................. 2-15
Unit 3: NFIP Flood Studies and Maps
A. NFIP Flood Studies................................................................................... 3-3
Flood Study Terminology........................................................................ 3-3
The base flood..................................................................................... 3-3
The 100-year flood.............................................................................. 3-4
Special flood hazard area and base flood elevation ............................ 3-4
Identifying Floodprone Areas.................................................................. 3-5
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Flood Insurance Study ........................................................................ 3-7
Flood County, USA and Incorporated Areas ...................................... 3-8
B. Riverine Studies ........................................................................................ 3-9
Hydrology ................................................................................................ 3-9
Cross Sections........................................................................................ 3-10
Hydraulics.............................................................................................. 3-12
Flood Profile .......................................................................................... 3-13
Floodplain Map...................................................................................... 3-16
Floodway Analysis................................................................................. 3-17
C. Coastal Flood Studies.............................................................................. 3-20
Storm Surge ........................................................................................... 3-20
Waves..................................................................................................... 3-20
Hydraulic Analysis................................................................................. 3-21
Coastal High Hazard Area ..................................................................... 3-22
Coastal Floodplain Map......................................................................... 3-22
D. Shallow flooding studies......................................................................... 3-24
E. Approximate Studies ............................................................................... 3-25
F. NFIP Maps............................................................................................... 3-26
General Map Features............................................................................ 3-26
Map Index .............................................................................................. 3-27
Title block ......................................................................................... 3-27
Map revision date.............................................................................. 3-27
Map scales and north direction ......................................................... 3-28
Elevation reference marks................................................................. 3-28
FIRM Zones ...................................................................................... 3-29
Flood Hazard Boundary Map (FHBM).................................................. 3-30
Flood Insurance Rate Map (FIRM) — old format (Pre 1986)............... 3-30
Flood Boundary and Floodway Map (Floodway Map) – Old format (Pre
1986) ...................................................................................................... 3-31
Flood Insurance Rate Map — new format (Since 1986) ....................... 3-33
Partial Map Initiatives FIRM................................................................. 3-35
FIRMs with Coastal and Lake Floodplains ........................................... 3-35
Coastal FIRMs .................................................................................. 3-35
Coastal Barrier Resources System .................................................... 3-35
Lakes ................................................................................................. 3-36
Shallow Flooding FIRMs....................................................................... 3-37
FIRMs with Flood Protection Projects .................................................. 3-37
Countywide FIRMs................................................................................ 3-38
Digital FIRMs ........................................................................................ 3-40
Digital Flood Insurance Rate Map (DFIRM).................................... 3-40
Q3 Flood Data................................................................................... 3-42
Unit 4: Using NFIP Studies and Maps
A. Using FIS Reports..................................................................................... 4-3
FIS Report Contents................................................................................. 4-3
Using Flood Data and Tables................................................................... 4-4
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Flood discharges ................................................................................. 4-4
Floodway Data Table .......................................................................... 4-5
Coastal and Lake Elevations.................................................................... 4-6
Relating Report Data to Maps and Profiles ............................................. 4-7
B. Using the Flood Maps ............................................................................... 4-9
Locating a Site ......................................................................................... 4-9
Determining Stationing.......................................................................... 4-10
Base Flood Elevations from Maps......................................................... 4-11
Locating the Floodway Boundary.......................................................... 4-11
C. Using Profiles.......................................................................................... 4-13
Profile Features ...................................................................................... 4-13
Determining Base Flood Elevations ...................................................... 4-14
Profiles .............................................................................................. 4-14
Other types of floodplains................................................................. 4-15
Relating flood elevations to the ground ............................................ 4-15
Relating Profiles to Maps....................................................................... 4-16
D. Maintaining and Revising NFIP Maps.................................................... 4-17
Ordering Maps ....................................................................................... 4-17
Changing NFIP Maps ............................................................................ 4-17
Types of Changes................................................................................... 4-19
Maps and Letters.................................................................................... 4-20
Requesting Map Changes ...................................................................... 4-22
Unit 5: The NFIP Floodplain Management Requirements
A. The NFIP’s Regulations............................................................................ 5-4
NFIP Regulations..................................................................................... 5-4
Community Types.................................................................................... 5-6
B. Maps and Data........................................................................................... 5-8
NFIP Maps and Data................................................................................ 5-8
When FIRM and Ground Data Disagree ................................................. 5-9
Regulating Approximate A Zones ......................................................... 5-10
Small developments .......................................................................... 5-11
Larger developments......................................................................... 5-12
Draft Revised NFIP Data....................................................................... 5-14
Advisory Flood Hazard Data ................................................................. 5-15
C. Permit Requirements............................................................................... 5-17
Development Permit .............................................................................. 5-17
Building permits................................................................................ 5-18
Small projects.................................................................................... 5-18
Permits from Other Agencies................................................................. 5-19
D. Encroachments........................................................................................ 5-21
Regulatory Floodways ........................................................................... 5-21
Encroachment Review ........................................................................... 5-21
Streams without Floodway Maps........................................................... 5-24
Allowable increases in Flood Heights ................................................... 5-25
E. New Buildings in A Zones Buildings..................................................... 5-27
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Elevation ................................................................................................ 5-27
Fill ..................................................................................................... 5-27
Piles, posts, piers or columns ............................................................ 5-28
Walls or crawlspace .......................................................................... 5-29
How high? ......................................................................................... 5-31
Elevation Certificate ......................................................................... 5-32
Enclosures.............................................................................................. 5-32
Openings ........................................................................................... 5-33
Use .................................................................................................... 5-36
Floodproofing ........................................................................................ 5-38
How high? ......................................................................................... 5-39
Basements .............................................................................................. 5-40
Basement Exceptions............................................................................. 5-40
Basements and LOMR-F Areas............................................................. 5-41
Anchoring .............................................................................................. 5-42
Flood-Resistant Material........................................................................ 5-43
Accessory Structures.............................................................................. 5-44
Manufactured Homes............................................................................. 5-45
Elevation ........................................................................................... 5-45
Anchoring.......................................................................................... 5-47
Recreational Vehicles ............................................................................ 5-48
AO and AH Zones ................................................................................. 5-49
A99 and AR Zones................................................................................. 5-49
F. New Buildings in V Zones ...................................................................... 5-51
Building Location .................................................................................. 5-51
Elevation on Piles or Columns............................................................... 5-51
Wind and water loads........................................................................ 5-52
Certification ...................................................................................... 5-54
Breakaway Walls ................................................................................... 5-54
Coastal AE Zones .................................................................................. 5-56
G. Other Requirements ................................................................................ 5-57
Subdivisions........................................................................................... 5-57
Water and Sewer Systems...................................................................... 5-58
Watercourse alterations.......................................................................... 5-58
Unit 6: Additional Regulatory Measures
Introduction.............................................................................................. 6-4
A. Taking ....................................................................................................... 6-5
B. State Regulatory Standards ....................................................................... 6-9
C. Higher Regulatory Standards .................................................................. 6-11
Location Restrictions ............................................................................. 6-12
Highly hazardous areas ..................................................................... 6-12
Subdivision design ............................................................................ 6-12
Setbacks ............................................................................................ 6-14
Manufactured homes......................................................................... 6-15
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Natural areas ..................................................................................... 6-15
Low-density zoning........................................................................... 6-15
Bulding Requirements ........................................................................... 6-16
Freeboard .......................................................................................... 6-16
Foundation standards ........................................................................ 6-17
Safety Requirements .............................................................................. 6-18
Critical facilities................................................................................ 6-18
Hazardous materials.......................................................................... 6-19
Dry land access ................................................................................. 6-19
Encroachment Standards........................................................................ 6-20
Compensatory Storage........................................................................... 6-21
Stormwater Management....................................................................... 6-22
Temporary Moratorium ......................................................................... 6-23
D. Flood Hazards of Special Concern.......................................................... 6-24
Coastal Erosion ...................................................................................... 6-24
Regulatory standards......................................................................... 6-25
Tsunamis................................................................................................ 6-25
Regulatory standards......................................................................... 6-25
Closed Basin Lakes................................................................................ 6-26
Regulatory standards......................................................................... 6-26
Uncertain Flow Paths............................................................................. 6-27
Regulatory standards......................................................................... 6-27
Dam Breaks............................................................................................ 6-28
Regulatory standards......................................................................... 6-28
Ice Jams.................................................................................................. 6-29
Regulatory standards......................................................................... 6-29
Mudflows ............................................................................................... 6-29
Regulatory standards......................................................................... 6-29
E. Environmental Protection Measures........................................................ 6-31
Strategies................................................................................................ 6-31
Federal Regulations ............................................................................... 6-32
Wetland Protection................................................................................. 6-32
Rare and Endangered Species................................................................ 6-33
On-site Sewage Disposal ....................................................................... 6-33
Facilities Siting ...................................................................................... 6-33
Water Quality Regulations..................................................................... 6-33
Special Designations.............................................................................. 6-34
Unit 7: Ordinance Administration
Introduction.............................................................................................. 7-4
A. The Ordinance........................................................................................... 7-5
Statutory Authority .................................................................................. 7-5
Types of ordinances ................................................................................. 7-6
Zoning ordinance ................................................................................ 7-6
Building codes..................................................................................... 7-7
Subdivision regulations....................................................................... 7-9
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Sanitary regulations............................................................................. 7-9
“Stand alone” ordinance...................................................................... 7-9
Contents ................................................................................................. 7-10
B. The Administrator ................................................................................... 7-12
Duties ..................................................................................................... 7-12
Qualifications......................................................................................... 7-15
Training.................................................................................................. 7-15
Liability.................................................................................................. 7-17
C. Development Permits .............................................................................. 7-20
When a permit is required...................................................................... 7-20
Exemptions ............................................................................................ 7-22
Permit Application Form ....................................................................... 7-22
Application Review ............................................................................... 7-23
Review for Completeness ...................................................................... 7-23
Review for Compliance ......................................................................... 7-26
Application Approval or Denial............................................................. 7-28
D. Inspections .............................................................................................. 7-36
First Inspection....................................................................................... 7-36
Second Inspection .................................................................................. 7-36
Checking elevations .......................................................................... 7-37
Third Inspection..................................................................................... 7-38
Certificate of occupancy ................................................................... 7-38
Later Inspections.................................................................................... 7-39
E. Enforcement ............................................................................................ 7-40
Voluntary Compliance........................................................................... 7-40
Administrative Steps.............................................................................. 7-40
Legal Recourses..................................................................................... 7-41
Section 1316........................................................................................... 7-42
F. Appeals, Special Uses and Variances...................................................... 7-44
Appeals.............................................................................................. 7-44
Special uses ....................................................................................... 7-44
Variances........................................................................................... 7-44
Boards ............................................................................................... 7-44
Variances................................................................................................ 7-45
NFIP requirements ............................................................................ 7-45
Historic buildings.............................................................................. 7-54
Functionally dependent use............................................................... 7-54
Records.............................................................................................. 7-55
G. Records.................................................................................................... 7-56
Permit File.............................................................................................. 7-56
Elevation Certificate .............................................................................. 7-57
Floodproofing Certificate....................................................................... 7-58
V Zone Certification .............................................................................. 7-59
No-rise Certification .............................................................................. 7-59
Biennial Report ...................................................................................... 7-60
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Unit 8: Substantial Improvement and Substantial Damage
Introduction.............................................................................................. 8-3
A. Substantial Improvement .......................................................................... 8-4
Projects affected....................................................................................... 8-4
Post-FIRM buildings........................................................................... 8-5
The Formula............................................................................................. 8-5
Market value ....................................................................................... 8-6
Substantial Improvement Examples ...................................................... 8-10
Example 1. Minor rehabilitation ....................................................... 8-10
Example 2. Substantial rehabilitation ............................................... 8-11
Example 3. Lateral addition—residential ......................................... 8-12
Example 4. Lateral addition—nonresidential ................................... 8-13
Example 5. Vertical addition—residential........................................ 8-14
Example 6. Vertical addition—nonresidential.................................. 8-15
Example 7. Post-FIRM building—minor addition ........................... 8-16
Example 8. Post-FIRM building—substantial improvement............ 8-17
B. Substantial Damage................................................................................. 8-18
Cost to Repair ........................................................................................ 8-18
Substantial Damage Examples............................................................... 8-20
Example 1. Reconstruction of a destroyed building ......................... 8-20
Example 2. Substantially damaged structure .................................... 8-21
Substantial Damage Software................................................................ 8-22
Increased Cost of Compliance ............................................................... 8-22
C. Special Situations .................................................................................... 8-25
Exempt Costs ......................................................................................... 8-25
Historic Structures ................................................................................. 8-25
Corrections of Code Violations ............................................................. 8-26
Example ............................................................................................ 8-27
Unit 9: Flood Insurance and Floodplain Management
A. Flood Insurance Policies ........................................................................... 9-3
Who’s Involved........................................................................................ 9-3
Coverage .................................................................................................. 9-3
Building coverage ............................................................................... 9-3
“Building” defined .............................................................................. 9-4
Contents coverage ............................................................................... 9-5
Basements ........................................................................................... 9-5
Enclosures ........................................................................................... 9-6
Amount of coverage............................................................................ 9-6
Waiting period..................................................................................... 9-7
The Mandatory Purchase Requirement............................................... 9-7
Where it applies .................................................................................. 9-8
How it works....................................................................................... 9-8
B. Rating Buildings...................................................................................... 9-11
Rating pre-FIRM buildings.................................................................... 9-11
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Rating New Buildings............................................................................ 9-14
Submit for rate .................................................................................. 9-19
Elevation certificates......................................................................... 9-19
Floodproofing.................................................................................... 9-19
Rating Unnumbered A Zones ................................................................ 9-19
Premiums ............................................................................................... 9-20
C. The Community Rating System .............................................................. 9-22
Benefits ............................................................................................. 9-22
CRS activities......................................................................................... 9-23
Public information activities ............................................................. 9-23
Mapping and regulation activities..................................................... 9-24
Flood damage reduction activities .................................................... 9-24
Flood preparedness activities ............................................................ 9-25
Publications............................................................................................ 9-25
D. The Coastal Barriers Resources System ................................................. 9-27
Unit 10: Disaster Operations and Hazard Mitigation
A. Disaster Operations................................................................................. 10-3
Emergency Operations........................................................................... 10-3
Building Condition Survey .................................................................... 10-4
High water marks .............................................................................. 10-4
Work maps ........................................................................................ 10-4
Conduct ............................................................................................. 10-5
Notice to owners ............................................................................... 10-5
Permit Requirements.............................................................................. 10-7
Permit required.................................................................................. 10-7
Clean up and emergency repairs ....................................................... 10-7
Enforcement........................................................................................... 10-7
Initial inspection................................................................................ 10-8
Posting............................................................................................... 10-8
Follow up ........................................................................................ 10-11
Flooded buildings............................................................................ 10-11
Contractor quality control ............................................................... 10-12
Administration ..................................................................................... 10-12
Permit forms.................................................................................... 10-12
Public information........................................................................... 10-13
Technical assistance........................................................................ 10-13
Staff assistance................................................................................ 10-14
B. Hazard Mitigation ................................................................................. 10-15
Mitigation Measures ............................................................................ 10-15
Prevention ....................................................................................... 10-16
Property protection.......................................................................... 10-16
Natural resource protection............................................................. 10-16
Emergency services......................................................................... 10-17
Structural projects ........................................................................... 10-17
Public information........................................................................... 10-18
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Mitigation Planning ............................................................................. 10-18
Benefits of planning ........................................................................ 10-18
The planning process ...................................................................... 10-19
Disaster Mitigation Act of 2000 Planning Requirements.................... 10-20
Multi-Objective Management.............................................................. 10-20
M-O-M guidelines........................................................................... 10-21
Benefits ........................................................................................... 10-22
C. Mitigation Assistance Programs............................................................ 10-24
Technical Assistance............................................................................ 10-24
Property Owners .................................................................................. 10-25
Flood Mitigation Assistance Program ................................................. 10-25
Planning grants................................................................................ 10-26
Project grants................................................................................... 10-27
Pre-Disaster Mitigation Program ......................................................... 10-28
Disaster Assistance .............................................................................. 10-28
Technical assistance........................................................................ 10-28
Financial assistance......................................................................... 10-29
Appendix A: FEMA Regional Offices ........................................................ A-1
Appendix B: State Contacts..........................................................................B-1
Appendix C: References ...............................................................................C-1
Appendix D: Glossary.................................................................................. D-1
Appendix E: NFIP Regulations ....................................................................E-1
Appendix F: FEMA Forms...........................................................................F-1
Appendix G: EMI Courses........................................................................... G-1
Appendix H: Learning Checks and Exercises ............................................. H-1
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UNIT O:
ORIENTATION
In this unit
This orientation presents a summary of the study guide and desk
reference:
♦ Its goals and objectives,
♦ How it is organized,
♦ The materials used, and
♦ Where to get help.
Orientation
O-1
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Contents
A. Introduction................................................................................................... O-3
Study guide objectives ............................................................................... O-4
B. Study guide materials ................................................................................. O-5
Notebook ...................................................................................................... O-5
Flood insurance study and maps ............................................................. O-6
Learning Checks ......................................................................................... O-6
C. Using the Study Guide ............................................................................... O-7
Where to get help........................................................................................ O-7
D. Acknowledgments....................................................................................... O-8
Illustrations ............................................................................................ O-8
Orientation
O-2
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A. INTRODUCTION
The responsibility for reducing
flood losses is shared by all units of
government—local,
state
and
federal—and the private sector.
Fulfilling this responsibility de
pends on having the knowledge and
skills to plan and implement needed
floodplain management measures.
The fundamental floodplain man
agement program that most others
are built on is the National Flood
Insurance Program (NFIP).
Cover
The house on the cover survived Hurricane
Ivan in September 2004 with minimal
damage. It is located in an AE Zone on
Perdido Bay in Escambia County, Florida.
The owner chose to elevate the building on
pilings to well above the Base Flood
Elevation (BFE). The storm surge in this
area approximated the BFE and the nearby
pre-FIRM buildings built on slabs were
demolished or severely damaged by waves
and debris.
The NFIP provides the maps and regulatory basis for local floodplain man
agement. It is also the primary source of insurance protection for floodprone
properties. Its success depends on the people responsible for administering its
mapping, regulatory and insurance aspects.
This document can serve two purposes. First, it can be used as a study
guide to enhance the knowledge and skills of local officials responsible for
administering and enforcing local floodplain management regulations. It is also
intended to broaden their understanding of floodplain management strategies
that can be applied at the local level. Local officials and others can use the
study guide to help them study for the exam for the Association of State Flood
plain Manager’s (ASFPM) Certified Floodplain Manager designation.
Second, the study guide can be used as a desk reference that you can refer to
when specific issues arise as you implement your floodplain management
ordinance. Guidance is included on how to handle many of these issues and
information provided that will help you explain the requirements to citizens of
your community. References are included on where to find more information
or guidance on many issues. The FEMA documents that are referenced are
available from the FEMA Distribution Center at 1-800-480-2520. The address
is: Federal Emergency Management Agency, Attention: Publications, PO Box
2012, Jessup, MD 20794-2012. Most of these publications can also be can be
downloaded from the FEMA website, http://www.fema.gov.
While any interested person may use this study guide and desk reference, it
is written specifically for the local official who is responsible for administering
his or her community's floodplain management regulations. Thus, references to
“you,” assume that you are a local official.
Orientation
O-3
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STUDY GUIDE OBJECTIVES
Upon completing this study guide, you should:
1. Be familiar with flood hazards and how human development interacts
with the natural process of flooding.
2. Understand the purpose of the NFIP and your community’s role in it.
3. Understand the basis for flood maps and data.
4. Be able to use floodplain studies and maps to support your floodplain
management program.
5. Be able to explain the minimum regulatory requirements of the NFIP.
6. Be familiar with additional regulatory standards that your community
could adopt.
7. Understand your responsibilities in administering your community’s
floodplain regulations for new construction.
8. Understand how to administer your community’s floodplain regulations
for repairs and improvements to existing buildings.
9. Be familiar with how flood insurance policies are written and how they
relate to your community’s regulations.
10. Be prepared to administer your floodplain regulations following a disas
ter.
These 10 objectives are the topics of the 10 units in this study guide.
Orientation
O-4
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B. STUDY GUIDE MATERIALS
Study guide materials include text pages and dividers that can be inserted
into a loose-leaf notebook. There is also a Flood Insurance Study and map for a
sample community that can be ordered separately.
NOTEBOOK
The loose-leaf notebook holds the primary instruc-
tional material —ten units—and eight appendices.
In Units 1 and 2, you’ll be introduced to the kinds of floods common to
communities in the United States, the concepts behind floodplain management
and the NFIP.
In Unit 3, you’ll learn about the various types of flood data needed to ad
minister a floodplain management program.
Unit 4 discusses how to use the data provided in NFIP studies and maps.
Unit 5 is the first of four units about administering floodplain management
regulations. In Unit 5, you’ll find out about the minimum regulatory require
ments communities must enforce under the NFIP.
Unit 6 contains additional measures recommended to help make your regu
lations more effective and more appropriate to your local flood conditions and
community needs.
Unit 7 discusses the steps needed to administer a floodplain management
ordinance.
Unit 8 goes into detail on the special situations of dealing with changes to
existing buildings.
In Unit 9, the relationship between flood insurance and your floodplain
management program is reviewed.
Unit 10 reviews the things you need to be ready for following a disaster and
how you can make your community’s program more effective in reducing flood
losses.
The eight appendices provide contacts for assistance, references, technical
terms, and NFIP materials.
Orientation
O-5
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FLOOD INSURANCE STUDY AND MAPS
The
fictitious
community
of
Flood
County, USA, has been selected as a sample
community for the purposes of this course.
The Flood Insurance Study and Flood In
surance Rate Map for Flood County provide
opportunities to read and interpret the data in
a typical flood insurance study and maps.
This town provides examples of both coastal
and riverine data and maps. The Flood
Insurance Study and Maps can be ordered
separately from the study guide and desk
reference.
Engineers Scale. You should obtain a
clear plastic engineer’s scale or similar
measuring devise for use in several of the exercises in this study guide and for
day-to-day implementation of your ordinance. A scale helps convert measure-
ments on a map to distance on the ground.
LEARNING CHECKS
Learning checks and unit learning exercises are included as Appendix H to
help you master the material. Answers to the learning checks and exercises are
included.
Orientation
O-6
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C. USING THE STUDY GUIDE
To administer a floodplain management program, you need to know about
regulations and procedures under the National Flood Insurance Program. This
study guide is designed to prepare you to serve as your community’s floodplain
management administrator.
As you can tell by the size of this volume and accompanying materials, you
need to acquire a daunting amount of information. Most of what you need is
covered in these pages, as this course is a comprehensive guide to the NFIP and
your role as administrator.
By design, this study guide will help you learn. Key words and phrases ap
pear with underlines and they are listed in the glossary in Appendix D. Each
unit has frequent learning checks and a comprehensive review at the end. Be
sure to do all of these – you learn best when you practice using the materials.
The study guide and desk reference does not have an index. However, each
of the ten units covers a specific topic or area. At the beginning of each unit
and at the beginning of the study guide are detailed Tables of Contents. You
should be able to find where an issue is addressed in the study guide by scan
ning the Table of Contents.
WHERE TO GET HELP
For help in understanding any of the course content, contact your FEMA
Regional Office or NFIP State Coordinator.
These offices are listed in Appendices A and B.
Orientation
O-7
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D. ACKNOWLEDGMENTS
This study guide and desk reference is based on a home-study course that
was developed through FEMA’s Emergency Management Institute (EMI) dated
March 1998. Although that course is not currently being offered by EMI, the
course materials provided a wealth of information that has proved useful to
local floodplain managers. For that reason, they have been updated and refor
matted into a study guide and desk reference.
The home-study course on which this study guide and desk reference is
based was prepared by French & Associates, Ltd., Park Forest, Illinois, under
FEMA task order EME-97-SA-0424. It was adapted from a home study course
created by FEMA Region IV for North Carolina, prepared by James M. Wright,
Nancy B. Sidell, Christy King and Steven Randolph. That course in turn was
based on materials from a resident course offered at the Emergency Manage
ment Institute, course E-273, Managing Floodplain Development through the
National Flood Insurance Program.
Many individuals and organizations helped create the original home study
course, particularly: Tom Boven and Tom Hirt, FEMA, EMI; Katie Hayden and
Elizabeth Lemersal, FEMA Mitigation Directorate, Washington, D.C.; Prairie
Wordsmiths, Urbana, Illinois (editing and design), and the NFIP State Coordi
nating Agencies from the following states who provided handbooks and
publications that proved very helpful: Delaware, Illinois, Maine, Michigan,
Minnesota, Missouri, North Carolina, Oklahoma, South Carolina, Washington,
and Wisconsin.
The home-study course was converted to a study guide and desk reference
and updated by FEMA staff in April 2004. At that time the study guide was
thoroughly reviewed to ensure consistency with current NFIP regulations,
procedures and policies. FEMA staff that participated in that effort include
Mike Robinson, David Stearrett, and Bill Lesser with support from Don Beaton,
Mark Crowell and Lois Forster. Michael Baker Jr., Inc. of Alexandria, Virgin
ina prepared the document for publication.
Questions or comments on the study guide and desk reference should be
sent to the Community Assistance Section, Risk Assessment Branch of
FEMA’s Mitigation Division.
Illustrations
Except as noted here, all illustrations are from FEMA or French & Associ
ates. Special thanks to Dewberry & Davis for its support in preparing many of
the figures.
Figure credits: 1-6: Managing Coastal Erosion, p. 31; 1-10: Landslide Loss
Reduction, Colorado Geological Survey, 1989, p. 15; 1-14: Striking a Balance –
Orientation
O-8
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A Guide to Coastal Processes and Beach Management in Delaware, Delaware
Department of Natural Resources and Environmental Control, 1985; 1-17:
Roanoke Times and World News; 5-17 Berry A. Williams & Associates, Inc.;
6-3: Subdivision Design in Flood Hazard Areas, p. 19; 6-5: Planning for
Hillside Development, p. 4; 6-6: Environmental Management: A Guide for
Town Officials, Maine Department of Environmental Protection, 1992, p. 4.
Orientation
O-9
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UNIT 1:
FLOODS AND FLOODPLAIN
MANAGEMENT
In this unit
Unit 1 lays the groundwork for the course by explaining:
♦ The more common types of floods and floodplains,
♦ How floods affect floodplain development,
♦ The strategies and tools for floodplain management, and
♦ Basic terms used throughout the course.
Floods and Floodplain Management
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Contents
Introduction.................................................................................................... 1-4
A. Floods and Floodplains ................................................................................... 1-5
Riverine Flooding .......................................................................................... 1-6
Overbank flooding ................................................................................... 1-7
Flash flooding .......................................................................................... 1-8
Riverine erosion....................................................................................... 1-8
Coastal flooding............................................................................................. 1-9
Coastal storms.......................................................................................... 1-9
Coastal erosion....................................................................................... 1-10
Tsunamis...................................................................................................... 1-11
Lake flooding......................................................................................... 1-11
Shallow Flooding......................................................................................... 1-11
Sheet flow .............................................................................................. 1-11
Ponding .................................................................................................. 1-12
Urban drainage....................................................................................... 1-12
Special Flood Hazards ................................................................................. 1-12
Closed basin lakes.................................................................................. 1-13
Uncertain flow paths.............................................................................. 1-13
Dam breaks ............................................................................................ 1-14
Ice jams .................................................................................................. 1-15
Mudflow................................................................................................. 1-15
Natural and beneficial floodplain functions................................................. 1-16
Natural flood and erosion control .......................................................... 1-17
Biologic resources and functions........................................................... 1-17
Societal resources and functions............................................................ 1-17
B. Floodplain Development............................................................................... 1-19
Floodplain Development Dynamics ............................................................ 1-19
Riverine floodplains............................................................................... 1-19
Watersheds............................................................................................. 1-20
Coasts..................................................................................................... 1-21
Flood Damage.............................................................................................. 1-22
Hydrodynamic forces............................................................................. 1-22
Debris impact......................................................................................... 1-24
Hydrostatic forces .................................................................................. 1-25
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Soaking .................................................................................................. 1-25
Sediment and contaminants ................................................................... 1-26
Safety and Health Hazards........................................................................... 1-27
C. Floodplain Management................................................................................ 1-28
Evolution...................................................................................................... 1-28
The Unified National Program for Floodplain Management....................... 1-29
Strategies and tools ................................................................................ 1-30
Floodplain Management Strategies.............................................................. 1-30
Strategy 1: Modify human susceptibility to flood damage.................... 1-30
Strategy 2: Modify the impact of flooding ............................................ 1-31
Strategy 3: Modify flooding itself ......................................................... 1-31
Strategy 4: Preserve and restore natural resources ................................ 1-32
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INTRODUCTION
Throughout time, floods have altered the floodplain landscape. These areas
are continuously shaped by the forces of water—either eroded or built up through
deposit of sediment. More recently, the landscape has been altered by human
development, affecting both the immediate floodplain and events downstream.
Historically, people have been attracted to bodies of water as places for living,
industry, commerce and recreation. During the early settlement of the United
States, locations near water provided necessary access to transportation, a water
supply and water power. In addition, these areas had fertile soils, making them
prime agricultural lands.
This pattern of development continued as communities grew. In recent dec
ades, development along waterways and shorelines has been spurred by the
aesthetic and recreational value of these sites.
The result has been an increasing level of damage and destruction wrought by
the natural forces of flooding on human development. It is probable that you are
taking this course because your community has experienced some of this. You,
yourself, or someone you know may have suffered through a flood and a long,
painful and expensive repair and recovery process.
The purpose of this study guide is to familiarize you with how this problem
can be curbed through proper management of how your floodplains are devel
oped. Communities that guide development following the standards of the
National Flood Insurance Program have seen the results – their new buildings and
neighborhoods have had less damage and suffering from flooding.
To start, we need an orientation into the natural processes of flooding. That is
the focus of Section A. Many terms are introduced in this section, such as water
shed and coastal erosion that are used throughout the course.
Next, we review of the other part of the equation – human development in the
path of that flooding. The final section in this unit discusses the Federal govern
ment’s overall floodplain management effort and the other strategies and tools
that help prevent and reduce flood damage.
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A. FLOODS AND FLOODPLAINS
Floods are part of the Earth’s natural hydrologic cycle.
The cycle circulates water throughout the environment (Figure 1-1). This pro
cess maintains an overall balance between water in the air, on the surface and in
the ground. Figure 1-1. The Hydrologic Cycle - Evaporation and Transpiration lead to Precipitation leading to Surface Runoff and Groundwater Recharge and Movement
Figure 1-1. The Hydrologic cycle
Sometimes the hydrologic cycle gets outs of balance, sending more water to
an area than it can normally handle.
The result is a flood.
A flood inundates a floodplain. There are different types of floodplains and
they are based on they type of flooding that forms them.
Most floods fall into one of three major categories:
♦ Riverine flooding
♦ Coastal flooding
♦ Shallow flooding
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RIVERINE FLOODING
A watershed is an area that drains into a lake, stream or other body of water.
Other names for it are basin or catchment area.
Watersheds vary in size. Larger ones can be divided into sub-watersheds.
Figure 1-2 shows a watershed and some of the key terms. The boundary of a
watershed is a ridge or divide. Water from rain and snowmelt are collected by the
smaller channels (tributaries) which send the water to larger ones and eventually
to the lowest body of water in the watershed (main channel).
Channels are defined features on the ground that carry water through and out
of a watershed. They may be called rivers, creeks, streams or ditches. They can be
wet all the time or dry most of the time.
When a channel receives too much water, the excess flows over its banks and
into the adjacent floodplain. Flooding that occurs along a channel is called river
ine flooding. Figure 1-2. Riverine Watershed and Floodplan - Picture showing Main Channel, Divide, and Tributary
Figure 1-2. Riverine Watershed and Floodplain
What happens in a watershed will affect events and conditions downstream.
Terrain helps determine the dynamics of riverine flooding. In relatively flat areas,
shallow, slow-moving floodwater may cover the land for days or even weeks.
In hilly and mountainous areas, a flood may come scant minutes after a heavy
rain. Such a flash flood gives short notice and moves so fast that it is particularly
dangerous to people and property in its path.
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Overbank flooding
The most common type of flooding in the United States is called overbank
flooding (Figure 1-3).
Overbank flooding occurs when downstream channels receive more rain or
snowmelt from their watershed than normal, or a channel is blocked by an ice jam
or debris. For either reason, excess water overloads the channels and flows out
onto the floodplain.
Overbank flooding varies with the watershed’s size and terrain. One measure
of a flood is the speed of its moving water, which is called velocity. Velocity is
measured in feet per second.
Hilly and mountainous areas have faster moving water, so velocity can pose a
serious hazard. In flat areas, the flood may move slowly, making its velocity less
of a hazard.
Terrain may affect how much warning people have that a flood is building.
Conditions on a river that drains a large watershed may warn of a pending flood
hours or even days before actual flooding. On the other hand, streams in hilly
areas may give no warning that a flash flood is about to strike.
Flood depths vary, as do flood durations. Generally, the larger the river, the
deeper the flood and the longer it will last. However, in hilly or mountainous
areas with narrow valleys, flooding can be very deep in small watersheds.
Depending on the size of the river and terrain of its floodplain, flooding can
last for days and cover wide areas. Figure 1-3. Riverine floodplain - Picture showing Wide floodplan in flat areas and Narrow floodplain in hilly areas.
Figure 1-3. Riverine floodplain
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Flash flooding
A severe storm that drops much rainfall in a short time can generate a flash
flood. All flash floods strike quickly and end swiftly.
While flash floods occur in all fifty states, areas with steep slopes and narrow
stream valleys are particularly vulnerable, as are the banks of small tributary
streams. In hilly areas, the high-velocity flows and short warning time make flash
floods hazardous and very destructive.
In urban areas, flash flooding can occur where impervious surfaces, gutters
and storm sewers speed runoff. Flash floods also can be caused by dam failure,
the release of ice-jam flooding, or collapse of debris dams.
Flash floods rank first as the cause of flood-related deaths in the United States.
In the 1970s, four flash floods in a five-year period killed 570 people. Death tolls
associated with the 1993 Mississippi River flood or hurricanes are in another
category because such events build over several days, giving people enough time
to evacuate safely.
♦ In 1972, 118 people died along Buffalo Creek in West Virginia when an
embankment made of coal refuse washed out, destroying 546 houses and
damaging as many more.
♦ Weeks later, 236 people died when heavy rain and a dam failure inundated
the area near Rapid City, South Dakota. Property damage exceeded $100
million.
♦ In 1976, heavy rains spawned floods in Colorado’s Big Thompson Can-
yon, killing 139 people.
♦ The next year, 77 people died in Johnstown, Pennsylvania, when heavy
rain overwhelmed a dam, causing $200 million in damage.
Riverine erosion
River channels change as water moves downstream, acting on the channel
banks and on the channel bottom (the thalweg). This force is made more potent
during a flood, when the river’s velocity increases.
Several features along a river are affected by this flow of water in different
ways. A meander is a curve in a channel. On the outside of a meander, the banks
are subject to erosion as the water scours against them (Figure 1-4). On the other
hand, areas on the inside of meanders receive deposits of sand and sediment
transferred from the eroded sites.
Floods and Floodplain Management
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Use the arrow keys to turn pagesFigur
Figure 1- 4. Erosion changes the shape of channels
Properties on the outside of
curves face a double threat of
inundation and undercutting from
riverine erosion during floods
(Figure 1- 5).
In addition, meanders do not
stay in the same place—they mi
grate
slowly
downstream
and
across the floodplain, reworking
the shape of the channel within the
floodplain. Figure 1-5. Riverine erosion can undercut structure - Picture of a house with water underneath a portion of it.
Figure 1-5. Riverine erosion can undercut
structures
COASTAL FLOODING
Development along the coasts of the oceans, the Gulf of Mexico, and large
lakes can be exposed to two types of flood problems not found in riverine areas:
coastal storms and coastal erosion. The Pacific and Caribbean coasts face a third
hazard: tsunamis.
Coastal storms
Hurricanes and severe storms cause most coastal flooding. These include
“Nor’easters,” which are severe storms on the Atlantic coast with winds out of the
northeast.
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Persistent high wind and changes in air pressure push water toward the shore,
causing a storm surge which can raise the level of a large body of water by several
feet. Waves can be highly destructive as they move inland, battering structures in
their path.
On open coasts, the magnitude of a flood varies with the tides. An increase in
the level of the ocean during high tide will flood larger areas than a storm that
strikes during low tide.
Major coastal storms can significantly change the shape of shoreline land
forms, making sandy coastal floodplains particularly unstable places for
development.
Wind and waves shape sand dunes, bluffs and barrier islands. Because these
landforms provide natural buffers from the effects of a storm, their preservation is
important to the protection of inland development.
Coastal erosion
Long-term coastal erosion is
another natural process that
shapes shorelines. It is a complex
process that involves natural and
human-induced
factors.
The
natural factors include sand
sources, sand size and density,
changes in water level, and the
effects of waves, currents, tides
and wind. These factors deter
mine whether a shoreline will
recede or accrete.
Human
activity—such
as
construction of groins or sea
walls, the dredging of channels
and placement of sandbags— Figure 1-6 - This area of Maryland shore shows how erosion can move or remove entire islands over a period of as short as 40 years - Picture shows examples from 1931 and 1972.
also can contribute to coastal
erosion by altering the natural
Figure 1-6. This area of the Maryland shore
shows how erosion can move or remove entire
systems that transport sand.
islands over a period as short as 40 years.
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TSUNAMIS
Another hazard along the coast is a tsunami, a large wave often called a “tidal
wave” even though tides and tsunamis are not related. Caused by an underwater
earthquake or volcano, a tsunami is a pressure wave that can raise water levels as
much as 15 feet.
In the open ocean, a tsunami’s wave may be only a few feet high. Because the
wave’s energy extends from the surface to the bottom, that energy is compressed
as the wave approaches shallow water, creating higher, more life-threatening
waves (Figure 1-7).
Tsunamis usually occur in the Pacific Ocean, but they have caused floods in
the Caribbean. Because they can happen on a clear day and are not related to
storms, they can catch many people unawares. Figure 1-7. Tsunami waves increase in shallo
Figure 1- 7. Tsunami waves increase in shallower water.
Lake flooding
Lake shores can flood in ways similar to ocean coasts. Along the Great Lakes,
severe storms can produce waves and cause shoreline erosion. FEMA is starting
to map Great Lakes flooding with the same techniques it uses for ocean coastal
flooding.
SHALLOW FLOODING
Shallow flooding occurs in flat areas where a lack of channels means water
cannot drain away easily. Shallow flood problems fall into three categories: sheet
flow, ponding and urban drainage.
Sheet flow
Where there are inadequate or no defined channels, floodwater spreads out
over a large area at a somewhat uniform depth in what’s called sheet flow.
Sheet flows occur after an intense or prolonged rainfall during which the rain
cannot soak into the ground. During sheet flow, the floodwaters move downhill
and cover a wide area.
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Ponding
In some flat areas, runoff collects in depressions and cannot drain out, creating
a ponding effect. Ponding floodwaters do not move or flow away. Floodwaters
will remain in the temporary ponds until they infiltrate into the soil, evaporate or
are pumped out.
Ponding is especially a problem in glaciated areas, where glaciers carved out
depressions; in areas where caves and sinkholes are common, and in other areas
where man-made features, such as roads and railroad embankments, have blocked
outlets.
Urban drainage
An urban drainage system comprises the ditches, storm sewers, retention
ponds and other facilities constructed to store runoff or carry it to a receiving
stream, lake or the ocean. Other man-made features in such a system include
yards and swales that collect runoff and direct it to the sewers and ditches.
When most of these systems were built, they were typically designed to han
dle the amount of water expected during a 10-year storm. Larger storms overload
them, and the resulting backed-up sewers and overloaded ditches produce shallow
flooding.
Another urban drainage problem occurs in the areas protected by levees. Be
ing in floodplains, they are flat and don’t drain naturally, especially when a levee
blocks the flow to the river.
To drain these areas, channels have been built and pumps installed to me
chanically move the water past the levee. Often, these man-made systems do not
have the capacity to handle heavy rains or intense storms.
SPECIAL FLOOD HAZARDS
The flooding types described so far are the more common types found in the
United States. There are many special local situations in which flooding or flood-
related problems do not fit the national norm.
This section discusses five of those special flood hazards:
♦ Closed basin lakes
♦ Uncertain flow paths.
♦ Dam breaks.
♦ Ice jams.
♦ Mudflows.
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Closed basin lakes
There are two types of closed basin lake:
♦ Lakes with no outlets, like the Great Salt Lake, Utah, Devil’s Lake, North
Dakota, and the Salton Sea, California; and
♦ Lakes with inadequate, regulated or elevated outlets, such as the Great
Lakes and many glacial lakes.
Seasonal increases in rainfall cause a closed basin lake’s level to rise faster
than it can drain. As a result, they are subject to large fluctuations in water surface
elevation. Floodwaters in closed basin lakes may stay up for weeks, months or
even years.
The long periods of high water make closed basin lake flooding particularly
problematic. Properties may not be heavily damaged, but they are unusable for
long periods because they are surrounded by—or under—water. Buildings are
isolated and septic fields are unusable. Properties are exposed to waves (and
sometimes ice) that add to the hazard.
Uncertain flow paths
The section on riverine erosion explained that stream channels change their
locations gradually or only after very large and rare floods. However, in some
areas of the country, every flood may change channels.
For example, in mountainous areas, high-velocity floodwater picks up sedi
ment and rock. At the base of the valley where the slope flattens out, the
floodwater decreases in speed and spreads out, as in a sheet flow, dropping sedi
ment and rock over a fan-shaped area called an alluvial fan.
Figure 1-8 shows how an alluvial fan can have numerous channels. During the
next flood, the channels may be in different locations.
Alluvial fan flooding is more common in the mountainous western states,
where there is less ground cover and more opportunity for erosion.
Alluvial fan floods are not as predictable as riverine floods—one never knows
where the floodwaters will spread out across the fan. Thus, they pose three haz
ards:
♦ Velocity of floodwaters and the debris they carry.
♦ Sediment and debris deposited by the floodwaters.
♦ The potential for the channel to move across the fan during the flood.
Floods and Floodplain Management
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Figure 1-8. An alluvial fan can have numerous channels.
The arid west is subject to another type of flooding that features uncertain
flow paths, known as movable stream beds.
When a high-velocity flood runs through an area with sand or loose soil, the
erosion and sedimentation can occur so fast that the stream channel can be low
ered, filled in or relocated through processes known as degradation, aggradation
and migration. In some cases, these processes may occur simultaneously, or one
process may occur in one flood and another process in a later event.
Dam breaks
A break in a dam can produce an extremely dangerous flood situation because
of the high velocities and large volumes of water released by such a break. Some
times they can occur with little or no warning on clear days when people are not
expecting rain, much less a flood.
Breaching often occurs within hours after the first visible signs of dam failure,
leaving little or no time for evacuation. (As noted in the earlier section on flash
flooding, three of the four top killer floods in the 1970s were related to the failure
of a dam or dam-like structure.)
Dam breaks occur for one of three reasons:
♦ The foundation fails due to seepage, settling or earthquake.
♦ The design, construction, materials or operation were deficient.
Floods and Floodplain Management
1-14
Figure 1-9. Likely Ice Jam Areas
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♦ Flooding exceeds the capacity of the dam’s spillway.
Proper design can prevent dam breaks. While dam safety programs can ensure
that new dams are properly designed, there are still many private or locally built
dams that were poorly designed and maintained.
Ice jams
Ice jam flooding generally occurs when warm weather and rain break up fro
zen rivers or any time there is a rapid cycle of freezing and thawing.
The broken ice floats downriver until it is blocked by an obstruction such as a
bridge or shallow area (Figure 1-9). An ice dam forms, blocking the channel and
causing flooding upstream. Figure 1-9. Likely ice jam areas: Picture includes shallows where channels can freeze solid, river sloap decreases, culverts that can freeze solid, and channel constrictions like a bridge.
Ice jams present three hazards:
♦ Sudden flooding of areas upstream from the jam, often on clear days with
little or no warning.
♦ Movement of ice chunks (floes) that can push over trees and crush build-
ings (see Figure 1-18).
♦ Sudden flooding of areas downstream when an ice jam breaks. The impact
is similar to a dam break, damaging or destroying buildings and structures.
Mudflow
A mudflow is a type of landslide that occurs when runoff saturates the ground.
Soil that is dry during dry weather turns into a liquid solution that slides downhill.
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They typically cause more damage than clear-water flooding due to the combina-
tion of debris and sediment, and the force of the debris-filled water.
The NFIP officially defines a “mudslide (i.e. mudflow)” as “a condition where
there is a river, flow or inundation of liquid mud down a hillside usually as a
result of a dual condition of loss of brush cover, and the subsequent accumulation
of water on the ground preceded by a period of unusually heavy or sustained
rain.” The NFIP provides flood insurance coverage for mudslides that meet this
definition, but does not map or require floodplain management measures in these
areas.
What many people view as mudfloods are technically landslides and are not
covered by the NFIP. Figure 1-10. Mudflows are caused by saturated soils - Picture shows source area leading down main trench to depositional area.
