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Published byLeslie Bradford Modified over 9 years ago
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Changes to FEMA Mapping John Grace, CFM Coastal Engineer - FEMA Region 1 - Boston March 14, 2014 – The Soil and Water Conservation Society – Winter Conference
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2 Program Overview Risk MAP Mapping – Flood hazard and risk identification Assessment – HAZUS and other risk assessment tools Planning – Hazard mitigation planning and HMA grants Risk MAP Vision Deliver quality data Increase public awareness of flood risk Encourage local/regional actions that reduce risk
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3 Risk MAP Project Timeline Discovery Meeting Project Kickoff Flood Study Review Resilience Meeting Final CCO Meeting 3-5 Year Process
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4 FEMA Mapping
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6 Detailed Study – Coastal Analysis Stillwater Level (storm surge) + Wave Set-up Overland Wave Propagation Wave Runup and Overtopping Primary Frontal Dune Coastal analysis - includes 4 main components:
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7 Detailed Study – Stillwater Level (SWEL) with Gage Data Return period gage analysis Linear interpolation between gage points
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8 Detailed Study – Wave Setup Numerically determined at each coastal transect Determining factors Average nearshore slope [depth of wave breaking to SWEL] Deepwater significant wave height SWEL + Wave Setup = Total Water Level (TWL) Areas where floodplain is restrictive, wave setup is removed and SWEL is mapped Constrictions such as low bridges Narrowing of the floodplain
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9 Detailed Study – Overland Wave Propagation
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10 LiMWA (Limit of Moderate Wave Action) Areas subject to wave heights greater than 1.5 feet, but less then 3 feet. Standard flood insurance requirements apply. No regulatory requirement. (Rhode Island requires V zone regulations) Defines the coastal A zone.
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11 Runupand Overtopping
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13 Primary Frontal Dune
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14 FLOOD RISK PRODUCTS
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15 Flood Risk Products These products are intended to help communities better understand and communicate flood risk Non - Regulatory All of these products are GIS based The following flood risk products may be available: Changes Since Last FIRM Flood Risk Assessment Contributing Engineering Factors Wave Height Grids Flood Risk Report
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16 Changes Since Last FIRM
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17 Annualized flood losses are displayed on the Census Block Data Aimed at depicting general flood loss areas Flood Risk Assessment
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18 Contributing Engineering Factors Provide insight into the factors behind the increase or decrease in the flood hazard areas Can prove to be useful for planning and mitigation measures
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19 Wave Height Grids Provided for 1% annual chance floods
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20 Flood Risk Report
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21 WEB LINKS Preliminary Data www.fema.gov/preliminaryfloodhazarddata Effective Data (including Future Effective) msc.fema.gov National Flood Insurance Program www.floodsmart.gov Flood Insurance Reform Act www.fema.gov/flood-insurance-reform-act-2012
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