West Virginia Flood Hazard Determination Tool
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Transcript of West Virginia Flood Hazard Determination Tool
West Virginia Flood Hazard Determination Tool
Tucker Clevenger, PE, CFM AMEC Environment and Infrastructure
Kevin Sneed West Virginia NFIP Coordinator
Brought to you by: WV Division of Homeland Security WVU GIS Technical Center FEMA Region III AMEC
Start with the Web site
WWW.MAPWV.GOV/FLOOD
Click Overview
Next is FEATURES
Important Contact Information
Data Layers
Resources and Glossary
Lets get started by clicking the LAUNCH TOOL button
Read the DISCLAIMER and then click I AGREE
ZOOM TO box
Navigation
Zoom In Zoom Out
Pan
Zoom by drawing box
In the ZOOM TO box you can navigate 1) by full address
2) by LAT LONG
Type in the ADDRESS if you know it
You can change it to EXPERT or RISK MAP view
Choose a BASE-MAP
For best view, choose BING or WV Best Leaf Off
Adjust transparency of flood layer
Reference will let you add more detail to your map
Draw and Measure Tools Icon
Markup Icon
Text typed here will show here
Add a Bookmark for later reference
Send what you look at to someone else to see
Just copy and past link
Help Icon
What you will see
TOPO Lines Studied Area
Unstudied Ares (Approximate A Zone)
If you click the PRINT Icon, the PRINT MAP as PDF box will appear.
Add your notes to the map
AFH Floodplain Modeling
• 2003 WV SAMB 3M DEM topographic data
• USGS Regression Equation Hydrology
• HEC-RAS Hydraulic Modeling • No hydraulic structures
included • No channel survey • Depth and water-surface
elevation grids developed • No BFEs on the FIRM
WV Flood Hazard Development Goals
• Improve upon effective approximate floodplains – Provide more accurate approximate floodplain boundaries – Resolve legacy “DFIRM Conversion” issues
WSEL=1170ft WSEL=1145ft WSEL=1170ft WSEL=1145ft
AFH=1143ft
WV Flood Hazard Development Goals
• Improve upon effective approximate floodplains – Provide more accurate approximate floodplain boundaries – Resolve legacy “DFIRM Conversion” issues
• Expand coverage of approximate floodplain boundaries – All streams down to 2 Square Miles – 4600 miles of approximate floodplains
WV Flood Hazard Development Goals
WV Flood Hazard Development Goals
• Improve upon effective approximate floodplains – Provide more accurate approximate floodplain boundaries – Resolve legacy “DFIRM Conversion” issues
• Expand coverage of approximate floodplain boundaries – All streams down to 2 Square Miles – 4600 miles of approximate floodplains
• Provide enhanced data utility -> leverage technology – Model backed floodplains with AFH elevations – Accessible via the WV Flood Determination Tool Website – Improve floodplain management and permitting decisions – Support LOMA determinations
WV Flood Hazard Refinement Goals
WV Terrain Data – DEMs
WV Terrain Data - LiDAR
7 ft 0.4 ft
0.9 ft
Comparison of Methods
Benefits/Future Enhancements
Alignment with FEMA Risk MAP Program West Virginia executing Risk MAP Program ahead of FEMA rollout Better Communicate Flood Risk Promote sound Floodplain Management All Approximate Floodplains now model backed
Now accepted by FEMA for LOMA Determinations/Elevation Certificates Growing importance with changing regulations/Biggert-Waters Future Enhancements
Data/Model Download Mobile Application
Limitations of Enhanced Approximate Studies
• Not accurate immediately upstream of hydraulic structures (bridges/culverts)
• No channel survey data included in HEC-RAS models • Cannot support BFE inclusion on FIRMs • Terrain Data
– Predominantly based on SAMB 3M DEMs – LiDAR/Aerial topo only selectively available
• Field survey data is always paramount