Figure 1-10. Mudflows are caused by saturated soil
NATURAL AND BENEFICIAL FLOODPLAIN FUNCTIONS
Floodplain lands and adjacent waters combine to form a complex, dynamic
physical and biological system found nowhere else. When portions of floodplains
are preserved in their natural state, or restored to it, they provide many benefits to
both human and natural systems.
Some are static conditions—such as providing aesthetic pleasure—and some
are active processes, such as reducing the number and severity of floods, helping
handle stormwater runoff and minimizing non-point water pollution. For example,
by allowing floodwater to slow down, sediments settle out, thus maintaining
water quality. The natural vegetation filters out impurities and uses excess nutri
ents.
Such natural processes cost far less money than it would take to build facili
ties to correct flood, stormwater, water quality and other community problems.
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Natural resources of floodplains fall into three categories: water resources, liv
ing resources and societal resources. The following sections describe each
category’s natural and beneficial functions.
Natural flood and erosion control
Over the years, floodplains develop their own ways to handle flooding and
erosion with natural features that provide floodwater storage and conveyance,
reduce flood velocities and flood peaks, and curb sedimentation.
Natural controls on flooding and erosion help to maintain water quality by fil
tering nutrients and impurities from runoff, processing organic wastes and
moderating temperature fluctuations.
These natural controls also contribute to recharging groundwater by promot-
ing infiltration and refreshing aquifers, and by reducing the frequency and
duration of low surface flows.
Biologic resources and functions
Floodplains enhance biological productivity by supporting a high rate of plant
growth. This helps to maintain biodiversity and the integrity of ecosystems.
Floodplains also provide excellent habitats for fish and wildlife by serving as
breeding and feeding grounds. They also create and enhance waterfowl habitats,
and help to protect habitats for rare and endangered species.
Societal resources and functions
People benefit from floodplains through the food they provide, the recrea-
tional opportunities they afford and the scientific knowledge gained in studying
them.
Wild and cultivated products are harvested in floodplains, which are enhanced
agricultural land made rich by sediment deposits. They provide open space, which
may be used to restore and enhance forest lands, or for recreational opportunities
or simple enjoyment of their aesthetic beauty.
Floodplains provide areas for scientific study and outdoor education. They
contain cultural resources such as historic or archaeological sites, and thus pro-
vide opportunities for environmental and other kinds of studies.
These natural resources and functions can increase a community’s overall
quality of life, a role that often has been undervalued. By transforming stream and
river floodplains from problem areas into value-added assets, the community can
improve its quality of life.
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Parks, bike paths, open spaces, wildlife conservation areas and aesthetic fea
tures are important to citizens. Assets like these make the community more
appealing to potential employers, investors, residents, property owners and tour
ists. Figure 1-11. Floodplains offer recreational and aesthetic benefits.
Figure 1-11 Floodplains offer recreation and aesthetic benefits.
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B. FLOODPLAIN DEVELOPMENT
Throughout time, floods have altered the floodplain landscape. These areas
are continuously shaped by the forces of water—either eroded or built up through
deposit of sediment. More recently, the landscape has been altered by human
development, affecting both the immediate floodplain and events downstream.
Historically, people have been attracted to bodies of water as places for living,
industry, commerce and recreation. During the early settlement of the United
States, locations near water provided necessary access to transportation, a water
supply and water power. In addition, these areas had fertile soils, making them
prime agricultural lands.
This pattern of development continued as communities grew. In recent dec
ades, development along waterways and shorelines has been spurred by the
aesthetic and recreational value of these sites.
Because floodplains have attracted people and industry, a substantial portion
of this country’s development is now subject to flooding. Floodplains account for
only seven percent of the nation’s total land area. However, they contain a tre
mendous amount of property value. It is estimated that there are 8 – 10 million
households in our floodplains.
Two problems result from floodplain development:
♦ Development alters the floodplain and the dynamics of flooding.
♦ Buildings and infrastructure are damaged by periodic flooding.
FLOODPLAIN DEVELOPMENT DYNAMICS
Human development can have an adverse impact on floods and floodplains.
Three types of problems are reviewed here.
Riverine floodplains
The most obvious impact of development on riverine flooding comes with
moving or altering channels or constructing bridges and culverts with small open
ings. Construction and regrading of the floodplain can obstruct or divert water to
other areas. Levees and dikes are the best known examples of this, but even small
construction projects have an impact (Figure 1-12).
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Filling obstructs flood flows, backing up floodwaters onto upstream and adja
cent properties. It also reduces the floodplain’s ability to store excess water,
sending more water downstream and causing floods to rise to higher levels. This
also increases floodwater velocity. Figure 1-12. Effects of development on a riverine floodplain. Picture shows before development and after, highlighting re-grading and
Figure 1-12. Effects of development on a riverine floodplain
Watersheds
Development in riverine
watersheds
affects
the
runoff of stormwater and
snowmelt. Buildings and
parking lots replace the
natural vegetation which
used to absorb water. When
rain falls in a natural set
ting, as much as ninety
percent of it will infiltrate
the ground; in an urbanized
area, as much as ninety
percent of it will run off
(Figure 1-13).
Figure 1-13. Effects of development on stormwater runoff.
(Data for Northeastern Illinois) Figure 1-13. Effects of development on stormwater runoff (data for Northeastern Illinois) - Graph shows: 1) Natural ground cover
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Urban features alter flood dynamics as well. Storm sewers and more efficient
ditches that come with urban drainage systems speed flood flows. The result of
urbanization is that there is more runoff in the watershed and it moves faster,
increasing flooding downstream. Thus, a 10-year storm may produce the runoff
equivalent of a 25-year storm, overloading the man-made drainage system.
Urbanization also changes the timing of flows along the tributaries. If one
subwatershed develops faster than another, the flood will leave sooner than it used
to, possibly arriving at the main channel at the same time as the peak arrives from
another tributary, causing increased flooding downstream.
Coasts
Coastal development similarly affects the dynamics of coastal flooding. Re-
moving the sand from beaches and dunes removes the natural barrier built up by
flood forces over the years and exposes inland areas to increased risk of flooding.
Coastal erosion is affected by construction of navigation channels, breakwa-
ters, and jetties, and mining of sand. Often construction of barriers, seawalls, or
even sandbag walls to protect buildings from flooding or erosion has an adverse
affect on properties at the end of the walls where erosion is accelerated. Figure 1-14. Jetties to protect a navigation inlet affect san
Figure 1-14. Jetties to protect a navigation inlet
affect sand accumulation and erosion.
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FLOOD DAMAGE
Floodplains are home to between 8 and 10 million households. In an average
year, floods kill 150 people and cause over $6 billion in property damage. Nation
ally, average annual flood losses continue to increase.
Floods can hurt or kill people, and damage property, in several ways. Knowing
the impact of a potential hazard—and guarding against it—is integral to adminis-
tering a floodplain management program.
As a floodplain management administrator, you need to be knowledgeable
about the five main causes of flood damage:
♦ Hydrodynamic forces
♦ Debris impact
♦ Hydrostatic forces
♦ Soaking
♦ Sediment and contaminants
Hydrodynamic forces
Moving water creates a hydrodynamic force which can damage a building’s
walls in three ways (see Figure 1-15):
♦ Frontal impact,
as water strikes
the structure.
♦ Drag effect, as
water runs
along the sides
of a structure.
♦ Eddies or
negative pres-
sures, created
as water passes
the down-
stream side. Figure 1-15. Hydrodynamic forces on a building.
Figure 1-15. Hydrodynamic forces on a building.
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The speed of moving water is called velocity, a force that is measured in feet
per second. The faster water moves, the more pressure it puts on a structure and
the more it will erode stream banks and scour the earth around a building’s foun-
dation.
Floodwaters moving faster than 5 feet per second comprise a high-velocity
flood, requiring special design considerations for buildings, roads, bridges and
other manmade structures in its path.
Figure 1-16. Beaches are particularly susceptible
to undermining of foundations due to velocity flows.
While velocity is one factor in determining the potential harm of a flood, the
total impact of moving water is related to the depth of the flooding. Studies have
shown that deep water and low velocities can cause as much damage as shallow
water and high velocities.
People are more susceptible to damage than buildings: Studies have shown
that it doesn’t take much depth or velocity to knock a person over. Thus, no areas
with moving floodwater can be considered safe for walking (Figure 1-17).
A car will float in only two feet of moving water, which is one reason floods
kill more people trapped in vehicles than anywhere else. Often victims put them-
selves in perilous situations by ignoring warnings about travel or mistakenly
thinking that a washed-out bridge is still open.
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Use the arrow keys to turn pagesFigure
Figure 1-17. Even shallow floodwaters can stop cars
and wash people off their feet
Debris impact
Debris also increases the hazard posed by moving water. Floodwaters can and
will pick up anything that will float—logs, lumber, ice, even propane tanks and
vehicles (Figure 1-18). Moving water will also drag or roll objects that don’t float.
All of this debris acts as battering rams that can knock holes in walls. Figure 1-18. Ice floes and other large items of de
Figure 1-18. Ice floes and other large items of debris can crush a house
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Hydrostatic forces
The weight of standing water puts hydrostatic pressure on a structure. The
deeper the water, the more it weighs and the greater the hydrostatic pressure.
Because water is fluid, it exerts the same amount of pressure sideways (lateral
pressure) as it does downward. As water gets deeper, it exerts more lateral pres-
sure than shallow water.
Most walls are not built to withstand lateral pressure. Studies and tests have
shown that the lateral force presented by three feet of standing water can be
enough to collapse the walls of a typical frame house.
Basement walls and floors are particularly susceptible to damage by hydro-
static pressure. Not only is the water deeper, a basement is subjected to the
combined weight of water and saturated earth. Water in the ground underneath a
flooded building will seek its own level – resulting in uplift forces that can break
a concrete basement floor (Figure 1-19). Figure 1-19. This basement floor broke from hydrostatic pressure - Picture shows broken floor.
Figure 1-19. This basement floor broke from hydrostatic pressure
Hydrostatic pressure can also cause damage due to floatation or buoyancy.
Improperly anchored buildings can float off their foundations and empty in-
ground storage tanks can pop out of the ground even forcing their way through
several inches on concrete.
Soaking
When soaked, many materials change their composition or shape.
Wet wood will swell, and if it is dried too fast it will crack, split or warp. Ply-
wood can come apart. Gypsum wallboard will fall apart if it is bumped before it
dries out. The longer these materials are wet, the more moisture they will absorb.
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Soaking can cause extensive damage to household goods. Wooden furniture
may get so badly warped that it can't be used. Other furnishings, such as uphol-
stery, carpeting, mattresses and books, usually are not worth drying out and
restoring. Electrical appliances and gasoline engines won't work safely until they
are professionally dried and cleaned.
Sediment and contaminants
Many materials, including wood and fiberglass or cellulose insulation, absorb
floodwater and its sediment. Even if allowed to dry out, the materials will still
hold the sediment, salt and contaminants brought by the flood. Simply letting a
flooded house dry out will not render it clean—and it certainly will not be as
healthy a place as it was before the flood.
Few floods, especially those that strike inland, have clear floodwater, and so
they leave a mess made of natural and man-made debris. Stormwater, snowmelt
and river water pick up whatever was on the ground, such as soil, road oil, and
farm and lawn chemicals. If a wastewater treatment plant upstream was inun
dated, the floodwaters will likely include untreated sewage.
Especially in the arid west and coastal areas, flooding can leave large amounts
of sand, sediment and debris (Figure 1-20) that require major cleanup efforts.
After the water recedes or evaporates, these sediments are left on and in a build-
ing, and its contents. Figure 1-20. Debris flows can completely fill a house with sediment. - Picture of filled home.
Figure 1-20. Debris flows can completely fill a house with sediment
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SAFETY AND HEALTH HAZARDS
Floods pose a variety of hazards as they build, crest and subside. At different
points in the life of a flood, people are displaced, damage occurs and finally a
cleanup can begin. Disruption of normal public utilities and the presence of flood
debris and damage can produce safety and health hazards.
When utilities are damaged, hazards arise. Electrocution is the second most
frequent cause of flood deaths, claiming lives in a flooded area that is carrying a
live current created when electrical components short. Floods also can damage
gas lines, floors and stairs, creating secondary hazards such gas leaks and unsafe
structures. If the water system loses pressure, a boil order may be issued to protect
people and animals from contaminated water.
Fire can be a result of too much water: floods can break gas lines, extinguish
pilot lights, and short circuit electrical wiring – causing conditions ripe for a fire.
Fire equipment may not be able reach a burning building during high water.
Floods bring and leave health hazards in the form of animal carcasses, gar-
bage and ponds that can become breeding grounds for germs and mosquitoes.
Any flooded items that come in close contact with people must be thrown out,
including such things as food, cosmetics, medicines, stuffed animals and baby
toys. Clothes and dishes need to be washed thoroughly.
Mold, mildew and bacteria grow in damp, flooded areas. One health hazard
occurs when heating ducts in a forced-air system are not properly cleaned follow-
ing inundation. When the furnace or air conditioner is turned on, the sediments
left in the ducts are circulated throughout the building and breathed in by the
occupants.
Flooding, especially repetitive flooding, takes a toll on people's mental health.
Stress comes from facing the loss of time, money, property and personal posses-
sions such as heirlooms. This is aggravated by fatigue during cleanup and anxiety
over lost income, health risks and damage to irreplaceable items.
Children and the elderly are especially susceptible to stress from the disrup-
tion of their daily routines.
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C. FLOODPLAIN MANAGEMENT
The strategies and tools available to prevent problems and protect people and
development from flooding have been developed over many years. A short history
of U.S. policy on floodplain management will help explain their evolution.
EVOLUTION
The federal government got involved in floodplain management in the 1800s,
when it had an interest in maintaining the navigability of rivers to facilitate inter-
state commerce. The great Mississippi River flood of 1927 led the federal
government to become a major player in flood control.
As defined by the Flood Control Acts of 1928 and 1936, the role of govern-
ment agencies was to build massive flood control structures to control the great
rivers, protect coastal areas and prevent flash flooding. The 1936 act alone author-
ized construction of some 250 projects for both flood control and relief work.
Until the 1960’s, such structural flood control projects were seen as the pri-
mary way to reduce flood losses. Public policy emphasized that flood losses could
be curbed by controlling floodwater with structures, such as dams, levees and
floodwalls. But people began to question the effectiveness of this single solution.
Disaster relief expenses were going up, making all taxpayers pay more to provide
relief to those with property in floodplains. Studies during the 1960s concluded
that flood losses were increasing, in spite of the number of flood control structures
that had been built.
One of the main reasons structural flood control projects failed to reduce flood
losses was that people continued to build in floodplains. In response, federal, state
and local agencies began to develop policies and programs with a “non-structural”
emphasis, ones that did not prescribe projects to control or redirect the path of
floods. Since the 1960s, floodplain management has evolved from heavy reliance
on flood control, or structural measures, to one using a combination of many
tools.
The creation of the National Flood Insurance Program in 1968 was a landmark
step in this evolution. The NFIP:
♦ Established an insurance program as an alternative to disaster relief.
♦ Distributed responsibility for floodplain management to all levels of gov
ernment and the private sector.
♦ Set a national standard for regulating new development in floodplains.
♦ Began a comprehensive floodplain mapping program.
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Also during the 1960s and 1970s, interest increased in protecting and restoring
the environment, including the natural resources and functions of floodplains.
Coordinating flood-loss reduction programs with environmental protection and
watershed management programs has since become a major goal of federal, state
and local programs.
As a result of this evolution, we no longer depend solely on structural projects
to control floodwater. U.S. floodplain policies are now multi-purpose and result in
a mix of solutions to suit many situations. Consequently, administrators like you
have several non-structural flood protection measures at their disposal. They
include:
♦ Regulations to prohibit development in high-hazard areas.
♦ Building codes requiring flood-resistant construction for new buildings in
floodprone areas.
♦ Acquisition and relocation of buildings in high hazard areas.
♦ Modifying or retrofitting existing buildings.
♦ Installing flood warning systems.
♦ Controlling stormwater runoff.
♦ Providing self-help advice to property owners.
THE UNIFIED NATIONAL PROGRAM FOR FLOODPLAIN
MANAGEMENT
To coordinate the efforts of the many government programs that can affect
flooding or floodplain development, Congress created the Unified National Pro-
gram for Floodplain Management under the National Flood Insurance Act of
1968.
The Unified National Program sets forth a conceptual framework for coordi-
nating the floodplain management efforts of federal, state and local agencies as
well as private parties.
The program is coordinated by a Federal Interagency Floodplain Management
Task Force made up of federal agencies that are involved in flooding, or with
development that can be affected by flooding.
The Task Force defines “floodplain management” as “a decision-making pro-
cess that aims to achieve the wise use of the nation’s floodplains.” “Wise use”
means both reduced flood losses and protection of the natural resources and
functions of floodplains.
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Where floodplain development is permitted, floodplain management results in
development and construction measures that minimize the risk to life and property
from floods and the risk to the floodplain’s natural functions posed by human
development.
Strategies and tools
The Task Force has identified four floodplain management strategies for re-
ducing the human economic losses from flooding as well as minimizing the losses
of natural and beneficial floodplain resources. Each strategy is supported by an
array of tools which are summarized in the rest of this section.
Many of the tools can be used in more than one strategy.
In most cases, a combination of these tools is needed to reduce risks and pro-
tect natural resources and functions. Because floodplain management is a process,
there is no one “best” set of tools or one single “wise use” of the floodplain.
The important message from this definition of floodplain management is to
consider all the options and account for both the hazard and the natural values
before developing or implementing any action that will change the floodplain.
FLOODPLAIN MANAGEMENT STRATEGIES
Strategy 1: Modify human susceptibility to flood damage
Reduce disruption by avoiding hazardous, uneconomic or unwise use of
floodplains.
Tools include:
♦ Regulating floodplain use by using zoning codes to steer development
away from hazardous areas or natural areas deserving preservation, estab
lishing rules for developing subdivisions, and rigorously following
building, health and sanitary codes.
♦ Establishing development and redevelopment policies on the design and
location of public services, utilities and critical facilities.
♦ Acquiring land in a floodplain in order to preserve open space and perma
nently relocate buildings.
♦ Elevating or floodproofing new buildings and retrofitting existing ones.
♦ Preparing people and property for flooding through forecasting, warning
systems and emergency plans.
♦ Restoring and preserving the natural resources and functions of flood
plains.
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Strategy 2: Modify the impact of flooding
Assist individuals and communities to prepare for, respond to and re
cover from a flood.
Tools include:
♦ Providing information and education to assist self-help and protection
measures.
♦ Following flood emergency measures during a flood to protect people and
property.
♦ Reducing the financial impact of flooding through disaster assistance,
flood insurance and tax adjustments.
♦ Preparing post-flood recovery plans and programs to help people rebuild
and implement mitigation measures to protect against future floods
Strategy 3: Modify flooding itself
Develop projects that control floodwater.
Tools include:
♦ Building dams and reservoirs that store excess water upstream from de
veloped areas.
♦ Building dikes, levees and floodwalls to keep water away from developed
areas.
♦ Altering channels to make them more efficient, so overbank flooding will
be less frequent.
♦ Diverting high flows around developed areas.
♦ Treating land to hold as much rain as possible where it falls, so it can infil
trate the soil instead of running off.
♦ Storing excess runoff with on-site detention measures.
♦ Protecting inland development with shoreline protection measures that ac
count for the natural movement of shoreline features.
♦ Controlling runoff from areas under development outside the floodplain.
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Strategy 4: Preserve and restore natural resources
Renew the vitality and purpose of floodplains by reestablishing and main
taining floodplain environments in their natural state.
Tools include:
♦ Floodplain, wetlands and coastal barrier resources or land use regulations,
such as zoning, can be used to steer development away from sensitive or
natural areas.
♦ Development and redevelopment policies on the design and location of
public services, utilities and critical facilities.
♦ Land acquisition; open space preservation; permanent relocation of build
ings; restoration of floodplains and wetlands, and preservation of natural
functions and habitats.
♦ Information and education to make people aware of natural floodplain re
sources and functions and how to protect them.
♦ Tax adjustments to provide a financial initiative for preserving lands or re
storing lands to their natural state.
♦ Beach nourishment and dune building to protect inland development by
maintaining the natural flood protection features.
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UNIT 2:
THE NATIONAL FLOOD
INSURANCE PROGRAM
In this unit
Unit 2 introduces the National Flood Insurance Program:
♦ How it evolved,
♦ How it works,
♦ The roles of the state and local partners participating in the
NFIP
♦ The community’s obligations to the program.
National Flood Insurance Program
2-1
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Contents
A. History............................................................................................................. 2-3
B. How the NFIP Works...................................................................................... 2-6
Mapping ......................................................................................................... 2-6
Insurance........................................................................................................ 2-7
Regulations .................................................................................................... 2-8
C. Roles and Responsibilities .............................................................................. 2-9
The community role....................................................................................... 2-9
The state role.................................................................................................. 2-9
The federal role............................................................................................ 2-10
D. Community Participation .............................................................................. 2-12
Joining the NFIP .......................................................................................... 2-12
Compliance .................................................................................................. 2-13
Probation................................................................................................ 2-14
Suspension ............................................................................................. 2-14
Sanctions for non-participation.................................................................... 2-15
National Flood Insurance Program
2-2
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A. HISTORY
Historically, people at risk from flooding could only hope for help from their
neighbors and charitable organizations in the event of a flood.
Government assistance varied from community to community, and flood in
surance was scarce. During the 1920s, the insurance industry concluded that flood
insurance could not be a profitable venture because the only people who would
want flood coverage would be those who lived in floodplains.
Since they were sure to be flooded, the rates would be too high to attract cus
tomers.
During the 1960s, Congress became concerned with problems related to the
traditional methods of dealing with floods and flood damage—construction of
structural projects and federal disaster assistance. Both were proving to be quite
expensive, with no end in sight.
Congress concluded that:
♦ Although Federal flood programs were funded by all taxpayers, they pri
marily helped only residents of floodplains.
♦ Flood protection structures were expensive and could not protect every
one.
♦ People continued to build and live in floodplains, thus still risking disaster.
♦ Disaster relief was both inadequate and expensive.
♦ The private insurance industry could not sell affordable flood insurance
because only those at high risk would buy it.
In 1968, Congress passed the National Flood Insurance Act to correct some of
the shortcomings of the traditional flood control and flood relief programs. The
act created the National Flood Insurance Program (NFIP) to:
♦ Transfer the costs of private property flood losses from the taxpayers to
floodplain property owners through flood insurance premiums.
♦ Provide floodplain residents and property owners with financial aid after
floods, especially smaller floods that do not warrant federal disaster aid.
♦ Guide development away from flood hazard areas.
♦ Require that new and substantially improved buildings be constructed in
ways that would minimize or prevent damage during a flood.
Congress charged the Federal Insurance Administration (which at that time
was in the Department of Housing and Urban Development) with responsibility
for the program. The program is currently administered by the Federal Emer-
National Flood Insurance Program
2-3
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gency Management Agency (FEMA) within the Department of Homeland Secu
rity.
Participation in the NFIP grew slowly. In 1972, Hurricane Agnes devastated a
wide area of the eastern United States. Disaster assistance costs were the highest
ever, leading Congress to examine why the NFIP was so little used. Investigators
found that few communities had joined the NFIP—there were fewer than 100,000
flood insurance policies in force nationwide. The availability of flood insurance
alone had not been enough to motivate communities to join the NFIP or individu
als to purchase flood insurance.
To remedy this, the Flood Disaster Protection Act was passed in 1973. The
Act prohibited most types of Federal assistance for acquisition or construction of
buildings in the floodplains of non-participating communities. It also required
that buildings located in identified flood hazard areas have flood insurance cover
age as a condition of receiving Federal financial assistance or loans from federally
insured or regulated lenders, and as a condition for receiving federal disaster
assistance. These “sanctions” for non-participation, which are detailed later in this
unit, make it hard for any community that wants federal assistance for properties
in floodplains to avoid joining the NFIP.
The 1973 Act spurred participation in the program dramatically. By the end of
the decade, more than 15,000 communities had signed on and about two million
flood insurance policies were in effect.
In 1979, the Federal Insurance Administration (FIA) and the NFIP were trans
ferred to the newly created Federal Emergency Management Agency (FEMA).
During the early 1980’s, FIA worked to reduce the program’s dependence on its
authority to borrow from the Federal Treasury. Through a series of rate increases
and other adjustments, the program has been self-supporting since 1986. The
NFIP is funded primarily through premium income, which pays nearly all admin
istrative and mapping costs as well as claims. In recent years the NFIP has
received supplemental funding from Congress to accelerate its Map Moderniza
tion program.
Since 1973, the program has been amended several times. The most important
changes came under the National Flood Insurance Reform Act of 1994 which fine
tuned various aspects of the program, such as authorizing the Community Rating
System, increasing the maximum amount of flood insurance coverage, strengthen
ing the mandatory purchase requirement, and establishing a grant program for
mitigation plans and projects.
The Reform Act and the initiation of a flood insurance advertising campaigns
boosted sales of flood insurance policies again. By the August of 2003, there were
nearly 4.4 million flood insurance policies in force.
National Flood Insurance Program
2-4
1968
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
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By January of 2004, there also were 19,937 participating communities. As
shown in Figure 2-1, the greatest growth in numbers of communities occurred in
the late 1970’s, after the provisions of the 1973 amendments took effect.
Fi
gure 2
-1. NFIP
communi
ty parti
cipation
Figure 2-1. NFIP community participation
National Flood Insurance Program
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B. HOW THE NFIP WORKS
The NFIP is based on a mutual agreement between the Federal Government
and the community. Federally backed flood insurance is made available in those
communities that agree to regulate development in their mapped floodplains. If
the communities do their part in making sure future floodplain development meets
certain criteria, FEMA will provide flood insurance for properties in the commu
nity.
Because most communities with a known flood problem are in the NFIP, this
reference guide does not cover how a community applies to join. However, it does
explain the three basic parts to the NFIP—mapping, insurance, and regulations.
As discussed below, these three parts are interconnected and mutually supportive.
MAPPING
FEMA has prepared a floodplain map and developed flood hazard data for
most communities in the country. The maps and data are used for several pur
poses:
♦ Communities, states and Federal agencies use them as the basis for the
regulating new floodprone construction,
♦ Insurance agents use them when rating flood insurance policies, and
♦ Lenders and Federal agencies used them to determine when flood insur
ance must be purchased as a condition of a loan or financial assistance.
FEMA has issued two kinds of maps:
♦ The first map received for most communities was called a Flood Hazard
Boundary Map (FHBM). This just showed the boundaries of the flood
plain using approximate methods.
♦ Most communities have had their FHBMs replaced by a Flood Insurance
Rate Map, or FIRM. A FIRM usually is based on a Flood Insurance Study
and includes flood elevations and other hazard information needed to bet
ter protect new construction from flood damage.
Buildings that pre-date the FIRM are treated differently than buildings built
after the flood hazard was made public on the FIRM. These existing structures are
called “pre-FIRM” buildings, while new construction is called “post-FIRM.”
The flood insurance rates for post-FIRM buildings are based on how protected
they are from the mapped hazard. Therefore, both the NFIP’s regulations and
insurance coverage depend on the accuracy and utility of the maps.
The NFIP’s maps and flood studies are covered in depth in Units 3 and 4.
National Flood Insurance Program
2-6
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INSURANCE
Every building located in a participating community may be covered by a
flood insurance policy—even buildings not located in a mapped floodplain. Cov
erage is for damage by a “flood.”
A flood is defined by NFIP regulations as
A “general and temporary condition of partial or complete inundation
of normally dry land areas from:
(1) “The overflow of inland or tidal waters or
(2) “The unusual and rapid accumulation or runoff of surface waters
from any source.”
The official definition also includes mudflows and erosion.
Flood insurance premiums for post-FIRM buildings are based on the degree of
flood protection they are provided. Therefore, it is very important for communi
ties to ensure that new buildings in the floodplain are constructed properly.
The flood insurance premium rates for pre-FIRM buildings are subsidized by
the NFIP. Owners of these policies do not pay “actuarial” rates, i.e., rates based
on the true risk the building is exposed to.
No matter whether a building is pre-FIRM or post-FIRM, with flood insur
ance, owners of floodprone properties pay more of their share toward flood relief.
And, they get claims paid when needed.
The NFIP has paid out over $12 billion in flood insurance claim payments for
big and small floods (see Figure 2-2). Insurance provides relief for all floods,
including those not large enough or severe enough to warrant federal disaster aid.
TROPICAL STORM ALLISON 6/01
$1,084 MILLION
LOUISIANA STORM
5/95
$584 MILLION
HURRICANE FLOYD
9/99
$437 MILLION
HURRICANE OPAL
10/95
$399 MILLION
HURRICANE HUGO
9/89
$376 MILLION
NOR’EASTER
10/92
$342 MILLION
MIDWEST FLOOD
6/93
$271 MILLION
HURRICANE FRAN
9/96
$214 MILLION
MARCH STORM
3/93
$211 MILLION
HOUSTON FLOODS
10/94
$217 MILLION
HURRICANE ANDREW
8/92
$168 MILLION
Figure 2-2. Largest claim events paid by the NFIP
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Flood insurance and its relation to construction regulations are discussed in
more detail in Unit 9.
REGULATIONS
The NFIP underwrites flood insurance coverage only in those communities
that adopt and enforce floodplain regulations that meet or exceed NFIP criteria.
Buildings built in accordance with these regulations have a lower risk of flooding
and can be insured at lower rates.
The community’s floodplain regulations are designed to ensure that new
buildings will be protected from the flood levels shown on the FIRM and that
development will not make the flood hazard worse. Over time, exposure to flood
damage should be reduced as the older pre-FIRM buildings are replaced by post-
FIRM buildings that comply with the regulations. Eventually a community should
have only post-FIRM building’s subject to little or no flood damage.
The NFIP construction regulations focus on protecting insurable buildings, but
they also provide a degree of protection to other types of development. These
criteria are detailed in Unit 5.
Floodplain regulations initially were controversial and difficult to enforce.
Many people wanted the freedom to build what they want without government
controls. In some areas, they still may not be aware they need a local permit to
build. However, as time has passed the regulations have become increasingly
accepted as necessary to reduce flood damages and protect citizens from loss.
As a result of public opposition, a community may be inclined to not fully en
force all of the provisions of its ordinance, which puts its participation in the
NFIP in peril. If the community does not fulfill its NFIP obligations to the federal
government and allows construction in violation of its regulations, three things
can happen:
♦ New buildings will be built subject to flood damage
♦ Insurance on an improperly constructed building may be very expensive.
♦ FEMA can impose sanctions on the community, to encourage it to correct
its floodplain management program. The sanctions are discussed in Sec
tion D.
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C. ROLES AND RESPONSIBILITIES
The National Flood Insurance Program is founded on a mutual agreement be
tween the federal government and each participating community. Local, state and
federal governments, and private insurance companies must share roles and re
sponsibilities to meet the goals and objectives of the NFIP.
The community’s role is of paramount importance. Residents and property
owners can get flood insurance only if the community carries out its responsibili
ties.
THE COMMUNITY ROLE
A community is a governmental body with the statutory authority to enact and
enforce development regulations. These governmental bodies vary form state to
state, but can include cities, towns, villages, townships, counties, parishes, special
districts, states and Indian nations.
The community enacts and implements the floodplain regulations required for
participation in the NFIP. The community’s measures must meet regulations set
by its state, as well as NFIP criteria. The NFIP requirements are covered in Unit
5.
A participating community commits itself to:
♦ Issuing or denying floodplain development/building permits.
♦ Inspecting all development to assure compliance with the local ordinance.
♦ Maintaining records of floodplain development.
♦ Assisting in the preparation and revision of floodplain maps.
♦ Helping residents obtain information on flood hazards, floodplain map
data, flood insurance and proper construction measures.
THE STATE ROLE
Each governor has selected a state coordinating agency for the NFIP. While
the role of this agency varies from state to state, it usually includes:
♦ Ensuring that communities have the legal authorities necessary to adopt
and enforce floodplain management regulations.
♦ Establishing minimum state regulatory requirements consistent with the
NFIP.
♦ Providing technical and specialized assistance to local governments.
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♦ Coordinating the activities of various state agencies that affect the NFIP.
Most states participate in the Community Assistance Program (CAP). Under
CAP, NFIP funds are available on a 75 percent / 25 percent cost share to help the
state coordinating agency provide technical assistance to communities and to
monitor and evaluate their work. The telephone numbers of the state coordinating
agencies are listed in Appendix B. Communities can contact their state coordinat
ing agency for technical assistance in meeting NFIP requirements.
States also participate in the NFIP by establishing and enforcing floodplain
management regulations for state-owned properties. This can be done through
legislation, but more often has been done through a governor’s executive order. A
number of states have their own floodplain management statutes and regulations
and operate floodplain management programs of their own in addition to support
ing implementation of the NFIP.
THE FEDERAL ROLE
The Federal Emergency Management Agency (FEMA) within the Department
of Homeland Security (DHS) administers the NFIP through its Regional Offices
and its Mitigation Division.
The ten FEMA Regional Offices each have a Mitigation Division that coordi
nates the NFIP with states and communities. Each FEMA regional office covers
four to eight states and territories. Together they work with the nearly 20,000
participating communities. A list of the regional offices, their addresses and the
states they cover appears in Appendix A.
The Regional Offices are responsible for:
♦ Assisting the state NFIP coordinating agencies.
♦ Assessing community compliance with the minimum NFIP criteria.
♦ Advising local officials responsible for administering the ordinance.
♦ Answering questions from design professionals and the public.
♦ Helping review and adopt new maps and data.
♦ Approving community floodplain management regulations.
♦ Providing information and training on the flood insurance purchase re
quirements.
The FEMA Mitigation Division in Washington, D.C., sets national policy for
floodplain regulations, researches floodplain construction practices and adminis
ters the flood hazard mapping program. The Division has mapped more than 100
million acres of flood hazard areas nationwide and designated some six million
acres of floodways along 40,000 stream and river miles.
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The Mitigation Division also administers the insurance portion of the pro
gram. It sets flood insurance rates, establishes coverage, monitors applications
and claims, and markets flood insurance.
The NFIP is operated as a self-supporting program. All NFIP expenses, in
cluding claims payments, floodplain management, and administration and, until
recently, flood hazard mapping, are paid through insurance premiums, fees on
insurance policies, and fees from map revision requests. Congress has recently
provided supplemental funding to accelerate the NFIP’s Map Modernization
program.
Private insurance companies write and service most NFIP flood insurance
policies through an arrangement with FEMA called the Write-Your-Own Pro
gram. The NFIP also contracts for agent training and other assistance through
regional insurance offices. They can be reached through the FEMA Regional
Offices.
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D. COMMUNITY PARTICIPATION
The NFIP is based on a cooperative agreement between the community and
FEMA. FEMA can only make flood insurance available in those communities that
agree to regulate future development in the floodplain.
JOINING THE NFIP
Participation in the NFIP is voluntary. There is no Federal law that requires a
community to join, although some states have requirements. However, as dis
cussed later in this section, a nonparticipating community faces sanctions, such as
loss of Federal aid for insurable buildings in the floodplain. These make participa
tion a very important decision for many communities.
To join, a community must adopt a resolution of intent to participate and co
operate with FEMA. The community agrees to “maintain in force…adequate land
use and control measures consistent with the [NFIP] criteria” and to:
(i) Assist the Administrator in the delineation of the floodplain,
(ii) Provide information concerning present uses and occupancy of the flood
plain,
(iii) Maintain for public inspection and furnish upon request, for the determina
tion of applicable flood insurance risk premium rates within all areas having
special flood hazards, elevation and floodproofing records on new construction,
(iv) Cooperate with agencies and firms which undertake to study, survey, map,
and identify flood plain areas, and cooperate with neighboring communities with
respect to the management of adjoining flood plain areas in order to prevent ag
gravation of existing hazards;
(v) Notify the Administrator whenever the boundaries of the community have
been modified by annexation or the community has otherwise assumed or no
longer has authority to adopt and enforce flood plain management regulations for
a particular area.
The community must also adopt and submit a floodplain management ordi
nance that meets or exceeds the minimum NFIP criteria. These criteria are
explained in Unit 5 of this course.
As shown in Figure 2-1, most communities joined in the 1970’s. At that time
they were provided with a Flood Hazard Boundary Map which showed only the
approximate boundaries of the floodplain. Generally, they entered the “Emer
gency Phase” whereby their regulatory responsibilities were limited because of
the limited flood hazard data provided on the map.
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Participating communities receive a Flood Insurance Rate Map (FIRM) and
most get a Flood Insurance Study with more detailed flood hazard data. After a
period to review and appeal the draft map and study, the community is given six
months to adopt the new data in a more comprehensive ordinance.
The FIRM takes effect at the end of the six month period. If the ordinance has
been adopted in time, the community is converted to the “Regular Phase” on that
date. That is also the date that differentiates “pre-FIRM” buildings from “post-
FIRM buildings.”
If the ordinance is not adopted in time, the community is suspended from the
NFIP. The FIRM still goes into effect on the same date and is used by lenders and
Federal agencies for determining where loans can be issued and federal assistance
can be provided.
As of the end of August 2003, 97% of the NFIP communities were in the
Regular Phase.
COMPLIANCE
The community’s floodplain management program and permit records are re
viewed periodically by the FEMA Regional Office or state NFIP coordinating
agency. Either agency may inspect records as part of a community assistance visit
(CAV) or community assistance contact (CAC).
If a community doesn’t uphold its part of the agreement and fails to ade
quately enforce its floodplain management regulations, FEMA has recourse
through three approaches:
♦ Reclassification under the Community Rating System
♦ Probation
♦ Suspension from the program
Reclassification under the Community Rating System
The Community Rating System (CRS) provides a disNFIP/CRS Logo - houses in background
count in the flood insurance premiums for properties in
communities that participate in the CRS and implement
floodplain management programs that exceed minimum
NFIP requirements. The CRS is explained in Unit 9, Section
C. As of May 1, 2004, 1,002 communities participate in
CRS. This represents 66% of policies in force.
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CRS Communities that are deemed to no longer be in full compliance with the
NFIP requirements can be reclassified to Class 10. Should that happen, residents
would lose their CRS flood insurance premium discounts.
Probation
Probation represents formal notification to the community that FEMA regards
the community’s floodplain management program as non-compliant with the
NFIP criteria.
Prior to imposing probation, FEMA provides the community a 90-day written
notice and lists specific deficiencies in its program and violations. FEMA also
notifies all policy holders of the impending probation, telling them that an addi
tional $50 premium will be charged on policies sold or renewed during the
probation period. The objective of this surcharge is to bring the policy holders’
attention to the fact that their community is not compliant and failure to correct
the problems may lead to suspension.
The community has 90 days to avoid this sanction by correcting the program
deficiencies and remedying the identified violations. Probation may be continued
for up to one year after the community corrects all program deficiencies. This
ensures that the community has truly changed its ways and become compliant and
that all policies holders are advised of the situation when their policies are re
newed.
Suspension
If, after a period of probation, a community fails to remedy its violations and
program deficiencies, it will be suspended from the NFIP for failure to enforce its
floodplain management regulations. Suspension means the community is no
longer in the NFIP. It is subject to the sanctions for non-participation that are
explained in the next section.
FEMA grants a community 30 days to show why it should not be suspended
and then sends it a 30-day suspension letter. FEMA may also conduct a written or
oral hearing before suspension takes effect.
A community suspended under the NFIP may apply to the FEMA Regional
Office for reinstatement by submitting the following:
♦ A local legislative or executive measure reaffirming the community’s in
tent to comply with the NFIP criteria.
♦ Evidence that all program deficiencies have been corrected.
♦ Evidence that any violations have been remedied to the maximum extent
possible.
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FEMA may reinstate the community to full program status, bring it to a proba
tionary status, or withhold reinstatement for up to one year after a satisfactory
submission from the community.
A community will also be suspended if, following due notice, it fails to adopt
revisions to its floodplain ordinance in response to flood map revisions or
amended minimum NFIP criteria. Communities have a 6 month period after a
new or revised map is issued to update their floodplain management regulations to
incorporate the new data and make any other necessary changes. If at the end of
the 6 months the community has not adopted a compliant ordinance, it is auto
matically be suspended.
It is not uncommon for communities to be suspended for failure to adopt
compliant ordinances. Sometimes communities get a late start revising their
ordinance and cannot complete the ordinance adoption process in the allotted 6
months. These communities are reinstated into the NFIP upon adoption of the
ordinance provided no non-compliant development has taken place during the
suspension.
SANCTIONS FOR NON-PARTICIPATION
A community that does not join the NFIP, has withdrawn from the program,
or is suspended from it faces the following sanctions:
♦ Flood insurance will not be available. No resident will be able to purchase
a flood insurance policy.
♦ If the community withdraws or is suspended, existing flood insurance
policies will not be renewed.
♦ No Federal grants or loans for the acquisition or construction of buildings
may be made in identified flood hazard areas under programs administered
by Federal agencies such as HUD, EPA, and SBA.
♦ No Federal disaster assistance may be provided to repair insurable build
ings located in identified flood hazard areas for damage caused by a flood.
♦ No Federal mortgage insurance or loan guarantees may be provided in
identified flood hazard areas. This includes policies written by FHA, VA,
and others.
♦ Federally insured or regulated lending institutions, such as banks and
credit unions, must notify applicants seeking loans for insurable buildings
in flood hazard areas that:
-- There is a flood hazard and
-- The property is not eligible for Federal disaster relief.
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These sanctions can be severe on any community with a substantial number of
buildings in the floodplain. Most communities with a flood problem have joined
the NFIP and are in full compliance with their regulatory obligations.
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UNIT 3:
NFIP FLOOD STUDIES AND MAPS
In this unit
This unit describes the flood data, studies, and maps that the National
Flood Insurance Program provides to communities to assist them in carrying
out their floodplain management program. It reviews:
♦ Flood study and map terminology,
♦ How flood studies are prepared along riverine floodplains,
♦ How flood studies are prepared on coastal floodplains, and
♦ How the NFIP maps display the study data.
Materials needed for this unit
♦ Flood Insurance Study, Flood County, USA and Incorporated Areas
♦ Flood Insurance Rate Map, Flood County, USA and Incorporated
Areas
Flood Studies and Maps
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Contents
A. NFIP Flood Studies ................................................................................................................. 3-3
Flood Study Terminology...................................................................................................... 3-3
The base flood ................................................................................................................. 3-3
The 100-year flood .......................................................................................................... 3-4
Special flood hazard area and base flood elevation......................................................... 3-4
Identifying Floodprone Areas ................................................................................................ 3-5
Flood Insurance Study..................................................................................................... 3-7
Flood County, USA and Incorporated Areas .................................................................. 3-8
B. Riverine Studies....................................................................................................................... 3-9
Hydrology .............................................................................................................................. 3-9
Cross Sections...................................................................................................................... 3-10
Hydraulics............................................................................................................................ 3-12
Flood Profile ........................................................................................................................ 3-13
Floodplain Map.................................................................................................................... 3-16
Floodway Analysis .............................................................................................................. 3-17
C. Coastal Flood Studies ............................................................................................................ 3-20
Storm Surge ......................................................................................................................... 3-20
Waves................................................................................................................................... 3-20
Hydraulic Analysis .............................................................................................................. 3-21
Coastal High Hazard Area ................................................................................................... 3-22
Coastal Floodplain Map....................................................................................................... 3-22
D. Shallow flooding studies ....................................................................................................... 3-24
E. Approximate Studies.............................................................................................................. 3-25
F. NFIP Maps ............................................................................................................................. 3-26
General Map Features.......................................................................................................... 3-26
Map Index............................................................................................................................ 3-27
Title block ..................................................................................................................... 3-27
Map revision date .......................................................................................................... 3-27
Map scales and north direction...................................................................................... 3-28
Elevation reference marks ............................................................................................. 3-28
FIRM Zones .................................................................................................................. 3-29
Flood Hazard Boundary Map (FHBM)................................................................................ 3-30
Flood Insurance Rate Map (FIRM) — old format (Pre 1986)............................................. 3-30
Flood Boundary and Floodway Map (Floodway Map) – Old format (Pre 1986)................ 3-31
Flood Insurance Rate Map — new format (Since 1986) ..................................................... 3-33
Partial Map Initiatives FIRM............................................................................................... 3-35
FIRMs with Coastal and Lake Floodplains.......................................................................... 3-35
Coastal FIRMs............................................................................................................... 3-35
Coastal Barrier Resources System................................................................................. 3-35
Lakes .......................................................................................................................... 3-36
Shallow Flooding FIRMs..................................................................................................... 3-37
FIRMs with Flood Protection Projects ................................................................................ 3-37
Countywide FIRMs.............................................................................................................. 3-38
Digital FIRMs ...................................................................................................................... 3-40
Digital Flood Insurance Rate Map (DFIRM) ................................................................ 3-40
Q3 Flood Data ............................................................................................................... 3-42
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A. NFIP FLOOD STUDIES
FLOOD STUDY TERMINOLOGY
Before describing how flood studies are developed, we first need to introduce
some of the common terms used in floodplain analysis and in the National Flood
Insurance Program (NFIP). The following terms are integral for understanding the
basis for flood studies and flood maps:
♦ The base flood,
♦ The 100-year flood,
♦ Special Flood Hazard Area, and
♦ Base Flood Elevation.
The base flood
Floods come in many sizes — with varying degrees of magnitude and
frequency.
Rivers and coastlines are expected to flood, as all bodies of water have
floodplains. But rivers and coastlines are different, as well; each has its own
probability of flooding. Probability is a statistical term having to do with the size
of a flood and the odds of that size of flood occurring in any year.
