Nation Flood Insurance Program (NFIP) Current Flood Insurance Rate Maps (FIRMs) & Special Flood Hazard Areas (SFHA) FEMA’s Map Modernization Program & Digital Flood Insurance Rate Maps (DFIRMs) DFIRMs for Hawaii County

1. FEMA Flood Mapping
County of Hawaii
Department of Public Works
Engineering Division
Presenter: Frank DeMarco, P.E.
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2. FEMA Flood Mapping
 Presentation Overview
 Nation Flood Insurance Program (NFIP)
 Current Flood Insurance Rate Maps (FIRMs) &
Special Flood Hazard Areas (SFHA)
 FEMA’s Map Modernization Program & Digital Flood
Insurance Rate Maps (DFIRMs)
 DFIRMs for Hawaii County
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3. FEMA Flood Mapping
 Nation Flood Insurance Program (NFIP)
 Created by Congress in 1968.
 Enables property owners in participating
communities to purchase Federal flood insurance.
 Nationally, ~21,000 communities participate, ~5.5
million structures insured, worth ~$1.1 trillion in
coverage.
 County of Hawaii, ~4,000 structures insured
~$900,000 in coverage.
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4.  The NFIP is based on an agreement between the
community and the federal government:
 Community adopts and enforces a floodplain management
ordinance (e.g., Hawaii County Code Chapter 27
http://www.hawaiicounty.gov/lb-countycode#countycode) to reduce
future flood risks to new construction in Special Flood
Hazard Areas (SFHA).
 Federal government makes Federal flood insurance
available to the community.
 NFIP has three parts: Floodplain Management, Insurance &
Mapping (i.e., Flood Insurance Rate Map).
FEMA Flood Mapping
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5. FEMA Flood Mapping
 Official community flood map that delineates the
special flood hazard areas (SFHA), or 1-
percent-annual chance flood areas (aka. 100-
year floodplains).
 Current FIRMs are based on 1970’s mapping
technology.
 Single layer of map information.
 Separate paper maps for individual
communities.
 Difficult and costly to change and distribute.
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 Flood Insurance Rate Map (FIRMs)

6. FEMA Flood Mapping
 Upgrade to GIS based digital flood
insurance rate map (DFIRM) format.
 Create 1 seamless community DFIRM.
 Incorporate Letters of Map Revisions.
 Convert the vertical reference datum for
flood elevation data (NGVD 29 to NAVD
88). For State of Hawaii, LTD.
 Most Map Modernization projects were
completed by 2010.
 In 2003, FEMA initiated a national five year $1 billion Flood
Map Modernization program to upgrade the paper FIRMs.
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7. FEMA Flood Mapping
 County protested/appealed FEMA’s 2008 & 2011 Preliminary
Digital Flood Insurance Rate Maps (Pre-DFIRMs)
 Insufficient time for review (i.e., 90-days):
 113 panels.
 Four volume Flood Insurance Study (110
pages on mapping basis & 384 flood
profiles).
 SFHA georeferencing onto the satellite
imagery does not comply with FEMA’s
horizonal accurancy criteria.
 Map Scale: 1:500 is 19 feet; 1:1000 is 38 feet
and 1:2000 is 45.6 feet. 7 of 11

8. FEMA Flood Mapping
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160 feet

9. FEMA Flood Mapping
 Feb 2013, FEMA & County agree to improve the
Pre-DFIRMs (Technical Cooperative Partnership)
 FEMA agreed to use 2010 NCRS imagery as the
base map and update Pre-DFIRM base on
County’s GIS data.
 Using ESRI ArcGIS Ver. 10, County agreed to:
 Digitize (*.tif or*.png) the current FIRMs, Letter of
Map Revisions (LOMRs) and Engineer’s LOMR work
maps (work maps).
 Georeference SFHA’s, LOMRs & work maps to the
2010 NRCS imagery.
 Deliverables based on 4 - 100 working days.
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10. FEMA Flood Mapping
 Waiakea Stream SFHAs, LOMRs & Engineer’s Work Maps
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11. FEMA Flood Mapping
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Questions?