For each river, engineers assign statistical probabilities to different size floods.
This is done to understand what might be a common or ordinary flood for a
particular river versus a less likely or a severe flood for that same river.
In order to have common standards, the NFIP adopted a baseline probability
called the base flood. The base flood is the one-percent annual chance flood. The
one-percent annual chance flood is the flood that has a one-percent (one out of
100) chance of occurring in any given year. The base flood, which is also
informally referred to as the 100-year flood, is the national standard used by the
NFIP and all Federal agencies for the purposes of requiring the purchase of flood
insurance and regulating new development
The one-percent annual chance flood was chosen as a compromise between a
more frequent flood (such as a 10-percent chance flood), which would permit
excessive exposure to flood risk, and a more infrequent flood (say, a 0.1-percent
chance flood), which would be considered an excessive and unreasonable
standard.
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The 100-year flood
The one-percent annual chance flood is also called the 100-year flood because
the inverse of one percent (one divided by one percent or 0.01) equals 100. This
calculation gives us the flood’s recurrence interval, in terms of probability, which
is 100 years.
The term “100-year flood” is often misconstrued. Commonly, people interpret
the 100-year flood definition to mean “once every 100 years.” This is wrong.
You could experience a 100-year flood two times in the same year, two years in a
row, or four times over the course of 100 years. You could also not experience a
100-year flood over the course of 200 or more years.
To avoid confusion (and because probabilities and statistics can be confusing),
the NFIP uses the term “base flood.” A 100-year base flood is defined as having a
one-percent chance of being reached or exceeded in any single year. Thus, the
100-year flood also is called the “one-percent annual chance flood.”
To restate, “100-year flood” and “base flood” both refer to a flood that has a
one-percent chance of occurring in any given year. The terms “base flood,” “100
year flood,” and “one-percent annual chance flood” are often used
interchangeably.
Special flood hazard area and base flood elevation
The land area covered by the floodwaters of the base flood is the base
floodplain. On NFIP maps, the base floodplain is called the Special Flood Hazard
Area (SFHA). The SFHA is designated as Zone A, AE, A1-30, AO, AH, V, VE
or V1-30 depending on the amount of flood data available, the severity of the
flood hazard, or the age of the flood map (see the discussion of zones in this Unit
for more information.).
The SFHA is the area where the NFIP’s floodplain management regulations
must be enforced by the community as a condition of participation in the NFIP
and the area where the mandatory flood insurance purchase requirement applies.
The computed elevation to which floodwater is anticipated to rise during the
base flood is the Base Flood Elevation (BFE).
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WHAT ARE THE ODDS OF
BEING FLOODED?
The term "100-year flood" has caused much confusion for
people not familiar with statistics. Another way to look at
flood risk is to think of the odds that a 100-year flood will
happen sometime during the life of a 30-year mortgage—a
26% chance for a structure located in the SFHA.
Chance of Flooding over a Period of Years
Time
Flood Size
Period
10-year
25-year
50-year
100-year
1 year
10%
4%
2%
1%
10 years
65%
34%
18%
10%
20 years
88%
56%
33%
18%
30 years
96%
71%
45%
26%
50 years
99%
87%
64%
39%
Even these numbers do not convey the true flood risk
because they focus on the larger, less frequent, floods. If a
house is low enough, it may be subject to the 10- or
25-year flood. During a 30-year mortgage, it may have a
26% chance of being hit by the 100-year flood, but the
odds are 96% (nearly guaranteed) that it will be hit by a
10-year flood. Compare those odds to the only 1-2%
chance that the house will catch fire during the same
30-year mortgage.
IDENTIFYING FLOODPRONE AREAS
The National Flood Insurance Act of 1968 directed the Federal Insurance
Administration (FIA) to:
♦ Identify all floodprone areas within the United States.
♦ Establish flood-risk zones within floodprone areas.
Today, the Federal Emergency Management Agency’s (FEMA) Mitigation
Division is responsible for implementing this directive. FEMA has conducted
flood studies and produced various forms of maps. The flood studies analyze the
terrain and the factors that affect flood hazards. This information is used to draw
the maps that delineate floodplain boundaries.
The maps and flood studies also show projected flood elevations, flood
velocities, floodway dimensions, insurance rating zones, and descriptions of how
the study was conducted and how the maps were prepared. This information is
needed for flood insurance and floodplain management purposes.
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All of this information is referred to as a community’s Flood Insurance Study
(FIS), which is conducted under standards set by FEMA for the NFIP. FEMA has
prepared flood insurance studies for more than 19,000 communities.
In keeping with the directive of the National Flood Insurance Act of 1968,
initial flood study and mapping efforts of the NFIP were focused on identifying
all floodprone areas within the United States. Flood data and floodplain
information from many sources — such as soils mapping, actual high water
profiles, aerial photographs of previous floods, topographic maps, etc. — were
used to overlay the approximate outline of the base (100-year) floodplain for
specific stream reaches on available community maps, usually U. S. Geological
Survey topographic quadrangle maps.
These documents were referred to as Flood Hazard Boundary Maps and were
based on approximate studies. Most communities used a Flood Hazard Boundary
Map when they first joined the NFIP.
As money was appropriated by Congress, FEMA performed more detailed
studies for many communities, resulting in the publication of Flood Insurance
Study reports and Flood Insurance Rate Maps (FIRMs). These studies provide
communities with data needed to adopt and implement more comprehensive
floodplain management measures and to enter the Regular Phase of the NFIP.
FISs, also referred to as detailed studies, were carried out for developed
communities and for those areas experiencing rapid growth. FISs contain
guidance on understanding the FIRM as well as information needed for new
construction allowed in developing and developed areas.
Today, almost every community in the NFIP has a FIRM, which may contain
approximate and/or detailed flood hazard analyses. The areas mapped with
approximate studies are areas where, originally, there was little or no
development or expectation of development. However, recent development may
have created a need for future detailed studies in these areas.
Flood maps are one of the most vital parts of a floodplain management
program, so it is important to understand how the maps were created and to be
familiar with the information that is available within the accompanying flood
study.
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Flood Insurance Study
When a flood study is completed for the NFIP, the information and maps are
assembled into a Flood Insurance Study (FIS). A FIS is a compilation and
presentation of flood risk data for specific watercourses, lakes, and coastal flood
hazard areas within a community.
The FIS report and associated maps delineate the SFHA, designate flood risk
zones and establish base flood elevations. They serve as the basis for rating flood
insurance and for regulating floodplain development and carrying out other
floodplain management measures.
The study has three components:
♦ The FIS — Flood Insurance Study report
♦ The FIRM — Flood Insurance Rate Map
♦ Prior to 1986, a separate Flood Boundary and Floodway Map (FBFM) was
issued as a component of the FIS for each community studied.
The FIS report includes:
♦ An appraisal of the community’s flood
problems in a narrative that describes:
-- the purpose of the study,
-- historic floods,
-- the area and flooding sources studied, and
-- the engineering methods employed.
♦ A vicinity map of the community and,
occasionally, photographs of historic floods.
♦ Tables summarizing various flood hazard data.
♦ Computed flood profiles for various recurrence
probabilities, usually the 10-, 50-, 100-, and/or
500-year floods. Picture of Flood Insurance Study cover page
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Flood County, USA and Incorporated Areas
Included in the reference guide materials are the FIS report and maps for
Flood County, USA and Incorporated Areas. This fictitious community was
developed to illustrate examples of both riverine and coastal flood hazards.
This unit uses these documents for Flood County, USA and Incorporated
Areas:
♦ The FIS report, and
♦ The FIRM, accompanying Map Index, and panels 25, 38, and 40.
Flood County is subject to flooding from several flooding sources; however,
this unit concentrates on the following three sources:
♦ The Rocky River, which drains from the west, and flows through the
Town of Floodville to the Atlantic Ocean.
♦ Cobb Brook, which flows from the west to the Rocky River.
♦ The Atlantic Ocean.
As you look at Flood County, you may find that some street names do not
appear on the FIRM. This is because flood hazard maps are created to show
details related to identified floodplains. If your community flood maps lack street
names, use a supplementary street map to assist you in locating properties
accurately.
As you work through this unit, we recommend that you locate similar sections
in your community’s FIS and see how this information pertains to your situation.
The outline is similar for all FISs, so you should be able to locate the same tables
and exhibits in the table of contents.
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B. RIVERINE STUDIES
Detailed flood studies are conducted differently for different types of
flooding, which are:
♦ Riverine flooding of rivers, streams or other waterways,
♦ Lacustrine flooding of lakes and ponds,
♦ Coastal flooding caused by hurricanes or severe storms, and
♦ Shallow flooding, ponding, and sheet flow.
As you recall from Unit 1, there are other types of flooding, such as alluvial
fans, ice jams, and mudflows. This unit does not cover how these areas are
studied because each situation is unique. If your community has these unique
hazards, Appendix C lists some reference materials that may be of assistance.
Riverine flooding occurs in rivers, streams, ditches or other waterways that
are subject to overbank flooding, flash floods, and urban drainage system
flooding. Riverine studies involve, among other factors, the collection and
analysis of information about the river’s watershed, the topography or the lay of
the land along the river, precipitation, and the characteristics of the river itself.
HYDROLOGY
In order to determine the depth of flood waters and to determine the size or
width of floodplains, engineers must first examine the watershed to determine the
amount of water that will reach a stream and be carried by the stream during a
flood event.
Hydrology, a science dealing with the distribution and circulation of water in
the atmosphere, on land surfaces, and underground, is used to determine flood
flow frequencies. The study of a watershed’s behavior during and after a
rainstorm is, therefore, hydrology. A hydrologic analysis determines the amount
of rainfall that will stay within a watershed — absorbed by the soil, trapped in
puddles, etc. — and the rate at which the remaining amount of rainfall will reach
the stream.
The rainfall that reaches the stream is called runoff. Increased runoff will, in
turn, increase flood discharge. Discharge is the amount of water flowing down a
stream channel. Discharges are measured in cubic feet per second or cfs. (A cubic
foot of water is about 7.5 gallons.) Data for this measurement is taken by stream
gauges at specified locations along a given stream also known as gaging stations.
Significant development or other changes in the watershed (both within a
community and any upstream communities) can significantly change the flood
discharges. Often, the increase in impervious areas associated with urbanization
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causes increase in stream discharges. In addition, new technical data such as new
regional equations, new design storms, and in some circumstance, increase in the
length of gage records, might significantly affect the base discharge estimation.
Runoff amounts and discharge rates vary depending on soil type, ground
slope, land use, and the presence of storm sewers. In general, more runoff occurs
on non-vegetated land, on paved and built-on urban land, and on steeper slopes.
Discharges are estimated by using rainfall and snowmelt data and historical
stream records or by using regional equations that represent such data. Computer
models allow engineers to incorporate numerous watershed characteristics into
the hydrologic analyses. Discharge rates also generally increase as the size of a
watershed increases.
Upon completion of the hydrologic analysis, engineers have flood discharges
for various size rainstorms that are measured at different points along a stream,
such as at the confluence with another stream and at the mouth of a tributary
stream.
CROSS SECTIONS
All detailed flood studies examine the areas through which floodwater will
flow. This requires a determination of ground elevations and obstructions to flow
(such as vegetation, buildings, bridges, and other development) for these areas.
Accurate data on the channel geometry and changes in the floodplain are obtained
from ground surveys, aerial photography, or topographic maps.
To locate the true elevations at a site, surveyors have established elevation
reference marks or bench marks that are referenced to a common vertical
elevation reference called a datum. The use of a datum ensures uniformity of
references to land elevations and avoids misinterpretation of flood elevations.
Established reference marks and bench marks with a recorded elevation allow
surveyors to describe the changes in the ground levels or stream characteristics as
elevations relative to the referenced datum. They are also used by surveyors to
determine the elevations of buildings that are at risk of flooding.
A cross section is a graphical depiction of the stream and the floodplain at a
particular point along the stream. It is taken at right angles to the flow of the
stream. At each cross section, the engineer has accurate information on the size
and geometry of the channel, the shape of the floodplain, and the changes in the
elevation of the ground. A typical surveyed cross section is shown in Figure 3-1.
Cross sections are taken of the floodplain at locations along the stream that are
representative of local conditions. Cross sections are taken at each bridge or other
major obstruction and at other locations, depending on how much the stream or
adjacent floodplain conditions change (Figure 3-2). The more changes there are in
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topography (perhaps steep riverbanks changing to large flat overbank areas), the
more cross sections are needed to define the floodplain accurately. Figure 3-1: Surveyed cross section - Pic
Figure 3-1: Surveyed cross section
About Datums and Elevations
During the 1920s, the U.S. government created a network of 21 tidal gages in the U.S.
and five in Canada to provide a fixed continental datum that would bring a consistent
relationship to all vertical elevation determinations in the U.S. This new datum was
known as the Mean Sea Level (MSL) Datum of 1929 and is the base elevation to which
all relief features and elevation data are referenced in the contiguous United States. In
1973, to avoid confusion in many communities that used a local mean sea level datum,
the name was changed to the National Geodetic Vertical Datum (NGVD) of 1929.
NGVD is also the datum of reference for the vast majority of FISs.
Most permanent elevation reference marks (or bench marks)
are referenced to the NGVD (see example). Reference marks
are not always brass caps; they can be chiseled squares or
other designated markers left by surveyors. The city or county
surveyor or engineer’s office should have a list of bench marks
in the community. An ultimate goal of the NFIP is to convert
all FISs to a newer standard called the North American
Vertical Datum (NAVD) of 1988. This latest standard will
eliminate inconsistencies caused when the NGVD is not
consistent at all 26 tidal stations.
When reporting elevations for structures, cross sections, or topographic mapping, it is
very important to note the datum to which the survey is referenced. Differences between
NAVD 88 and NGVD 29 vary by as much as –1.5 feet along the east coast of southern
Florida to + 4.9 feet in the Rocky Mountains of Colorado. Software for converting
between NAVD 88 and NGVD 29 is available from the National Geodetic Survey.
There are now 600,000 permanent benchmarks associated with the NAVD of 1988. See
Flood Insurance Study: Guidelines and Specifications for Study Contractors, FEMA-37
(1995), for further information.
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Figure 3-2: Typical cross section locations
The surveyors and engineers also estimate the roughness factor along the
floodplain to determine how fast floodwater will flow through the area.
Roughness factors are related to ground surface conditions, and they reflect
changes in floodwater velocity due to ground friction. For example, water will
flow faster over mowed grass and pavement than it will over an area covered in
bushes and trees, or planted in tall crops.
A portion of the collected survey information is used in the hydrologic
analysis, but the surveyed cross sections and other survey information are the
building blocks of the hydraulic analysis and mapping efforts.
HYDRAULICS
Hydraulics, a science that deals with fluids in motion, is used to determine
how a quantity of water will flow through a channel or floodplain. For purposes
of floodplain analysis, hydraulics is the study of floodwaters moving through the
stream and the floodplain. Hydraulic analysis combines:
♦ Flood hydrology, or discharges,
♦ The cross section data on how much area there is to carry the flood, and
♦ Stream characteristics — roughness, slope, locations and sizes of
structures.
The data are usually processed using a computer model, most commonly
HEC-2 or HEC-RAS, which were developed by the U.S. Army Corps of
Engineers’ Hydrologic Engineering Center.
Changes in hydraulic conditions of a stream usually occur when new bridges,
culverts and road crossings are constructed, and when there are changes in the
physical characteristics of the stream. If a bridge or culvert is not properly sized, it
can cause flood waters to back-up, which increases flood levels upstream.
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Although most bridge openings and culverts are designed to allow stream flows
associated with frequent storm events to pass without such backwater effects, they
may still cause increase in the base flood elevation. Therefore, any bridges,
culverts, or other road crossings that have been constructed since the analyses for
the effective FIS and FIRM were completed should be evaluated for their
potential effect on the base flood and the associated floodway. In addition, any
significant changes in the stream channel or floodplain geometry could affect the
floodplain and floodway. One should always ask the questions: 1) has any portion
of the floodplain been filled? 2) has the stream channel migrated or changed
location because of significant erosion and/or depositions? 3) have any portions of
the stream been channelized, widened, or dredged? 4) have there been significant
changes in the vegetation in the floodplain? Aerial photographs are useful tools in
evaluating changes in stream channels and floodplains.
The hydraulic study produces determinations of flood elevations, velocities,
and floodplain widths at each cross section for a range of flood flow frequencies
(Figure 3-3). These elevations are the primary source of data used by engineers to
map the floodplain. Figure 3-3: Cross Section with flood elevations - Picture showing 100 year floodplain channel at 500 year, 100 year, 50 year, and 10 year W.S.E.L.
Figure 3-3: Cross section with flood elevations
A FIS typically produces elevations for the 10-, 50-, 100-, and 500-year
floods. Water-Surface Elevations (WSEL) for the 10-, 50-, and 500-year floods
are typically used for other floodplain management purposes. For example, the
10-year flood data may be used for locating septic systems, the 50-year flood for
placing bridges and culverts, and the 500-year for siting critical facilities, such as
hospitals or emergency operation facilities.
FLOOD PROFILE
The hydraulic computer program generates potential flood elevations at each
cross section, but flood elevations at locations between the cross sections need to
be determined as well. This is done by plotting the elevations at the cross sections
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on a graph and connecting the plotted points. Such a graph is called a flood
profile.
Figure 3-4 shows a portion of the flood profile for the Rocky River. The entire
profile is found in the back of the Flood County FIS report.
The bottom of the graph (the horizontal axis or x-axis) shows the distance
along the stream, which is commonly called stationing. For stationing, you start at
the mouth of a stream (its point of discharge into a larger body of water) and look
upstream. Generally, when profiles are plotted, the slope of the streambed will
rise as you read the graph from left to right.
River distances are measured in either feet or miles (1mile=5280 feet), or
meters and kilometers (1 kilometer=1000 meters). For most profiles, the distance
is measured above the mouth of the stream or above its confluence (where it
meets with another stream). In the case of Flood County, the stream distances for
the Rocky River are measured above the County Boundary.
The left and right sides of the graph (the vertical axis or y-axis) show
elevations in feet (NGVD). The legend at the bottom right corner shows the
symbol for each flood profile plotted. Bridges are indicated with an “I” shaped
symbol. The bottom of the “I” represents the bridge’s low chord (lowest beam)
and the top of the “I” represents the top of the roadway or the top of a solid bridge
railing.
Additional information is provided on the profiles, such as corporate limits
and confluences of smaller streams. Profiles also provide a picture of stream
characteristics, such as steep sections of the streambed and where restrictive
bridge openings cause floodwaters to back up (see the footbridge in Figure 3-4).
By reading a profile, you can determine the flood elevation at any point along
the stream. Reading profiles is covered in Unit 4.
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Figure 3-4: Rocky River flood profile
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FLOODPLAIN MAP
The next step in the mapping process is to transfer the flood elevation data
onto a map showing ground elevation data. This is called a topographic map or
contour map because points with the same elevation are connected by a contour
line. The topographic or contour map is often referred to as the base map.
The most common topographic maps used are produced by the U.S.
Geological Survey. Some communities have prepared their own topographic maps
and provided them to FEMA during the study process to improve the accuracy of
their floodplain maps.
The base flood elevations from the cross sections and profiles are plotted on
the topographic map. Floodplain boundary lines are drawn connecting these
plotted points using the contour lines as a guide. The completed map illustrates
the SFHA (Figure 3-5). Figure 3-5: The BFEs at the cross sections from the Rocky River profile are used to plot the BFEs on the countour map.
Figure 3-5: The BFEs at the cross sections from the Rocky River profile are
used to plot the BFEs on the contour map.
Lines are connected to show the floodplain boundary on a map.
It is important to remember that floodplain map boundaries are only as
accurate as the topographic map on which they are drawn. Since the U.S.
Geological Survey topographic quadrangle maps have so small a scale, the SFHA
boundaries cannot be precisely mapped. This is important to remember when
determining if a building is in or out of the floodplain, and, therefore, the use of
other relevant measurements may be required and is recommended.
Correlating map features with ground features requires care, because maps do
not always represent exact conditions on the ground. Where there is an apparent
discrepancy between floodplain boundaries shown on a map and actual ground
conditions, as the local administrator, you can use elevation data to resolve the
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Figure 3-6 Floodway cross section and map
Figure 3-6: Floodway cross section and map
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matter by locating the flood elevation on the ground via an elevation survey. This
elevation represents the actual extent of flooding for that particular flood.
Note: Banks, lending institutions and others who must read the FIRM to determine if flood
insurance is required must go by the map. They cannot make on-site interpretations
based on data other than the FIRM. However, they may recommend that the property
owner submit a request for a map revision or map amendment so the map can be
officially changed to reflect the more accurate data (see Unit 4, Section D).
FLOODWAY ANALYSIS
The final step in preparing most riverine flood studies is to produce the
floodway analysis, which identifies where encroachment by development will
increase flood elevations significantly and worsen flood conditions.
The floodway is the stream channel and that portion of the adjacent floodplain
that must remain open to permit passage of the base flood. Floodwaters generally
are deepest and swiftest in the floodway, and anything in this area is in the
greatest danger during a flood. FEMA has mapped designated floodways in more
than 8,000 communities.
The remainder of
the floodplain is called
the flood fringe
(Figure 3-6), where
water may be
shallower and slower.
The floodway and the
flood fringe together
comprise the base
floodplain or special
flood hazard area. On
the flood map these
areas will be
designated as Zone
A1-30 or AE. NFIP
minimum standards
provide that other
areas outside the
boundaries of the
floodway can be
developed without
further analysis.
Consequently, most
communities permit development in the flood fringe if the development is
elevated or otherwise protected to the base flood level (or any higher state or local
standards). Development in the floodway is allowed if it can be demonstrated that
no rise in the base flood elevation will occur. It is recommended, however, that
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floodway development be discouraged or even prohibited because of the
hazardous nature of this area.
A floodway analysis determines the boundaries of the floodway using these
floodplain management concepts:
♦ Continued development in the floodplain will likely further obstruct flood
flows, which will back water up or divert it to other properties.
♦ Properties on both sides of a river or stream should be treated equitably.
The degree of obstruction permitted now for one should be permitted in
the future for the other.
♦ Property owners should be allowed to develop their land, provided they do
not obstruct flood flows, cause damage or create a nuisance to others. (A
community may allow development in the flood fringe that cumulatively
increases the BFE, but NFIP regulations specify that such total increases
cannot exceed one foot at any point along the stream. Some states or
communities have more restrictive standards that must be met.)
A floodway analysis is done with a computer program that can make the
necessary calculations of the effects of further development. Beginning at both
edges of the floodplain, the computer model starts “filling” the floodplain. This
“squeezes” the floodwater toward the channel and causes the flood level to rise.
At the point where this process reaches a one foot rise, the floodway boundaries
are drawn (Figure 3-7). Figure 3-7: Computer floodway analysis.
Figure 3-7: Computer floodway analysis
The floodway boundaries at each cross section are transferred to the
topographic or contour map that shows the SFHA boundaries. The plotted points
are connected to show the floodway and flood fringe on the floodplain map.
Not every cross section will show an exact one-foot rise. Topographic
conditions and the need to “smooth out” the floodway line will result in some
cross sections having increases of less than one foot.
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Allowing flood heights to rise up to one foot is a compromise standard.
Prohibiting any rise in flood heights would prohibit most types of new
development or redevelopment. On the other hand, allowing development to
cause significant increases in flood heights can cause great problems for others.
States and communities may use a more restrictive standard for delineating a
floodway. Some may allow only a 0.5-foot or 0.1-foot rise in the base flood
elevation in the floodway analysis. This results in wider floodways and less area
in the flood fringe.
A floodway analysis should be prepared with close coordination between the
modeling engineer and those who are responsible for community planning and
floodplain management.
The number of possible floodway configurations is almost limitless.
Therefore, in choosing a regulatory configuration, the interests of individual
property owners and the community as a whole must be weighed.
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C. COASTAL FLOOD STUDIES
Coastal flood studies are conducted for communities along the Atlantic and
Pacific Oceans, the Gulf of Mexico, the Great Lakes, and the Caribbean Sea.
Coastal studies are used to establish a base flood and an SFHA, but they may also
designate a coastal high hazard area (V Zone).
Note that coastal communities, particularly counties, may also have riverine
floodplains with designated floodways.
STORM SURGE
Most coastal floods are caused by coastal storms, usually hurricanes and
northeasters. Such storms bring air pressure changes and strong winds that “pile”
water up against the shore in what is called a storm surge.
A computer simulation of a coastal storm is developed based on data from
past storms. Such data include wind speeds, wind direction, and air pressure from
historical hurricanes and northeasters. The resulting surge elevations are then
calibrated using historical information so the probabilities for each event can be
determined.
The coastal storm surge computer program produces stillwater flood
elevations — the elevations of various coastal floods, not including waves. The
computer model is calibrated by reproducing the observed historical stillwater
elevations. The program determines the stillwater elevation from these historical
data.
WAVES
In addition to storm surge, wave action is an important aspect of coastal
storms. Wind-driven waves produce velocities and impacts that may cause
significant structural damage. The coastal flood study analyzes how high the wave
crest elevation will be above the stillwater elevation as water is driven onshore.
When waves hit the shore, water is moving with such force that it keeps
traveling inland. This is called wave runup, when land areas that are higher than
the stillwater elevation are flooded (Figure 3-8). Wave setup is defined as the
additional elevation of the water surface over normal surge elevation caused by
onshore mass transport of the water by wave action. Wave set-up is a function of
deepwater wave height and duration.
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Figure 3-8: Wave runup - Picture of two houses at waterfront at different depths.
Typical transect schematic showing VZone for wave height greater than 3 feet and less than 3 feet
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Figure 3-8: Wave runup
HYDRAULIC ANALYSIS
As with riverine studies, a coastal hydraulic analysis determines where
moving water goes. Using similar surveying techniques as in a riverine study, the
coastal flood engineer surveys transects instead of cross sections.
A transect shows the elevation of the ground both onshore and offshore. The
ground elevation data are used by computer programs to determine the expected
height of the wave crests and runup above the storm surge.
A transect schematic is shown in Figure 3-9. A transect location map appears
on page 11 of Flood County’s FIS report. This map shows where the transects
were measured.
Figure 3-9. Transect schematic
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Underwater topography, called bathymetry, and the shapes and locations of
coastal islands, headlands, estuaries, harbors, and other coastal features are also
taken into consideration in determining flood elevations.
The official BFE is the stillwater elevation plus wave runup, or the wave crest
elevation, whichever is greater. The resulting BFE can be many feet higher than
the stillwater elevation.
Obstructions such as dunes or buildings break the waves, dissipating wave
energy so that wave height and BFEs are reduced as you go inland. Figure 3-9
shows that as water moves inland, the waves break and the base flood elevation
(including wave effects) is reduced while the stillwater elevation stays the same.
COASTAL HIGH HAZARD AREA
Waves pack a lot of power. Much more destructive than standing or slow-
moving water, their power increases dramatically with their height. For the
purposes of the NFIP, the flood study identifies the coastal high hazard area as
that most hazardous part of the coastal floodplain, due to its exposure to wave
effects. This is typically the area between the shoreline and the most landward of
the following points:
♦ where the computed wave heights for the base flood are three feet or more,
♦ the inland limit of the primary frontal dune, or
♦ where the eroded ground profile is three feet below the computed runup
elevation.
The three-foot wave height threshold was selected because a three-foot wave
generally carries enough energy to break a wall panel away from a floor to which
it has been nailed.
These areas are designated as V Zones, where the “V” stands for “velocity
wave action.” V Zones are subject to more stringent regulatory requirements and
a different flood insurance rate structure because they are exposed to an increased
degree of risk. Coastal flood areas not within the coastal high hazard area are
mapped as A Zones (see Figure 3-9).
COASTAL FLOODPLAIN MAP
After gathering stillwater elevation and wave height data at the transects, the
coastal flood engineer then transfers the elevation data to the best available
topographic map. Flood elevations between transects are interpolated, taking local
topography into consideration.
Flood County FIRM number 99009C, Panel 0040 D, shows a coastal
floodplain for the Atlantic Ocean coastline. Note that south of Flower Street, the
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V Zone boundaries meander along the shoreline, and the BFEs decrease over a
relatively wide space from 14 feet to 12 feet (above NGVD, or roughly sea level).
Landward of the Zone VE (EL 12) boundary, the zones change to Zone AE, with
BFEs decreasing from 11 feet to 10 feet NGVD. These wider flood zones are
typical of gradually varying topography on barrier island beaches or marshland.
In contrast, the V Zone boundaries between Flower Street and Public Way are
narrower and roughly parallel to the shoreline, with BFEs decreasing rapidly from
14 feet to 13 feet NGVD. Note also that the area directly landward of the Zone
VE (EL 13) is designated Zone AO (Depth 2’), signifying shallow flooding of 2
feet NGVD or less. This situation often occurs when a substantial dune line or
flood protection structure exists along the shoreline.
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D. SHALLOW FLOODING STUDIES
For the NFIP, shallow flooding is defined as flooding with an average depth
of one to three feet in areas where a clearly defined channel does not exist.
Shallow flooding can exist in any of the following situations:
♦ Ponding: In flat areas, water collects or “ponds” in depressions.
♦ Sheet flow: In steeper areas where there are no defined channels or on flat
plains, water will spread out over the land surface.
♦ Urban drainage: Local drainage problems can be caused where runoff
collects in yards or swales or when storm sewers back up.
♦ Coastal flooding: Wave runup will send water inland over flat areas or
over dunes. Often it may collect or pond behind an obstruction which
keeps it from draining back into the ocean.
For the purposes of the NFIP, shallow flooding is distinguishable from
riverine or coastal flooding because it occurs in areas where there is no channel or
identifiable flow path.
Shallow flooding is mapped based on historic flood experiences and a study of
the topography. In some areas, the techniques used for riverine studies are used.
The result will either be a BFE or a base flood depth (in feet above the ground). A
shallow flooding study usually produces data for the base flood, but not for the
10-year or other floods.
On Flood County’s FIRM, there is a small area upstream of Argyle Way, on
Panel 0038, that is shown as “Zone AO (Depth 2’),” indicating that the base flood
depth is two feet above the ground. Therefore, it is a sheet flow area. Sheet flow
areas (which usually have depths established) are AO Zones, and ponding areas
(which have BFEs established) are usually designated AH Zones on a FIRM.
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E. APPROXIMATE STUDIES
Detailed studies are expensive — a riverine study typically costs $5,000 to
$10,000 per mile of stream that is to be mapped — so it is not cost effective to
perform a detailed study in watersheds where there is little or no development and
none is anticipated, such as in rural areas.
Therefore, some NFIP maps show floodplains that were mapped using
approximate study methods. Flood data and floodplain information from a variety
of sources — such as soils mapping, actual high water profiles, aerial photographs
of previous floods, and topographic maps — were used to overlay the
approximate outline of the base floodplain for specific stream reaches on
available community maps, usually U.S. Geological Survey topographic
quadrangle maps.
In addition, many flooding sources have been studied by other Federal, State,
or local agencies. Some of these studies do not meet the NFIP standards for a FIS,
but often contain valuable flood hazard information, which may be incorporated
into the NFIP maps as approximate studies. Those types of studies typically cover
developed or developing areas. They often contain flood elevation profiles that
can be used as “best available data” for floodplain management purposes.
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F. NFIP MAPS
This section will explain how flood hazards and flood insurance zones are
depicted on NFIP maps. The Flood County, USA and Incorporated Areas maps
will be referenced wherever possible. As this information is presented, look for
similar types of maps or map features on your community’s maps.
Maps published with an FIS are:
♦ The Flood Insurance Rate Map (the FIRM), which is published in an old
format in studies prepared before 1986 and a new format in studies
prepared after 1986.
♦ The Flood Boundary and Floodway Map (the FBFM or Floodway Map),
which was included in studies prepared before 1986.
♦ Again, since 1986, the Flood Boundary and Floodway Map information
has been incorporated into the Flood Insurance Rate Map.
The maps allow you to identify SFHAs, determine the location of a specific
property in relation to the SFHA, determine the BFE at a specific site, locate
regulatory floodways, and identify undeveloped coastal barriers where flood
insurance is not available.
The flood maps, particularly the FIRMs, come in many formats because of the
mapping of additional hazards, the need for more regional flood maps, and the
increased use of computer generated maps. Several general features are included
on all maps.
Originally, the FIRMs were designed for use by insurance agents and lenders.
The Floodway Maps were created for use by local floodplain managers and
administrators. For all studies conducted since 1986, the FIRM contains both the
flood insurance rate zones and floodways.
GENERAL MAP FEATURES
Flood maps are either flat or Z-fold. Flat maps are on 11-inch-by-17-inch
“ledger” size paper. Z-fold maps are on larger pages and get their name from the
way they are folded. The current flood maps for most communities are now Z-
fold.
Your packet includes the FIRM panels for Flood County, USA and
Incorporated Areas, which are Z-fold maps.
All flood maps are prepared with general features or elements that may
include an index, a legend (or key to map), a title block, community name and
number information, panel or map number information, an arrow pointing north
on the map, and effective date or revision date information.
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Many communities, especially counties, are geographically too large to fit on
one map or panel at a usable scale. Maps for these communities are divided into
two or more panels with unique panel numbers. Whenever a community requires
more than one panel, a Map Index for both the FIRM and Floodway Map is
prepared.
In this section, we will discuss the Map Index, elevation reference marks, and
map scales and direction. Other map features will be presented as we discuss
FIRMs and Floodway Maps.
MAP INDEX
The Map Index shows the community’s boundaries, highlighting prominent
features such as major highways, railroads, and streams. The map index shows
how the community is displayed on the various panels.
Flood County’s Map Index shows that the county’s FIRM has three panels,
0025, 0038, and 0040. In cases where panels have no identified flood hazard areas
(or no floodways on a Floodway Map), they are not printed. Note that panel
0030 D was not printed, as is indicated on the index by an asterisk (*).
The number of panels that have been printed for a particular community
appears in the title block (“Panels Printed: 25, 38, 40).
Title block
The title block is the lower right portion of the opened map for both the Map
Index and the FIRM panels. The FIRM panel title block includes:
♦ the community’s name -- Flood County, USA and Incorporated Areas,
♦ the six-digit community identification number or map number -- 99009C,
♦ the panel number, such as “0025,” “0038,” or “0040,”
♦ a map panel suffix – “D,” which indicates the number of revisions that
have been made (e.g., “D” is the fourth publishing of that panel), and
♦ a map effective or revision date – “August 19, 1998.”
Map revision date
The date in the title block shows the map’s most recent revision. As changes
occur within a community that results in a change in flood elevations or
floodplain delineations, FEMA republishes only the Map Index and the changed
map panels. Any revised panels are given a new map revision date and a new
suffix letter.
Once the panels are issued to the community, the date on the panel is referred
to as the effective date. Some communities have map panels with different
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effective dates. The Map Index lists the current effective date for the most
recently revised panel of a FIRM or of the FIRM itself, if all panels were revised.
With each revision comes a new panel suffix. Note that Flood County’s panels
were last revised in 1998 and have the suffix “D.”
Map scales and north direction
Different scales may be used for a single community with more than one
panel. As an example, the map scale on the Flood County FIRM Panel 0038 is 1
inch = 500 feet (one inch equals 500 feet), and the scale of panel 40 is 1 inch =
1,000 feet.
Different scales are used on FIRM and
Floodway Maps, depending on the size of the
mapped area for a community and the base map
that is used. Picture of approximate scale
An arrow pointing north is shown on all maps, including the map index. For
FIRMs and Floodway Maps, the north direction arrow is located near the map
scale. The north direction on the maps may be “turned” to maximize the mapped
area that can be shown on a panel and to minimize the number of panels. To
ensure correct orientation and accurate use of the FIRM, it is very important to
pay attention to the direction of the north arrow on the panel.
Elevation reference marks
Elevation reference marks are located on FIRMs and Floodway Maps. For
these two types of maps, locations are identified with a small “x” and the
designation “ERM” or “RM” simply followed by a reference mark number. For
the newer Digital FIRMs (DFIRMs), locations are identified with a small “x” and
the designation “ERM” or “RM” followed by the panel number and the number of
the reference mark. Descriptions of the marks,
including their elevations, appear either on
FIRM panels, on Floodway Maps, or in the
FIS text. Note that some ERM and RM
descriptions may appear on a different map
panel than the mark itself due to space
limitations.
ERMs and RMs are important sites. They provide a ground elevation
reference for surveyors to start from when they determine the elevation of a
building, a cross, section, or topography for a site. Occasionally, an ERM cannot
be found as described on the FIRM or Floodway Map because new construction
or some other change in the area has obliterated the monument. In these instances,
the next closest ERM may be used. Alternatively, USGS, USC&GS, or NGS
bench marks, which are marked on most USGS 7.5 minute series topographic
maps, may be used. Picture showing reference marks
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FIRM Zones
FIRMs show different floodplains with different zone designations. These are
primarily for insurance rating purposes, but the zone differentiation can be very
helpful for other floodplain management purposes. The more common zones are
listed in Figure 3-10.
Zone A
The 100-year or base floodplain. There are six types of A Zones:
A
The base floodplain mapped by approximate methods, i.e., BFEs are
not determined. This is often called an unnumbered A Zone or an
approximate A Zone.
A1-30
These are known as numbered A Zones (e.g., A7 or A14). This is the
base floodplain where the FIRM shows a BFE (old format).
AE
The base floodplain where base flood elevations are provided. AE
Zones are now used on new format FIRMs instead of A1-A30 Zones.
AO
The base floodplain with sheet flow, ponding, or shallow flooding.
Base flood depths (feet above ground) are provided.
AH
Shallow flooding base floodplain. BFEs are provided.
A99
Area to be protected from base flood by levees or Federal Flood
Protection Systems under construction. BFEs are not determined.
AR
The base floodplain that results from the decertification of a
previously accredited flood protection system that is in the process of
being restored to provide a 100-year or greater level of flood
protection.
Zone V and
V
The coastal area subject to a velocity hazard (wave action) where
VE
BFEs are not determined on the FIRM.
VE
The coastal area subject to a velocity hazard (wave action) where
BFEs are provided on the FIRM.
Zone B and
Zone X
(shaded)
Area of moderate flood hazard, usually the area between the limits of the 100
year and 500-year floods. B Zones are also used to designate base floodplains
of lesser hazards, such as areas protected by levees from the 100-year flood, or
shallow flooding areas with average depths of less than one foot or drainage
areas less than 1 square mile.
Zone C and
Zone X
(unshaded)
Area of minimal flood hazard, usually depicted on FIRMs as above the 500-
year flood level. Zone C may have ponding and local drainage problems that
don’t warrant a detailed study or designation as base floodplain. Zone X is the
area determined to be outside the 500-year flood and protected by levee from
100-year flood.
Zone D
Area of undetermined but possible flood hazards.
Figure 3-10: Flood Insurance Rate Map Zones
Note that the special Flood Hazard Area (SFHA) includes only A and V Zones.
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FLOOD HAZARD BOUNDARY MAP (FHBM)
FHBMs (Figure 3-18) were initially prepared to provide flood maps to many
communities in a short period of time. They were made in the 1970s and early
1980s without benefit of detailed studies or hydraulic analyses for nearly all
floodprone communities in the nation (over 21,000). They were intended for
interim use in most communities until more detailed studies could be carried out.
FHBMs are still being used where detailed Flood Insurance Studies have not
been prepared or cannot be justified. They are to be used for floodplain
management, in conjunction with other local studies and other available data.
On the FHBM, the SFHA is designated as a shaded area labeled “Zone A,”
and no base flood elevations are given (see Figure 3-18). Figure 3-18: Flood haza
Figure 3-18: Flood Hazard Boundary Map
In some cases, FEMA simply converted the FHBM to a FIRM by issuing a
letter to the community stating that the FHBM shall be considered a FIRM. In
those cases, the community was instructed to line out FHBM on the map’s title
box and write in FIRM.
FLOOD INSURANCE RATE MAP (FIRM) — OLD FORMAT
(PRE 1986)
The FIRM is used to generally determine:
♦ Whether a property is in the floodplain.
♦ The flood insurance zone that applies to the property.
♦ The approximate base flood elevation (BFE) at the site.
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Date: Several dates may be listed in the FIRM legend, including:
♦ Initial Identification — date of the first Flood Hazard Boundary Map
(FHBM).
♦ Any dates of revisions to the FHBM that have occurred since the initial
identification.
♦ Flood Insurance Rate Map Effective — the date of the initial or first
FIRM. This is the date used to determine whether a building is “pre-
FIRM” or “post-FIRM.”
♦ Flood Insurance Rate Map Revisions — dates of subsequent revisions to
the FIRM.
The FIRM also will show:
Base (100-year) floodplain or SFHA: Designated by the dark-shaded areas
(Insurance Zones A, A1–A30, A99, AO, AH, AR, V, V1–V30).
500-year floodplain:
Designated by the lighter-shaded areas (Insurance
Zone B).
Base Flood Elevation (BFE): The water surface elevation of the base flood
at that point of the stream is denoted in whole numbers by wavy lines running
across the floodplain. Coastal Zones within the area of 100-year tidal flooding, as
well as some AH Zones, may have BFE lines, and some lake AE Zones have the
base flood elevation noted in parentheses beneath the zone designations.
Zone break line (Gutter line): The thin white line separates flood insurance
rate zones within the 100-year floodplain.
Approximate floodplain areas: The 100-year floodplain areas are delineated
using approximate methods. No BFEs are shown in approximate floodplain areas;
these areas are classified as (unnumbered) A Zones.
An example of an approximate floodplain may be found in the upper left
corner of Flood County FIRM Panel 0040, on Rocky River. The detailed study
does not extend upstream of cross section K. Note that there are no cross sections
or BFEs shown in this A Zone, which extends onto Panel 0025.
FLOOD BOUNDARY AND FLOODWAY MAP (FLOODWAY
MAP) – OLD FORMAT (PRE 1986)
The Flood Boundary and Floodway Map is also known as the FBFM or,
simply, the Floodway Map. The Floodway Map shows how the floodplain is
divided into the floodway and flood fringe where streams are studied in detail.
They also show general floodplain areas where floodplains have been studied by
approximate methods.
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Floodway Maps have these features:
Title block: Includes the community name, county name, panel number,
community number, and the map date. The panel numbers may be different from
the FIRM panel numbers.
Map scale: The Floodway Map may have the same or a different scale than
the FIRM for the same community.
Cross section line:
These lines represent the location of some of the
surveyed cross sections used in the computer model of the stream for calculating
100-year flood elevations. These cross sections can be used to relate a specific
point on the Floodway Map to the flood profile and floodway data table.
Floodway: The 100-year floodplain has been divided into two areas, the
floodway and the flood fringe. The white area adjacent to and including the
channel is the floodway. The shaded
area is the fringe.
One problem with this method of
delineating
floodways
is
that
sometimes people confuse the white
floodway
with
the
white
area
representing land that is free from
flooding.
Also,
because
the
floodway is mapped separately,
often property owners, lenders, real
estate agents, and others do not have
easy access to the Floodway Maps
and do not know of the severe flood
hazard associated with the floodway.
FISs published since 1986 have corrected this problem — they do not have
separate FIRM and Floodway Maps. Floodways are delineated on the newer
FIRMs as a diagonally hatched area (see Figures 3-11 and 3-12).
Note that no BFEs or flood zone names are shown on the Floodway Map.
The floodway is usually wider in flatter, wider floodplains and narrower in
steeper areas where floodplains are narrower.
If a map panel area does not include any detailed study streams or floodways,
a Floodway Map will not be printed; only a FIRM panel will be printed. Because
coastal studies do not have floodways, all of the data needed are shown in the FIS
report and on the FIRM.
Flood fringe: The fringe is shown as a shaded area outside of the floodway
but still within the 100-year floodplain. The flood fringe and the floodway
together comprise the special flood hazard area. Example of a Key to Map
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500-year floodplain: More lightly shaded areas adjacent to, but outside of,
the 100-year floodplain delineate the 500-year floodplain for streams studied in
detail.
Approximate floodplain areas:
The 100-year floodplain areas are
determined using approximate methods. The boundaries of the approximate
floodplain on the Floodway Map are shown as dashed lines.
FLOOD INSURANCE RATE MAP — NEW FORMAT (SINCE
1986)
Flood maps have been redesigned over the years since the first FISs were
prepared in the late 1960s, making them easier to use. A new format for FIRMs
was introduced in 1986 that includes:
♦ Floodways and other floodplain management information, such as cross
sections, that were previously provided on separate Flood Boundary and
Floodway Maps (Floodway Maps). (Except in a few instances, Floodway
Maps are no longer being prepared.)
♦ Simplified flood insurance zone designations. The previous Zones A1-A30
and V1-V30 were replaced by the designations AE and VE; Zones B and C
were replaced by Zone X. The 500-year floodplain is still shown as “shaded”
portions of Zone X.
Figure 3-11 shows the legend for the new FIRM format. Figure 3-12 is an
example of a new format FIRM with a floodway. With these changes, the FIRMs
are more easily used by community officials for floodplain management, by
lenders to determine the need for flood insurance, by insurance agents to rate
policy applications, and by land surveyors, engineers, property owners and others
to determine flood hazards in a given location. The Flood County, USA and
Incorporated Areas map uses the newer format.
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Figure 3-11: New format FIRM legend
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Figure 3-11: New format FIRM legend
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Figure 3-12: Floodway in new FIRM format
PARTIAL MAP INITIATIVES FIRM
In some cases, it is more cost efficient for FEMA to update and print only a
portion of the total FIRM and FBFM panels for a community in the new format.
This is referred to as Partial Map Initiatives FIRM. Here, instead of printing the
entire set of separate FIRM and FBFM panels for the community, only those
panels affected by the revision elements are combined into the new format FIRM
panel. To clarify this for the community, the FBFM index would show that those
FBFM panels were no longer printed and that the floodway mapping information
would appear on the new format FIRM showing that same area. The FIS report
would also indicate on the Notice to User Page the combination of FIRM and
FBFM panels and the differentiation between the old and new format zone
labeling.
FIRMS WITH COASTAL AND LAKE FLOODPLAINS
Coastal FIRMs
Coastal areas include the shores of the Atlantic and Pacific Oceans, the Gulf
of Mexico and the Caribbean Sea, and inlets subject to tides. They also include
the shorelines of the Great Lakes.
Coastal high hazard areas subject to flooding and wave action of three feet or
more are designated as V Zones. The number in parentheses after or below the V
Zone designation is the BFE. There are several V Zones on Panel 0040 of Flood
County FIRM.
Coastal Barrier Resources System
Undeveloped portions of coastal barrier islands and similar land forms in the
Coastal Barrier Resources System (CBRS) — such as coastal mainland along the
shore of the Great Lakes, along bays, inlets, or estuaries — have been identified
and included on applicable map panels. They are called CBRA areas, established
by the Coastal Barrier Resources Act of 1982 and the Coastal Barrier
Improvement Act of 1990.
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The Acts provide protection to CBRA areas by prohibiting most expenditures
of federal funds including the provision of flood insurance for new and
substantially improved buildings in the mapped area. The restrictions are covered
in more detail in Unit 9, Section D.
The designations for these undeveloped coastal barriers depend on when they
were designated by the acts; therefore, not all CBRA areas have the same date of
designation. Examples of the three different screens used on the FIRM are shown
in the legend for Flood County FIRM Panel 0040. The prohibition date is
indicated for each CBRA zone on the FIRM. It should be noted that although
FEMA shows CBRA areas on its FIRMs, only Congress can authorize a revision
to their boundaries.
Flood County has an extensive CBRA area, which appears on FIRM Panels
0038 and 0040. Note that the designation and delineation of CBRS units are not
directly related to the floodplain.
Lakes
Most lakes have a BFE, shown in parentheses below the flood zone that has
been rounded off to the nearest whole number (see Figure 3-13). The actual BFE,
to the nearest tenth of a foot, can be obtained from the FIS report. However, many
long lakes, especially reservoirs, have a higher BFE at the upstream end than at
the outfall. These types of lakes and reservoirs have BFEs shown with wavy lines,
the same as riverine BFEs. They also appear on the stream profiles in the FIS
report. Figure 3-13: FIRM with lake floodplain
Figure 3-13: FIRM with lake floodplain
Where studies have been carried out for lakes and reservoirs, information on
BFEs is contained in Section 3.0 of the FIS report. A Summary of Stillwater
Elevations table is provided in the FIS report (Figure 3-14). Note that the actual
BFEs to the nearest one-tenth of a foot appear in the table, but the BFE on the
FIRM is shown in parentheses rounded to the nearest whole number. For the most
accurate BFE, use the “100-year flood elevation” from the table, not the FIRM.
For a shortcut method, you can add 0.4 foot to the elevation shown on the FIRM.
This will get you an elevation at least as high as the number shown in the table.
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FLOODING SOURCE
AND LOCATION
10-YEAR
ELEVATION (ft. NGVD)
50-YEAR
100-YEAR
500-YEAR
STONE LAKE
Entire shoreline within Flood
County
7.0
9.0
10.2
12.8
Figure 3-14: Summary of stillwater elevations for a lake
SHALLOW FLOODING FIRMS
Under the NFIP, ponding or sheet flow constitutes shallow flooding, which is
mapped based on historic flood experiences and study of the topography.
An example of a shallow flooding area is on the Flood County FIRM, panel
0038, upstream of Argyle Way, in an area marked “Zone AO (Depth 2’).” Also,
Panel 0040 shows an area where wave runup overtops and ponds behind a
seawall, berm, or other feature that keeps the water from flowing back to the
ocean.
We don’t know how high the base flood is in relation to sea level in Flood
County “Zone AO (Depth 2’).” However, we do know that the base flood should
be no deeper than two feet above the ground.
FIRMS WITH FLOOD PROTECTION PROJECTS
Some FIRMs may show areas protected from flooding by the 100-year flood
because of the presence of a levee, concrete dike, floodwall, seawall, or other
structure. These areas are usually designated as shaded Zone X and marked with
the following note:
♦ This area protected from the 100-year flood from (Flooding Source Name)
by LEVEE, DIKE, or other structure subject to failure or overtopping
during larger floods.
♦ This is an indication that the flood protection structure has either been
evaluated and found to meet all of the NFIP requirements for flood control
structures, or has been certified by a Federal agency with levee design
responsibility as having been adequately designed and constructed to
provide protection from the 100-year flood.
♦ Floodways will be delineated at the landside toe of a levee that is
recognized as providing 100-year flood protection.
♦ A levee that provides a lower level of protection, and that is not certified
or does not meet the requirements for levees, may be shown on the FIRM,
and flood elevations are computed as if the levee did not exist.
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COUNTYWIDE FIRMS
The Flood County FIS report and FIRM covers the unincorporated areas of
Flood County and all incorporated areas within Flood County. Therefore, it is
referred to as a countywide FIRM. Countywide FIRMs show flood hazard
information for all geographic areas of the county, including other jurisdictions
such as villages, towns, and cities.
Previously, FHBM, FIRM and FBFM maps were prepared separately for each
jurisdiction. County FIRMs, for example, showed the flood hazards identified
only in the unincorporated areas of the county and did not show any flood
information inside the corporate limits of a municipality. In countywide mapping,
once the countywide map is produced, all of the identified flood hazard areas
within the boundaries of the county are shown on one set of maps along with all
floodway information maps (see section titled Flood Insurance Rate Map—New
Format).
The countywide FIRM format has a number of advantages, and one in
particular is that the user can see the relationship and simultaneous effect of each
floodplain on a number of communities. In addition, FIRMs do not need to be
updated when municipal boundaries change. Although boundaries might change,
communities will continue to find the flood hazard information they need on the
same countywide FIRM.
Figure 3-15 shows the title block of a countywide FIRM panel. The title block
lists the communities mapped on that panel and their six-digit NFIP community
ID numbers. The FIRM panel has a map number with five digits consisting of the
NFIP-assigned state number as the first two digits and the NFIP-assigned county
number as the next three digits followed by the letter “C,” which stands for
“countywide,” and then the four digit panel number and suffix. Do not confuse
the map panel number with the community number.
All previous map dates for each floodprone community in a countywide FIS
are located on the community map history Table (Figure ).The initial FIRM date
for each community is shown on the FIRM index. These are the “post-FIRM”
dates for insurance rating. Don’t confuse them with the effective date of the latest
FIRM panel, which is shown in the title block.
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Figure 3-15: Title block of countywide FIRM panel
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DIGITAL FIRMS
The conversion of FIRMs to a digital format has many benefits. For example,
they can be revised and updated easily with just a few keystrokes, and they can be
incorporated in the community’s mapping system and tied in with other
geographic information systems, such as the zoning map.
Users must bear in mind that the simple conversion of FIRMs to a digital
format does not inherently improve the engineering quality of the product. Many
of the same difficulties with interpretation of flood risk data — and the
requirement that users apply sound judgment in methods selected for decision
making and map interpretation — remain unchanged.
FEMA charges a fee for all digital FIRM data products. Any questions
regarding these products may be directed to:
Federal Emergency Management Agency
Map Service Center
P.O. Box 1038
Jessup, Maryland 20794-1038
Phone: 800/358-9616
Fax: 800/358-9620
Internet: http://www.fema.gov
Digital Flood Insurance Rate Map (DFIRM)
The FIRM for Flood County, USA and
Incorporated Areas is actually a Digital
Flood Insurance Rate Map, or DFIRM. This
is because it is a more recent publication,
created with new digital methods; however,
whether the maps are new DFIRMs or
conventional FIRMs, they are still generally
referred to as FIRMs. The DFIRM is
comprised of all digital data required to
create the hardcopy FIRM. These data
include base map information, graphics, text,
shading, and other geographic and graphic
data. An example of a hardcopy paper
DFIRM is shown in Figure 3-16. Figure 3-16: Hardcopy DFIRM
Figure 3-16: Hardcopy DFIRM
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The majority of DFIRMs are produced in a countywide format, where all
flood hazards for the county and incorporated communities are shown on one set
of maps. It can be used for floodplain management purposes in a manner similar
to other flood maps, but it can also be combined with other digital map
information to create new information for planning purposes. DFIRMs are also
produced for single jurisdictions when producing a countywide map would not be
cost effective.
Digital Flood Insurance Rate Map – Digital Line Graph
The Digital Flood Insurance Rate Map - Digital Line Graph (DFIRM-DLG) is
intended to be the primary means of transferring flood-risk data depicted on
FIRMs to Geographic Information Systems (GIS). GISs are computer-based map
systems that allow the user to keep a map updated easily and to correlate
geographic information with other data, such as tax records on properties.
The Digital Flood Insurance Rate Map - Digital Line Graph (DFIRM-DLG) is
a database created by extracting certain flood risk data from the DFIRM. The
DFIRM-DLG does not include base map information, nor does it include graphic
data required to create a hardcopy FIRM.
Communities whose digital base mapping files were used as the base map for
the DFIRM will find that they may easily use the DFIRM-DLG files for determi-
nation of flood zones and for enforcement of regulations. A graphic image of a
DFIRM-DLG is shown in
Figure 3-17.
The digital data captured
from the hardcopy DFIRM
consists
of
FEMA
hydrography (location of water
bodies), flood hazard zones,
BFEs, cross-section locations,
and elevation reference marks.
All lines and area features
in DLG files are encoded with
one
or
more
seven-digit
attribute codes that provide the
user with detailed information
about the features. FEMA
intends to make the DFIRM-
DLG available on CD-ROM Figure 3-17: Graphic image of a DFIRM-DLG
compatible with Insurance
Figure 3-17: Graphic image of a
DFIRM-DLG
Services Office (ISO) 9660
standards.
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With many commercially available GIS software packages, DLG data can be
directly converted into vector data usable within the GIS environment. Third-
party conversion software is also available that will convert DLG data to other
proprietary GIS formats.
The DFIRM-DLG, when coupled with digital base map files or the local
community digital base, can be used in a GIS to determine whether a structure is
located within an SFHA. It should be noted that if a GIS is used to determine that
a structure is within or near an SFHA, and a different base map source was used
to generate the hardcopy DFIRM, the determination should be confirmed by
referencing the printed hardcopy DFIRM.
Q3 Flood Data
In the Q3 Flood Data Product, FEMA has developed a graphical
representation of certain features of the FIRM. The Q3 Flood Data are in three
formats that are usable with desktop mapping and GIS software packages. These
formats are:
♦ Digital Line Graph
♦ ARC/INFO
♦ MapInfo
Q3 Flood Data are created by digitally capturing certain key features from the
current effective paper FIRMs. These features are converted into area features in
one countywide data layer. The following vectorized (lines and areas) data
features are included:
♦ SFHA and 500-year floodplain,
♦ Flood insurance zone designations,
♦ Floodway boundaries (if available),
♦ COBRA zones,
♦ Political boundaries,
♦ Community/map panel identification numbers,
♦ Boundaries between FIRM panels, and
♦ U.S. Geological Survey 7.5 minute (1:24,000 scale) quadrangle neatlines.
Several features are not included. They are:
♦ Hydrographic features,
♦ Base flood elevations,
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♦ Cross section lines,
♦ Roads, road names or address ranges, and
♦ Elevation reference mark locations and elevations.
Q3s were developed to support insurance-related activities and are designed to
provide guidance and a general proximity of the location of SFHAs. Q3s do not
replace paper FIRMs as the legal document.
The data are not suitable for applications such as detailed site design and
development plans or flood risk determinations. They cannot be used to determine
absolute delineations of floodplain boundaries, but instead should be seen as
portraying zones of uncertainty and possible risks associated with flooding.
Q3 Flood Data incorporate map revisions and letters of map revision and
amendment. However, they do not correct for edge-matching errors, overlaps,
etc., that were in the original paper FIRMs.
FEMA has produced Q3s for almost 900 counties nationwide. They are
organized by county and contain data from all existing paper FIRM panels for the
incorporated and unincorporated areas of the county.
Q3 Flood Data are available on CD-ROM from the FEMA Map Service
Center. You can access the list of Q3 counties on the Internet and download
sample data, data standards, and other Q3 information (http://www.fema.gov).
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UNIT 4:
USING NFIP STUDIES AND MAPS
In this unit
This unit covers how to use the materials introduced in Unit 3:
♦ How to find and use the data provided in a Flood Insurance Study
♦ How to find a site on a flood map
♦ How to obtain flood elevations from a profile
♦ How to keep the maps and data up-to-date over the years
Materials needed for this Unit
♦ Flood Insurance Study, Flood County, USA, and Incorporated Areas
♦ Flood Insurance Rate Map, Flood County, USA, and Incorporated
Areas
♦ Engineer’s scale
♦ Additional information can be found in Answers
to Questions About the National Flood Insurance
Program, questions 81 – 95.
Using NFIP Studies and Maps
4-1
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Contents
A. Using FIS Reports....................................................................................................... 4-3
FIS Report Contents............................................................................................. 4-3
Using Flood Data and Tables............................................................................... 4-4
Flood discharges ...................................................................................... 4-4
Floodway Data Table............................................................................... 4-5
Coastal and Lake Elevations................................................................................ 4-6
Relating Report Data to Maps and Profiles ......................................................... 4-7
B. Using the Flood Maps ................................................................................................. 4-9
Locating a Site ..................................................................................................... 4-9
Determining Stationing...................................................................................... 4-10
Base Flood Elevations from Maps..................................................................... 4-11
Locating the Floodway Boundary...................................................................... 4-11
C. Using Profiles............................................................................................................ 4-13
Profile Features .................................................................................................. 4-13
Determining Base Flood Elevations .................................................................. 4-14
Profiles ................................................................................................... 4-14
Other types of floodplains...................................................................... 4-15
Relating flood elevations to the ground................................................. 4-15
Relating Profiles to Maps................................................................................... 4-16
D. Maintaining and Revising NFIP Maps...................................................................... 4-17
Ordering Maps ................................................................................................... 4-17
Changing NFIP Maps ........................................................................................ 4-17
Types of Changes............................................................................................... 4-19
Maps and Letters................................................................................................ 4-20
Requesting Map Changes .................................................................................. 4-22
Using NFIP Studies and Maps
4-2
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A. USING FIS REPORTS
The majority of Flood Insurance Study (FIS) reports use the same outline and
numbering system. In this section, we will highlight the report’s contents; explore the
report’s data, tables, and profiles; and describe how they are related to the Flood
Insurance Rate Map (FIRM) and Floodway Map.
The most important reason for using a FIS report, in conjunction with a Floodway
Map and/or a FIRM, is to determine whether or not a site is located in a Special Flood
Hazard Area (SFHA), a V Zone, and/or a floodway, and to determine the Base Flood
Elevation (BFE).
Important: Because the elevation determinations for riverine or coastal floodplains are
typically used to establish flood elevations for construction in SFHAs and other purposes,
accuracy is critical. You may want to have another person double check your
determinations before using them in the permit application process.
FIS REPORT CONTENTS
The Flood County FIS report cover has an
outline map. Note that the location of Flood County
is pinpointed on the outline map. The date of the
FIS and the community identification numbers are
also indicated on the cover page.
Section 1.0 of all FIS reports states the purpose
of the FIS, authority of and acknowledgments by its
authors, and coordination steps taken during the
preparation of the study.
Section 2.0 provides background information on
the community, its flood problems, which areas
were studied, and what flood protection measures
are in effect.
Section 3.0 discusses the engineering methods
used. Section 3.1 covers the hydrologic analysis — how much water will flow through
the floodplain during peak floods. Section 3.2 describes the hydraulic analysis — how
high the water will get. Development of this information was described in Unit 3. Picture of Flood Insurance Study cover p
Section 4.0 discusses how the flood map was prepared from flood data for floodplain
management applications. Section 4.1 covers mapping the floodplain boundaries —
where the water will go. If the study included a floodway determination, Section 4.2
describes the floodway study and mapping. Section 4.0 also includes the Floodway Data
Table. How to interpret and use these and other data is covered later in this unit.
Using NFIP Studies and Maps
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Table 3 Excerpt
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Section 5.0 covers data related to flood insurance, some of which you will not need to
use. This section can be a useful reference, as it describes the flood insurance zones
identified on the map.
Completing the FIS report are the following four sections: Section 6.0, Flood
Insurance Rate Map; Section 7.0, Other Studies; Section 8.0, Location of Data; and,
Section 8.0, Bibliography and References.
Most riverine FIS reports include flood profiles as an exhibit at the end of the
document. Coastal analyses include a map of transect locations and tables containing data
relating the transects to the stillwater and base flood elevations. The Flood County FIS
report has both.
USING FLOOD DATA AND TABLES
Flood discharges
Turn to Table 3, Summary of Discharges, in Section 3.1 on page 9 of the Flood
County FIS report. An excerpt from that table is shown below (Figure 4-1).
Figure 4-1: Flood County, FIS Report Table 3 - Summary of Discharges
Figure 4-1 (Table 3 – Summary of Discharges) summarizes the peak amount of water
discharge for various flood frequencies at locations within the study area. The hydrologic
study procedures for arriving at these amounts were discussed in Unit 3, Section B. The
sizes of the drainage areas (watersheds) contributing to the water runoff producing the
floods are also shown in the table.
The 100-year flood discharge for Cobb Brook at its confluence with the Rocky River
is 1,080 cubic feet per second (cfs). This means that during the peak of the base or 100-
year flood 1,080 cubic feet of water will pass this point each second.
Those administering the local ordinance may never have a need for these data. They
are, however, important in making subsequent calculations of flood elevations as part of
the hydraulic engineering study.
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Floodway Data Table
The Floodway Data Table in Section 4.2 of the FIS report presents data from the
hydraulic analysis (Table 6, page 17 in the report). Part of this table is reproduced below
(Figure 4-2). Reproduction of portion of Floodway data table
Figure 4-2: Flood County, USA, FIS Report Table 6 - Floodway Data
All numbers in the table are calculated at each floodplain cross section. The first two
columns under “Flooding Source” identify the stream name and the cross sections used in
the FIS, and the distance of the given cross section from some reference point, usually the
mouth of the flooding source, a corporate limit, or a county boundary. The footnotes at
the bottom of the Floodway Data Table identify this reference point.
The locations of these cross sections are shown on the accompanying FIRM and
Flood Profile (unless otherwise indicated on the Floodway Data Table). Cross-section A
of the Rocky River is approximately 500 feet below (or downstream of) Glebe Way. You
can find cross-section A on FIRM panel 38. It is the line that crosses the Rocky River and
has the letter “A” in a hexagon at each end.
Remember that a floodway’s width usually is not symmetrical; it varies with the
topography at each cross section. The next three columns (“Floodway”) provide data at
each cross section. At cross-section A, on the Rocky River, the floodway is 115 feet
wide. This means that from the floodway boundary on one side of the stream of this cross
section to the floodway boundary on the other side of the stream is 115 feet. This is
useful for double-checking the width of the floodway portrayed on the FIRM.
Figure 4-3 is a representation of the description of cross-section A given in Table 6.
Using NFIP Studies and Maps
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Use the arrow keys to turn pagesFigur
Figure 4-3: Representation of cross-section A of the Rocky River
The cross sectional area of the floodway here is 1,233 square feet. This is the cross
sectional area of the floodway below the elevation of the base flood at this location (the
shaded area of Figure 4-3). The average or mean velocity of the base flood in the
floodway is 6.1 feet per second. This is an average velocity. Velocities will generally be
higher in the channel than in the over bank areas.
Of the last four columns under “Base Flood Water Surface Elevation,” you should be
primarily concerned with the first one, “Regulatory,” which provides the regulatory flood
elevation. This is equivalent to the 100-year flood elevation or BFE. The other columns
depict the increase in water-surface elevation if the floodplain is encroached upon so that
the water-surface elevation is increased no more than 1 foot. This amount of
encroachment is used to define the floodway width. Notice that no cross section has an
increase of more than 1.0 foot, in accordance with NFIP standards. Some States and
communities regulate to the “With Floodway” elevation to take into account possible
future increases in flood stage that will occur as the floodplain is developed.
COASTAL AND LAKE ELEVATIONS
Coastal flood elevations. Table 4, Transect Descriptions, on page 12 in the FIS
report for Flood County, shows the stillwater elevations and the maximum wave crest
elevations of 100-year flood events along the coast.
Coastal regulatory flood elevations include the increase due to wave height.
Therefore, use the BFE from the FIRM, not the stillwater elevations in the table.
The base flood elevations on the FIRM are rounded to the nearest foot, which means
that if a base flood elevation was actually 8.3 feet, it would show as 8 feet on the FIRM.
To correct for this, the recommended rule of thumb is to add 0.4 foot to the rounded BFE
on the FIRM. This makes sure that the regulatory elevation you use will be high enough.
For the coast, use the base flood elevation from the FIRM (plus 0.4 foot), not the
table.
Lake flood elevations. On inland lakes and reservoirs, the FIS generally does not
include the effects of waves. For these areas, information on base flood elevations is
contained in Section 3.0 of the FIS report, and data is presented in a table titled Summary
of Stillwater Elevations. Note that in this table the BFE is shown to the nearest one-tenth
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of a foot, but the BFE shown in parentheses on the FIRM is rounded to the nearest whole
number (Figure 3-13).
For lakes and reservoirs, use the base flood elevation from the table, not the FIRM.
RELATING REPORT DATA TO MAPS AND PROFILES
Unit 3 described the data that are developed and used in preparing an FIS for a
community. Each set of data is used for calculations needed to produce additional data
for the FIS.
The data contained in the FIS report are consistent with those found on the
accompanying profiles and FIRM. For example, the base flood water-surface elevations
at each identified cross section can be found in the Floodway Data Table, read from the
flood profiles, and interpolated from the FIRM. Within the limits of map accuracy, you
should obtain the same answer regardless of which source you use.
In the same way, the distances between cross sections, or their distance from some
reference, can be found using any or all of the above data sources. Again, the answers
should be about the same.
The elevations of the computed profiles contained in the FIS report are used with
ground elevation data to determine the limits of the various zones shown on the FIRM.
Again, flood elevations can be determined at any location along the studied stream using
either the flood profiles or the FIRM. All the data fit one another. If obvious mistakes are
found, please advise the FEMA Regional Office.
Note: Due to the limited detail and large scale of the base maps used for most
FIRMs, much interpolation between contour lines is done in mapping the floodplain
boundaries. This is why you may find discrepancies when actual ground elevations are
surveyed: the maps are just the best available graphic representations of the BFEs.
Here’s the order of precedence for identifying the BFE at a particular location:
♦ The most accurate BFEs are found in the Floodway Data Table (for a riverine
floodplain) and the Summary of Stillwater Elevations table (for a lake). These BFEs
are listed to 0.1 foot. However, the Floodway Data Table is only good for sites on or
next to a cross section.
♦ The next most accurate source of elevation data is the profile. This plot of the cross-
section data is difficult to read accurately.
♦ The least accurate source of elevation data for a riverine floodplain is the FIRM.
BFEs are rounded to the nearest whole foot. However, the FIRM is the only source of
base flood elevations for coastal floodplains and AO and AH Zones.
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BFEs take precedence if there is a dispute between the BFE and the boundaries of the
SFHA shown on the maps. As a local permit administrator, you can make your decisions
based on the most accurate source of data.
It must be noted that banks (and others who must read the FIRM to determine if flood insurance
is required) must go by the map. They cannot make on-site interpretations based on data other
than the FIRM. However, they may recommend that the property owner submit a request for a
Letter of Map Revision based on Fill (LOMR-F) or a Letter of Map Amendment (LOMA) so the
map can be officially changed to reflect the more accurate data (see Unit 4, Section D).
Again, only FEMA can amend or correct the maps. Discrepancies should be brought
to FEMA’s attention through a request for a map change, such as a Letter of Map
Amendment (LOMA) (see Section D in this unit).
Reading and using flood profiles, the last set of data contained in a Flood Insurance
Study report, will be covered in Section C of this unit.
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B. USING THE FLOOD MAPS
LOCATING A SITE
How easily you can locate a site on an NFIP map will depend on your familiarity with
properties in the community and with the scale of the flood maps.
For our exercise purposes here, the general location of the sites are shown on the
Flood County Map Index. The site is adjacent to the Rocky River, just downstream of the
corporate limits of Floodville. (Remember to check your north arrow. The top of the map
is not always north.)
To locate a site, follow these steps:
The steps for a site in Flood County are shown in italics. The general location of the sites
are shown on the Flood County Map Index. Site A is close to Floodville Lake.
♦ If your community has more than one map panel, use the map index to determine
which panel to use. Use map landmarks —highways, streets, or streams —to find the
site on the index.
The Map Index for Flood County shows the site adjacent to Floodville
Lake on panel 38.
♦ Find the area containing Floodville Lake on the map panel. Be sure the map panel is
the most recent one — compare its suffix letter with the suffix letter for that panel on
the current Map Index. Remember, in many communities, panels will have different
effective dates due to revisions that do not affect the whole community.
Floodville Lake is shown at the top right side of panel 38.
♦ If there is an asterisk on the panel number, either no flood hazard has been identified
in that area or it is entirely one flood zone and the panel was not printed.
See panel 30 on the Map Index for Flood County as an example.
♦ Locate the site as accurately as possible. Use a detailed street or road map as well as
the tax appraiser’s plat map to identify the property boundaries, if necessary. You will
probably have to obtain the distance on the ground between the site and one or more
identifiable points, such as the centerline of a road or street, a bridge, or some other
feature on the map. Locate these points on the flood map.
Site A is bounded to the north by Good Place, to the south by Kalef Lane,
beginning 200 feet west of Barclay Lane and extending west for 200 feet.
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♦ Convert the distance to the map scale and plot the site on the map.
Flood County FIRM panel 38 has a scale of 1 inch = 500 feet. This means
you should use the “50” scale on the engineer’s scale provided with this
course. Example: If you read a length of 5 on the scale, this would be
equivalent to 500 feet on the map.
DETERMINING STATIONING
In order to identify the BFE at a development site, the stream stationing for the site
must be determined. The stationing of a site will allow us to read the flood profiles. In
some cases stationing may be referred to as mileage.
♦ Locate Site B on the Flood County FIRM that shows cross sections. Identify which
labeled cross sections are nearest to your site, both upstream and downstream.
Site B is near Glebe Way adjacent to the Rocky River. It is located
approximately 100' south of the southern portion of Glebe Way and
approximately 350' west of the intersection of Foley Drive and Chris
Drive. Follow the steps in the previous discussion to locate this site on the
Flood County FIRM.
♦ Check the map scale used for the panel. The scale is in the map legend or key.
For Flood County panel 38 the map scale is 1 inch = 500 feet. Image of an engineer's scale
Use an engineer’s scale to measure the distance along the
stream from the site to the nearest cross section, following all
bends and curves of the stream. It would be worthwhile to
measure the distances to both cross sections to check accuracy.
Site B is approximately 650' downstream of cross-section B and
approximately 300' upstream (north) of cross-section A, East of the Rocky
River.
♦ If the stationing is based on mileage, convert these distances to miles by dividing by
5,280. In the case of Flood County, the stationing is based on feet.
When converting to miles, we lose a little accuracy. Rounding the
numbers, our site is 0.12 mile downstream of cross-section B and 0.06
mile upstream of cross-section A.
Keep these numbers in mind; they will be used shortly. This approach will also work
by measuring from another point that shows up on the profile, such as a bridge or
confluence with another stream.
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BASE FLOOD ELEVATIONS FROM MAPS
BFEs are shown on the FIRMs as whole numbers. For AE Zones, or coastal and lake
floodplains, use the BFE printed in parentheses below the flood zone designation. No
interpolation is necessary. The same holds true for AH Zones with whole number base
flood elevations.
The base flood elevation for properties in the vicinity of the Rocky River at
the confluence of Cobb Brook is 10 feet (NGVD or above mean sea level).
For other numbered AE Zones, read the BFE from the nearest wavy “base flood
elevation line.” Refer to the map legend or key if you are unsure of the line markings.
For the Site B example, the base flood elevations on the FIRM, are
marked “10,” above and below the site. If the site fell between the base
flood elevations of 10 and 11, such as the area north of Site B between
Glebe Way and Martling Way along the Rocky River, we could interpolate
to find a correct base flood elevation based on the distance of the site from
the base flood elevation lines. We could also locate the site on the profile
based on how far upstream or downstream it is from cross-section A or B.
Lastly, we could chose the higher base flood elevation, (e.g., 11) to best
ensure protection from flooding.
Zone A areas indicate approximate floodplain boundaries. No detailed study has been
performed to determine base flood elevations in these areas.
There are no base flood elevations in AO Zones with base flood depths. Instead, the
equivalent flood protection level is the number of feet shown in parentheses after the
“Zone AO.” This is not an elevation above sea level, it is the depth of flooding measured
above ground level. The zones are also described in the Flood County FIS report Section
5.0, page 18, Insurance Applications.
West of the intersection between Barclay Lane and Argyle Way on FIRM
panel 38 is a small Zone AO (Depth 2 feet). The base flood elevation for a
site in this zone would be two feet above the grade of any adjacent
building.
LOCATING THE FLOODWAY BOUNDARY
If the site is at a surveyed cross section, floodway width data from the Floodway Data
Table may be used as a more accurate measure than field and map measurements.
Remember that the width listed in the table is the distance from the floodway boundary
on one side of the stream to the floodway boundary on the other side of the stream.
If the floodway width measured on the map at that site is at a cross section, the map
should be used because it is the floodway officially adopted by the community. If there is
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a significant difference between the map width at the site and the closest cross section
width in the Floodway Data Table, contact the FEMA Regional Office for an
interpretation.
Most sites won’t fall conveniently on a cross section, so here are the steps using the
map as shown in the video:
♦ Locate Site C on the map and select the correct engineer’s scale for the map scale.
Site C is located between Floodville Lake and Barclay Lane on Flood
County FIRM panel 38. It is approximately 1,130 feet upstream of Argyle
Way, and approximately 230 feet east of the intersection of Good Place
and Barclay Lane. Image of engineer's scale
Using the engineer’s scale, measure the distance from the
floodway boundary to a nearby feature on the ground. For
streets, use the center of the street, both on the map and on the
ground.
The floodway boundary is approximately 105 feet from the intersection of
Barclay Lane and Good Place.
♦ If any portion of the building site, proposed grading, fill, bridge, or other obstruction
is determined to be within the floodway, the floodway provisions of your ordinance
also apply.
♦ Site C falls inside of the floodway.
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C. USING PROFILES
As discussed in Unit 3, Section B, a flood profile is a graph of computed flood
elevations at the floodplain cross sections. It can be used to determine elevations of
floods of various frequencies at any location along the studied stream.
PROFILE FEATURES
Four flood levels are typically shown on the flood profile fold-out sheets at the back
of the FIS report: the 10-, 50-, 100-, and 500-year (10%, 2%, 1%, and 0.2%) floods. Only
the 100- year flood is used for compliance with NFIP standards; the others are useful for
other floodplain management applications, such as septic system design and location,
bridge and culvert design, urban stormwater management, selecting sites for critical
facilities, and determining how frequently a site or facility will flood.
In addition to the flood elevation lines, FIS profile sheets contain:
♦ a plot of the stream bed elevation,
♦ the locations of the cross sections used in the FIS and shown on the FIRM (a letter
within a hexagon),
♦ the locations of roads, and
♦ culverts and bridges (usually depicted as a large “I”).
The data are plotted on a grid to facilitate their interpretation. With few exceptions,
the large grid squares are one inch on each side and are divided into 10 squares in both
directions. This grid pattern makes taking measurements much easier.
Refer to the profile for Cobb Brook at the back of the Flood County FIS report. The
bottom, or x-axis, shows the distance along the river in feet upstream of the confluence
with the Rocky River. For this profile, each large square is 200 feet and each little square
is 20 feet.
The left side, or y-axis, shows the elevation in feet NGVD. Each large square
represents 10 feet and each small square is 1.0 foot. Be aware that profiles in other FIS
reports may have different scales.
Figure 4-5 shows a sample of the data that are plotted on the profile shown for Cobb
Brook in Flood County. Before you look at it, measure the distance (in feet) and base
flood elevations from the profile for cross-sections A, B, and C.
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Cross section
Feet above
confluence with
Rocky River
100-Year
Flood elevation
A
1,080
10.14
B
1,880
23.8
C
2,600
31.1
Figure 4-5: Plotted Data, Flood Profile 01P, Cobb Brook
DETERMINING BASE FLOOD ELEVATIONS
Profiles
Here are the steps to determine the BFE for a site using the flood profiles in the FIS
report:
...[TRUNCATED FOR SIZE]...
s of the flood plain
boundaries and floodway.
(2) Changes affecting hydraulic conditions. The
following data shall be submitted:
(i) General description of the changes (e.g.,
channelization or new bridge, culvert, or levee).
(ii) Construction plans for as-built conditions.
(iii) New hydraulic analysis and flood elevation
profiles accounting for the effects of the changes
and using the original flood discharge values
upon which the original map is based.
(iv) Revised delineations of the flood plain
boundaries and floodway.
(3) Changes involving topographic conditions.
The following data shall be submitted:
(i) General description of the changes (e.g.,
grading or filling).
(ii) New topographic information, such as spot
elevations, cross sections grading plans, or
contour maps.
(iii) Revised delineations of the flood plain
boundaries and, if necessary, floodway.
(d)
Data
requirements
for
incorporating
improved data. Requests for revisions based on
the use of improved hydrologic, hydraulic, or
topographic data shall include the following
data:
(1) Data that are believed to be better than those
used in the original analysis (such as additional
years of stream gage data).
(2) Documentation of the source of the data.
(3) Explanation as to why the use of the new
data will improve the results of the original
analysis.
(4)
Revised
hydrologic
analysis
where
hydrologic data are being incorporated.
(5) Revised hydraulic analysis and flood
elevation profiles where new hydrologic or
hydraulic data are being incorporated.
(6) Revised delineations of the flood plain
boundaries and floodway where new hydrologic,
hydraulic, or topographic data are being
incorporated.
(e)
Data
requirements
for
incorporating
improved methods. Requests for revisions based
on the use of improved hydrologic or hydraulic
methodology shall include the following data:
(1) New hydrologic analysis when an alternative
hydrologic methodology is being proposed.
(2) New hydraulic analysis and flood elevation
profiles when an alternative hyrologic or
hydraulic methodology is being proposed.
(3) Explanation as to why the alternative
methodologies are superior to the original
methodologies.
(4) Revised delineations of the flood plain
boundaries and floodway based on the new
analysis(es).
NFIP Regulations
E-35
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(f) Certification requirements. All analysis and
data submitted by the requester shall be certified
by a registered professional engineer or licensed
land surveyor, as appropriate, subject to the
definition of ``certification'' given at Sec. 65.2 of
this subchapter.
(g) Submission procedures. All requests shall be
submitted to the FEMA Regional Office
servicing the community's geographic area or to
the FEMA Headquarters Office in Washington,
DC, and shall be accompanied by the
appropriate payment, in accordance with 44
CFR part 72.
[51 FR 30314, Aug. 25, 1986, as amended at 53
FR 16279, May 6, 1988; 54 FR 33550, Aug. 15,
1989; 61 FR 46331, Aug. 30, 1996; 62 FR 5736,
Feb. 6, 1997; 66 FR 22442, May 4, 2001]
§ 65.7 Floodway revisions.
(a) General. Floodway data is developed as part
of FEMA Flood Insurance Studies and is
utilized by communities to select and adopt
floodways as part of the flood plain management
program required by Sec. 60.3 of this
subchapter. When it has been determined by a
community that no practicable alternatives exist
to revising the boundaries of its previously
adopted floodway, the procedures below shall be
followed.
(b) Data requirements when base flood elevation
changes are requested. When a floodway
revision is requested in association with a
change to base flood elevations, the data
requirements of Sec. 65.6 shall also be
applicable.
In
addition,
the
following
documentation shall be submitted:
(1) Copy of a public notice distributed by the
community stating the community's intent to
revise the floodway or a statement by the
community that it has notified all affected
property
owners
and
affected
adjacent
jurisdictions.
(2) Copy of a letter notifying the appropriate
State agency of the floodway revision when the
State has jurisdiction over the floodway or its
adoption by communities participating in the
NFIP.
(3) Documentation of the approval of the revised
floodway by the appropriate State agency (for
communities where the State has jurisdiction
over
the
floodway
or
its
adoption
by
communities participating in the NFIP).
(4) Engineering analysis for the revised
floodway, as described below:
(i) The floodway analysis must be performed
using the hydraulic computer model used to
determine the proposed base flood elevations.
(ii) The floodway limits must be set so that
neither the effective base flood elevations nor
the proposed base flood elevations if less than
the effective base flood elevations, are increased
by more than the amount specified under Sec.
60.3 (d)(2). Copies of the input and output data
from the original and modified computer models
must be submitted.
(5) Delineation of the revised floodway on the
same topographic map used for the delineation
of the revised flood boundaries.
(c) Data requirements for changes not associated
with
base
flood
elevation
changes.
The
following data shall be submitted:
(1) Items described in paragraphs (b) (1) through
(3) of this section must be submitted.
(2) Engineering analysis for the revised
floodway, as described below:
(i) The original hydraulic computer model used
to develop the established base flood elevations
must be modified to include all encroachments
that have occurred in the flood plain since the
existing
floodway was developed. If the original
hydraulic computer model is not available, an
alternate hydraulic computer model may be used
provided the alternate model has been calibrated
so as to reproduce the original water surface
profile of the original hydraulic computer model.
The alternate model must be then modified to
include all encroachments that have occurred
since the existing floodway was developed.
(ii) The floodway analysis must be performed
with the modified computer model using the
desired floodway limits.
(iii) The floodway limits must be set so that
combined effects of the past encroachments and
the new floodway limits do not increase the
effective base flood elevations by more than the
amount specified in Sec. 60.3(d)(2). Copies of
the input and output data from the original and
modified computer models must be submitted.
(3) Delineation of the revised floodway on a
copy of the effective NFIP map and a suitable
topographic map.
(d) Certification requirements. All analyses
submitted shall be certified by a registered
NFIP Regulations
E-36
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professional engineer. All topographic data shall
be certified by a registered professional engineer
or licensed land surveyor. Certifications are
subject to the definition given at Sec. 65.2 of this
subchapter.
(e) Submission procedures. All requests that
involve changes to floodways shall be submitted
to the appropriate FEMA Regional Office
servicing the community's geographic area.
[51 FR 30315, Aug. 25, 1986]
§ 65.8 Review of proposed projects.
A community, or an individual through the
community, may request FEMA's comments on
whether a proposed project, if built as proposed,
would
justify
a
map
revision.
FEMA's
comments will be issued in the form of a letter,
termed a Conditional Letter of Map Revision, in
accordance with 44 CFR part 72. The data
required to support such requests are the same as
those required for final revisions under Sec.Sec.
65.5, 65.6, and 65.7, except as-built certification
is not required. All such requests shall be
submitted to the FEMA Headquarters Office in
Washington, DC, and shall be accompanied by
the appropriate payment, in accordance with 44
CFR part 72.
[62 FR 5736, Feb. 6, 1997]
§ 65.9
Review and response by the
Administrator.
If any questions or problems arise during
review, FEMA will consult the Chief Executive
Officer
of
the
community
(CEO),
the
community official designated by the CEO,
and/or the requester for resolution. Upon receipt
of a revision request, the Administrator shall
mail an acknowledgment of receipt of such
request to the CEO. Within 90 days of receiving
the request with all necessary information, the
Administrator shall notify the CEO of one or
more of the following:
(a) The effective map(s) shall not be modified;
(b) The base flood elevations on the effective
FIRM shall be modified and new base flood
elevations shall be established under the
provisions of part 67 of this subchapter;
(c) The changes requested are approved and the
map(s) amended by Letter of Map Revision
(LOMR);
(d) The changes requested are approved and a
revised map(s) will be printed and distributed;
(e) The changes requested are not of such a
significant nature as to warrant a reissuance or
revision of the flood insurance study or maps
and will be deferred until such time as a
significant change occurs;
(f) An additional 90 days is required to evaluate
the scientific or technical data submitted; or
(g) Additional data are required to support the
revision request.
(h) The required payment has not been
submitted in accordance with 44 CFR part 72,
no
review
will
be
conducted
and
no
determination will be issued until payment is
received.
[51 FR 30315, Aug. 25, 1986; 61 FR 46331,
Aug. 30, 1996, as amended at 62 FR 5736, Feb.
6, 1997]
§ 65.10 Mapping of areas protected by levee
systems.
(a) General. For purposes of the NFIP, FEMA
will only recognize in its flood hazard and risk
mapping effort those levee systems that meet,
and continue to meet, minimum design,
operation, and maintenance standards that are
consistent with the level of protection sought
through
the
comprehensive
flood
plain
management criteria established by Sec. 60.3 of
this subchapter. Accordingly, this section
describes the types of information FEMA needs
to recognize, on NFIP maps, that a levee system
provides protection from the base flood. This
information must be supplied to FEMA by the
community or other party seeking recognition of
such a levee system at the time a flood risk study
or restudy is conducted, when a map revision
under the provisions of part 65 of this
subchapter is sought based on a levee system,
and upon request by the Administrator during
the review of previously recognized structures.
The FEMA review will be for the sole purpose
of
establishing
appropriate
risk
zone
determinations for NFIP maps and shall not
constitute a determination by FEMA as to how a
structure or system will perform in a flood event.
(b) Design criteria. For levees to be recognized
by FEMA, evidence that adequate design and
operation and maintenance systems are in place
to provide reasonable assurance that protection
from the base flood exists must be provided. The
following requirements must be met:
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(1) Freeboard. (i) Riverine levees must provide a
minimum freeboard of three feet above the
water-surface level of the base flood. An
additional one foot above the minimum is
required within 100 feet in either side of
structures (such as bridges) riverward of the
levee or wherever the flow is constricted. An
additional one-half foot above the minimum at
the upstream end of the levee, tapering to not
less than the minimum at the downstream end of
the levee, is also required.
(ii) Occasionally, exceptions to the minimum
riverine freeboard requirement described in
paragraph (b)(1)(i) of this section, may be
approved. Appropriate engineering analyses
demonstrating adequate protection with a lesser
freeboard must be submitted to support a request
for such an exception. The material presented
must evaluate the uncertainty in the estimated
base flood elevation profile and include, but not
necessarily be limited to an assessment of
statistical confidence limits of the 100-year
discharge;
changes
in
stage-discharge
relationships; and the sources, potential, and
magnitude
of
debris,
sediment,
and
ice
accumulation. It must be also shown that the
levee will remain structurally stable during the
base flood when such additional loading
considerations
are
imposed.
Under
no
circumstances will freeboard of less than two
feet be accepted.
(iii) For coastal levees, the freeboard must be
established at one foot above the height of the
one percent wave or the maximum wave runup
(whichever is greater) associated with the 100
year stillwater surge elevation at the site.
(iv) Occasionally, exceptions to the minimum
coastal levee freeboard requirement described in
paragraph (b)(1)(iii) of this section, may be
approved. Appropriate engineering analyses
demonstrating adequate protection with a lesser
freeboard must be submitted to support a request
for such an exception. The material presented
must evaluate the uncertainty in the estimated
base
flood
loading
conditions.
Particular
emphasis must be placed on the effects of wave
attack and overtopping on the stability of the
levee. Under no circumstances, however, will a
freeboard of less than two feet above the 100
year stillwater surge elevation be accepted.
(2) Closures. All openings must be provided
with closure devices that are structural parts of
the system during operation and design
according to sound engineering practice.
(3)
Embankment
protection.
Engineering
analyses must be submitted that demonstrate that
no appreciable erosion of the levee embankment
can be expected during the base flood, as a result
of either currents or waves, and that anticipated
erosion will not result in failure of the levee
embankment or foundation directly or indirectly
through reduction of the seepage path and
subsequent instability. The factors to be
addressed in such analyses include, but are not
limited to: Expected flow velocities (especially
in constricted areas); expected wind and wave
action; ice loading; impact of debris; slope
protection techniques; duration of flooding at
various stages and velocities; embankment and
foundation materials; levee alignment, bends,
and transitions; and levee side slopes.
(4) Embankment and foundation stability.
Engineering
analyses
that
evaluate
levee
embankment stability must be submitted. The
analyses provided shall evaluate expected
seepage during loading conditions associated
with the base flood and shall demonstrate that
seepage into or through the levee foundation and
embankment will not jeopardize embankment or
foundation stability. An alternative analysis
demonstrating that the levee is designed and
constructed
for
stability
against
loading
conditions for Case IV as defined in the U.S.
Army Corps of Engineers (COE) manual,
``Design and Construction of Levees'' (EM
1110-2-1913, Chapter 6, Section II), may be
used. The factors that shall be addressed in the
analyses include: Depth of flooding, duration of
flooding, embankment geometry and length of
seepage path at critical locations, embankment
and
foundation
materials,
embankment
compaction, penetrations, other design factors
affecting seepage (such as drainage layers), and
other design factors affecting embankment and
foundation stability (such as berms).
(5) Settlement. Engineering analyses must be
submitted
that
assess
the
potential
and
magnitude of future losses of freeboard as a
result of levee settlement and demonstrate that
freeboard will be maintained within the
minimum standards set forth in paragraph (b)(1)
of this section. This analysis must address
embankment
loads,
compressibility
of
embankment soils, compressibility of foundation
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soils, age of the levee system, and construction
compaction methods. In addition, detailed
settlement analysis using procedures such as
those described in the COE manual, “Soil
Mechanics Design--Settlement Analysis” (EM
1100-2-1904) must be submitted.
(6) Interior drainage. An analysis must be
submitted that identifies the source(s) of such
flooding, the extent of the flooded area, and, if
the average depth is greater than one foot, the
water-surface elevation(s) of the base flood. This
analysis must be based on the joint probability
of interior and exterior flooding and the capacity
of facilities (such as drainage lines and pumps)
for evacuating interior floodwaters.
(7) Other design criteria. In unique situations,
such as those where the levee system has
relatively high vulnerability, FEMA may require
that other design criteria and analyses be
submitted to show that the levees provide
adequate protection. In such situations, sound
engineering practice will be the standard on
which FEMA will base its determinations.
FEMA will also provide the rationale for
requiring this additional information.
(c) Operation plans and criteria. For a levee
system to be recognized, the operational criteria
must be as described below. All closure devices
or mechanical systems for internal drainage,
whether manual or automatic, must be operated
in accordance with an officially adopted
operation manual, a copy of which must be
provided to FEMA by the operator when levee
or drainage system recognition is being sought
or when the manual for a previously recognized
system is revised in any manner. All operations
must be under the jurisdiction of a Federal or
State agency, an agency created by Federal or
State law, or an agency of a community
participating in the NFIP.
(1) Closures. Operation plans for closures must
include the following:
(i) Documentation of the flood warning system,
under the jurisdiction of Federal, State, or
community officials, that will be used to trigger
emergency
operation
activities
and
demonstration that sufficient flood warning time
exists for the completed operation of all closure
structures, including necessary sealing, before
floodwaters each the base of the closure.
(ii) A formal plan of operation including specific
actions and assignments of responsibility by
individual name or title.
(iii) Provisions for periodic operation, at not less
than one-year intervals, of the closure structure
for testing and training purposes.
(2) Interior drainage systems. Interior drainage
systems associated with levee systems usually
include storage areas, gravity outlets, pumping
stations, or a combination thereof. These
drainage systems will be recognized by FEMA
on NFIP maps for flood protection purposes
only if the following minimum criteria are
included in the operation plan:
(i) Documentation of the flood warning system,
under the jurisdiction of Federal, State, or
community officials, that will be used to trigger
emergency
operation
activities
and
demonstration that sufficient flood warning time
exists to permit activation of mechanized
portions of the drainage system.
(ii) A formal plan of operation including specific
actions and assignments of responsibility by
individual name or title.
(iii) Provision for manual backup for the
activation of automatic systems.
(iv) Provisions for periodic inspection of interior
drainage systems and periodic operation of any
mechanized portions for testing and training
purposes. No more than one year shall elapse
between either the inspections or the operations.
(3) Other operation plans and criteria. Other
operating plans and criteria may be required by
FEMA to ensure that adequate protection is
provided in specific situations. In such cases,
sound emergency management practice will be
the standard upon which FEMA determinations
will be based.
(d) Maintenance plans and criteria. For levee
systems to be recognized as providing protection
from the base flood, the maintenance criteria
must be as described herein. Levee systems must
be maintained in accordance with an officially
adopted maintenance plan, and a copy of this
plan must be provided to FEMA by the owner of
the levee system when recognition is being
sought or when the plan for a previously
recognized system is revised in any manner. All
maintenance activities must be under the
jurisdiction of a Federal or State agency, an
agency created by Federal or State law, or an
agency of a community participating in the NFIP
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that must assume ultimate responsibility for
maintenance. This plan must document the
formal procedure that ensures that the stability,
height, and overall integrity of the levee and its
associated
structures
and
systems
are
maintained. At a minimum, maintenance plans
shall specify the maintenance activities to be
performed, the frequency of their performance,
and the person by name or title responsible for
their performance.
(e) Certification requirements. Data submitted to
support that a given levee system complies with
the
structural
requirements
set
forth
in
paragraphs (b)(1) through (7) of this section
must be certified by a registered professional
engineer. Also, certified as-built plans of the
levee must be submitted. Certifications are
subject to the definition given at Sec. 65.2 of this
subchapter.
In
lieu
of
these
structural
requirements,
a
Federal
agency
with
responsibility for levee design may certify that
the levee has been adequately designed and
constructed to provide protection against the
base flood.
[51 FR 30316, Aug. 25, 1986]
§ 65.11 Evaluation of sand dunes in mapping
coastal flood hazard areas.
(a) General conditions. For purposes of the
NFIP, FEMA will consider storm-induced dune
erosion potential in its determination of coastal
flood hazards and risk mapping efforts. The
criterion to be used in the evaluation of dune
erosion will apply to primary frontal dunes as
defined in Sec. 59.1, but does not apply to
artificially designed and constructed dunes that
are not well-established with long-standing
vegetative cover, such as the placement of sand
materials in a dune-like formation.
(b) Evaluation criterion. Primary frontal dunes
will not be considered as effective barriers to
base flood storm surges and associated wave
action where the cross-sectional area of the
primary frontal dune, as measured perpendicular
to the shoreline and above the 100-year
stillwater flood elevation and seaward of the
dune crest, is equal to, or less than, 540 square
feet.
(c) Exceptions. Exceptions to the evaluation
criterion may be granted where it can be
demonstrated through authoritative historical
documentation that the primary frontal dunes at
a specific site withstood previous base flood
storm surges and associated wave action.
[53 FR 16279, May 6, 1988]
§ 65.12 Revision of flood insurance rate maps
to reflect base flood elevations caused by
proposed encroachments.
(a) When a community proposes to permit
encroachments upon the flood plain when a
regulatory floodway has not been adopted or to
permit
encroachments
upon
an
adopted
regulatory floodway which will cause base flood
elevation increases in excess of those permitted
under paragraphs
(c)(10) or (d)(3) of Sec. 60.3 of this subchapter,
the community shall apply to the Administrator
for conditional approval of such action prior to
permitting the encroachments to occur and shall
submit the following as part of its application:
(1) A request for conditional approval of map
change and the appropriate initial fee as
specified by Sec. 72.3 of this subchapter or a
request for exemption from fees as specified by
Sec. 72.5 of this subchapter, whichever is
appropriate;
(2) An evaluation of alternatives which would
not result in a base flood elevation increase
above that permitted under paragraphs (c)(10) or
(d)(3)
of
Sec.
60.3
of
this
subchapter
demonstrating why these alternatives are not
feasible;
(3) Documentation of individual legal notice to
all impacted property owners within and outside
of the community, explaining the impact of the
proposed action on their property.
(4) Concurrence of the Chief Executive Officer
of any other communities impacted by the
proposed actions;
(5) Certification that no structures are located in
areas which would be impacted by the increased
base flood elevation;
(6) A request for revision of base flood elevation
determination according to the provisions of
Sec. 65.6 of this part;
(7) A request for floodway revision in
accordance with the provisions of Sec. 65.7 of
this part;
(b)
Upon
receipt
of
the
Administrator's
conditional approval of map change and prior to
approving the proposed encroachments, a
community shall provide evidence to the
Administrator of the adoption of flood plain
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management
ordinances
incorporating
the
increased base flood elevations and/or revised
floodway reflecting the post-project condition.
(c)
Upon
completion
of
the
proposed
encroachments, a community shall provide as-
built certifications in accordance with the
provisions of Sec. 65.3 of this part. The
Administrator will initiate a final map revision
upon receipt of such certifications in accordance
with part 67 of this subchapter.
[53 FR 16279, May 6, 1988]
§ 65.13 Mapping and map revisions for areas
subject to alluvial fan flooding.
This section describes the procedures to be
followed and the types of information FEMA
needs to recognize on a NFIP map that a
structural flood control measure provides
protection from the base flood in an area subject
to alluvial fan flooding. This information must
be supplied to FEMA by the community or other
party seeking recognition of such a flood control
measure at the time a flood risk study or restudy
is conducted, when a map revision under the
provisions of part 65 of this subchapter is
sought, and upon request by the Administrator
during the review of previously recognized flood
control measures. The FEMA review will be for
the sole purpose of establishing appropriate risk
zone determinations for NFIP maps and shall not
constitute a determination by FEMA as to how
the flood control measure will perform in a flood
event.
(a) The applicable provisions of Sec. 65.2, 65.3,
65.4, 65.6, 65.8 and 65.10 shall also apply to
FIRM revisions involving alluvial fan flooding.
(b) The provisions of Sec. 65.5 regarding map
revisions based on fill and the provisions of part
70 of this chapter shall not apply to FIRM
revisions involving alluvial fan flooding. In
general, elevations of a parcel of land or a
structure by fill or other means, will not serve as
a basis for removing areas subject to alluvial fan
flooding from an area of special food hazards.
(c) FEMA will credit on NFIP maps only major
structural flood control measures whose design
and construction are supported by sound
engineering analyses which demonstrate that the
measures will effectively eliminate alluvial fan
flood hazards from the area protected by such
measures. The provided analyses must include,
but are not necessarily limited to, the following:
(1) Engineering analyses that quantify the
discharges and volumes of water, debris, and
sediment movement associated with the flood
that has a one-percent probability of being
exceeded in any year at the apex under current
watershed
conditions and under potential
adverse conditions (e.g., deforestation of the
watershed by fire). The potential for debris flow
and sediment movement must be assessed using
an engineering method acceptable to FEMA.
The
assessment
should
consider
the
characteristics and availability of sediment in the
drainage basin above the apex and on the
alluvial fan.
(2) Engineering analyses showing that the
measures will accommodate the estimated peak
discharges and volumes of water, debris, and
sediment, as determined in accordance with
paragraph (c)(1) of this section, and will
withstand the associated hydrodynamic and
hydrostatic forces.
(3) Engineering analyses showing that the
measures have been designed to withstand the
potential erosion and scour associated with
estimated discharges.
(4) Engineering analyses or evidence showing
that the measures will provide protection from
hazards associated with the possible relocation
of flow paths from other parts of the fan.
(5) Engineering analyses that assess the effect of
the project on flood hazards, including depth and
velocity of floodwaters and scour and sediment
deposition, on other areas of the fan.
(6) Engineering analyses demonstrating that
flooding from sources other than the fan apex,
including local runoff, is either insignificant or
has been accounted for in the design.
(d)
Coordination.
FEMA
will
recognize
measures that are adequately designed and
constructed, provided that: evidence is submitted
to show that the impact of the measures on flood
hazards in all areas of the fan (including those
not protected by the flood control measures),
and the design and maintenance requirements of
the measures, were reviewed and approved by
the impacted communities, and also by State and
local agencies that have jurisdiction over flood
control activities.
(e) Operation and maintenance plans and
criteria. The requirements for operation and
maintenance of flood control measures on areas
subject to alluvial fan flooding shall be those
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specified under Sec. 65.10, paragraphs (c) and
(d), when applicable.
(f) Certification requirements. Data submitted to
support that a given flood control measure
complies with the requirements set forth in
paragraphs (c) (1) through (6) of this section
must be certified by a registered professional
engineer. Also, certified as-built plans of the
flood control measures must be submitted.
Certifications are subject to the definition given
at Sec. 65.2.
(Approved by the Office of Management and
Budget under control number 3067-0147)
[54 FR 33551, Aug. 15, 1989]
§ 65.14 Remapping of areas for which local
flood protection systems no longer provide
base flood protection.
(a) General. (1) This section describes the
procedures to follow and the types of
information FEMA requires to designate flood
control restoration zones. A community may be
eligible to apply for this zone designation if the
Administrator determines that it is engaged in
the process of restoring a flood protection
system that was:
(i) Constructed using Federal funds;
(ii) Recognized as providing base flood
protection on the community's effective FIRM;
and
(iii) Decertified by a Federal agency responsible
for flood protection design or construction.
(2) Where the Administrator determines that a
community is in the process of restoring its
flood protection system to provide base flood
protection, a FIRM will be prepared that
designates the temporary flood hazard areas as a
flood control restoration zone (Zone AR).
Existing special flood hazard areas shown on the
community's effective FIRM that are further
inundated by Zone AR flooding shall be
designated as a ``dual'' flood insurance rate zone,
Zone AR/AE or AR/AH with Zone AR base
flood elevations, and AE or AH with base flood
elevations and Zone AR/AO with Zone AR base
flood elevations and Zone AO with flood depths,
or Zone AR/A with Zone AR base flood
elevations and Zone A without base flood
elevations.
(b) Limitations. A community may have a flood
control restoration zone designation only once
while restoring a flood protection system.
This limitation does not preclude future flood
control restoration zone designations should a
fully restored, certified, and accredited system
become decertified for a second or subsequent
time.
(1) A community that receives Federal funds for
the purpose of designing or constructing, or
both, the restoration project must complete
restoration or meet the requirements of 44 CFR
61.12 within a specified period, not to exceed a
maximum of 10 years from the date of submittal
of the community's application for designation
of a flood control restoration zone.
(2) A community that does not receive Federal
funds for the purpose of constructing the
restoration project must complete restoration
within a specified period, not to exceed a
maximum of 5 years from the date of submittal
of the community's application for designation
of a flood control restoration zone. Such a
community is not eligible for the provisions of
Sec.61.12. The designated restoration period
may not be extended beyond the maximum
allowable under this limitation.
(c)
Exclusions.
The
provisions of
these
regulations do not apply in a coastal high hazard
area as defined in 44 CFR 59.1, including areas
that would be subject to coastal high hazards as
a result of the decertification of a flood
protection system shown on the community's
effective FIRM as providing base flood
protection.
(d) Effective date for risk premium rates. The
effective date for any risk premium rates
established for Zone AR shall be the effective
date of the revised FIRM showing Zone AR
designations.
(e) Application and submittal requirements for
designation of a flood control restoration zone.
A community must submit a written request to
the Administrator, signed by the community's
Chief Executive Officer, for a floodplain
designation as a flood control restoration zone.
The request must include a legislative action by
the community requesting the designation. The
Administrator will not initiate any action to
designate flood control restoration zones without
receipt of the formal request from the
community that complies with all requirements
of this section. The Administrator reserves the
right to request additional information from the
community to support or further document the
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community's formal request for designation of a
flood control restoration zone, if deemed
necessary.
(1) At a minimum, the request from a
community that receives Federal funds for the
purpose of designing, constructing, or both, the
restoration project must include:
(i) A statement whether, to the best of the
knowledge of the community's Chief Executive
Officer, the flood protection system is currently
the subject matter of litigation before any
Federal, State or local court or administrative
agency, and if so, the purpose of that litigation;
(ii) A statement whether the community has
previously requested a determination with
respect to the same subject matter from the
Administrator, and if so, a statement that details
the disposition of such previous request;
(iii) A statement from the community and
certification by a Federal agency responsible for
flood protection design or construction that the
existing flood control system shown on the
effective FIRM was originally built using
Federal funds, that it no longer provides base
flood protection, but that it continues to provide
protection from the flood having at least a 3
percent chance of occurrence during any given
year;
(iv) An official map of the community or legal
description, with supporting documentation, that
the community will adopt as part of its flood
plain management measures, which designates
developed areas as defined in Sec.59.1 and as
further defined in Sec.60.3(f).
(v) A restoration plan to return the system to a
level of base flood protection. At a minimum,
this plan must:
(A) List all important project elements, such as
acquisition of permits, approvals, and contracts
and construction schedules of planned features;
(B) Identify anticipated start and completion
dates for each element, as well as significant
milestones and dates;
(C) Identify the date on which ``as built''
drawings and certification for the completed
restoration project will be submitted. This date
must provide for a restoration period not to
exceed the
maximum allowable restoration period for the
flood protection system, or;
(D) Identify the date on which the community
will submit a request for a finding of adequate
progress
that
meets
all
requirements
of
Sec.61.12. This date may not exceed the
maximum allowable restoration period for the
flood protection system;
(vi) A statement identifying the local project
sponsor responsible for restoration of the flood
protection system;
(vii) A copy of a study, performed by a Federal
agency responsible for flood protection design
or construction in consultation with the local
project sponsor, which demonstrates a Federal
interest in restoration of the system and which
deems that the flood protection system is
restorable to a level of base flood protection.
(viii) A joint statement from the Federal agency
responsible for flood protection design or
construction involved in restoration of the flood
protection system and the local project sponsor
certifying that the design and construction of the
flood control system involves Federal funds, and
that the restoration of the flood protection
system will provide base flood protection;
(2) At a minimum, the request from a
community that receives no Federal funds for
the purpose of constructing the restoration
project must:
(i) Meet the requirements of Sec.65.14(e)(1)(i)
through (iv);
(ii) Include a restoration plan to return the
system to a level of base flood protection. At a
minimum, this plan must:
(A) List all important project elements, such as
acquisition of permits, approvals, and contracts
and construction schedules of planned features;
(B) Identify anticipated start and completion
dates for each element, as well as significant
milestones and dates; and
(C) Identify the date on which ``as built''
drawings and certification for the completed
restoration project will be submitted. This date
must provide for a restoration period not to
exceed the
maximum allowable restoration period for the
flood protection system;
(iii) Include a statement identifying the local
agency responsible for restoration of the flood
protection system;
(iv) Include a copy of a study, certified by
registered
Professional
Engineer,
that
demonstrates that the flood protection system is
restorable to provide protection from the base
flood;
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(v) Include a statement from the local agency
responsible
for
restoration
of
the
flood
protection system certifying that the restored
flood protection system will meet the applicable
requirements of Part 65; and
(vi) Include a statement from the local agency
responsible
for
restoration
of
the
flood
protection system that identifies the source of
funds for the purpose of constructing the
restoration project and a percentage of the total
funds contributed by each source. The statement
must demonstrate, at a minimum, that 100
percent of the total financial project cost of the
completed flood protection system has been
appropriated.
(f) Review and response by the Administrator.
The review and response by the Administrator
shall be in accordance with procedures specified
in Sec. 65.9.
(g) Requirements for maintaining designation of
a flood control restoration zone. During the
restoration period, the community and the cost-
sharing Federal agency, if any, must certify
annually to the FEMA Regional Office having
jurisdiction
that
the
restoration
will
be
completed in accordance with the restoration
plan within the time period specified by the plan.
In addition, the community and the cost-sharing
Federal agency, if any, will update the
restoration plan and will identify any permitting
or construction problems that will delay the
project completion from the restoration plan
previously submitted to the Administrator. The
FEMA Regional Office having jurisdiction will
make an annual assessment and recommendation
to the Administrator as to the viability of the
restoration plan and will conduct periodic on-
site inspections of the flood protection system
under restoration.
(h) Procedures for removing flood control
restoration zone designation due to adequate
progress or complete restoration of the flood
protection system. At any time during the
restoration period:
(1) A community that receives Federal funds for
the purpose of designing, constructing, or both,
the restoration project shall provide written
evidence of certification from a Federal agency
having flood protection design or construction
responsibility that the necessary improvements
have been completed and that the system has
been restored to provide protection from the
base flood, or submit a request for a finding of
adequate progress that meets all requirements of
Sec.61.12. If the Administrator determines that
adequate progress has been made, FEMA will
revise the zone designation from a flood control
restoration zone designation to Zone A99.
(2)
After
the
improvements
have
been
completed, certified by a Federal agency as
providing base flood protection, and reviewed
by FEMA, FEMA will revise the FIRM to
reflect the completed flood control system.
(3) A community that receives no Federal funds
for the purpose of constructing the restoration
project must provide written evidence that the
restored flood protection system meets the
requirements of Part 65.
A community that receives no Federal funds for
the purpose of constructing the restoration
project is not eligible for a finding of adequate
progress under Sec.61.12.
(4)
After
the
improvements
have
been
completed and reviewed by FEMA, FEMA will
revise the FIRM to reflect the completed flood
protection system.
(i) Procedures for removing flood control
restoration zone designation due to non
compliance with the restoration schedule or as a
result of a finding that satisfactory progress is
not being made to complete the restoration. At
any time during the restoration period, should
the Administrator determine that the restoration
will not be completed in accordance with the
time frame specified in the restoration plan, or
that satisfactory progress is not being made to
restore the flood protection system to provide
complete flood protection in accordance with the
restoration plan, the Administrator shall notify
the community and the responsible Federal
agency, in writing, of the determination, the
reasons for that determination, and that the
FIRM will be revised to remove the flood
control restoration zone designation. Within
thirty (30) days of such notice, the community
may submit written information that provides
assurance that the restoration will be completed
in accordance with the time frame specified in
the restoration plan, or that satisfactory progress
is being made to restore complete protection in
accordance with the restoration plan, or that,
with reasonable certainty, the restoration will be
completed within the maximum allowable
restoration period. On the basis of this
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information the Administrator may suspend the
decision to revise the FIRM to remove the flood
control restoration zone designation. If the
community does not submit any information, or
if, based on a review of the information
submitted, there is sufficient cause to find that
the restoration will not be completed as provided
for in the restoration plan, the Administrator
shall revise the FIRM, in accordance with 44
CFR Part 67, and shall remove the flood control
restoration
zone
designations
and
shall
redesignate those areas as Zone A1-30, AE, AH,
AO, or A.
[62 FR 55717, Oct. 27, 1997]
§ 65.15 List of communities submitting new
technical data.
This section provides a cumulative list of
communities where modifications of the base
flood elevation determinations have been made
because of submission of new scientific or
technical data. Due to the need for expediting
the modifications, the revised map is already in
effect and the appeal period commences on or
about the effective date of the modified map. An
interim rule, followed by a final rule, will list the
revised map effective date, local repository and
the name and address of the Chief Executive
Officer of the community. The map(s) is (are)
effective for both flood plain management and
insurance purposes.
[51 FR 30317, Aug. 25, 1986. Redesignated at
53 FR 16279, May 6, 1988, and further
redesignated at 54 FR 33551, Aug. 15, 1989.
Redesignated at 59 FR 53599, Oct. 25, 1994]
Editorial Note: For references to FR pages
showing lists of eligible communities, see the
List of CFR Sections Affected, which appears in
the Finding Aids section of the printed volume
and on GPO Access.
§
65.16
Standard
Flood
Hazard
Determination Form and Instructions.
(a) Section 528 of the National Flood Insurance
Reform Act of 1994 (42 U.S.C. 1365(a)) directs
FEMA to develop a standard form for
determining, in the case of a loan secured by
improved real estate or a mobile home, whether
the building or mobile home is located in an area
identified by the Director as an area having
special flood hazards and in which flood
insurance under this title is available. The
purpose of the form is to determine whether a
building or mobile home is located within an
identified Special Flood Hazard Area (SFHA),
whether flood insurance is required, and whether
federal flood insurance is available. Use of this
form will ensure that required flood insurance
coverage is purchased for structures located in
an SFHA, and will assist federal entities for
lending regulation in assuring compliance with
these purchase requirements.
(b) The form is available by written request to
Federal Emergency Management Agency, PO
Box 2012, Jessup, MD 20794; ask for the
Standard Flood Hazard Determination form. It is
also available by fax-on-demand; call (202) 646
3362, form #23103. Finally, the form is
available
through
the
Internet
at
http://www.fema.gov/nfip/mpurfi.htm.
[63 FR 27857, May 21,
1998]
§ 65.17 Review of determinations.
This section describes the procedures that shall
be followed and the types of information
required by FEMA to review a determination of
whether a building or manufactured home is
located within an identified Special Flood
Hazard Area (SFHA).
(a) General conditions. The borrower and lender
of a loan secured by improved real estate or a
manufactured home may jointly request that
FEMA review a determination that the building
or manufactured home is located in an identified
SFHA. Such a request must be submitted within
45 days of the lender's notification to the
borrower that the building or manufactured
home is in the SFHA and that flood insurance is
required. Such a request must be submitted
jointly by the lender and the borrower and shall
include
the
required
fee
and
technical
information
related to the building or manufactured home.
Elevation data will not be considered under the
procedures described in this section.
(b) Data and other requirements. Items required
for FEMA's review of a determination shall
include the following:
(1) Payment of the required fee by check or
money order, in U.S. funds, payable to the
National Flood Insurance Program;
(2) A request for FEMA's review of the
determination, signed by both the borrower and
the lender;
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(3) A copy of the lender's notification to the
borrower that the building or manufactured
home is in an SFHA and that flood insurance is
required (the request for review of the
determination must be postmarked within 45
days of borrower notification);
(4) A completed Standard Flood Hazard
Determination Form for the building or
manufactured home, together with a legible hard
copy of all technical data used in making the
determination; and
(5) A copy of the effective NFIP map (Flood
Hazard Boundary Map (FHBM) or Flood
Insurance Rate Map (FIRM)) panel for the
community
in
which
the
building
or
manufactured home is located, with the building
or manufactured home location indicated.
Portions of the map panel may be submitted but
shall include the area of the building or
manufactured home in question together with
the map panel title block, including effective
date, bar scale, and north arrow.
(c) Review and response by FEMA. Within 45
days after receipt of a request to review a
determination, FEMA will notify the applicants
in writing of one of the following:
(1) Request submitted more than 45 days after
borrower notification; no review will be
performed and all materials are being returned;
(2) Insufficient information was received to
review
the
determination;
therefore,
the
determination stands until a complete submittal
is received; or
(3) The results of FEMA's review of the
determination,
which
shall
include
the
following:
(i) The name of the NFIP community in which
the building or manufactured home is located;
(ii) The property address or other identification
of the building or manufactured home to which
the determination applies;
(iii) The NFIP map panel number and effective
date upon which the determination is based;
(iv) A statement indicating whether the building
or manufactured home is within the Special
Flood Hazard Area;
(v)
The
time
frame
during
which
the
determination is effective.
[60 FR 62218, Dec. 5, 1995]
PART
70--PROCEDURE
FOR
MAP
CORRECTION
Mapping Deficiencies Unrelated to
Community - Wide Elevation Determinations
Sec.
70.1 Purpose of part.
70.2 Definitions.
70.3 Right to submit technical information.
70.4 Review by the Director.
70.5 Letter of Map Amendment.
70.6 Distribution of Letter of Map Amendment.
70.7 Notice of Letter of Map Amendment.
70.8 Premium refund after Letter of Map
Amendment.
70.9 Review of proposed projects.
Authority:
42
U.S.C.
4001
et
seq.;
Reorganization Plan No. 3 of 1978, 43 FR
41943, 3 CFR, 1978 Comp., p. 329; E.O. 12127
of Mar. 31, 1979, 44 FR 19367, 3 CFR, 1979
Comp., p. 376.
§ 70.1 Purpose of part.
The purpose of this part is to provide an
administrative
procedure
whereby
the
Administrator will review the scientific or
technical submissions of an owner or lessee of
property who believes his property has been
inadvertently included in designated A, AO, A1
30, AE, AH, A99, AR, AR/A1-30, AR/AE,
AR/AO, AR/AH, AR/A, VO, V1-30, VE, and V
Zones, as a result of the transposition of the
curvilinear line to either street or to other readily
identifiable features. The necessity for this part
is due in part to the technical difficulty of
accurately delineating the curvilinear line on
either an FHBM or FIRM. These procedures
shall not apply when there has been any
alteration of topography since the effective date
of the first NFIP map (i.e., FHBM or FIRM)
showing the property within an area of special
flood hazard. Appeals in such circumstances are
subject to the provisions of part 65 of this
subchapter.
[62 FR 55718, Oct. 27, 1997]
§ 70.2 Definitions.
The definitions set forth in part 59 of this
subchapter are applicable to this part.
[41 FR 46991, Oct. 26, 1976. Redesignated at 44
FR 31177, May 31, 1979]
§ 70.3 Right to submit technical information.
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(a) Any owner or lessee of property (applicant)
who believes his property has been inadvertently
included in a designated A, AO, A1-30, AE,
AH, A99, AR, AR/A1-30, AR/AE, AR/AO,
AR/AH, AR/A, VO, V1-30, VE, and V Zones
on a FHBM or a FIRM, may submit scientific or
technical information to the Administrator for
the Administrator's review.
(b) Scientific and technical information for the
purpose of this part may include, but is not
limited to the following:
(1) An actual copy of the recorded plat map
bearing the seal of the appropriate recordation
official (e.g. County Clerk, or Recorder of
Deeds) indicating the official recordation and
proper citation (Deed or Plat Book Volume and
Page Numbers), or an equivalent identification
where annotation of the deed or plat book is not
the practice.
(2) A topographical map showing (i) ground
elevation contours in relation to the National
Geodetic Vertical Datum (NVGD) of 1929, (ii)
the total area of the property in question, (iii) the
location of the structure or structures located on
the property in question, (iv) the elevation of the
lowest adjacent grade to a structure or structures
and (v) an indication of the curvilinear line
which represents the area subject to inundation
by a base flood. The curvilinear line should be
based upon information provided by any
appropriate authoritative source, such as a
Federal Agency, the appropriate state agency
(e.g. Department of Water Resources), a County
Water Control District, a County or City
Engineer, a Federal Emergency Management
Agency
Flood
Insurance
Study,
or
a
determination by a Registered Professional
Engineer;
(3) A copy of the FHBM or FIRM indicating the
location of the property in question;
(4) A certification by a Registered Professional
Engineer or Licensed Land Surveyor that the
lowest grade adjacent to the structure is above
the base flood elevation.
[41 FR 46991, Oct. 26, 1976. Redesignated at 44
FR 31177, May 31, 1979, as amended at 48 FR
44544 and 44553, Sept. 29, 1983; 49 FR 4751,
Feb. 8, 1984; 50 FR 36028, Sept. 4, 1985; 51 FR
30317, Aug. 25, 1986; 53 FR 16280, May 6,
1988; 59 FR 53601, Oct. 25, 1994; 62 FR
55719, Oct. 27, 1997]
§ 70.4 Review by the Director.
The Director, after reviewing the scientific or
technical information submitted under the
provisions of Sec. 70.3, shall notify the applicant
in writing of his/her determination within 60
days after we receive the applicant's scientific or
technical information that we have compared
either the ground elevations of an entire legally
defined parcel of land or the elevation of the
lowest adjacent grade to a structure with the
elevation of the base flood and that:
(a) The property is within a designated A, A0,
A1-30, AE, AH, A99, AR, AR/A1-30, AR/AE,
AR/AO, AR/AH, AR/A, V0, V1-30, VE, or V
Zone, and will state the basis of such
determination; or
(b) The property should not be within a
designated A, A0, A1-30, AE, AH, A99, AR,
AR/A1-30, AR/AE, AR/AO, AR/AH, AR/A,V0,
V1-30, VE, or V Zone and that we will modify
the FHBM or FIRM accordingly; or
(c) The property is not within a designated A,
A0, A1-30, AE, AH, A99, AR, AR/A1-30,
AR/AE, AR/AO, AR/AH, AR/A,V0, V1-30,
VE, or V Zone as shown on the FHBM or FIRM
and no modification of the FHBM or FIRM is
necessary; or(d) We need an additional 60 days
to make a determination.
[66 FR 33900, June 26, 2001]
§ 70.5 Letter of Map Amendment.
Upon determining from available scientific or
technical information that a FHBM or a FIRM
requires modification under the provisions of
Sec. 70.4(b), the Administrator shall issue a
Letter of Map Amendment which shall state:
(a) The name of the Community to which the
map to be amended was issued;
(b) The number of the map;
(c) The identification of the property to be
excluded from a designated A, AO, A1-30, AE,
AH, A99, AR, AR/A1-30, AR/AE, AR/AO,
AR/AH, AR/A, VO, V1-30, VE, or V Zone.
[41 FR 46991, Oct. 26, 1976. Redesignated at 44
FR 31177, May 31, 1979, as amended at 48 FR
44553, Sept. 29, 1983; 49 FR 4751, Feb. 8,
1984; 50 FR 36028, Sept. 4, 1985; 59 FR 53601,
Oct. 25, 1994; 62 FR 55719, Oct. 27, 1997]
§ 70.6 Distribution of Letter of Map
Amendment.
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(a) A copy of the Letter of Map Amendment
shall be sent to the applicant who submitted
scientific or technical data to the Administrator.
(b) A copy of the Letter of Map Amendment
shall be sent to the local map repository with
instructions that it be attached to the map which
the Letter of Map Amendment is amending.
(c) A copy of the Letter of Map Amendment
shall be sent to the map repository in the state
with instructions that it be attached to the map
which it is amending.
(d) A copy of the Letter of Map Amendment
will be sent to any community or governmental
unit
that
requests
such
Letter
of
Map
Amendment.
(e) [Reserved]
(f) A copy of the Letter of Map Amendment will
be maintained by the Agency in its community
case file.
[41 FR 46991, Oct. 26, 1976. Redesignated at 44
FR 31177, May 31, 1979, as amended at 48 FR
44544 and 44553, Sept. 29, 1983; 49 FR 4751,
Feb. 8, 1984]
§ 70.7 Notice of Letter of Map Amendment.
(a) The Administrator, shall not publish a notice
in the Federal Register that the FIRM for a
particular community has been amended by
letter determination pursuant to this part unless
such amendment includes alteration or change of
base flood elevations established pursuant to
part 67. Where no change of base flood
elevations has occurred, the Letter of Map
Amendment provided under Sec. 70.5 and 70.6
serves to inform the parties affected.
(b) [Reserved]
Editorial Note: For a list of communities issued
under this section and not carried in the CFR see
the List of CFR Sections Affected, which
appears in the Finding Aids Section of the
printed volume and on GPO Access.
§ 70.8 Premium refund after Letter of Map
Amendment.
A Standard Flood Insurance Policyholder whose
property has become the subject of a Letter of
Map Amendment under this part may cancel the
policy within the current policy year and receive
a premium refund under the conditions set forth
in Sec. 62.5 of this subchapter.
[41 FR 46991, Oct. 26, 1976. Redesignated at 44
FR 31177, May 31, 1979]
§ 70.9 Review of proposed projects.
An individual who proposes to build one or
more structures on a portion of property that
may be included inadvertently in a Special Flood
Hazard Area (SFHA) may request FEMA's
comments on whether the proposed structure(s),
if built as proposed, will be in the SFHA.
FEMA's comments will be issued in the form of
a letter, termed a Conditional Letter of Map
Amendment. The data required to support such
requests are the same as those required for final
Letters of Map Amendment in accordance with
Sec. 70.3, except as-built certification is not
required and the requests shall be accompanied
by the appropriate payment, in accordance with
44 CFR part 72. All such requests for CLOMAs
shall be submitted to the FEMA Regional Office
servicing the community's geographic area or to
the FEMA Headquarters Office in Washington,
DC.
[62 FR 5736, Feb. 6, 1997]
NFIP Regulations
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APPENDIX F:
FEMA FORMS
This Appendix includes copies of the following certificates that are mentioned in the Study
Course and used in implementing your floodplain management ordinances:
♦ FEMA Form 81-31, Elevation Certificate and Instructions
♦ FEMA Form 81-65, Floodproofing Certificate
The following FEMA forms may be of interest to local officials, but are not included in this
Appendix:
♦ FEMA Form 81-92, MT-EZ, Application Form for Single Residential Lot or Structure
Amendments to National Flood Insurance Program Maps;
♦ FEMA Form 81-87, MT-1, Application Forms for Conditional and Final Letters of Map
Amendment and Letters of Map Revision Based on Fill;
♦ FEMA Form 81-89, MT-2, Application Forms for Conditional Letters of Map Revision and
Letters of Map Revision; and
♦ Standard Flood Hazard Determination form.
Current copies of all of these certificates and forms can be obtained from the following
sources:
♦ They may be downloaded from FEMA’s website at http://www.fema.gov/nfip/forms.shtm;
♦ They are available on the CD-ROM version of the National Flood Insurance Program
(NFIP) Floodplain Management Requirements: A Study Guide and Desk Reference for
Local Officials;
♦ You may request the forms by calling the FEMA Map Assistance Center (FMAC) toll-free at
1-877-FEMA-MAP (1-877-336-2627); and
♦ You may request the forms electronically at femamapspecialist@patlive.com.
While some of the forms may have passed their expiration dates, they are still current and
should still be used.
They may be reproduced for local use.
FEMA Forms
F-1
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FEMA Forms
F-2
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FEMA Forms
F-3
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FEDERAL EMERGENCY MANAGEMENT AGENCY
NATIONAL FLOOD INSURANCE PROGRAM
ELEVATION CERTIFICATE
AND
INSTRUCTIONS
FEMA Forms
F-4
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NATIONAL FLOOD INSURANCE PROGRAM
ELEVATION CERTIFICATE
PAPERWORK BURDEN DISCLOSURE NOTICE
FEMA Form 81-31
The public reporting burden for this form is estimated to be 3.0 hours per response. The burden
estimate includes the time for reviewing instructions, searching existing data sources, gathering and
maintaining the needed data, and completing, reviewing, and submitting the form. You are not required
to respond to this collection of information unless a valid OMB control number appears in the upper right
corner of this form. Send comments regarding the accuracy of the burden estimate and any suggestions
for reducing this burden to: Information Collections Management, Federal Emergency Management
Agency, 500 C Street, SW, Washington, DC 20472, Paperwork Reduction Project (3067-0077). NOTE:
Please do not send your completed form to the above address.
PURPOSE OF THE ELEVATION CERTIFICATE
The Elevation Certificate is an important administrative tool of the National Flood Insurance Program
(NFIP). It is to be used to provide elevation information necessary to ensure compliance with community
floodplain management ordinances, to determine the proper insurance premium rate, and to support a
request for a Letter of Map Amendment or Revision (LOMA or LOMR-F).
The Elevation Certificate is required in order to properly rate post-FIRM buildings, which are
buildings constructed after publication of the Flood Insurance Rate Map (FIRM), for flood insurance
Zones A1-A30, AE, AH, A (with BFE), VE, V1-V30, V (with BFE), AR, AR/A, AR/AE, AR/A1-A30,
AR/AH, and AR/AO. The Elevation Certificate is not required for pre-FIRM buildings unless the
building is being rated under the optional post-FIRM flood insurance rules.
As part of the agreement for making flood insurance available in a community, the NFIP requires the
community to adopt a floodplain management ordinance that specifies minimum requirements for
reducing flood losses. One such requirement is for the community to obtain the elevation of the lowest
floor (including basement) of all new and substantially improved buildings and maintain a record of such
information. The Elevation Certificate provides a way for a community to comply with this requirement.
Use of this certificate does not provide a waiver of the flood insurance purchase requirement. Only a
LOMA or LOMR-F from the Federal Emergency Management Agency (FEMA) can amend the FIRM
and remove the Federal mandate for a lending institution to require the purchase of flood insurance.
However, the lending institution has the option of requiring flood insurance even if a LOMA/LOMR-F
has been issued by FEMA. The Elevation Certificate may be used to support a LOMA or LOMR-F
request. Lowest floor and lowest adjacent grade elevations certified by a surveyor or engineer will be
required if the certificate is used to support a LOMA or LOMR-F request.
This certificate is used only to certify building elevations. A separate certificate is required for
floodproofing. Under the NFIP, non-residential buildings can be floodproofed up to or above the Base
Flood Elevation (BFE). A floodproofed building is a building that has been designed and constructed to
be watertight (substantially impermeable to floodwaters) below the BFE. Floodproofing of residential
buildings is not permitted under the NFIP unless FEMA has granted the community an exception for
FEMA Forms
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residential floodproofed basements. The community must adopt standards for design and construction of
floodproofed basements before FEMA will grant a basement exception. For both floodproofed non
residential buildings and residential floodproofed basements in communities that have been granted an
exception by FEMA, a floodproofing certificate is required.
INSTRUCTIONS FOR COMPLETING THE ELEVATION CERTIFICATE
The Elevation Certificate is to be completed by a land surveyor, engineer, or architect who is
authorized by law to certify elevation information when elevation information is required for Zones A1
A30, AE, AH, A (with BFE), VE, V1-V30, V (with BFE), AR, AR/A, AR/AE, AR/A1-A30, AR/AH, or
AR/AO. Community officials who are authorized by law or ordinance to provide floodplain management
information may also complete this form. For Zones AO and A (without BFE), a community official, a
property owner, or an owner’s representative may provide information on this certificate, unless the
elevations are intended for use in supporting a LOMA or LOMR-F. Certified elevations must be included
if the purpose of completing the Elevation Certificate is to obtain a LOMA or LOMR-F.
In Puerto Rico only, elevations for building information and flood hazard information may be entered
in meters.
SECTION A - PROPERTY OWNER INFORMATION
This section identifies the building, its location, and its owner. Enter the name(s) of the building
owner(s), the building’s complete street address, and the lot and block number. If the building’s address
is different from the owner’s address, enter the address of the building being certified. If the address is a
rural route or a Post Office box number, enter the lot and block numbers, the tax parcel number, the legal
description, or an abbreviated location description based on distance and direction from a fixed point of
reference. For the purposes of this certificate, “building” means both a building and a manufactured
(mobile) home.
A map may be attached to this certificate to show the location of the building on the property. A tax
map, FIRM, or detailed community map is appropriate. If no map is available, provide a sketch of the
property location, and the location of the building on the property. Include appropriate landmarks such as
nearby roads, intersections, and bodies of water. For building use, indicate whether the building is
residential, non-residential, an addition to an existing residential or non-residential building, an accessory
building (e.g., garage), or other type of structure. Use the Comments area of Section F if needed.
If latitude and longitude data are available, enter them in degrees, minutes, and seconds, or in decimal
degrees, taken at the center of the front of the building. Enter arc seconds to two decimal places. Indicate
the horizontal datum and the source of the measurement data (for example, taken with GPS, scaled from a
USGS Quad Map, etc.).
SECTION B - FLOOD INSURANCE RATE MAP (FIRM) INFORMATION
Complete the Elevation Certificate on the basis of the FIRM in effect at the time of the certification.
The information for Section B is obtained by reviewing the FIRM panel that includes the building’s
location. Information about the current FIRM and a pamphlet titled “Guide to Flood Maps” are available
from the Federal Emergency Management Agency (FEMA) website at http://www.fema.gov or by calling
1-800-427-4661. If a Letter of Map Amendment (LOMA) or Letter of Map Revision (LOMR-F) has
been issued by FEMA, please provide the letter date and case number in the Comments area of Section D
or Section G, as appropriate.
FEMA Forms
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Item B1. NFIP Community Name & Community Number. Enter the complete name of the
community in which the building is located and the associated 6-digit community number. For a building
that is in an area that has been annexed by one community but is shown on another community’s FIRM,
enter the community name and 6-digit number of the annexing community. For a newly incorporated
community, use the name and 6-digit number of the new community. Under the NFIP, a “community” is
any State or area or political subdivision thereof, or any Indian tribe or authorized native organization,
which has authority to adopt and enforce floodplain management regulations for the areas within its
jurisdiction. To determine the current community number, see the NFIP Community Status Book,
available on FEMA’s website at http://www.fema.gov or by calling 1-800-427-4661.
Item B2. County Name. Enter the name of the county or counties in which the community is located.
For an unincorporated area of a county, enter “unincorporated area.” For an independent city, enter
“independent city.”
Item B3. State. Enter the 2-letter state abbreviation (for example, VA, TX, CA).
Item B4. Map and Panel Number. Enter the 10-digit number shown on the FIRM panel where the
building or manufactured (mobile) home is located. The first six digits will not match the NFIP
community number: 1) when the sixth digit is a “C,” in which case the FIRM panel is in a countywide
format; or 2) when one community has annexed land from another community but the FIRM panel has
not been updated to reflect this annexation. If the sixth digit is a “C,” it is followed by a four-digit map
number. For maps not in countywide format, enter the “community panel number” shown on the FIRM.
Item B5. Suffix. Enter the suffix letter shown on the FIRM panel that includes the building’s
location.
Item B6. FIRM Index Date. Enter the effective date or map revised date shown on the FIRM Index.
Item B7. FIRM Panel Effective/Revised Date. Enter the map effective date or the map revised date
shown on the FIRM panel. This will be the latest of all dates shown on the map. The current FIRM panel
effective date can be determined by calling 1-800-427-4661.
Item B8. Flood Zone(s). Enter the flood zone, or flood zones, in which the building is located. All
flood zones containing the letter “A” or “V” are considered Special Flood Hazard Areas. The flood zones
are A, AE, A1-A30, V, VE, V1-V30, AH, AO, AR, AR/A, AR/AE, AR/A1-A30, AR/AH, and AR/AO.
Each flood zone is defined in the legend of the FIRM panel on which it appears.
Item B9. Base Flood Elevation(s). Using the appropriate Flood Insurance Study (FIS) Profile, Flood
Elevation Table, or FIRM panel, locate the property and enter the BFE (or base flood depth) of the
building site. If the building is located in more than one flood zone in Item B8., list all appropriate BFEs
in Item B9. BFEs are shown on a FIRM or FIS Profile for Zones A1-A30, AE, AH, V1-V30, VE, AR,
AR/A, AR/AE, AR/A1-A30, AR/AH, and AR/AO; flood depth numbers are shown for Zone AO. Use
the AR BFE if the building is located in any of Zones AR/A, AR/AE, AR/A1-A30, AR/AH, or AR/AO.
In A or V zones where BFEs are not provided on the FIRM, the community may have established BFEs
or obtained BFE data from other sources. For subdivisions and other developments of more than 50 lots
or 5 acres, establishment of BFEs is required by the community’s floodplain management ordinance. If
the BFE is obtained from another source, enter the BFE in Item B9.
Item B10. Indicate the source of the BFE that you entered in Item B9.
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Item B11. Indicate the elevation datum to which the elevations on the applicable FIRM are
referenced.
Item B12. Indicate whether the building is located in a Coastal Barrier Resources System (CBRS) area or
Otherwise Protected Area (OPA). Federal flood insurance is prohibited in designated CBRS areas for
buildings or manufactured (mobile) homes built or substantially improved after the date of the CBRS
designation. An information sheet explaining CBRS areas may be obtained on FEMA’s website at
http://www.fema.gov or by calling 1-800-427-4661.
SECTION C - BUILDING ELEVATION INFORMATION
(SURVEY REQUIRED)
Complete Section C if the building is located in any of Zones A1-A30, AE, AH, A (with BFE), VE,
V1-V30, V (with BFE), AR, AR/A, AR/AE, AR/A1-A30, AR/AH, or AR/AO, or if this certificate is
being used to support a LOMA or LOMR-F. If the building is located in Zone AO or Zone A (without
BFE), complete Section E instead. To ensure that all required elevations are obtained, it may be
necessary to enter the building (for instance, if the building has a basement or sunken living room, split-
level construction, or machinery and equipment).
Surveyors may not be able to gain access to some crawl spaces to shoot the elevation of the crawl space
floor. If access to the crawl space cannot be gained, use the following guidance:
♦ Use a yardstick or tape measure to measure the floor height to the “next higher floor,”
and then subtract the crawl space height from the elevation of the “next higher floor.”
♦ Contact the local floodplain administrator of the community that the building is located in. The
community may have documentation of the elevation of the crawl space floor as part of the
permit issued for the building.
♦ If the property owner has documentation or knows the height of the crawl space floor to the next
higher floor, try to verify this by looking inside the crawl space through any openings or vents.
In all three cases, provide the elevation in the Comments area and a brief description of how the
elevation was obtained.
Item C1. Indicate whether the elevations to be entered in this section are based on construction
drawings, a building under construction, or finished construction. For either of the first two choices, a
post-construction Elevation Certificate will be required when construction is complete. If the building is
under construction, include only those elevations that can be surveyed in Items C3.a-g. Use the
Comments area to provide elevations obtained from the construction plans or drawings. Select “finished
construction” only when all machinery and/or equipment—furnaces, hot water heaters, heat pumps, air
conditioners, and elevators and their associated equipment—have been installed and the grading around
the building is completed.
Item C2. Select the diagram on pages 6 and 7 that best represents the building. Then enter the
diagram number and use the diagram to identify and determine the appropriate elevations requested in
Items C3.a-g. If you are unsure of the correct diagram, select the diagram that most closely resembles the
building being certified, or provide a sketch or photograph of the building and enter all elevations in Items
C3.a-g.
Item C3. Indicate whether the elevation reference mark (benchmark) used during the field survey is
an elevation mark on the FIRM. If it is not, indicate the source and datum for the elevation. Vertical
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control benchmarks other than those shown on the FIRM are acceptable for elevation determinations.
Show the conversion from the field survey datum used to the datum used for the BFE(s) entered in Item
B9. All elevations for the certificate must be referenced to the datum on which the BFE is based. Show
the datum conversion, if applicable, in this section or in the Comments area of Section D. For property
experiencing ground subsidence, the most recently adjusted reference mark elevations must be used for
determining building elevations. However, when subsidence is involved, the BFE should not be adjusted.
Enter elevations in Items C3.a-g to the nearest tenth of a foot (nearest tenth of a meter, in Puerto Rico).
Items C3.a-d. Enter the building elevations (excluding the attached garage) indicated by the selected
building diagram (Item C2.) in Items C3.a-c. If there is an attached garage, enter the elevation for top of
attached garage slab in Item C3.d. (Because elevation for top of attached garage slab is self-explanatory,
attached garages are not illustrated in the diagrams.) If the building is located in a V zone on the FIRM,
complete Item C3.c. If the flood zone cannot be determined, enter elevations for all of Items C3.a-g. For
buildings in A zones, elevations a, b, d, and e should be measured at the top of the floor. For buildings in
V zones, elevation c must be measured at the bottom of the lowest horizontal structural member of the
floor (see drawing below). For buildings elevated on a crawl space, Diagram 8, enter the elevation of the
top of the crawl space floor in Item C3.a, whether or not the crawl space has openings (flood vents). If
any item does not apply to the building, enter “N/A” for not applicable. elevation levels as desc
Item C3.e. Enter the lowest elevation of machinery and/or equipment—furnaces, hot water heaters,
heat pumps, air conditioners, and elevators and their associated equipment—in an attached garage or
enclosure or on an open utility platform that provides utility services for the building. If the machinery
and/or equipment is mounted to a wall, pile, etc., enter the platform elevation of the machinery and/or
equipment. Indicate machinery/equipment type in the Comments area of Section D or Section G, as
appropriate. If this item does not apply to the building, enter “N/A” for not applicable.
Items C3.f-g. Adjacent grade is defined as the elevation of the ground, sidewalk, patio slab, or deck
support immediately next to the building. If the certificate is to be used for a LOMA or LOMR-F, provide
in the Comments area the lowest adjacent grade elevation measured at the deck support or stairs if that
elevation is lower than the building's lowest adjacent grade. For Zone AO, use the natural grade elevation,
if available. This measurement must be to the nearest tenth of a foot (nearest tenth of a meter, in Puerto
Rico) if this certificate is being used to support a request for a LOMA or LOMR-F.
Items C3.h-i. Enter the number of permanent openings (flood vents) in the walls supporting the
building, including the attached garage, that are no higher than 1.0 foot above the adjacent grade.
Determine the total area of all such openings in square inches (square cm, in Puerto Rico), and enter the
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total in Item C3.i. If the building has no permanent openings (flood vents) within 1.0 foot above adjacent
grade, enter “0” (zero) for each of Items C3.h and C3.i. Enter in the Comments area whether the
openings are on the foundation walls of the building and/or on the walls of the garage.
SECTION D - SURVEYOR, ENGINEER, OR ARCHITECT
CERTIFICATION
Complete as indicated. This section of the Elevation Certificate may be signed by only a land
surveyor, engineer, or architect who is authorized by law to certify elevation information. Place
embossed seal and signature in the box next to elevations in Section C. A flat stamp is acceptable only in
states that do not authorize use of an embossed seal over the signature of a professional. You are
certifying that the information in Sections A, B, and C on this certificate represents your best efforts to
interpret the data available and that you understand that any false statement may be punishable by fine or
imprisonment under 18 U.S. Code, Section 1001. Use the Comments area of Section D, on the back of
the certificate, to provide datum, elevation, or other relevant information not specified on the front.
SECTION E - BUILDING ELEVATION INFORMATION (SURVEY NOT
REQUIRED) FOR ZONE AO & ZONE A (WITHOUT BFE)
Complete Section E if the building is located in Zone AO or Zone A (without BFE). Otherwise,
complete Section C instead.
Item E1. Select the diagram on pages 6 and 7 that best represents the building; then enter the
diagram number. If you are unsure of the correct diagram, select the diagram that most closely resembles
the building, or provide a sketch or photograph. Explain in the Comments area if the measurement
provided under Item E.2, E.3, or E.4 is based on the “natural grade.”
Item E2. Enter the height in feet and inches (meters and centimeters, in Puerto Rico) of the top of the
bottom floor (as indicated in the applicable diagram) above or below the highest adjacent grade (HAG).
For post-FIRM buildings in Zone AO, the community’s floodplain management ordinance requires that
this value equal or exceed the base flood depth on the FIRM. Buildings in Zone A (without BFE) may
qualify for a lower insurance rate if an engineered BFE is developed at the site.
Item E3. For Building Diagrams 6-8 with proper openings (see page 7), enter the height in feet and
inches (meters and centimeters, in Puerto Rico) of the next higher floor or elevated floor (as indicated in
the applicable diagram) above the highest adjacent grade (HAG). Be sure that you have completed Items
C3.h and C3.i on the front of the form to show the number of permanent openings (flood vents) within 1
foot above adjacent grade and the total area of the openings.
Item E4. Enter the height in feet and inches, in relation to the highest adjacent grade next to the
building, of the platform that supports the machinery and/or equipment servicing the building. Indicate
machinery/equipment type in the Comments area of Section E. If this item does not apply to the building,
enter “N/A” for not applicable.
Item E5. For those communities where this base flood depth is not available, the community will
need to determine whether the top of the bottom floor is elevated in accordance with the community’s
floodplain management ordinance.
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SECTION F - PROPERTY OWNER (OR OWNER’S REPRESENTATIVE)
CERTIFICATION
Complete as indicated. This section is provided for certification of measurements taken by a property
owner or property owner’s representative when responding to Sections A, B, C (Items C3.h and C3.i
only), and E. The address entered in this section must be the actual mailing address of the property owner
or property owner’s representative who provided the information on the certificate.
SECTION G - COMMUNITY INFORMATION (OPTIONAL)
Complete as indicated. The community official who is authorized by law or ordinance to administer
the community’s floodplain management ordinance can complete Sections A, B, C (or E), and G of this
Elevation Certificate. If the authorized community official completes Sections C, E, or G, complete the
appropriate item(s) and sign this section.
Check Item G1. if Section C is completed with elevation data from other documentation, including
elevations obtained from the Community Rating System Elevation Software, that has been signed and
embossed by a licensed surveyor, engineer, or architect who is authorized by law to certify elevation
information. Indicate the source of the elevation data and the date obtained in the Comments area of
Section G. If you are both a community official and a licensed land surveyor, engineer, or architect
authorized by law to certify elevation information, and you performed the actual survey for a building in
Zones A1-A30, AE, AH, A (with BFE), VE, V1-V30, V (with BFE), AR, AR/A, AR/A1-A30, AR/AE,
AR/AH, or AR/AO, you must also complete Section D.
Check Item G2. if information is entered in Section E by the community for a building in Zone A
(without a FEMA-issued or community-issued BFE) or Zone AO.
Check Item G3. if the information in Items G4-G9 has been completed for community floodplain
management purposes to document the as-built lowest floor elevation of the building. Section C of the
Elevation Certificate records the elevation of various building components but does not determine the
lowest floor of the building or whether the building, as constructed, complies with the community’s
floodplain management ordinance. This must be done by the community. Items G4-G9 provide a way to
document these determinations.
Item G4. Permit Number. Enter the permit number or other identifier to key the Elevation
Certificate to the permit issued for the building.
Item G5. Date Permit Issued. Enter the date the permit was issued for the building.
Item G6. Date Certificate of Compliance Issued. Enter the date that the Certificate of Compliance or
Occupancy or similar written official documentation of as-built lowest floor elevation was issued by the
community as evidence that all work authorized by the floodplain development permit has been
completed in accordance with the community’s floodplain management laws or ordinances.
Item G7. New Construction or Substantial Improvement. Check the applicable box. “Substantial
Improvement” means any reconstruction, rehabilitation, addition, or other improvement of a building, the
cost of which equals or exceeds 50 percent of the market value of the building before the start of
construction of the improvement. The term includes buildings that have incurred substantial damage,
regardless of the actual repair work performed.
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Item G8. As-built lowest floor elevation. Enter the elevation of the lowest floor (including
basement) when the construction of the building is completed and a final inspection has been made to
confirm that the building is built in accordance with the permit, the approved plans, and the community’s
floodplain management laws or ordinances. Indicate the elevation datum used.
Item G9. BFE. Using the appropriate FIRM panel, FIS, or other data source, locate the property and
enter the BFE (or base flood depth) of the building site. Indicate the elevation datum used.
Enter your name, title, and telephone number, and the name of the community. Sign and enter the
date in the appropriate blanks.
The following eight diagrams illustrate various types of buildings. Compare the features of the
building being certified with the features shown in the diagrams and select the diagram most applicable.
Enter the diagram number in Item C2. and the elevations in Items C3.a-C3.g.
In A zones, the floor elevation is taken at the top finished surface of the floor indicated; in V zones,
the floor elevation is taken at the bottom of the lowest horizontal structural member (see drawing in
instructions for Section C).
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c
(determined by
existing grade)
(For V zones only)
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DIAGRAM 5
All buildings elevated on piers, posts, piles, columns, or
parallel shear walls. No obstructions below the elevated
floor.
ELEVATED
FLOOR
NEXT HIGHER
FLOOR
Distinguishing Feature – For all zones, the area below the elevated floor is open,
with no obstruction to flow of flood waters (open lattice work and/or readily
removable insect screening is permissible).
a
(For V zones only)
c
f
(determined by existing grade)
g
b
GRADE
DIAGRAM 6
All buildings elevated on piers, posts, piles, columns, or
parallel shear walls with full or partial enclosure below the
elevated floor.
f
g
Distinguishing Feature – For all zones, the area below the elevated floor is
enclosed, either partially or fully. In A Zones, the partially or fully enclosed area
below the elevated floor is with or without openings** present in the walls of the
enclosure. Indicate information about openings in Section C, Building Elevation
Information (Survey Required).
ENCLOSURE
NEXT HIGHER
FLOOR
a
ELEVATED
FLOOR
GRADE
DIAGRAM 7
All buildings elevated on full-story foundation walls with a
partially or fully enclosed area below the elevated floor. This
includes walkout levels, where at least one side is at or above
grade. The principal use of this building is located in the
elevated floors of the building.
NEXT HIGHER
FLOOR
b
a
f
g
WALKOUT LEVEL
Distinguishing Feature – For all zones, the area below the elevated floor is
enclosed, either partially or fully. In A Zones, the partially or fully enclosed area
below the elevated floor is with or without openings** present in the walls of the
enclosure. Indicate information about openings in Section C, Building Elevation
Information (Survey Required).
OPENINGS**
GRADE
DIAGRAM 8
All buildings elevated on a crawl space with the floor of the
crawl space at or above grade on at least one side, with or
without an attached garage.
NEXT HIGHER
FLOOR
a
OPENINGS**
CRAWL SPACE
g
b
Distinguishing Feature – For all zones, the area below the first floor is enclosed by
solid or partial perimeter walls. In all A zones, the crawl space is with or without
openings** present in the walls of the crawl space. Indicate information about the
openings in Section C, Building Elevation Information (Survey Required).
GRADE
f
**An “opening” (flood vent) is defined as a permanent opening in a wall that allows for the free
passage of water automatically in both directions without human intervention. Under the NFIP, a
minimum of two openings is required for enclosures or crawl spaces with a total net area of not less than
one square inch for every square foot of area enclosed. Each opening must be on different sides of the
enclosed area. If a building has more than one enclosed area, each area must have openings on exterior
walls to allow floodwater to directly enter. The bottom of the openings must be no higher than one foot
above the grade underneath the flood vents. Alternatively, you may submit a certification by a registered
professional engineer or architect that the design will allow for the automatic equalization of hydrostatic
flood forces on exterior walls. A window, a door, or a garage door is not considered an opening
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Course Name
Course
Code
Course Description
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APPENDIX G:
EMI COURSES
The courses summarized in this Appendix are presented one or more times
each year at FEMA’s Emergency Management Institute (EMI), located in
Emmitsburg, Maryland.
Tuition for these courses is free for State and local government officials and
travel stipends are available. For more information, contact the training office of
your state emergency management agency, or call 1-800-238-3358 or visit EMI’s
Website at http://training.fema.gov/EMIWeb.
Selection Criteria
Managing Floodplain
E273
This course is designed
Local officials responsible
Development
to provide an organized
for administering local
Through the National
training opportunity for
floodplain management
Flood Insurance
local officials
ordinances, including but
Program (NFIP)
responsible for
administering their local
floodplain ordinance.
The course will focus
on the NFIP and
concepts of floodplain
management, maps
and studies, ordinance
administration, and the
relationship between
floodplain management
and flood insurance.
not limited to floodplain
management
administrators, building
inspectors, code
enforcement/zoning
officers, planners,
city/county managers,
attorneys, engineers, and
public works officials.
Federal/State/regional
floodplain managers also
are encouraged to attend.
The course is designed for
those officials with limited
floodplain management
experience. Attendance
will be limited to two
participants from any state
for each offering.
National Flood
Insurance
Program/Community
Rating System
(NFIP/CRS)
E278
This course covers the
CRS, a nationwide
initiative of FEMA’s
NFIP. It describes
activities eligible for
credit under CRS, how
a community applies,
and how a community
modifies an application
to improve its
classification.
FEMA regional office staff,
NFIP State coordinators,
those managing floodplain
services for local
governments, and others
interested in learning about
CRS so they can provide
technical assistance to
communities seeking to
apply for CRS credit.
Attendance is limited to two
participants from any one
community per fiscal year.
EMI Courses
G-1
Course Name
Course
Code
Course Description
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Selection Criteria
Mitigation for Tribal
Officials
E344
This course provides
Tribal members and
their representatives
with an overview of
FEMA’s mitigation
programs, to outline
tribal mitigation
responsibilities, and to
discuss opportunities
for achieving mitigation
successes. The course
will cover mitigation
planning, the National
Flood Insurance
Program (NFIP), and
mitigation grant
programs.
The course will be limited
to federally recognized
tribal members and their
representatives.
Retrofitting Flood-
Prone Residential
Buildings
E279
This course is designed
to provide engineering
and economic guidance
on what constitutes
proper retrofitting
techniques for flood-
prone residential
structures. The course
will focus on the
concepts of flood
proofing, regulatory
framework, controlling
parameters, design
practices, and benefit,
cost, and technical
feasibility analysis.
There is a case study
design exercise and a
written examination.
The audience comprises
engineers and architects,
and building code,
floodplain management,
hazard mitigation, planning,
zoning, and public works
officials. This course is
intended for those with
engineering, architectural,
or building science
knowledge.
EMI Courses
G-2
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APPENDIX H:
LEARNING CHECKS AND EXERCISES
UNIT 1
LEARNING CHECK #1
1.
This unit describes a number of types of floods. Which types occur in your
community?
2.
What are the three most common types of flooding?
3.
Which type of flooding has accounted for the most flood-related deaths in
recent history?
4.
What is a “meander?”
5.
What’s the major cause of coastal flooding?
6.
What causes a tsunami?
7.
List the five types of special flood hazards covered in this course. Does your
community have any of these?
8.
List at least three benefits that floodplains, in a relatively undisturbed condi
tion, actually contribute or could contribute to your community.
Floods and Floodplain Management
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UNIT 1 - LEARNING CHECK #2
1. What two problems result from floodplain development?
2. What does watershed development do to flooding?
3. What is one of the problems with constructing seawalls to protect buildings
from flooding or erosion?
4. What are the five main causes of flood damage?
5. Standing water as little as
feet deep can collapse the walls of a frame
house.
6. What are some of the safety and health hazards that accompany floods?
7. Prior to the 1960’s what was the primary way to reduce flood losses?
8. What is the Unified National Program for Floodplain Management’s defini
tion of “floodplain management?”
9. What are the two primary goals of floodplain management?
Floods and Floodplain Management
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UNIT 1 - LEARNING EXERCISE
1.
What areas are conducive to flash flooding?
2.
Is erosion only a threat in coastal areas?
3.
What is “ponding?”
4.
Are plants and animals the only beneficiaries of the “natural and beneficial
functions” of floodplains?
5.
What does filling in a floodplain do?
6.
Does moving sand and sand dunes affect flooding?
7.
Hydrodynamic forces are caused by ______________ water and hydrostatic
forces are caused by ______________ water.
8.
List three materials or household items that are particularly susceptible to
flood damage by soaking.
9.
What are examples of non-structural flood protection measures?
10. What are the Unified National Program for Floodplain Management’s four
main floodplain management strategies?
Floods and Floodplain Management
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UNIT 1 - LEARNING CHECK #1 - ANSWERS
1.
This unit describes a number of types of floods. Which types occur in your
community?
Depends on the community
2.
What are the three most common types of flooding?
Riverine, coastal, shallow
3.
Which type of flooding has accounted for the most flood-related deaths in
recent history?
Flash flooding.
4.
What is a “meander?”
It’s a curve or turn in a river channel.
5.
What’s the major cause of coastal flooding?
Storm surge.
6.
What causes a tsunami?
Underwater earthquakes or volcanoes.
7.
List the five types of special flood hazards covered in this course. Does your
community have any of these?
— Closed basin lakes
— Uncertain flow paths
— Dam breaks
— Ice jams
— Mudflows
If your community has one or more of these hazards, you should become
familiar with their natural processes and the appropriate regulatory
measures discussed in Unit 6.
8.
List at least three benefits that floodplains, in a relatively undisturbed condi
tion, actually contribute or could contribute to your community.
Although this depends on the community, there are a large number of
benefits they could potentially provide.
Floods and Floodplain Management
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UNIT 1 – LEARNING CHECK #2 - ANSWERS
1.
2.
3.
4.
5.
6.
7.
8.
What two problems result from floodplain development?
- Development alters the floodplain and the dynamics of flooding.
- Buildings and infrastructure are damaged by periodic flooding.
What does watershed development do to flooding?
The increase in impervious surface results in increased runoff and higher
flood levels.
What is one of the problems with constructing seawalls to protect buildings
from flooding or erosion?
It can accelerate erosion on properties at the end of the wall.
What are the five main causes of flood damage?
Hydrodynamic forces
Debris impact
Hydrostatic forces
Soaking
Sediment and contaminants
Standing water as little as
feet deep can collapse the walls of a frame
house.
Three feet
What are some of the safety and health hazards that accompany floods?
Disruption of public utilities
Electrocution
Contamination of water supplies
Fire
Animal carcasses, garbage and ponds that can become breeding grounds
for germs and mosquitoes.
Mold, mildew and bacteria that grow in damp, flooded areas
Contaminated air from dirty heating ducts
Stress and mental health problems.
Prior to the 1960’s what was the primary way to reduce flood losses?
Structural flood control projects
What is the Unified National Program for Floodplain Management’s defini
tion of “floodplain management?”
Floods and Floodplain Management
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“A decision-making process that aims to achieve the wise use of the na
tion’s floodplains.”
9.
What are the two primary goals of floodplain management?
To reduce the loss of life, disruption, and damage caused by floods
To preserve and restore the natural resources and functions of floodplains
Floods and Floodplain Management
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UNIT 1 – LEARNING EXERCISE - ANSWERS
1.
What areas are conducive to flash flooding?
-Hilly areas with steep slopes and narrow valleys
-Urban areas with large amounts of impervious surfaces and storm sewers
-Areas downstream of dams or subject to ice jams
2.
Is erosion only a threat in coastal areas?
No. Riverine erosion can move stream channels and undercut structures.
3.
What is “ponding?”
Where stormwater runoff collects in depressions and cannot drain out.
4.
Are plants and animals the only beneficiaries of the “natural and beneficial
functions” of floodplains?
No. People benefit from floodplains through the food they provide, the
recreational opportunities they afford and the scientific knowledge gained
in studying them. Floodplains also recharge groundwater supplies and
their filtering actions help improve water quality.
5.
What does filling in a floodplain do?
Filling reduces the floodplain’s ability to store excess water, sending more
water downstream and causing floods to rise to higher levels.
6.
Does moving sand and sand dunes affect flooding?
Yes, it may remove a natural barrier that protects inland properties.
7.
Hydrodynamic forces are caused by ______________ water and hydrostatic
forces are caused by ______________ water.
Moving, standing
8.
List three materials or household items that are particularly susceptible to
flood damage by soaking.
- Wood
- Gypsum wallboard
- Furniture and upholstery
- Carpeting
- Mattresses
- Books
- Electrical appliances
- Gasoline engines
9.
What are examples of non-structural flood protection measures?
Floods and Floodplain Management
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- Regulations to prohibit development in high-hazard areas.
- Building codes requiring flood-resistant construction for new buildings
in floodprone areas.
- Acquisition and relocation of buildings in high hazard areas.
- Modifying or retrofitting existing buildings.
- Installing flood warning systems.
- Controlling stormwater runoff.
- Providing self-help advice to property owners.
10. What are the Unified National Program for Floodplain Management’s four
main floodplain management strategies?
- Modify human susceptibility to flood damage
- Modify the impact of flooding
- Modify flooding itself
-Preserve and restore natural resources
Floods and Floodplain Management
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UNIT 2
LEARNING CHECK #1
1.
What are the objectives of the NFIP?
2.
What are the three basic parts of the NFIP?
3.
Who uses NFIP maps?
4.
What should happen to buildings in NFIP communities over time?
National Flood Insurance Program
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UNIT 2 - LEARNING CHECK #2
1.
What types of governmental bodies are considered to be “communities” by
the NFIP?
2.
What office is the state coordinating agency for your community?
3.
Which FEMA office works directly with communities?
4.
What is the Write Your Own Program?
5.
When a community applies to join the NFIP, what must it submit?
6.
What are the sanctions if a community does not participate in the NFIP?
National Flood Insurance Program
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UNIT 2 - LEARNING EXERCISE
1.
Where does most of the money come from to pay the expenses of the NFIP?
2.
How many communities currently participate in the NFIP?
3.
What is a “pre-FIRM” building.
4.
Is there any relation between how a community regulates new construction
and flood insurance rates?
5.
List two things your community committed itself to when it joined the
NFIP.
6.
Insurance companies set flood insurance rates and coverage rules. True or
false?
7.
What can FEMA do to encourage a community to adequately enforce its
floodplain management regulations?
8.
What are the sanctions if a community is suspended from the NFIP?
National Flood Insurance Program
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UNIT 2- LEARNING CHECK #1 - ANSWERS
1.
What are the objectives of the NFIP?
- The National Flood Insurance Act created the National Flood Insurance
Program (NFIP) to:
- Transfer the costs of private property flood losses from the taxpayers to
floodplain property owners through flood insurance premiums.
- Provide floodplain residents and property owners with financial aid after
floods, especially smaller floods that do not warrant federal disaster aid.
- Guide development away from flood hazard areas.
- Require that new and substantially improved buildings be constructed in
ways that would minimize or prevent damage in a flood.
2.
What are the three basic parts of the NFIP?
- Mapping
- Insurance
- Regulations
3. Who uses NFIP maps?
- Communities, states and Federal agencies use them as the basis for
regulating new floodprone construction,
- Insurance agents use them when rating flood insurance policies, and
- Lenders and Federal agencies use them to determine when flood insur
ance must be purchased as a condition of a loan or financial assistance.
4.
What should happen to buildings in NFIP communities over time?
Over time, exposure to flood damage should be reduced, as the older pre-
FIRM buildings are replaced by post-FIRM buildings. Eventually a com
munity should have only post-FIRM building’s subject to little or no flood
damage.
National Flood Insurance Program
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UNIT 2 – LEARNING CHECK #2 - ANSWERS
1.
2.
3.
4.
5.
6.
What types of governmental bodies are considered to be “communities” by
the NFIP?
These governmental bodies vary from state to state, but can include cities,
towns, villages, townships, counties, parishes, special districts, states and
Indian nations with the statutory authority to enact and enforce regula
tions.
What office is the state coordinating agency for your community?
See Appendix B.
Which FEMA office works directly with communities?
The ten Regional Offices.
What is the Write Your Own Program?
An arrangement whereby private insurance companies write and service
NFIP flood Insurance policies under their own name.
When a community applies to join the NFIP, what must it submit?
A resolution of intent to “maintain in force…adequate land use and con
trol measures” and to cooperate with FEMA
Its adopted floodplain management ordinance.
What are the sanctions if a community does not participate in the NFIP?
- Flood insurance will not be available. No resident will be able to pur
chase a flood insurance policy through the NFIP.
- If the community withdraws or is suspended, existing flood insurance
policies will not be renewed.
- No Federal grants or loans for development may be made in identified
flood hazard areas under programs administered by Federal agencies
such as HUD, EPA, and SBA.
- No Federal disaster assistance may be provided to repair insurable
buildings located in identified flood hazard areas for damage caused by a
flood.
- No Federal mortgage insurance or loan guarantees may be provided in
identified flood hazard areas. This includes policies written by FHA, VA,
and others.
- Federally insured or regulated lending institutions, such as banks and
credit unions, must notify applicants seeking loans for insurable buildings
in flood hazard areas that:
- There is a flood hazard and
- The property is not eligible for Federal disaster relief.
National Flood Insurance Program
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UNIT 2 – LEARNING EXERCISE - ANSWERS
1.
2.
3.
4.
5.
6.
7.
8.
Where does most of the money come from to pay the expenses of the NFIP?
Premium income. The NFIP has been self-supporting since 1986.
How many communities currently participate in the NFIP?
More than 19,000
What is a “pre-FIRM” building?
A building built before the effective date of the community’s Flood Insur
ance Rate Map.
Is there any relation between how a community regulates new construction
and flood insurance rates?
Yes. Buildings built in accordance with the community’s regulations have
a lower risk of flooding and can be insured at lower rates.
List two things your community committed itself to when it joined the
NFIP.
- Issuing or denying floodplain development/building permits.
- Inspecting all development to assure compliance with the local ordi
nance.
- Maintaining records of floodplain development.
- Assisting in the preparation and revision of floodplain maps.
- Helping residents obtain information on flood hazards, floodplain map
data, flood insurance and proper construction measures.
Insurance companies set flood insurance rates and coverage rules. True or
false?
False. Flood insurance rates and coverage rules are set by FEMA’s Fed
eral Insurance Administration.
What can FEMA do to encourage a community to adequately enforce its
floodplain management regulations?
If the community is in the Community Rating System, it can reclassify it to
a Class 10 (no insurance premium discount).
The community can be put on probation.
The community can be suspended.
What are the sanctions if a community is suspended from the NFIP?
The same as for nonparticipation (see question 6, Learning Check 2). Sus
pension means the community is no longer a participant in the NFIP.
National Flood Insurance Program
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UNIT 3
LEARNING CHECK #1
1.
As directed by the National Flood Insurance Act of 1968, FEMA conducts
flood studies in order to determine __________________________ and
___________________ .
2.
The base flood is a flood that has a ____________________ of occurring in
any year.
3.
The base flood is also called the ________ - year flood.
4.
Determine whether the following statements are true or false. Circle T for
True and F for False.
♦ A 100-year flood will occur only once every 100 years.
T
F
♦ A 100-year flood could occur two times in one year.
T
F
♦ The 100-year flood might not occur in a 200-year period.
T
F
♦ The base flood could occur in two consecutive years in a row. T
F
5.
On NFIP maps, the base floodplain is called the _____________
_____________ ____________ ___________ . (4 words)
6.
BFE is the acronym for __________ __________ _____________ .
7.
What are the components of a Flood Insurance Study?
Flood Studies and Maps
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UNIT 3 - LEARNING CHECK #2
1.
For purposes of a riverine flood study, ______________ is the study of the
distribution and circulation of water in the environment, and
______________ is the study of fluids in motion and how water will flow
through the channel.
2.
The rate at which runoff (an amount of water) flows downstream is called
the flood ______________ .
3.
What probable effect does increase in urbanization within a community or
upstream of it have on the stream discharges within that community?
4.
What consequence on flood water level of a stream would usually occur
when a bridge is constructed over a stream?
5.
To locate the true elevations at a site, surveyors have established
_______________ _______________ marks also known as
_______________ marks.
6.
Cross sections describe the
of the floodplain.
7.
What is the datum used for your FIS, FIRM, and profiles?
8.
Flood profiles are developed by plotting the flood elevations at the
_____________ _____________ and connecting the plotted points.
9.
To make a floodplain map, the base flood elevations are plotted on a
_____________ map or a _____________ map.
10. The ______________ is defined as the stream channel and that portion of
the adjacent floodplain that must remain open to permit passage of the base
flood.
11. A floodway analysis conducted to the minimum NFIP standard allows the
fringe to be obstructed until the base flood level is increased by how much?
Flood Studies and Maps
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UNIT 3 - LEARNING CHECK #3
1.
What causes storm surge?
2.
What is wave runup?
3.
Instead of cross sections, coastal flood engineers survey ____________ .
4.
The BFEs for coastal studies are the __________ ___________ plus the
__________ ______________________________ .
5.
The most hazardous part of the coastal floodplain is the ______________
__________ ___________ area, which is shown on the map as a ____
Zone.
6.
What differentiates shallow flooding from riverine flooding?
7.
Flood studies that do not identify BFEs are called __________
______________ .
Flood Studies and Maps
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UNIT 3 - LEARNING CHECK #4
1.
Prior to 1986, the maps published with an FIS were the ___________ and
the ___________ .
2.
Since 1986, the map published with an FIS is the ________________.
3.
Is your community’s FIRM a flat or Z-fold map?
4.
How many panels does your FIRM have?
5.
What is the map scale of your FIRM?
6.
What does an elevation reference mark look like on a FIRM?
7.
What is an AO Zone?
8.
What is the FIRM effective date for your community?
9.
How is a floodway shown on the Flood Boundary and Floodway Map?
10. How is a floodway shown on the new format FIRM?
11. A Zone C on an old format FIRM is shown as a Zone ____ on the new
format FIRM.
12. CBRA stands for ______________ ______________ ______________
______________ .
13. What communities’ floodplains are shown on a countywide FIRM?
14. Floodways are shown along the ______________ toe of a levee on the
FIRM.
15. Areas behind recognized levees are designated as _____________
______________.
Flood Studies and Maps
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UNIT 3 - LEARNING EXERCISE
1.
The base flood elevation is the elevation of the ____ - year flood or the ___
% annual chance flood.
2.
The Special Flood Hazard Area or SFHA is what the ______________
floodplain is called on FEMA maps.
3.
The SFHA is shown on a FIRM as a Zone that begins with the letter ___ or
___ .
4.
What are the components of a Flood Insurance Study?
5.
List three things that a FIRM is used to determine.
6.
_________________ is the study of a watershed’s behavior during and after
a storm.
7.
Surveyors reference elevation to a common ______________ .
8.
Most permanent FIS elevation reference marks are referenced to what da
tum?
9.
A hydraulic study uses the hydrology, cross section information, and stream
characteristics to determine the flood ______________ .
10. Cross sections are shown on which map?
11. Flood profiles are used to determine what?
12. In riverine situations, the floodplain is divided into two separate parts for
floodplain management purposes. These parts are the _____________ and
the _______________.
13. Based on the minimum NFIP standard, if the flood fringe were completely
filled, how high could the base flood elevation go up?
14. What FIRM zone has wave heights greater than three feet?
Flood Studies and Maps
_________________________________________________
__________________________________________________
__________________________________________________
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15. Instead of using a base flood elevation, some shallow flooding areas are
defined using a base flood _________ .
16. An approximate study shows the base ____________________ but does not
show the base flood ______________ .
17. How many digits are there in the NFIP community identification number?
18. What is an AH Zone?
19. What was the problem with the way the floodway was shown on the old
format Flood Boundary and Floodway Maps?
20. The new format FIRMs include:
21. Do Q3 Flood Data show base flood elevations if they are available?
Flood Studies and Maps
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UNIT 3 - LEARNING CHECK #1 - ANSWERS
1.
As directed by the National Flood Insurance Act of 1968, FEMA conducts
flood studies in order to determine __________________________ and
___________________ .
floodprone areas and flood risk zones
2.
The base flood is a flood that has a ____________________ of occurring in
any year.
one percent chance
3.
The base flood is also called the ________ - year flood.
100-year
4.
Answer the following questions (circle T for True and F for False):
♦ A 100-year flood will occur only once every 100 years.
T
F
♦ A 100-year flood could occur two times in one year.
T
F
♦ The 100-year flood might not occur in a 200-year period.
T
F
♦ The base flood could occur two consecutive years in a row.
T
F
F T T T
5.
On NFIP maps, the 100-year floodplain is called the _____________
_____________ ____________ ___________ .
Special Flood Hazard Area
6.
BFE is the acronym for __________ __________ _____________ .
base flood elevation
7.
What are the components of a Flood Insurance Study?
The FIS — Flood Insurance Study report
The FIRM — Flood Insurance Rate Map
The Flood Boundary and Floodway Map, which is included in studies pre
pared before 1986 (Since 1986, floodways are shown on the FIRM)
Flood Studies and Maps
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UNIT 3 – LEARNING CHECK #2 - ANSWERS
1.
For purposes of a riverine flood study, ________________ is the study of
the distribution and circulation of water in the environment, and
_____________ is the study of fluids in motion and how water will flow
through the channel.
Hydrology, hydraulics
2.
The rate at which runoff flows downstream is called the flood
______________ .
discharge
3.
What probable effect does increase in urbanization within a community or
upstream of it have on the stream discharges within that community?
Stream discharges usually will increase as a consequence to the increase
in urbanization within a community or upstream of it.
4.
What consequence on flood water level of a stream would usually occur
when a bridge is constructed over a stream?
A hydraulic analysis is always required to determine the effect of any
bridge construction over a stream. However, construction over a stream is
considered an obstruction to the flow and therefore may increase the flood
water level upstream of the construction.
5.
To locate the true elevations at a site, surveyors have established
_______________ _______________ marks also known as
_______________ marks.
elevation reference, bench
6.
Cross sections describe the
of the floodplain.
shape
7.
What is the datum used for your community’s flood insurance study, FIRM,
and profiles?
Depends on the community. Check the Legend or Key to your FIRM.
8.
Flood profiles are developed by plotting the flood elevations at the
_____________ _____________ and connecting the plotted points.
cross sections
9.
To make a floodplain map, the base flood elevations are plotted on a
_____________ map or a _____________ map.
topographic or contour
10. The ______________ is defined as the stream channel and that portion of
the adjacent floodplain that must remain open to permit passage of the base
flood.
Flood Studies and Maps
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Floodway
11. A floodway analysis conducted to the minimum NFIP standard allows the
fringe to be obstructed until the base flood level is increased by how much?
one foot
Flood Studies and Maps
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UNIT 3 – LEARNING CHECK #3 - ANSWERS
1.
What causes storm surge?
Storms that bring air pressure changes and strong winds that “pile” water
up against the shore
2.
What is wave runup?
When waves hit the shore, water moves with such force that it keeps trav
eling inland higher than the stillwater flood level.
3.
Instead of cross sections, coastal flood engineers survey ____________ .
transects
4.
The BFEs for coastal studies are the __________ ___________ plus the
__________ __________ .
stillwater elevations, wave runup
5.
The most hazardous part of the coastal floodplain is the ______________
__________ ___________ area, which is shown on the map as a ____
Zone.
coastal high hazard, V
6.
What differentiates shallow flooding from riverine flooding?
Shallow flooding is distinguishable from riverine or coastal flooding be
cause it occurs in areas where there is no channel or identifiable flow
path.
7.
Flood studies that do not identify BFEs are called __________
______________ .
approximate studies
Flood Studies and Maps
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UNIT 3 – LEARNING CHECK #4 - ANSWERS
1.
Prior to 1986, the maps published with an FIS are the ___________ and the
___________ . Since 1986, the map published with an FIS is the
_______________________.
old format FIRM, FBFM or Floodway Map
new format FIRM
Is your community’s FIRM a flat or Z-fold map?
Depends on the community.
2.
How many panels does your FIRM have?
Depends on the community.
3.
What is the map scale of your FIRM?
Depends on the community.
4.
What does an elevation reference mark look like on a FIRM?
Locations are identified with a small “x” and the designation “ERM” or
“RM” followed by a number.
5.
What is an AO Zone?
The area subject to sheet flow, ponding, or shallow flooding.
6.
What is the FIRM effective date for your community?
Depends on the community. This is the date of the first FIRM for your
community. It is an important date to know as it determines whether build
ings are considered pre-FIRM or post-FIRM. If you are unsure of the
date, contact your FEMA Regional Office or State NFIP Coordinator.
7.
How is a floodway shown on the Flood Boundary and Floodway Map?
It’s the white area adjacent to and including the channel.
8.
How is a floodway shown on the new format FIRM?
It is a shaded area with diagonal lines.
9.
A Zone C on an old format FIRM is shown as a Zone ____ on the new
format FIRM.
Zone X
Flood Studies and Maps
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10. CBRA stands for ______________ ______________ ______________
______________ .
Coastal Barriers Resources Act
11. What communities’ floodplains are shown on a countywide FIRM?
All the communities in the county, even those currently not in the NFIP.
12. Floodways are shown along the ____________ toe of a levee on the FIRM.
landside
13. Areas behind recognized levees are designated as ____________
___________.
Shaded Zone X
Flood Studies and Maps
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UNIT 3 – LEARNING EXERCISE - ANSWERS
1.
The base flood elevation is the elevation of the ____ - year flood or the ___
% annual chance flood.
100, 1
2.
The Special Flood Hazard Area or SFHA is how the ______________
floodplain is shown on FEMA maps.
base flood
3.
The SFHA is shown on a FIRM as a Zone that begins with the letter ___ or
___ .
A or V
4.
What are the components of a Flood Insurance Study?
Flood Insurance Study report
Flood Insurance Rate Map
Flood Boundary and Floodway Map for studies conducted prior to 1986.
In studies conducted since 1986, the floodway data are shown on the
FIRM and there is no separate Flood Boundary and Floodway Map.
5. List three things that a FIRM is used to determine.
Whether a property is in the floodplain
The flood insurance zone that applies to a property
The approximate BFE at a site
6.
_____________ is the study of a watershed’s behavior during and after a
storm.
hydrology
7.
Surveyors reference elevation to a common ______________ .
datum
8.
Most permanent FIS elevation reference marks are referenced to what da
tum?
National Geodetic Vertical Datum or NGVD
9.
A hydraulic study uses the hydrology, cross-section information, and stream
characteristics to determine the flood ______________ .
elevations (also velocities and floodplain widths)
10. Cross sections are shown on which map?
Floodway Map
Flood Studies and Maps
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New format FIRM
11. Flood profiles are used to determine what?
Flood elevations along a river or a stream between cross sections
12. In riverine situations, the floodplain is divided into two separate parts for
floodplain management purposes. These parts are the _____________ and
the _______________.
floodway, flood fringe
13. Based on the minimum NFIP standard, if the flood fringe were completely
filled, how high could the base flood elevation go up?
one foot
14. What FIRM zone has wave heights greater than three feet?
V Zone
15. Instead of using a base flood elevation, some shallow flooding areas are
defined using a base flood _________ .
depth
16. An approximate study shows the base ____________________ but does not
show the base flood ______________ .
Floodplain, elevation
17. How many digits are there in the NFIP community identification number?
They always have six digits. This is important to avoid confusion with the
five-digit countywide FIRM Number. The community identification num
ber does not include the panel number and other numbers that appear
near it on the FIRM title block.
18. What is an AH Zone?
Shallow flooding base floodplain with base flood elevations.
19. What was the problem with the way the floodway was shown on the old
format Flood Boundary and Floodway Maps?
The white area looked like it was a C Zone outside the floodplain. Also,
people who had only a FIRM did not know of the floodway hazard.
20. The new format FIRMs include:
floodways and floodplain management information
simplified flood insurance zones
21. Do Q3 Flood Data show base flood elevations if they are available?
No. They are designed primarily to determine if a property is in or out of
the SFHA.
Flood Studies and Maps
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UNIT 4
LEARNING CHECK #1
Using what you have learned so far, use the FIS report and FIRM for Flood County,
USA to answer the following questions.
1.
What is the base flood discharge on the Rocky River just upstream of Wel
lington Road?
2.
What is the 10-year peak discharge for Cobb Brook?
3.
How many cross sections were surveyed for Cobb Brook?
4.
What is the width of the floodway for the Rocky River at cross-section G?
5.
What is the flood elevation at cross-section G of the Rocky River that you
would use for regulating new construction?
6.
What is the best source of base flood elevation data for regulatory purposes
for a coastal floodplain?
7.
In which FIRM Zone is Site F located?
8.
What is the regulatory base flood elevation at Site F?
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UNIT 4 - LEARNING CHECK #2
1.
How many feet does one inch on Flood County FIRM panel 38 represent?
2.
How many feet does one inch on Flood County FIRM panel 25 represent?
3.
Using Flood County FIRM panel 40 and the engineer’s scale, what is the
width of the floodway at cross-section F on the Rocky River?
4.
Using the Floodway Data Table, what is the floodway width at cross-section
F on the Rocky River?
5.
Using FIRM panel 40 and the engineer’s scale, what is the distance between
cross-sections F and G on the Rocky River?
6.
What is the distance between cross-sections F and G on the Rocky River
according to the Floodway Data Table?
7.
Site C is within the Town of Floodville. How high is the base flood eleva
tion at Site C?
8.
What is the regulatory base flood elevation at cross-section D on the Rocky
River?
9.
RM 40-2 is located on panel 40 near the intersection of South Road and
Dairy Road. How far is RM 40-2 from the closest SFHA?
10. Site E is on panel 25 at the western limit of Cedar Hill Road just north of
Dean Lake. What is the base flood elevation at Site E?
11. A 50' x 50' building is located 200 feet south of RM 40-2 on panel 40. Is it
in the floodway?
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UNIT 4 - LEARNING CHECK #3
1.
What is the base flood elevation for the Rocky River at cross-section C:
a. Using the flood profiles in the FIS report?
b. Using the Floodway Data Table?
c. If these numbers are different, which BFE should you use?
2.
An “I” symbol is plotted 1,910 feet upstream of the confluence with the
Rocky River on Flood Profile 01P. What does this symbol represent?
3.
Is the footbridge upstream or downstream from the limit of detailed study?
4.
Using Flood Profile 03P, determine the BFE on the Rocky River for a site
that is 520 feet downstream of Fox Croft Drive.
5.
How far is the Fox Croft Drive bridge from cross-section D on the Rocky
River?
6.
A developer proposes to place a structure 625 feet (0.12) miles upstream
from the Martling Way Bridge adjacent to the Rocky River (FIRM panel
38). Using the flood profiles, tell the developer how high the structure
would have to be elevated to be above the base flood elevation as well as
the 500-year flood elevation.
7.
A particular site is 750 feet upstream of Argyle Way adjacent to the Rocky
River (FIRM panel 38). What is the base flood elevation here?
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UNIT 4 - LEARNING CHECK #4
1.
What office is the primary repository for your FIS, FIRM, or Floodway
Map?
2.
How do you get more copies of your FIRM?
3.
What are the four types of map changes?
4.
Mrs. Murphy says she has a survey that shows that her house is higher than
the flood level. What type of map change should she request?
5.
For what locations on her property will Mrs. Murphy need elevation data?
6.
A builder wants to get a bank loan to develop an area. His plans are to fill
some low spots and get all the building sites out of the floodplain. His
banker will not grant a loan for the project unless she is reassured that the
FIRM will be changed when the project is finished. What type of map
change should the builder request?
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UNIT 4 - LEARNING EXERCISE
1.
Using the Flood Insurance Study for Flood County, USA and Incorporated
Areas:
2.
What is the community number for the unincorporated areas of Flood
County?
3.
What is the best map to use to determine if a property is in the SFHA?
4.
What is the best map to use to determine if a property is in a floodway?
5.
What is the effective date of the Flood County FIRM?
6.
Is the Flood County FIRM in the old format or new format?
7.
Look at the Flood County FIRM Index. Why is there no FIRM panel for the
northwest corner of the county?
8.
If you measured a distance on the ground as 500 feet, how many inches
would it be on the Flood County FIRM panel 25?
9.
How many miles of stationing would there be if you measured a distance
between two cross sections as 1,050 feet?
10. Marge’s house is located at Site F on Flood County FIRM panel 40. How far
is her house from the boundary of the nearest coastal barrier?
11. Examining the Atlantic Coastline, what is the highest wave crest elevation
shown on the FIRM?
12. What FIRM panel is RM 38-1 on?
13. What is the base flood elevation at the location given orally?
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14. If a surveyor wanted to locate RM 38-1 on the ground, what would he or she
look for?
15. How high above sea level is RM 40-1?
16. A site is located at the point formed by the intersection of Glebe Way and
Foley Drive between Foley Drive and the Rocky River.
17. On which FIRM panel is the site?
18. In which FIRM zone is the site?
19. What is the base flood elevation at the site?
20. The property is in which of the following? (Check those that apply.)
____ 100-year floodplain
____ 100-year floodway
____ 500-year floodplain
____ Coastal High Hazard Area
____ Designated coastal barrier
21. A site is on the banks of Cobb Brook, 100 feet west of Tullamore Lane
bridge.
a. On which FIRM panel is the site?
b. In which FIRM zone is the site?
c. What is the base flood elevation at the site using the FIRM?
d. What is the base flood elevation at the site using the profile?
22. A vacant lot near Site D was recently purchased. The new owners ask for
your help in locating the best spot to build a new house. The FIRM shows
the entire property in the SFHA. You are handy with a transit, so you sur
vey the proposed building site during a visit to the property. You find that
the building site is above the BFE. The owners want you to inform their
bank so they won’t have to buy flood insurance. What do you say?
23. When the Flood County FIS was completed, the watershed of the Rocky
River was relatively undeveloped. Over the last 15 years, there has been a
Using NFIP Studies and Maps
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lot of new construction throughout this small watershed. The Town Engi
neer says that the base flood elevations are probably out of date and
underestimate the true flood hazard. What can you do to attempt to get your
FIRM updated?
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UNIT 4 - LEARNING CHECK #1 - ANSWERS
1.
What is the base flood discharge on the Rocky River just upstream of Wel
lington Road?
2,610 cubic feet per second (cfs). See Table 3 on page 9 of the Flood
County FIS report. This is a tough question if you forgot that the base
flood is the same as the 100-year flood.
2.
What is the 10-year peak discharge for Cobb Brook?
560 cfs. See Figure 4-1 or Table 3 on page 9 of the Flood County FIS re
port.
3.
How many cross sections were surveyed for Cobb Brook?
3; cross-sections A through C
4.
What is the width of the floodway for the Rocky River at cross-section G?
230 feet
5.
What is the flood elevation at cross-section G of the Rocky River that you
would use for regulating new construction?
11.6 feet. Don’t forget to use the “regulatory” base flood water-surface
elevation.
6.
What is the best source of base flood elevation data for regulatory purposes
for a coastal floodplain?
The FIRM
7.
In which FIRM Zone is site F?
VE
8.
What is the regulatory base flood elevation at site F?
13.4 feet, NGVD (13 feet from the FIRM plus 0.4 foot to make sure that
the regulatory elevation will be high enough)
9.
How many feet does one inch on the Flood County FIRM panel 38 repre
sent?
500 feet
10. How many feet does one inch on the Flood County FIRM panel 25 repre
sent?
2,000 feet
11. Using the Flood County FIRM panel 40 and the engineer’s scale, what is the
width of the floodway at cross-section F on the Rocky River?
Approximately 250 feet
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12. Using the Floodway Data Table, what is the floodway width at cross-section
F on the Rocky River?
270 feet
13. Using the FIRM panel 40 and the engineer’s scale, what is the distance
between cross-sections F and G on the Rocky River?
Approximately 700 feet (0.13 mile) measured along the stream channel.
14. What is the distance between cross-sections F and G on the Rocky River
according to the Floodway Data Table?
668 feet (0.13 mile)
15. Site C is within the Town of Floodville. How high is the base flood eleva
tion at Site C?
11 feet
16. What is the regulatory base flood elevation at cross-section D on the Rocky
River?
11.2 feet
17. RM 40-2 is located on panel 40 near the intersection of South Road and
Dairy Road. How far is RM 40-2 from the closest SFHA?
Approximately 500 feet to Zone AE to the south.
18. Site E is on panel 25 at the western limit of Cedar Hill Road just north of
Dean Lake. What is the base flood elevation at Site E?
We don’t know. It’s an approximate A Zone.
19. A 50’ x 50’ building is located 200 feet south of RM 40-2 on panel 40. Is it
in the floodway?
No, it is not because the floodway boundary is approximately 600 feet
south of RM 40-2.
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UNIT 4 –LEARNING CHECK #2 - ANSWERS
1.
What is the base flood elevation for the Rocky River at cross-section C:
a.
Using the flood profiles in the FIS report?
11.0 feet
b.
Using the Floodway Data Table?
10.9 feet
2.
If these numbers are different, which BFE should you use?
The BFE provided in the Floodway Data Table is more accurate.
3.
An “I” symbol is plotted 1,910 feet upstream of the confluence with the
Rocky River on Flood Profile 01P. What does this symbol represent?
A footbridge
4.
Is the footbridge upstream or downstream from the limit of detailed study?
Downstream
5.
Using Flood Profile 03P, determine the BFE on the Rocky River for a site
that is 520 feet downstream of Fox Croft Drive.
11.4 feet. On profile 03P, 5,200 feet is one inch from the x-axis. The site is
approximately one inch to the left of the “I” symbol for the Fox Croft
Drive bridge.
6.
Using Flood Profile 03P, determine how far the Fox Croft Drive bridge is
from cross-section D of the Rocky River.
1,980 feet, or 0.38 mile
7.
A developer proposes to place a structure, 625 feet (0.125 miles) upstream
from the Martling Way bridge adjacent to the Rocky River (FIRM Panel
38). Using the flood profiles, tell the developer how high the structure
would have to be elevated to be protected from the base flood elevation and
the 500-year flood elevation.
For the base flood, the structure should be elevated above 10.8 feet
NGVD. For the 500-year flood, it should be elevated above 11.8 feet
NGVD.
8.
A particular site is 750 feet upstream of Argyle Way adjacent to the Rocky
River (FIRM panel 38). What is the BFE here?
11.2 feet NGVD as seen on Flood Profile 03P.
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UNIT 4 – LEARNING CHECK #3 - ANSWERS
1.
What office is the primary repository for your FIS, FIRM, and/or Floodway
Map?
Depends on the community, but it is a local community office.
2.
How do you get more copies of your FIRM?
Call or send a mail or fax request to the Map Service Center in Jessup,
Maryland.
3.
What are the four types of map changes?
A restudy is a new Flood Insurance Study for some or all of the commu
nity.
A limited map maintenance project (LMMP) is a small-scale restudy that
is limited in size and cost.
An amendment is used to remove an area that was inadvertently included
in the SFHA.
A map revision is used for all other cases.
4.
Mrs. Murphy says she has a survey that shows that her house is higher than
the flood level. What type of map change should she request?
A Letter of Map Amendment (LOMA) is the appropriate way to remove a
single lot from the SFHA based on elevation data.
5.
For which locations on her property will Mrs. Murphy need elevation data?
The elevation of the lowest grade adjacent to the building.
6.
A builder wants to get a bank loan to develop an area. His plans are to fill
some low spots and get all the building sites out of the floodplain. His
banker will not grant a loan for the project unless she is reassured that the
FIRM will be changed when the project is finished. What type of map
change should the builder request?
A Conditional Letter of Map Revision based on fill (CLOMR-F).
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UNIT 4 – LEARNING EXERCISE - ANSWERS
1.
Using the Flood Insurance Study for Flood County, USA and Incorporated
Areas:
2.
What is the community number for the unincorporated areas of Flood
County?
990099
3.
What is the best map to use to determine if a property is in the SFHA?
FIRM
4.
What is the best map to use to determine if a property is in a floodway?
FIRM
5.
What is the effective date of the Flood County FIRM?
August 19, 1998
6.
Is the Flood County FIRM in the old format or new format?
New format
7.
Look at the Flood County FIRM Index. Why is the FIRM not printed for the
northwest corner of the county?
There is no SFHA on this panel. The area covered by panel 0030 D is in
Zone C.
8.
If you measured a distance on the ground as 500 feet, how many inches
would it be on Flood County FIRM panel 25?
The scale of panel 25 is 1"=2,000'. 500 feet would be 0.25 inches.
9.
How many miles of stationing would there be if you measured a distance
between two cross sections as 1,050 feet?
About 0.2 mile. 1,050 feet / 5,280 feet per mile = 0.198 miles, rounded to
0.2.
10. Marge’s house is located at Site F on Flood County FIRM panel 0040. How
far is her house from the boundary of the nearest coastal barrier?
Approximately 2,900 feet.
11. Examining the Atlantic Coastline, what is the highest wave crest elevation
shown on the FIRM?
14 feet
12. What FIRM panel is RM 38-1 on?
0038 D
13. What is the base flood elevation at the location given orally?
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The answer depends on location given.
14. If a surveyor wanted to locate RM 38-1 on the ground, what would he or she
look for?
A chiseled square in the southwest corner of northwest wing wall of Ar
gyle Way Bridge over the Rocky River. See the Elevation Reference Marks
legend on the left border of FIRM panel 38.
15. How high above sea level is RM 40-1?
16.54 feet NGVD.
16. A site is located at the point formed by the intersection of Glebe Way and
Foley Drive between Foley Drive and the Rocky River.
17. On which FIRM panel is the site?
0038 D
18. In which FIRM zone is the site?
Zone AE
19. What is the base flood elevation at the site?
10 feet
20. The property is in which of the following? (Check those that apply.)
____ 100-year floodplain
yes
____ 100-year floodway no
____ 500-year floodplain yes
21. (If it’s in the 100-year floodplain, it’s in the 500-year floodplain too.)
____ Coastal High Hazard Area no (it’s not in the V Zone)
____ Designated coastal barrier no
22. A site is on the banks of Cobb Brook, 100 feet west of Tullamore Lane
bridge.
23. On which FIRM panel is the site?
0038 D
24. In which FIRM zone is the site?
Unshaded Zone X
25. What is the base flood elevation at the site using the FIRM?
No BFEs in Zone X.
26. What is the base flood elevation at the site using the profile?
There are no profiles for Zone X.
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27. A vacant lot near Site D was recently purchased. The new owners ask for
your help in locating the best spot to build a new house. The FIRM shows
the entire property in the SFHA. You are handy with a transit, so you sur
vey the proposed building site during a visit to the property. You find that
the building site is above the BFE. The owners want you to inform their
bank so they won’t have to buy flood insurance. What do you say?
It must be noted that banks (and others who must read the FIRM to deter
mine if flood insurance is required) must go by the map. They cannot make
on-site interpretations based on data other than the FIRM. However, they
may recommend that the property owner submit a request for a letter of
map revision or map amendment to FEMA so the map can be officially
changed to reflect the more accurate data.
28. When the Flood County FIS was completed, the watershed of the Rocky
River was relatively undeveloped. Over the last 15 years, there has been a
lot of new construction throughout this small watershed. The Town Engi
neer says that the base flood elevations are probably out of date and
underestimate the true flood hazard. What can you do to attempt to get your
FIRM updated?
Request a restudy or a limited map maintenance project from FEMA.
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UNIT 5
LEARNING CHECK #1
1. What publication has the NFIP requirements for communities?
2. Most of the requirements relative to your community’s ordinance are in 44
CFR Parts ____ and ____ .
3. Does your ordinance comply with the latest NFIP requirements?
4. Which part of 44 CFR 60.3 covers the requirements for areas with a FIRM,
but no base flood elevations?
5. What is “Basic rule #1” for using maps and data?
6. What map do you use if recently annexed areas do not show up on your
community’s FIRM?
7. If you find information that shows the ground to be higher than the BFE, can
a bank use that data when determining whether a flood insurance policy
must be purchased?
8. Site E is in the approximate A Zone of Dean Lake. A developer wants to
build a small commercial building on a 3 acre site. Where do you get a base
flood elevation for Site E?
9. A developer downstream of Dean Lake wants to build a 40 acre subdivision
that crosses Ireland Creek. You need a base flood elevation before you re
view the plans. What options do you tell the developer he has?
10. A restudy was performed on the Josias River. The preliminary study will not
be final for another five months. It shows a new BFE at Site N that is two
feet higher than the BFE in your current FIS. Which one do you use to de
termine the flood protection level for a new home at Site N?
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UNIT 5 - LEARNING CHECK #2
1.
What is basic rule #2 on what needs a permit in the floodplain?
2.
Define “development” as the term is used in your ordinance.
3.
Does your community only require building permits? If so, does someone
who wants to fill a vacant lot need a permit from the community?
4.
The State in which Flood County is situated requires a permit from the state
Department of Environmental Protection for development on primary sand
dunes. A permit applicant wants to build on one near Site F. Department
staff informs you that based on the plans they have seen, they will have to
deny the state permit. Should the Flood County permit officer issue a flood
plain development permit?
5.
What is Basic rule #3 as it relates to encroachments in riverine floodplains?
6.
An encroachment review should review projects in a floodway for what two
things?
7.
A farmer wants to build a dairy barn in the floodway. Will he need to pro
vide you with a “no-rise” certification before you can issue the permit?
8.
The same farmer wants to build a small addition onto his farmhouse (also in
the floodway). Can this be designed so he won’t have to pay for an engi
neer’s encroachment review?
9.
In a riverine AE Zone with a base flood elevation, what must a developer
show in order to demonstrate that he is meeting Basic Rule #3?
10. Does your state have a more restrictive standard than allowing flood heights
to increase by one foot?
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UNIT 5 - LEARNING CHECK #3
1.
What does Basic rule #4 say about new buildings in A Zones?
2.
Where would elevation on piles or columns be preferred?
3.
Can a basement be considered the “lowest floor?”
4.
If a residence is elevated above the BFE in an A Zone, where do you meas
ure how high the building is?
5.
What can be allowed under the lowest floor of an elevated building?
6.
Mr. Jones shows you plans for a house elevated on a concrete block crawl
space. The area of the crawlspace will be 1,750 square feet.
How many standard 8” x 16” openings will be needed?
How high can they be above ground level?
Can Mr. Jones put his hot water heater in the crawlspace?
7.
Mrs. Smith is elevating a house in the AE Zone 8’ above grade. How can
you make sure that the area below the lowest floor won’t be improved, fin
ished or otherwise turned into living space?
8.
What three things do you need to check for to ensure that a building is
floodproofed?
9.
Can a new home in the flood fringe be floodproofed?
10. What’s the NFIP definition of “basement?”
11. If a building is proposed to be located in a riverine floodplain with flood
velocities of 8-10 feet per second, what should you ask the builder to pro
vide to assure you that the building won’t get washed away during a flood?
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12. The builder of a house to be elevated on concrete columns wants to use
wood for the stairway. He is concerned that wood will swell and warp if it
gets wet during a flood. Can a portion of the house below the BFE be built
of wood?
13. How is a manufactured home outside of a manufactured housing park
treated differently from a conventional “stick built” home?
14. How is a 600 square foot motor home that is permanently attached to a
reinforced block wall foundation treated differently from a manufactured
home?
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UNIT 5 - LEARNING CHECK #4
1.
What does Basic rule #5 say about new buildings in V Zones?
2.
Can a new building be built in the V Zone elevated on a crawlspace?
3.
Where is the lowest floor measured in a V Zone?
4.
What does the permit official do to be sure that a V Zone building will be
adequate to resist the wind and water loads?
5.
What’s the best way to deal with sand dunes in a V Zone development site?
6.
If a subdivider makes sure that all building sites are above the BFE, does he
need to do anything more to meet the NFIP requirements?
7.
How can you protect a sewer system from flooding?
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UNIT 5 - LEARNING EXERCISE
1.
In what part of the Code of Federal Regulations would you find the defini
tion for “development.?”
2.
Where do I find the NFIP requirements for areas mapped with V Zones?
3.
If a community has a FIRM that shows floodways and V Zones, which parts
of 44 CFR 60.3 must it abide by?
4.
If your community follows the requirements of 44 CFR 60.3(d), does it have
to worry about what’s in 44 CFR 60.3(b)?
5.
A building official finds it easier to read an old flood map prepared on an
aerial photograph by the Corps of Engineers. He doesn’t want to use the
current FIRM because it doesn’t show all the buildings and features that the
photograph does. Can he make permit decisions based on the Corps map in
stead of the FIRM?
6.
A developer wants to build in an area mapped as an approximate A Zone on
Ireland Creek. He conducts a detailed flood study which is approved by the
Town Engineer. It shows that several lots in the A Zone are actually higher
than the BFE calculated in the study.
7.
Can you issue permits for building on those sites and treat them as C Zone
sites?
8.
Will the buyers of the properties have to buy flood insurance policies?
9.
Joe Hunter wants to build a small hunting cabin on a lake in an approximate
A Zone. It will be the only building within two miles. There are no known
sources of a base flood elevation. The cabin will cost less than $10,000 and
he does not want to pay $2,000 for an engineering study to develop a BFE.
What can you do to make sure the property is protected from flooding?
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10. Will a developer in an approximate A Zone have to prepare a detailed study
to calculate base flood elevations if the development is:
4 acres?
60 lots?
Reserving all the SFHA as open space?
11. A restudy was performed on the Rocky River. The preliminary study will
not be final for another five months. It shows a new BFE at Site B that is
two feet lower than the BFE in your current FIS. Which one do you use to
determine the flood protection level for a new home at Site A?
12. Does dredging a creek to make it deeper to reduce flood levels need a flood
plain permit?
13. Does replacing an old manufactured home with a new one on the same
foundation need a permit?
14. If an old manufactured home is replaced with a new one on the same foun
dation, will the new one have to be elevated above the BFE?
15. If a project will involve filling a wetland, is it likely that a federal or state
permit will be needed?
16. A builder wants to put a house in the floodway. How much can his project
increase the base flood elevation (in feet)?
17. Will paving a dirt street in the floodway need an engineer’s “no-rise” certi
fication?
18. A city councilman complains that the NFIP floodway regulations prevent
construction of a flood control dam that will protect people from flooding.
What can you tell him?
19. Does a substantial improvement to an existing building have to meet the
same requirements as construction of a new building?
20. Can a new nonresidential building be built:
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21.
22.
23.
24.
25.
26.
27.
a. On fill in the flood fringe?
b. On fill in the floodway?
c. On fill in the V Zone?
d. At grade, but floodproofed in the flood fringe?
e. At grade, but floodproofed in the V Zone?
A builder wants to build an apartment building on stem walls parallel to the
flow of water with the lowest floor 8’ above grade. Can the lower area be
used as a parking lot?
What’s the best record to keep to be sure that a house was elevated high
enough?
How many standard 8” x 16” openings are needed for a building that will
have a 2,250 square foot crawlspace?
Can the owner store garden tools in a floodable crawlspace?
A business on the Mississippi River wants to build a floodproofed ware
house in the flood fringe. The plans are to have the walls built of reinforced
concrete up to the BFE. Several garage doors will be open at grade to allow
trucks in and out, but the design includes movable shields that can be put in
place before floodwaters arrive. There would be no other openings below
the BFE. The warehouse will have a 24-hour security force that will be
trained on how to install the shields. The design engineer will certify that
the building will be floodproofed (with human intervention) up to the base
flood elevation. Can you approve these plans?
A builder wants to build a “bi-level” house where the lowest floor is three
feet below grade. The lowest floor has large windows and includes three
bedrooms and a bathroom. Because it is habitable space, the owner does not
consider this a “basement.” Does the NFIP consider this a “basement?”
The area below a planned elevated house in the V Zone will have a 260
square foot enclosure to house the entryway and storage closets. The builder
wants to insulate the area and finish it with wallboard, wallpaper and carpet
ing. He says it’s OK because the area is under 300 square feet. What do you
tell him?
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28. Where can you find standards for tying down manufactured homes?
29. A new house is planned to be built in an SFHA marked “Zone AO (depth 3
feet).” How high should the lowest floor be?
30. Why are pilings and posts preferred in V Zones?
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UNIT 5 – LEARNING CHECK #1 - ANSWERS
1.
2.
3.
4.
5.
6.
7.
8.
What publication has the NFIP requirements for communities?
Chapter 44 of the Code of Federal Regulations
Most of the requirements relative to your community’s ordinance are in 44
CFR Parts ___ and ___.
59 and 60
Does your ordinance comply with the latest NFIP requirements?
Check with your FEMA Regional Office or State NFIP Coordinator
Which part of 44 CFR 60.3 covers the requirements for areas with a FIRM,
but no base flood elevations?
44 CFR 60.3(b)
What is “Basic rule #1” for using maps and data?
You must use the latest maps and flood data published by FEMA.
What map do you use if recently annexed areas do not show up on your
community’s FIRM?
The FIRM for the county or the community the property used to be in. It is
important to note that the community generally must also adapt the map in
its ordinance to be legally enforceable.
If you find information that shows the ground to be higher than the BFE, can
a bank use that data when determining whether a flood insurance policy
must be purchased?
No. Insurance agents and lenders must use the current FIRM when setting
insurance rates and determining whether flood insurance is required. If a
person wants to vary from the current FIRM to obtain different premium
rates or to not have to purchase a flood insurance policy, the FIRM must
be officially revised or amended. This can be done through a LOMA.
Site E is in the approximate A Zone of Dean Lake. A developer wants to
build a small commercial building on a 3 acre site. Where do you get a base
flood elevation for Site E?
Try these sources (in order of preference):
Check with your state NFIP coordinator, local water-related districts, the
Corps of Engineers, etc. to see if there are any existing studies.
It is possible that the highway agency did a study of the stream when the
Turnpike bridge was built.
See if the Town Engineer or the developer’s engineer will conduct a study.
Use the flood of record plus a margin of protection
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9.
A developer downstream of Dean Lake wants to build a 40 acre subdivision
that crosses Ireland Creek. You need a base flood elevation before you re
view the plans. What options do you tell the developer he has?
He can conduct a flood study and produce the BFEs at his expense or
He can set the A Zone aside as open space and not conduct a flood study.
10. A restudy was performed on the Josias River. The preliminary study will not
be final for another five months. It shows a new BFE at Site N that is two
feet higher than the BFE in your current FIS. Which one do you use to de
termine the flood protection level for a new home at Site N?
The draft revised data should be used unless the community disagrees with
the data and intends to appeal it. As noted previously, the community must
first legally adapt the preliminary study in their ordinance.
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UNIT 5 – LEARNING CHECK #2 - ANSWERS
1.
2.
3.
4.
5.
6.
7.
What is basic rule #2 on what needs a permit in the floodplain?
A permit is required for all development in the SFHA.
Define “development” as the term is used in your ordinance.
Your ordinance should have a definition that reads very much like: “’De
velopment’ means any man-made change to improved or unimproved real
estate, including but not limited to buildings or other structures, mining,
dredging, filling, grading, paving, excavation or drilling operations or
storage of equipment or materials.”
Does your community only require building permits? If so, does someone
who wants to fill a vacant lot need a permit from the community?
Depends on the community. If the answer is not “yes,” then you need to
revise your ordinance and permit procedures.
The state in which Flood County is situated requires a permit from the state
Department of Environmental Protection for development on primary sand
dunes. A permit applicant wants to build on one near Site F. Department
staff informs you that based on the plans they have seen, they will have to
deny the state permit. Should the Flood County permit officer issue a flood
plain development permit?
No. The local permit should not be issued until staff are certain that the
other agencies’ requirements are met. If it is just a question of time and a
state permit is expected to be issued, a local permit could be issued condi
tioned on obtaining a state permit. However, if it is clear that the project
violates the state regulations, a local permit should not be issued until the
matter is settled.
What is Basic rule #3 as it relates to encroachments in riverine floodplains?
Development must not increase the flood hazard on other properties.
An encroachment review should review projects in a floodway for what two
things?
You must determine whether the project will obstruct flood flows and
cause an increase in flood heights upstream or adjacent to the project site
and
You should determine whether the project will result in increases in down
stream flooding by removing an existing obstruction. While you are not
required to do this by NFIP minimum requirements, these changes can
cumulatively cause significant increases in downstream flooding.
A farmer wants to build a dairy barn in the floodway. Will he need to pro
vide you with a “no-rise” certification before you can issue the permit?
Yes
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8.
The same farmer wants to build a small addition onto his farmhouse (also in
the floodway). Can this be designed so he won’t have to pay for an engi
neer’s encroachment review?
Yes, if it is located in the conveyance shadow of the farmhouse.
9.
In a riverine AE Zone with a base flood elevation, what must a developer
show in order to demonstrate that he is meeting Basic Rule #3?
He must conduct an encroachment review that demonstrates that the cu
mulative effect of the proposed development, when combined with all
other existing and anticipated development:
Will not increase the water surface elevation of the base flood more than
one foot at any point within the community, and
Is consistent with the technical criteria contained in Chapter 5 (Hydraulic
Analyses) of the Flood Insurance Study: Guidelines and Specifications for
Study Contractors, FEMA-37, 1995.
10. Does your state have a more restrictive standard than allowing flood heights
to increase by one foot?
Depends on the state. Some states have more restrictive encroachment
standards, such as 0.5’ or 0.1’.
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UNIT 5 – LEARNING CHECK #3 - ANSWERS
1.
2.
3.
4.
5.
6.
7.
8.
What does Basic rule #4 say about new buildings in A Zones?
New, substantially improved or substantially damaged buildings must be
protected from damage by the base flood.
Where would elevation on piles or columns be preferred?
In areas where flooding is likely to have high velocities or waves.
Can a basement be considered the “lowest floor?”
Yes.
If a residence is elevated above the BFE in an A Zone, where do you meas
ure how high the building is?
At the top of the lowest floor.
What can be allowed under the lowest floor of an elevated building?
Only building access, vehicle parking, and storage.
Mr. Jones shows you plans for a house elevated on a concrete block crawl
space. The area of the crawlspace will be 1,750 square feet.
How many standard 8” x 16” vents will be needed?
14. 1,750 divided by 128 = 13.67, rounded up to 14 vents
How high can they be above ground level?
The bottom of the vents must be no higher than one foot above grade.
Can Mr. Jones put his hot water heater in the crawlspace?
No. Unless the water heater can be entirely above the BFE.
Mrs. Smith is elevating a house in the AE Zone 8’ above grade. How can
you make sure that the area below the lowest floor won’t be improved, fin
ished or otherwise turned into living space?
Require that the lower area must be kept open or require the owner to sign
a nonconversion agreement (requiring large openings will also help).
What three things do you need to check for to ensure that a building is
floodproofed?
Below the BFE:
Walls are watertight (substantially impermeable to the passage of water),
Structural components can resist hydrostatic and hydrodynamic loads and
effects of buoyancy, and
Utilities are protected from flood damage.
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9.
Can a new home in the flood fringe be floodproofed?
No. Elevation is the only method allowed for new residential buildings in
the SFHA.
10. What’s the NFIP definition of “basement?”
"Basement" means any area of the building having its floor subgrade (be
low ground level) on all sides.
11. If a building is proposed to be located in a riverine floodplain with flood
velocities of 8-10 per second, what should you ask the builder to provide to
assure you that the building won’t get washed away during a flood?
A statement from an architect or engineer that the design of the building
includes “anchoring adequate to prevent flotation, collapse and lateral
movement” during the base flood. These are hazardous velocities and you
should discourage development in these areas.
12. The builder of a house to be elevated on concrete columns wants to use
wood for the stairway. He is concerned that wood will swell and warp if it
gets wet during a flood. Can a portion of the house below the BFE be built
of wood?
Yes, provided it is pressure treated (.40 CCA minimum), naturally decay
resistant lumber or marine grade plywood
13. How is a manufactured home outside of a manufactured housing park
treated differently from a conventional “stick built” home?
They are both treated the same. They must meet the same construction and
elevation requirements.
14. How is a 600 square foot motor home that is permanently attached to a
reinforced block wall foundation treated differently from a manufactured
home?
They are both treated the same. They must meet the same construction and
elevation requirements.
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UNIT 5 – LEARNING CHECK #4 - ANSWERS
1.
2.
3.
4.
5.
6.
7.
What does Basic rule #5 say about new buildings in V Zones?
There are special building requirements in addition to the building protec
tion requirements for buildings in A Zones.
Can a new building be built in the V Zone elevated on a crawlspace?
No. It can only be elevated on pilings, posts, piers or columns to avoid ob
structions to the wave action.
Where is the lowest floor measured in a V Zone?
At the bottom of the lowest horizontal structural member.
What does the permit official do to be sure that a V Zone building will be
adequate to resist the wind and water loads?
Have an engineer certify that the design and planned methods of construc
tion are in accordance with accepted standards of practice to resist
flotation, collapse and lateral movement due to the effects of wind and wa
ter loads acting simultaneously on all building components.
What’s the best way to deal with sand dunes in a V Zone development site?
Don’t touch them. They provide important flood protection by breaking
waves during coastal storms. If they are to be disturbed, the permit appli
cant should have an engineer’s or geologist’s report that their removal
will not increase flood damage.
If a subdivider makes sure that all building sites are above the BFE, does he
need to do anything more to meet the NFIP requirements?
The subdivider also needs to make sure that:
All public utilities and facilities, such as sewer, gas, electrical, and water
systems are located and constructed to minimize or eliminate flood dam
age, and
Adequate drainage is provided to reduce exposure to flood hazards;
How can you protect a sewer system from flooding?
Through careful system design. Manholes should be raised above the 100
year flood level or equipped with seals to prevent leakage. Pumping sta
tions should have electrical panels elevated above the BFE.
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UNIT 5 – LEARNING EXERCISE - ANSWERS
1.
2.
3.
4.
5.
6.
7.
8.
9.
In what part of the Code of Federal Regulations would you find the defini
tion for “development.?”
44 CFR 59.1 Definitions
Where do I find the NFIP requirements for areas mapped with V Zones?
44 CFR 60.3(e)
If a community has a FIRM that shows floodways and V Zones, which parts
of 44 CFR 60.3 must it abide by?
All parts up through 60.3(e)
If your community follows the requirements of 44 CFR 60.3(d), does it have
to worry about what’s in 44 CFR 60.3(b)?
Yes. The requirements are cumulative in Section 60.3.
A building official finds it easier to read an old flood map prepared on an
aerial photograph by the Corps of Engineers. He doesn’t want to use the
current FIRM because it doesn’t show all the buildings and features that the
photograph does. Can he make permit decisions based on the Corps map in
stead of the FIRM?
No. The community must use the latest maps and data provided by FEMA.
If the other map shows a higher BFE and a larger floodplain, the commu
nity may adopt it in its ordinance as the regulatory floodplain and exceed
the minimum NFIP requirements. The map must be approved by the
FEMA Regional Office before this is done.
A developer wants to build in an area mapped as an approximate A Zone on
Ireland Creek. He conducts a detailed flood study which is approved by the
Town Engineer. It shows that several lots in the A Zone are actually higher
than the BFE calculated in the study.
Can you issue permits for building on those sites and treat them as C Zone
sites?
- Yes, as long as the Town Engineer assures you that the developer’s study
- Reasonably reflects flooding conditions expected during the base flood,
- Is technically correct, and
- Represents the best data available.
Will the buyers of the properties have to buy flood insurance policies?
Yes, unless a map amendment or Letter of Map Amendment (LOMA) is is
sued by FEMA.
Joe Hunter wants to build a small hunting cabin on a lake in an approximate
A Zone. It will be the only building within two miles. There are no known
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10.
11.
12.
13.
14.
15.
16.
17.
sources of a base flood elevation. The cabin will cost less than $10,000 and
he does not want to pay $2,000 for an engineering study to develop a BFE.
What can you do to make sure the property is protected from flooding?
Require that the lowest floor of the cabin be at least five feet above grade.
Will a developer in an approximate A Zone have to prepare a detailed study
to calculate base flood elevations if the development is:
4 acres?
No
60 lots?
Yes
Reserving all the SFHA as open space? No
A restudy was performed on Rocky River. The preliminary study will not be
final for another five months. It shows a new BFE at Site B that is two feet
lower than the BFE in your current FIS. Which one do you use to determine
the flood protection level for a new home at Site B?
When the BFE in the new study is lower than the BFE in the existing
study, the existing FIS data should be used until the new study is final.
Does dredging a creek to make it deeper to reduce flood levels need a flood
plain permit?
Yes. It is considered development and all development needs a permit.
Does replacing an old manufactured home with a new one on the same
foundation need a permit?
Yes
If an old manufactured home is replaced with a new one on the same foun
dation, will the new one have to be elevated above the BFE?
Yes, unless it is in an existing manufactured home park. Then the owner
has the option of elevating either above the BFE or 36” above grade on
reinforced piers.
If a project will involve filling a wetland, is it likely that a federal or state
permit will be needed?
Yes. The U.S. Army Corps of Engineers requires a Section 404 permit for
most wetland filling activities. A local permit should not be issued until it
is clear that the project does not violate Section 404 rules.
A builder wants to put a house in the floodway. How much can his project
increase the base flood elevation (in feet)?
Zero. A project in a floodway is not allowed to cause any increase in
floodwaters.
Will paving a dirt street in the floodway need an engineer’s “no-rise” certi
fication?
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No, as long as the grade of the street is no higher than it was before the
paving project.
18. A city councilman complains that the NFIP floodway regulations prevent
construction of a flood control dam that will protect people from flooding.
What can you tell him?
The community can apply for a conditional letter of map revision if it can
provide the following:
An evaluation of alternatives which, if carried out, would not result in an
increase in the BFE more than allowed, along with documentation as to
why these alternatives are not feasible.
Documentation of individual legal notice to all affected property owners
(anyone affected by the increased flood elevations, within and outside of
the community) explaining the impact of the proposed action on their
properties.
Concurrence, in writing, from the chief executive officer of any other
communities affected by the proposed actions.
Certification that no structures are located in areas which would be af
fected by the increased BFE (unless they have been purchased for
relocation or demolition).
A request for revision of BFE determinations in accordance with the pro
visions of 44 CFR 65.6 of the FEMA regulations.
19. Does a substantial improvement to an existing building have to meet the
same requirements as construction of a new building?
Yes
20. Can a new nonresidential building be built:
On fill in the flood fringe? Yes
21. On fill in the floodway? Probably not. It would be hard to show that the fill
does not cause an increase in flood heights.
On fill in the V Zone? No
At grade, but floodproofed in the flood fringe? Yes
At grade, but floodproofed in the V Zone? No
22. A builder wants to build an apartment building on stem walls parallel to the
flow of water with the lowest floor 8’ above grade. Can the lower area be
used as a parking lot?
Yes
23. What’s the best record to keep to be sure that a house was elevated high
enough?
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24.
25.
26.
27.
28.
29.
30.
31.
A FEMA Elevation Certificate. Any surveyor’s or engineer’s record of the
elevation of the lowest floor meets the NFIP requirements, but the FEMA
form is recommended.
How many standard 8” x 16” openings are needed for a building that will
have a 2,250 square foot crawlspace?
18. 2,250 divided by 128 = 17.57, rounded up to 18.
Can the owner store garden tools in a floodable crawlspace?
Yes, if there is enough warning time to move it.
A business on the Mississippi River wants to build a floodproofed ware
house in the flood fringe. The plans are to have the walls built of reinforced
concrete up to the BFE. Several garage doors will be open at grade to allow
trucks in and out, but the design includes movable shields that can be put in
place before floodwaters arrive. There would be no other openings below
the BFE. The warehouse will have a 24-hour security force that will be
trained on how to install the shields. The design engineer will certify that
the building will be floodproofed (with human intervention) up to the base
flood elevation. Can you approve these plans?
Yes, assuming there is adequate warning time to install the shields, which
there probably is on the Mississippi River.
A builder wants to build a “bi-level” house where the lowest floor is three
feet below grade. The lowest floor has large windows and includes three
bedrooms and a bathroom. Because it is habitable space, the owner does not
consider this a “basement.” Does the NFIP consider this a “basement?”
Yes and the lowest floor (i.e., the basement) must be above the BFE.
The area below a planned elevated house in the V Zone will have a 260
square foot enclosure to house the entryway and storage closets. The builder
wants to insulate the area and finish it with wallboard, wallpaper and carpet
ing. He says it’s OK because the area is less than 300 square feet. What do
you tell him?
It’s not OK. Any enclosed space below the lowest floor must be built of
flood resistant materials and free of obstruction, or constructed with non
supporting breakaway walls, open wood latticework or insect screening.
Where can you find standards for tying down manufactured homes?
Check first to see if there are state regulations. If not, see FEMA’s Manu
factured Home Installation in Flood Hazard Areas, FEMA-85.
A new house is planned to be built in an SFHA marked “Zone AO (depth 3
feet).” How high should the lowest floor be?
At least 3 feet above the highest adjacent grade.
Why are pilings and posts preferred in V Zones?
They can better withstand the wind and water loads.
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UNIT 6
LEARNING CHECK #1
1. What NFIP program recognizes local regulatory standards that are more
restrictive than the minimum NFIP regulations?
2. If a regulatory requirement prohibits an owner from any use of his land, it is
referred to by the legal term ______________ .
3. In how many court cases have the NFIP regulations been overruled as un
constitutional?
4. If a state requirement is more restrictive than the NFIP requirements, which
set of rules must a community follow?
5. Does your community’s ordinance have any provisions that are more restric
tive than the minimum NFIP requirements?
6. Name two higher regulatory standards that can be used to encourage build
ing sites completely out of the floodplain?
7. What is freeboard?
8. What is the preferred flood protection approach for critical facilities?
9. How does compensatory storage work?
10. What is “stormwater management?”
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UNIT 6 - LEARNING CHECK #2
1. Is your community subject to any of the following flood hazards of special
concern?
Coastal erosion
Tsunamis
Closed basin lakes
Uncertain flow paths or alluvial fans
Upstream dams
Ice jams
Mudflows
2. If so, have you enacted any additional regulatory provisions to better protect
future development from damage?
3. Since there are several federal agencies that regulate wetland development,
protect rare and endangered species, etc., is there any need for your commu
nity to consider any additional environmental protection measures?
4. Name three types of regulations that can protect natural resources in your
floodplains.
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UNIT 6 - LEARNING EXERCISE
1. Does the NFIP allow communities to enact more restrictive regulatory stan
dards?
2. Can a floodplain regulation ever prohibit new buildings from a portion of
the floodplain?
3. Name two types of floodprone areas where many communities prohibit de
velopment.
4. What’s the advantage of requiring dry land access if buildings are protected
from flooding?
5. How could a developer of an 80-acre subdivision reduce the amount of run
off that leaves the property during a storm?
6. Do Federal agencies have to meet any floodplain development rules similar
to the NFIP requirements?
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UNIT 6 - LEARNING CHECK #1 - ANSWERS
1. What NFIP program recognizes local regulatory standards that are more
restrictive than the minimum NFIP regulations?
The Community Rating System (CRS)
2. If a regulatory requirement prohibits an owner from any use of his land, it is
referred to by the legal term ______________ .
Taking
3. In how many court cases have the NFIP regulations been overruled as un
constitutional?
None.
4. If a state requirement is more restrictive than the NFIP requirements, which
set of rules must a community follow?
The more restrictive state requirement.
5. Does your community’s ordinance have any provisions that are more restric
tive than the minimum NFIP requirements?
Depends on the community.
6. Name two higher regulatory standards that can be used to encourage build
ing sites completely out of the floodplain?
Subdivision design that encourages cluster development on high ground
Low density zoning that gives owners large lots large enough to avoid
small floodplains
7. What is freeboard?
An additional height requirement above the base flood elevation that pro
vides a margin of safety against extraordinary or unknown risks.
8. What is the preferred flood protection approach for critical facilities?
Keep them out of the 500-year floodplain. The next best approach is to
protect them to the 500-year flood level.
9. How does compensatory storage work?
The developer is required to offset new fill put in the floodplain by exca
vating an additional floodable area to replace the lost flood storage area.
10. What is “stormwater management?”
Efforts that reduce the impact of increased runoff that results from new
development in the watershed.
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UNIT 6 - LEARNING CHECK #2 - ANSWERS
1. Is your community subject to any of the following flood hazards of special
concern?
Coastal erosion
Tsunamis
Closed basin lakes
Uncertain flow paths or alluvial fans
Upstream dams
Ice jams
Mudflows
Depends on the community.
2. If so, have you enacted any additional regulatory provisions to better protect
future development from damage?
Depends on the community.
3. Since there are several federal agencies that regulate wetland development,
protect rare and endangered species, etc., is there any need for your commu
nity to consider any additional environmental protection measures?
Probably. Federal programs may not address the particular needs of your
locality.
4. Name three types of regulations that can protect natural resources in your
floodplains.
Wetland protection regulations
Habitat protection regulations
Restrictions on on-site sewage disposal
Water quality regulations and rules on stormwater runoff (non point
sources of pollution)
Designating unique or valuable areas for special protection
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UNIT 6 – LEARNING EXERCISE - ANSWERS
1. Does the NFIP allow communities to enact more restrictive regulatory stan
dards?
Yes. “.. any flood plain management regulations adopted by a State or a
community which are more restrictive than the criteria set forth in this
part are encouraged and shall take precedence.” (44 CFR 60.1(d))
2. Can a floodplain regulation ever prohibit new buildings from a portion of
the floodplain?
Yes, if the area is sufficiently dangerous and/or there is a clear relation
ship between the prohibition and protecting the public from the hazard
created by the development.
3. Name two types of floodprone areas where many communities prohibit de
velopment.
High hazard areas, such as flash flood areas and very deep floodways
Natural or sensitive areas, such as wetlands
4. What’s the advantage of requiring dry land access if buildings are protected
from flooding?
It protects people by allowing them to evacuate when floodwaters come up
and allows emergency service vehicles to protect the properties during a
flood.
5. How could a developer of an 80-acre subdivision reduce the amount of run
off that leaves the property during a storm?
Include stormwater detention or retention basins to hold or delay the run
off from the site.
6. Do Federal agencies have to meet any floodplain development rules similar
to the NFIP requirements?
Yes. The National Environmental Policy Act (NEPA) and Executive Order
11988 require Federal agencies to meet the same or more restrictive de
velopment standards.
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UNIT 7
LEARNING CHECK #1
1. Review your floodplain regulations and identify where the following provi
sions are found.
Purpose statement
Definitions of
— base flood elevation
— building or structure
— development
— floodway
— lowest floor
— substantial improvement
— substantial damage
Adoption of the FIRM or other floodplain map
Adoption of the Flood Insurance Study
Requirement for a permit for all development in the floodplain
Construction standards:
— floodway construction (if applicable)
— encroachment analysis where floodways are not mapped
— building elevation criteria
— floodproofing criteria
— anchoring requirements
— standards for manufactured (mobile) homes
— standards for manufactured home parks
— construction standards in V Zones
— construction standards peculiar to the zones in your community
— standards for subdivisions
— standards for water and sewer service
— rules on water course alterations
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Designation of administrator
Duties of the administrator
Appeals process
Enforcement procedures and penalties
Abrogation and greater restriction
Severability
2. Check your community’s other regulatory ordinances to determine if there
are any inconsistencies between them and your floodplain construction stan
dards.
Ordinance Administration
H-71
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UNIT 7 - LEARNING CHECK #2
1. What activities are exempt from regulation under your floodplain ordi
nance?
2. Does your community have a permit application form that makes sure things
like a floodway encroachment analysis or V Zone certification are not
missed?
3. What five items need to be checked to ensure an application for a permit is
complete?
4. What departments or offices in your community should review a permit ap
plication before it is approved?
5. During your permit review, you find that the applicant’s site plan shows that
the ground is currently higher than the BFE. Should you continue to treat
this as a floodplain development permit?
6. What’s the best way to make sure the applicant’s engineering certifications
are sufficient?
7. What are the key items you need to check when reviewing the plans for a
new house to be built on pilings in the V Zone?
8. Match the list of proposed projects with the documents that will be needed
in order to determine if the project should be built in the floodplain.
♦ New shopping center parking lot in the floodway
♦ New house in the fringe
♦ New business in the V Zone
♦ Reconstruction of a state highway bridge
♦ New house built over a floodable, but enclosed garage
♦ Floodplain development permit application
♦ Site and/or building plans
Ordinance Administration
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♦ Floodway encroachment analysis
♦ Floodproofing certification
♦ Non-conversion agreement
♦ V Zone certification
Ordinance Administration
H-73
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UNIT 7 - LEARNING CHECK #3
1. When is the best time to make the first site inspection?
2. When should you make the second inspection of a building on a slab foun
dation?
3. What are your two options for making sure a new building is high enough
before you allow construction to proceed after the second inspection?
4. What should you check for during the third inspection?
5. If a project meets all of the ordinance requirements and is built according to
the approved plans, what does the owner get after the final inspection?
Ordinance Administration
H-74
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UNIT 7 - LEARNING CHECK #4
1. If a FEMA staff person finds a project in violation of the FEMA NFIP re
quirements in your community, who is responsible for correcting the
violation?
2. You discover that Mrs. Murphy has ordered five truckloads of fill to raise
her back yard in the floodway. She never asked for a permit. What is the
recommended first step to dealing with this situation?
3. If a project is found underway in the floodplain, what is the first step you
should take?
4. What legal recourses do you and your attorney have to bring a violation into
compliance?
5. What are the NFIP procedures for submitting an appeal to your Board of
Appeals?
6. Mr. Wilson wants to build a new house at grade instead of to the BFE, six
feet above grade. You tell him he will need a variance. Which of the follow
ing are good and sufficient causes for granting him a variance?
7. An elevated house will look bad
8. Mrs. Wilson is old and has trouble with stairs
9. It will cost more money than the builder can afford
10. The builder has a contract with the bank to have it completed and sold in
four months and changing plans will prevent meeting that deadline.
11. No one has ever seen a flood on that site.
Ordinance Administration
H-75
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12. Mr. Wilson is applying for a variance to build his house below the BFE.
What two things must you tell him (in writing)?
Ordinance Administration
H-76
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UNIT 7 - LEARNING CHECK #5
1. Why should you keep permit records?
2. What records should be kept in your permit file?
3. Who is responsible for ensuring that the elevation certificate is completed
correctly?
4. What are the four situations when a record of an engineer's or surveyor’s
certification is needed?
5. A property has been annexed from the county into your city, but the FIRM
has not been revised to reflect the annexation. What is the NFIP community
number that is recorded in Item 1, Section B of the FEMA Elevation Certifi
cate?
6. Is a V Zone Certification needed for a residential building?
7. Where do you get a Biennial Report to send in to FEMA?
Ordinance Administration
H-77
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UNIT 7 - LEARNING EXERCISE
1. Does your community have formal written permit review procedures to en
sure that a development proposal is properly reviewed and inspected?
2. What are the four situations where a certification will be needed before a
floodplain development permit can be issued?
3. A development plan proposes to fill and re-grade an area of the fringe to
give most of the lots building sites that are above the BFE. The developer
says “then we won’t have the banks telling people my subdivision is in the
floodplain.” What do you tell the developer?
4. What are the key items you need to check when reviewing the plans for a
new house to be built on a slab foundation on fill in the fringe?
5. You deny an application to build a house in the floodplain because the plans
show a proposed basement 6’ below the BFE. What recourses does the ap
plicant have now?
6. What should you check for during the first site inspection?
7. When should you make the second inspection for a building to be elevated
on a crawlspace or columns?
8. If you use a level to verify the elevation of a building during the second in
spection, will the builder still need to provide an as-built elevation
certificate?
9. When is the best time to see if a crawlspace has adequate openings?
10. During the second inspection, you find that the builder wants to build the
lowest floor three feet below the BFE in order to save on construction costs.
What repercussions would the owner face if the community issued a certifi
cate of occupancy for the building and did not pursue any enforcement
action?
Ordinance Administration
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11. If the third inspection reveals that the builder of an apartment house has
made a change to the structure that results in a major violation of your
floodplain regulations, what can you do?
12. How can Section 1316 help a local permit official faced with a subdivider
who refuses to build houses in compliance with the floodplain regulations?
13. Can a community grant a variance to allow a project in the floodway that
will cause a ½ foot increase in flood heights.
14. Name two situations where special exceptions may be granted for a vari
ance.
15. Permit records should be kept systematically. Your system should be keyed
so you can retrieve permit files by:
16. What are the advantages of using the FEMA Elevation Certificate as a re
cord of a building’s lowest floor elevation?
17. Can a surveyor sign a Floodproofing Certificate?
18. What is needed to support a No-rise certification?
Ordinance Administration
H-79
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UNIT 7 - LEARNING CHECK #1 - ANSWERS
1. This learning check is a review of where the various NFIP requirements ap
pear in your own ordinance. There are no correct answers, only the need to
make sure that all the items listed in the learning check are covered.
UNIT 7 - LEARNING CHECK #2 - ANSWERS
2. What activities are exempt from regulation under your floodplain ordi
nance?
Depends on the community. Small projects and activities by other gov
ernmental agencies may be exempt. Check with your State NFIP
Coordinator to verify that any exempt activities are either covered by
other regulations or are too small to be of concern.
3. Does your community have a permit application form that makes sure things
like a floodway encroachment analysis or V Zone certification are not
missed?
Depends on the community. If not, you’ll find Figure 7-4 very helpful.
4. What five items need to be checked to ensure an application for a permit is
complete?
All forms are completed and signed
Site, grading, building, etc. plans are complete
All necessary certifications are provided
All necessary state and federal permits are being obtained
Copies of the application are forwarded to other departments for review
5. What departments or offices in your community should review a permit ap
plication before it is approved?
Depends on the community. This is a very important procedure to check to
be sure that a project will meet all of your community’s development re
quirements.
6. During your permit review, you find that the applicant’s site plan shows that
the ground is currently higher than the BFE. Should you continue to treat
this as a floodplain development permit?
You do not have to. It’s still a good idea to encourage the applicant to in
corporate flood protection measures in case a future flood is higher than
the predicted BFE (e.g., don’t build any homes with basements).
7. What’s the best way to make sure the applicant’s engineering certifications
are sufficient?
Ordinance Administration
H-80
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Have your community’s engineer review them.
8. What are the key items you need to check when reviewing the plans for a
new house to be built on pilings in the V Zone?
The proposed elevation of the lowest floor
Whether there will be any enclosures below the elevated floor
The V Zone certification signed by a registered professional architect or
engineer.
The materials used in the area below the BFE.
9. Match the list of proposed projects with the documents that will be needed
in order to determine if the project should be built in the floodplain.
__New shopping center parking lot in the floodway a, b, c
__New house in the fringe a, b
__New business in the V Zone a, b, f
__Reconstruction of a state highway bridge see below
__New house built over a floodable, but enclosed garage a, b, e
a. Floodplain development permit application
b. Site and/or building plans
c. Floodway encroachment analysis
d. Floodproofing certification
e. Non-conversion agreement
f. V Zone certification
The state highway department may be exempt from local regulations.
However, it is a good idea to talk to the State NFIP Coordinator to ensure
that the project meets all state floodplain management requirements.
Ordinance Administration
H-81
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UNIT 7 – LEARNING CHECK #3 - ANSWERS
1. When is the best time to make the first site inspection?
After the site is staked out and before permanent foundation work has be
gun.
2. When should you make the second inspection of a building on a slab foun
dation?
When the forms are in place, but before the concrete is poured.
3. What are your two options for making sure a new building is high enough
before you allow construction to proceed after the second inspection?
Have the builder provide an elevation certificate
Check the elevation yourself during the second inspection
4. What should you check for during the third inspection?
Ensure that the foundation and floor elevation have not been altered since
the second inspection.
Obtain an as-built elevation or floodproofing certificate.
Verify that enclosures below the lowest floors have adequate openings.
Ensure that nothing subject to flood damage, such as a furnace or air
conditioning unit, has been located below the lowest floor.
Check breakaway walls in V Zones.
Check for floodway encroachments.
Check the anchoring system used in securing manufactured homes.
5. If a project meets all of the ordinance requirements and is built according to
the approved plans, what does the owner get after the final inspection?
A certificate of occupancy, certificate of compliance, use permit or other
official document that allows the building to be occupied or used.
Ordinance Administration
H-82
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UNIT 7 – LEARNING CHECK #4 - ANSWERS
1. If a FEMA staff person finds a project in violation of the FEMA NFIP re
quirements in your community, who is responsible for correcting the
violation?
Your local permit official.
2. You discover that Mrs. Murphy has ordered five truckloads of fill to raise
her back yard in the floodway. She never asked for a permit. What is the
recommended first step to dealing with this situation?
Talk to Mrs. Murphy and explain why a permit is needed and why it is im
portant not to fill in the floodway. You should get voluntary compliance.
3. If a project is found underway in the floodplain, what is the first step you
should take?
Advise the owner to stop work and tell him or her (in writing) that the pro
ject is in violation and what should be done to correct it.
4. What legal recourses do you and your attorney have to bring a violation into
compliance?
A fine (that can increase for each day the violation continues)
Recording the violation in the property’s deed records
A court injunction to stop work
5. What are the NFIP procedures for submitting an appeal to your Board of
Appeals?
There are none, or, more correctly, they are whatever your ordinance
specifies.
6. Mr. Wilson wants to build a new house at grade instead of to the BFE, six
feet above grade. You tell him he will need a variance. Which of the follow
ing are good and sufficient causes for granting him a variance?
7. An elevated house will look bad
8. Mrs. Wilson is old and has trouble with stairs
9. It will cost more money than the builder can afford
10. The builder has a contract with the bank to have it completed and sold in
four months and changing plans will prevent meeting that deadline.
11. No one has ever seen a flood on that site.
None of these. They do not show an exceptional hardship, they are not
unique to the property, nor do they pertain to the land, not the owners.
12. Mr. Wilson is applying for a variance to build his house below the BFE.
What two things must you tell him (in writing)?
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(i) the issuance of a variance to construct a structure below the base flood
level will result in increased premium rates for flood insurance up to
amounts as high as $25 for $100 of insurance coverage and;
(ii) such construction below the base flood level increases risks to life and
property.
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UNIT 7 – LEARNING CHECK #5 - ANSWERS
1.
2.
3.
4.
Why should you keep permit records?
Records do the following:
Show what you approved and what you told the developer.
Form a paper trail needed for administrative or legal proceedings.
Give future owners information about the property.
Are checked by FEMA or the state to determine if your community is in
full compliance with the NFIP.
What records should be kept in your permit file?
The permit application form and all attachments, including the site plan.
All correspondence pertinent to the project.
Flood and floodway data prepared by the developer.
Engineering analyses of floodway encroachments and watercourse altera
tions.
Special engineering designs for enclosures below the BFE.
In coastal high hazard areas, engineering certifications of designs and
construction methods of new and substantially improved buildings.
In coastal high hazard areas, certification of specially designed break
away walls.
Any variances or appeals proceedings.
Records of inspections of the project while under construction.
Documentation of the As-built lowest floor elevation of all new and sub
stantially improved buildings.
Certification of the elevation to which any nonresidential building has
been floodproofed.
Certificates of compliance or occupancy.
Who is responsible for ensuring that the elevation certificate is completed
correctly?
The permit official
What are the four situations when a record of an engineer's or surveyor’s
certification is needed?
Elevation certificate: needed for new or substantially improved buildings
that are elevated in the SFHA
Floodproofing certificate: needed for new or substantially improved non
residential buildings that are floodproofed.
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V Zone certification: needed for new or substantially improved buildings
in V Zones
No-rise certification: needed for development projects in floodways (or its
equivalent in riverine floodplains where the floodway has not been
mapped)
5. A property has been annexed from the county into your city, but the FIRM
has not been revised to reflect the annexation. What is the NFIP community
number that is recorded in Item 1, Section B of the FEMA Elevation Certifi
cate?
Your city’s NFIP number. The county NFIP number is entered in Item 2 of
Section B.
6. Is a V Zone Certification needed for a residential building?
Yes. It is needed for all buildings and substantial improvements in the V
Zone.
7. Where do you get a Biennial Report to send in to FEMA?
Don’t worry. FEMA sends it to the community every two years.
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UNIT 7 – LEARNING EXERCISE - ANSWERS
1. Does your community have formal written permit review procedures to en
sure that a development proposal is properly reviewed and inspected?
The answer should be “yes,” although there is no NFIP requirement for
written procedures. You are responsible for ensuring that your ordinance
is legally enforceable and that will require that you be able to demonstrate
that you have adequate administrative procedures.
2. What are the four situations where a certification will be needed before a
floodplain development permit can be issued?
Floodway encroachment analysis
Engineer’s certification of floodproofing design
Non-conversion agreement for enclosed lower areas
V Zone design certification
3. A development plan proposes to fill and re-grade an area of the fringe to
give most of the lots building sites that are above the BFE. The developer
says “then we won’t have the banks telling people my subdivision is in the
floodplain.” What do you tell the developer?
While the permit office can use better ground elevation data to determine
that a building location is above the BFE (and therefore outside the
SFHA), the property will remain in the SFHA on the FIRM. That means
that it is still subject to the flood insurance purchase requirement and the
rates will be set at SFHA rates. It is the owner’s responsibility to submit a
request for a Letter of Map Revision (LOMR) in order to have the FIRM
reflect the better data.
4. What are the key items you need to check when reviewing the plans for a
new house to be built on a slab foundation on fill in the fringe?
The proposed elevation of the lowest floor
Your building code should also require you to make sure the fill will be
properly compacted and protected from erosion and will not cause local
drainage problems on neighboring properties.
5. You deny an application to build a house in the floodplain because the plans
show a proposed basement 6’ below the BFE. What recourses does the ap
plicant have now?
He can drop the idea and withdraw the application
He can redesign the house so the lowest floor (including basement) is
above the required flood protection level.
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He can appeal to the Board of Appeals if he thinks you misread or misin
terpreted the requirements
He can apply for a variance to allow the basement.
6. What should you check for during the first site inspection?
The location of the floodplain and floodway boundaries.
Setbacks from lot lines, channel banks, etc.
Floodway encroachments, if applicable.
7. When should you make the second inspection for a building to be elevated
on a crawlspace or columns?
After the foundation is completed, so you can check if it is high enough be
fore the lowest floor is built.
8. If you use a level to verify the elevation of a building during the second in
spection, will the builder still need to provide an as-built elevation
certificate?
Yes
9. When is the best time to see if a crawlspace has adequate openings?
During the second inspection, before the floor is built. This will allow the
builder to install the needed openings with a minimum of disruption to the
structure.
10. During the second inspection, you find that the builder wants to build the
lowest floor three feet below the BFE in order to save on construction costs.
What repercussions would the owner face if the community issued a certifi
cate of occupancy for the building and did not pursue any enforcement
action?
Even though the certificate of occupancy says the owner had a “legal”
building, the flood insurance rates would be based on the elevation of the
lowest floor. The annual insurance premium would be very high. A few
years of such premiums would likely be more expensive than the extra cost
of meeting the ordinance’s elevation requirement.
11. If the third inspection reveals that the builder of an apartment house has
made a change to the structure that results in a major violation of your
floodplain regulations, what can you do?
Withhold the certificate of occupancy. (This assumes that you have an or
dinance that states that utilities cannot be turned on and/or apartments
cannot be rented until the certificate is issued.)
12. How can Section 1316 help a local permit official faced with a subdivider
who refuses to build houses in compliance with the floodplain regulations?
It authorizes FEMA to deny flood insurance to a property declared in vio
lation of the community’s ordinance. Among other things, this will prevent
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the property from receiving any federal grants and loans and may limit
mortgages from federally regulated or insured lending institutions.
13. Can a community grant a variance to allow a project in the floodway that
will cause a ½ foot increase in flood heights.
No. “Variances shall not be issued by a community within any designated
regulatory floodway if any increase in flood levels during the base flood
discharge would result…” (44 CFR 60.6(a)1.)
14. Name two situations where special exceptions may be granted for a vari
ance.
Historic buildings and functionally dependent uses.
15. Permit records should be kept systematically. Your system should be keyed
so you can retrieve permit files by:
Geographical identifier, such as street address
16. What are the advantages of using the FEMA Elevation Certificate as a re
cord of a building’s lowest floor elevation?
It includes all the data needed for NFIP compliance
It meets the requirements of the Community Rating System
It is needed by insurance agents to write a policy.
17. Can a surveyor sign a Floodproofing Certificate?
No, it must be signed by a registered professional engineer.
18. What is needed to support a No-rise certification?
The engineering or no-rise certification must be supported by technical
data and signed by a registered professional engineer. The supporting
technical data should be based on the standard step-backwater computer
model used to develop the 100-year floodway shown on your FIRM or
Flood Boundary and Floodway Map and the results tabulated in your
Flood Insurance Study.
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UNIT 8
LEARNING CHECK #1
1. What is the basic rule on improvements and repairs to existing buildings in the
floodplain?
2. Mrs. Murphy got a permit two months ago to remodel her living room and
kitchen. Now she wants a permit to remodel three bedrooms and two bath
rooms. Should you check each of these separately to determine if each project
is a substantial improvement?
3. What is the substantial improvement formula?
4. Which of the following items must be included when calculating the cost of
an improvement project?
— Attached deck
— Plumbing
— Permit fees
— Contractor’s overhead and profit
— Architect’s plans
— Landscaping
— Built-in bookcases
5. What factors are considered when determining market value?
6. What are three good sources for obtaining the market value of a house?
7. Mr. Jones proposes a $50,000 addition to his $80,000 home in the floodplain.
Is this a substantial improvement?
8. If Mr. Jones’ project will be a substantial improvement, what do you need to
check to see if the whole house has to be elevated or just the addition?
Substantial Improvement/Damage
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UNIT 8 - LEARNING CHECK #2
1. What is the formula for determining substantial damage?
2. What is the basic rule on calculating the cost of the damage?
3. A tornado swept through town and substantially damaged 25 buildings in
the floodplain. How can you help the property owners comply with the
floodplain ordinance’s substantial damage regulations?
4. Mr. Johnson prepared a list of everything he has to do to repair his flooded
home. Which of the following items are counted toward the cost of repairs
when determining substantial damage? What is the dollar amount that
should be counted?
— Clearing broken trees and debris away from the house ($2,500)
— Replacing the warped flooring ($3,000)
— New doors ($1,000) to replace old ones (worth $500)
— Replacing the old kitchen cabinets (valued at $5,000) with custom hard
wood cabinets valued at $15,000.
— New wall to wall carpeting ($1,800)
— New furniture ($12,000)
— New wiring ($2,000) to bring the building up to current code (This is a
standard requirement of the community. The building was not cited as
having a code violation.)
— Permit fee ($500)
— Clean out and test the furnace (done free as a public service by the utility
company, but otherwise worth $250 if done by a private contractor)
— New bushes and replacement fence ($1,500)
5. What’s the best way to determine if a building is “historic” and eligible for
exemption from the substantial improvement requirement?
Substantial Improvement/Damage
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UNIT 8 - LEARNING EXERCISE
1. What kind of projects need a permit so you can check to see if they would be
substantial improvements?
2. A home was built to post-FIRM standards in 1990. The lowest floor was
elevated four feet above grade, to the BFE in effect at that time. In 1995, a
new FIRM went into effect. The new BFE is now six feet above grade at that
site.
How high would a small (less than substantial) addition have to be ele
vated?
How high would a large (substantial) addition have to be elevated?
3. Mrs. Murphy bought her property for $100,000 last year. Is this a good basis
for determining its market value?
4. Based on tax assessor’s records, the market value of 123 Main Street is
$75,000. The owner wants to replace the HVAC and plumbing, remodel the
kitchen and both bathrooms and convert his basement to a finished family
room. His total cost is $20,000 for supplies. If a contractor were to do the job,
the total cost would be $45,000. However, since he is a handyman and will do
all the work himself, the total cost of his project is $20,000. What is your re
sponse?
5. Mrs. Smith wants a new second story that will double the size and value of her
house. The floor of the new story will be above the BFE. Will the old first
floor have to be elevated?
6. The substantial damage regulations only apply if the building was damaged by
a flood. True or false?
7. A flooded property owner has a brother who is a plumbing contractor. His
brother’s repair estimate shows the damage at 48% of the building’s value.
You think it should be higher. What can you do to prevent an argument over
who’s numbers are right?
Substantial Improvement/Damage
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8. Mrs. McGillicudy is on a fixed income. Her home was flooded and substan
tially damaged. Her flood insurance policy will pay for the repairs. When told
that she will also have to elevate her house, she thinks she should apply for a
variance due to the financial hardship. What do you tell her?
9. Before the flood, Mr. Johnson had been cited by the community for a code
violation. The paint on his garage door had been peeling, which was a viola
tion of the local housing maintenance code. Since the flood left mud up to the
high water line, he decided to repaint the whole house. Can he claim exemp
tion of the cost of the painting because it had been cited as a code violation?
Substantial Improvement/Damage
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UNIT 8 - LEARNING CHECK #1 - ANSWERS
1.
2.
3.
4.
5.
6.
What is the basic rule on improvements and repairs to existing buildings in the
floodplain?
If the cost of improvements or the cost to repair the damage exceeds 50
percent of the market value of the building, it must be brought up to cur
rent floodplain management standards.
Mrs. Murphy got a permit two months ago to remodel her living room and
kitchen. Now she wants a permit to remodel three bedrooms and two bath
rooms. Should you check each of these separately to determine if each project
is a substantial improvement?
No. They should be counted as one project and their total cost combined.
What is the substantial improvement formula?
A project is a substantial improvement if:
Cost of improvement project > 50 percent
Market value of the building
Which of the following items must be included when calculating the cost of
an improvement project?
— Attached deck yes
— Plumbing yes
— Permit fees no
— Contractor’s overhead and profit yes
— Architect’s plans
no
— Landscaping
no
— Built-in bookcases yes
What factors are considered when determining market value?
“The price a willing buyer and seller agree upon.” Factors to consider
are the building’s original quality, subsequent improvements, age and
current condition.
What are three good sources for obtaining the market value of a house?
An independent appraisal by a professional appraiser.
Detailed estimates of the structure’s actual cash value (the replacement
cost for a building, minus a depreciation percentage based on age and
condition).
Substantial Improvement/Damage
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Property appraisals used for tax assessment purposes with an adjustment
recommended by the tax appraiser to reflect market conditions (adjusted
assessed value).
The value of buildings taken from NFIP claims data (usually actual cash
value).
Qualified estimates based on sound professional judgment made by the
staff of the local building department or tax assessor’s office.
7. Mr. Jones proposes a $50,000 addition to his $80,000 home in the floodplain.
Is this a substantial improvement?
Yes, 50,000 divided by 80,000 = 0.625, more than 50%
8. If Mr. Jones’ project will be a substantial improvement, what do you need to
check to see if the whole house has to be elevated or just the addition?
Check the extent of work on the common wall and the existing building. If
the common wall is demolished as part of the project, the existing building
and the addition must be elevated.
Substantial Improvement/Damage
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UNIT 8 – LEARNING CHECK #2 - ANSWERS
1. What is the formula for determining substantial damage?
A building was substantially damaged if:
Cost to repair
> 50 percent
Market value of the building
2. What is the basic rule on calculating the cost of the damage?
Substantial damage is determined regardless of the actual cost to the
owner. You must figure the true cost of bringing the building back to its
pre-damage condition using qualified labor and materials obtained at
market prices.
3. A tornado swept through town and substantially damaged 25 buildings in
the floodplain. How can you help the property owners comply with the
floodplain ordinance’s substantial damage regulations?
Help the owner obtain financial assistance. Many programs are available
after a disaster declaration.
4. Mr. Johnson prepared a list of everything he has to do to repair his flooded
home. Which of the following items are counted toward the cost of repairs
when determining substantial damage? What is the dollar amount that
should be counted?
— Clearing broken trees and debris away from the house ($2,500) $0
— Replacing the warped flooring ($3,000) $3,000
— New doors ($1,000) to replace old ones (worth $500) $1,000
— Replacing the old kitchen cabinets (valued at $5,000) with custom hard
wood cabinets valued at $15,000.
$15,000
— New wall to wall carpeting ($1,800)
$1,800
— New furniture ($12,000)
$0 (not part of the structure)
— New wiring ($2,000) to bring the building up to current code (This is a
standard requirement of the community. The building was not cited as
having a code violation.)
$2,000
— Permit fee ($500) $0
— Clean out and test the furnace (done free as a public service by the utility
company, but otherwise worth $250 if done by a private contractor) $250
— New bushes and replacement fence ($1,500) $0 (not part of the structure)
5. What’s the best way to determine if a building is “historic” and eligible for
exemption from the substantial improvement requirement?
See if it’s on an approved list of historic structures (see Figure 7-13)
Substantial Improvement/Damage
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UNIT 8 – LEARNING EXERCISE - ANSWERS
1.
2.
3.
4.
5.
6.
What kind of projects need a permit so you can check to see if they would be
substantial improvements?
Remodeling projects.
Rehabilitation projects.
Building additions.
A home was built to post-FIRM standards in 1990. The lowest floor was
elevated four feet above grade, to the BFE in effect at that time. In 1995, a
new FIRM went into effect. The new BFE is now six feet above grade at that
site.
a. How high would a small (less than substantial) addition have to be ele
vated?
To at least four feet above grade.
b. How high would a large (substantial) addition have to be elevated?
To at least six feet above grade.
Mrs. Murphy bought her property for $100,000 last year. Is this a good basis
for determining its market value?
It’s a start, but the true market value may be different this year, depending
on the local housing market. You also need to subtract the value of the
land, landscaping, and detached structures that would have been in the
purchase price for the property.
Based on tax assessor’s records, the market value of 123 Main Street is
$75,000. The owner wants to replace the HVAC and plumbing, remodel the
kitchen and both bathrooms and convert his basement to a finished family
room. His total cost is $20,000 for supplies. If a contractor were to do the job,
the total cost would be $45,000. However, since he is a handyman and will do
all the work himself, the total cost of his project is $20,000. What is your re
sponse?
The total cost of the project must be the true cost, including the cost of la
bor and donated materials. This project will be a substantial improvement.
Mrs. Smith wants a new second story that will double the size and value of her
house. The floor of the new story will be above the BFE. Will the old first
floor have to be elevated?
Yes. The project should be a substantial improvement and the entire build
ing will need to be elevated in this situation.
The substantial damage regulations only apply if the building was damaged by
a flood. True or false?
False, the damage can be from any cause.
Substantial Improvement/Damage
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7. A flooded property owner has a brother who is a plumbing contractor. His
brother’s repair estimate shows the damage at 48% of the building’s value.
You think it should be higher. What can you do to prevent an argument over
who’s numbers are right?
Get the cost to repair from an objective third-party or undebatable source,
such as:
A licensed general contractor.
A professional construction estimator.
Insurance adjustment papers (exclude damage to contents).
Damage assessment field surveys conducted by building inspection, emer
gency management or tax assessment agencies after a disaster.
8. Mrs. McGillicudy is on a fixed income. Her home was flooded and substan
tially damaged. Her flood insurance policy will pay for the repairs. When told
that she will also have to elevate her house, she thinks she should apply for a
variance due to the financial hardship. What do you tell her?
Her flood insurance policy has Increased Cost of Compliance coverage
that will help pay for the cost of meeting the ordinance’s requirement to
elevate. Your office may be able to help her find financial assistance to
pay for the rest of the cost, if needed.
9. Before the flood, Mr. Johnson had been cited by the community for a code
violation. The paint on his garage door had been peeling, which was a viola
tion of the local housing maintenance code. Since the flood left mud up to the
high water line, he decided to repaint the whole house. Can he claim exemp
tion of the cost of the painting because it had been cited as a code violation?
No. Only exempt the items specifically required by the citation and what is
minimally necessary to comply.
Substantial Improvement/Damage
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UNIT 9
LEARNING CHECK #1
1. Where does a property owner go to buy a flood insurance policy?
2. Can I buy a flood insurance policy with building coverage on the following?
•
An apartment building
•
A septic tank
•
An open sided park pavilion
•
A motor home
•
A boat dock
•
A mobile home on a foundation in a mobile home park
•
A flower garden
3. What is the maximum amount of contents coverage I can get for a single
family dwelling?
4. Can I wait and buy a flood insurance policy after I hear the National
Weather Service issue a flood warning?
5. Which of the following programs is likely to require a flood insurance pol
icy as a condition of financial assistance?
•
Department of Veterans Affairs mortgage loan guarantees
•
HUD Community Development Block Grants
•
Federal disaster assistance
•
Home improvement loans from a bank participating in FDIC
•
Mortgage from a federal credit union
6. Does your local government have flood insurance coverage on the buildings
it owns in the floodplain?
7. Do I need an elevation certificate to purchase a flood insurance policy on a
pre-FIRM building?
8. Is there much of a cost savings on flood insurance if the lowest floor of a
Post-FIRM building is one foot above the BFE instead of at the BFE?
9. Can I get a good flood insurance rate on a building in an AE Zone that is
floodproofed to the base flood elevation?
10. What’s the best way to get a good flood insurance rate for a new building in
an approximate A Zone?
Flood Insurance
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UNIT 9 - LEARNING CHECK #2
1. What are some of the benefits of joining the Community Rating System?
2. Does your community implement any of the 18 activities credited by the
CRS?
3. What is a CBRS zone?
4. Can I request a LOMA to get my property out of a CBRS zone?
5. Are there any CBRS zones in Flood County?
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UNIT 9 LEARNING EXERCISE
1. Who sets the rates and coverage rules for flood insurance policies, FEMA or
private insurance companies?
2. What are the two types of flood insurance coverage available?
3. Can I get flood insurance coverage for furniture in a basement?
4. Can a bank require flood insurance for a property outside the SFHA shown
on the latest FIRM?
5. What are the two key factors in rating Post-FIRM buildings?
6. How do I know how much a flood insurance policy will cost for a Post-
FIRM building with the lowest floor four feet below the BFE?
7. How can your community help its residents get lower flood insurance rates?
8. Can a community get CRS credit for activities implemented by a state
agency on behalf of the community?
9. Can non-CRS communities obtain and benefit from CRS publications?
10. RM 38-1 is located near Site A on Flood County’s FIRM. Is RM 38-1 in an
SFHA?
11. Is RM 38-1 in a CBRS zone?
12. Mrs. Murphy’s Chowder House was built at the east end of Vassar Road on
panel 38 in 1994. The restaurant got flooded last month. Which of the fol
lowing can help Mrs. Murphy rebuild her damaged restaurant?
- An NFIP flood insurance policy
- A FEMA disaster assistance grant
- A Small Business Administration disaster loan
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UNIT 9 - LEARNING CHECK #1 - ANSWERS
1. Where does a property owner go to buy a flood insurance policy?
To any licensed casualty insurance agent.
2. Can I buy a flood insurance policy with building coverage on the following?
An apartment building yes
A septic tank
no
An open sided park pavilion
no
A motor home no, unless it’s permanently attached to a foundation
A boat dock
no
A mobile home on a foundation in a mobile home park yes
A flower garden
no
3. What is the maximum amount of contents coverage I can get for a single
family dwelling?
$100,000
4. Can I wait and buy a flood insurance policy after I hear the National
Weather Service issue a flood warning?
Yes, but no claim can be paid. There is a 30-day waiting period before
coverage takes effect.
5. Which of the following programs is likely to require a flood insurance pol
icy as a condition of financial assistance?
- Department of Veterans Affairs mortgage loan guarantees yes
- HUD Community Development Block Grants yes
- Federal disaster assistance
yes
- Home improvement loans from a bank participating in FDIC yes
- Mortgage from a federal credit union yes
6. Does your local government have flood insurance coverage on the buildings
it owns in the floodplain?
Depends on the community. This is an important thing to check because flood
insurance may be the only source of funds to rebuild and repair those buildings
after a flood.
Flood Insurance
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Do I need an elevation certificate to purchase a flood insurance policy on a Pre-
FIRM building?
No. However, if you have one that shows the building to be at or above the
BFE, you can get a Post-FIRM actuarial rate that is lower than the rate
for Pre-FIRM buildings.
7. Is there much of a cost savings on flood insurance if the lowest floor of a
Post-FIRM building is one foot above the BFE instead of at the BFE?
Yes. For example, the rate for the first layer of building coverage for a
single family building located in an AE Zone goes from $.89/$100 cover
age to $..55, a savings of nearly 40%.
8. Can I get a good flood insurance rate on a building in an AE Zone that is
floodproofed to the base flood elevation?
Probably not. Unless the building is floodproofed to at least one foot
above the BFE, the rate will be based on the elevation of the lowest floor.
If the lowest floor is two or more feet below the BFE, it will be a submit
for rate.
9. What’s the best way to get a good flood insurance rate for a new building in
an unnumbered A Zone?
Obtain or develop a base flood elevation for the site and require the build
ing to be elevated above it.
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UNIT 9 – LEARNING CHECK #2 - ANSWERS
1. What are some of the benefits of joining the Community Rating System?
Residents get reduced flood insurance premiums
The community's flood program receives recognition from a national
evaluation program.
Technical assistance in designing and implementing some activities is
available at no charge from ISO.
It encourages the community to maintain its program during times of di
minished interest in flood issues.
2. Does your community implement any of the 18 activities credited by the
CRS?
Depends on the community. If your community implements five or more of
the activities listed, it may be worth your while to obtain a copy of the CRS
Application or contact the ISO/CRS Specialist for your area. Call
317/848-2898, your State NFIP Coordinator or your FEMA Regional Of
fice for the name and phone number of your ISO/CRS Specialist.
3. What is a CBRS zone?
An undeveloped coastal barrier (barrier island, sand spit, or similar land
form) that is designated as part of the Coastal Barriers Resources System.
4. Can I request a LOMA to get my property out of a CBRS area ?
No. The U.S. Fish and Wildlife Services can interpret the boundaries and
FEMA can correct map errors, but only Congress can change the designa
tion.
5. Are there any CBRS area in Flood County?
Yes. Panels 38 and 40 of Flood County contain CBRS areas designated in
1983 and after 1990.
Flood Insurance
H-104
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UNIT 9 – LEARNING EXERCISE - ANSWERS
1. Who sets the rates and coverage rules for flood insurance policies, FEMA or
private insurance companies?
FEMA
2. What are the two types of flood insurance coverage available?
Building and contents coverage
3. Can I get flood insurance coverage for furniture in a basement?
No
4. Can a bank require flood insurance for a property outside the SFHA shown
on the latest FIRM?
Yes. Any lender can require flood insurance wherever it wants (Federal
law doesn’t give lenders a choice for properties in the SFHA).
5. What are the two key factors in rating Post-FIRM buildings?
FIRM Zone and the lowest floor’s elevation in relation to the BFE
6. How do I know how much a flood insurance policy will cost for a Post-
FIRM building with the lowest floor four feet below the BFE?
The insurance agent has to send information on the building in for a spe
cial individualized rating known as “submit for rate.”
7. How can your community help its residents get lower flood insurance rates?
Join the Community Rating System (CRS)
8. Can a community get CRS credit for activities implemented by a state
agency on behalf of the community?
Yes
9. Can non-CRS communities obtain and benefit from CRS publications?
Yes
10. RM 38-1 is located near Site A on Flood County’s FIRM. Is RM 38-1 in an
SFHA?
Yes
11. Is RM 38-1 in a CBRS zone?
No
12. Mrs. Murphy’s Chowder House was built at the east end of Vassar Road on
panel 38 in 1994. The restaurant got flooded last month. Which of the fol
lowing can help Mrs. Murphy rebuild her damaged restaurant?
An NFIP flood insurance policy
A FEMA disaster assistance grant
Flood Insurance
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A Small Business Administration disaster loan
None of these programs are available because the building was built in a
CBRS area 4 years after it was designated as such.
Flood Insurance
H-106
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UNIT 10
LEARNING CHECK #1
1. Who is responsible for disaster and emergency response activities in your
community?
2. Is there a written emergency response plan that identifies your department’s
duties during and after a disaster?
3. What are the objectives of a building condition survey?
4. What are the three categories of building condition that are determined dur
ing the building condition survey?
5. What is one of the best guides you can give to owners and residents of
flooded buildings?
6. Can your community waive the requirement for a development permit so
people can repair their flooded homes more quickly?
7. When you inspect a flooded building to determine if the structure is substan
tially damaged, which of the following items should you check?
Walls and ceiling
Foundation
Deck or porch
Molding and built-in bookcase
Ductwork
Water heater
Kitchen cabinets
8. Does your community or state license contractors or have procedures to pre
vent “fly by night” unqualified contractors from preying on disaster victims?
9. What sources of assistance are there to help your post-disaster permit opera
tions?
Disaster Operations
H-107
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UNIT 10 - LEARNING CHECK #2
1. What’s a good definition of “flood hazard mitigation?”
2. What are the six basic strategies of flood hazard mitigation measures?
3. What are some of the benefits of preparing a mitigation plan?
4. What are the guidelines of multi-objective management?
5. Where can you get technical help in planning and implementing a mitigation
program?
6. List some of the sources of financial assistance that are available for a miti
gation program.
7. Could my community be eligible for a Section 404 Hazard Mitigation Grant
even if it did not receive a disaster declaration?
Disaster Operations
H-108
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UNIT 10 - LEARNING EXERCISE
1. The Building condition survey identifies three categories of building condi
tion. Which two need permits?
2. What type of work may not need a permit after a flood?
3. Once you advise an owner that a permit may be necessary, do you need to
inspect the building or can you save time and just wait for a permit applica
tion?
4. Who can help you make sure people don’t reoccupy damaged buildings be
fore they have passed an inspection?
5. Can constructing a levee and maintaining sand dunes be considered flood
hazard mitigation measures?
6. What’s more important: a plan document or the planning process?
7. Which of the following are benefits of multi-objective management?
It helps look at all possible solutions
It coordinates flood issues with other community concerns.
The cost of implementing programs is shared with others.
The floodplain and watershed are treated as resources.
8. What are the two types of grants available through the Flood Mitigation As
sistance Program?
9. If a flood is bad enough to result in a Presidential disaster declaration, why
should my city need flood insurance policies on the buildings it owns in the
floodplain?
Disaster Operations
H-109
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UNIT 10 - LEARNING CHECK #1 - ANSWERS
1.
2.
3.
4.
5.
6.
7.
Who is responsible for disaster and emergency response activities in your
community?
Each community may have a different name for the emergency manager.
Get to know yours.
Is there a written emergency response plan that identifies your department’s
duties during and after a disaster?
Depends on the community. There should be one that clearly identifies
what is expected of your office.
What are the objectives of a building condition survey?
To determine if any building is so dangerous that it should not be reen
tered without a careful inspection, and
To determine which buildings will need a floodplain development permit
before they can be repaired or reoccupied.
What are the three categories of building condition that are determined dur
ing the building condition survey?
Apparently safe: No exterior signs of structural damage. People can be
allowed back in, but they will need building permits for repairs.
Building obviously substantially damaged: The flood swept the building
away, it has collapsed or it is missing one or more walls. The building
cannot be reoccupied without major structural work.
Could be substantially damaged: The building may be substantially dam
aged, but such damage is not obvious.
What is one of the best guides you can give to owners and residents of
flooded buildings?
Repairing Your Flooded Home
Can your community waive the requirement for a development permit so
people can repair their flooded homes more quickly?
No. You can waive the permit fee, but you must require permits to see if
the buildings could be substantially damaged and subject to your flood
plain ordinance’s requirements.
When you inspect a flooded building to determine if the structure is substan
tially damaged, which of the following items should you check?
Walls and ceiling
Foundation
Disaster Operations
H-110
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Deck or porch
Molding and built-in bookcase
Ductwork
Water heater
Kitchen cabinets
All of the above need to be checked because the NFIP considers all of
them part of the building’s structure.
8. Does your community or state license contractors or have procedures to pre
vent “fly by night” unqualified contractors from preying on disaster victims?
Depends on the community. It’s worth checking out before the disaster
happens.
9. What sources of assistance are there to help your post-disaster permit opera
tions?
State NFIP coordinator
FEMA Regional Office
State building code agency
Model building code organization
Local or state health department
Cooperative Extension Service
Other communities willing to provide mutual aid
Building officials association
Disaster Operations
H-111
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UNIT 10 – LEARNING CHECK #2 - ANSWERS
1.
2.
3.
4.
5.
What’s a good definition of “flood hazard mitigation?”
All actions that can be taken to reduce property damage and the threat to
life and public health from flooding.
What are the six basic strategies of flood hazard mitigation measures?
Prevention
Property protection
Natural resource protection
Emergency services
Structural projects
Public information
What are some of the benefits of preparing a mitigation plan?
Preparing a plan will:
Ensure that all possible activities are reviewed and implemented.
Link floodplain management policies to specific activities.
Ensure that activities are coordinated.
Educate residents
Build public and political support
Fulfill planning requirements for state or federal assistance programs.
Facilitate implementation of floodplain management activities
What are the guidelines of multi-objective management?
Keep the effort locally based.
Understand the flood problem and its relation to the watershed.
Think broadly about possible solutions to reduce the flood problem.
Identify the other community concerns and goals that could have a bear
ing on the flood problem.
Obtain expert advice and assistance from government agencies and pri
vate organizations.
Build a partnership among the private and public groups and individuals
that can be enlisted to work on the objectives.
Where can you get technical help in planning and implementing a mitigation
program?
National Park Service’s Rivers, Trails and Conservation Assistance Pro
gram
Disaster Operations
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The soil and water conservation district.
Natural Resources Conservation Service
Cooperative Extension Service
Watershed, stormwater management or flood control districts.
Regional or metropolitan water, sewer or sanitary districts.
Regional planning commissions and councils of government
The state or county emergency management or civil defense agency (see
Appendix B).
The state natural resources or water resources agency.
Local watershed councils or associations.
U.S. Army Corps of Engineers.
Association of State Floodplain Managers.
Floodplain Management Resource Center
6. List some of the sources of financial assistance that are available for a miti
gation program.
Property owners willing to cost share on projects that help them
FEMA’s Flood Mitigation Assistance Program
FEMA’s Public/Infrastructure Program
FEMA’s Human Services programs
FEMA’s Hazard Mitigation Grant Program
7. Could my community be eligible for a Section 404 Hazard Mitigation Grant
even if it did not receive a disaster declaration?
Yes, under a 1997 FEMA ruling, all communities in the state are eligible
after the disaster declaration.
Disaster Operations
H-113
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UNIT 10 – LEARNING EXERCISE - ANSWERS
1.
2.
3.
4.
5.
6.
7.
The Building condition survey identifies three categories of building condi
tion. Which two need permits?
Building obviously substantially damaged: The flood swept the building
away, it has collapsed or it is missing one or more walls. The building
cannot be reoccupied without major structural work.
Could be substantially damaged: The building may be substantially dam
aged, but such damage is not obvious.
What type of work may not need a permit after a flood?
Cleanup and temporary emergency repairs
Once you advise an owner that a permit may be necessary, do you need to
inspect the building or can you save time and just wait for a permit applica
tion?
As soon as possible after the notice is delivered, your office should inspect
each flooded property to review needed repairs and determine if a permit
is needed.
Who can help you make sure people don’t reoccupy damaged buildings be
fore they have passed an inspection?
Make sure that utility companies won’t turn service back on unless there is
an “Approved to Connect” sign posted on the building.
Instruct police and other departments about the permit requirements and
ask them to report to you any construction projects under way without
posted permit signs.
Get the news media to help spread the word on the requirements and why
they are needed.
Can constructing a levee and maintaining sand dunes be considered flood
hazard mitigation measures?
Yes
What’s more important: a plan document or the planning process?
The process.
Which of the following are benefits of multi-objective management?
It helps look at all possible solutions
It coordinates flood issues with other community concerns.
The cost of implementing programs is shared with others.
The floodplain and watershed are treated as resources.
All of these are benefits of M-O-M.
Disaster Operations
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8. What are the two types of grants available through the Flood Mitigation As
sistance Program?
Planning grants to help develop or update a flood mitigation plan
Project grants to implement projects in conformance with the flood miti
gation plan
9. If a flood is bad enough to result in a Presidential disaster declaration, why
should my city need flood insurance policies on the buildings it owns in the
floodplain?
Federal disaster assistance for a flooded public building will be reduced
by the amount of flood insurance coverage the community should have on
that building. It does not matter whether the building is insured; FEMA
will still only provide assistance for damage that exceeded the level of in
surance.
Disaster Operations
H-115
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"...inside the corporate limits of a municipality. In countywide mapping, once the countywide map is produced, all of the identified flood hazard areas within the boundaries of the county are shown on one set of maps along with all floodway information maps (see section titled Flood Insurance Rate Map—New Format). The..."
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Apr 6, 2026
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