west virginia flood hazard determination tool update · west virginia flood hazard determination...

West Virginia Flood Hazard Determination Tool Update

Tucker Clevenger, PE, CFM AMEC Environment and Infrastructure

Eric Hopkins West Virginia University

June 4, 2012

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AMEC has been working with FEMA Region III as an IDIQ contractor with FEMA Region III since 2001 and has been responsible for the majority of Map Mod updates in VA As Map Mod transitions to Risk MAP, we have encouraged our existing IDIQ contractors to assist with this transition by pursuing alternatives to identify, assess and communicate flood risk. Today, we are going to cover the potential benefits of digital mapping byproducts as well as some potential tools to better communicate risk. As technology in developing flood risk data continues to evolve, it provides us with opportunities to leverage many of the byproducts of this technology to enable more accurate risk assessments and more comprehensive risk communication to the public.

AFH Overview

WV AFH Partnership AMEC – Floodplain Modeling and Data Development WVGISTC – Tool Development and Data Hosting WVDHSEM – Overall vision, outreach, and prioritization FEMA Region III – funding and FEMA program support

AFH Overview


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

AFH Overview



Now accepted by FEMA for LOMA Determinations/Elevation Certificates

AFH Overview



Now accepted by FEMA for LOMA Determinations/Elevation Certificates Growing importance with changing regulations/Biggert-Waters

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



► Expand coverage of approximate floodplain boundaries § All streams down to 2 Square Miles § 4600 miles of approximate floodplains



► 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

Statewide Status Update

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Mon, Richie, Roane, Taylor – Doddridge and Preston

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

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Automated FP Development basics Having digital terrain data is really what opens doors for enhanced risk evaluation Enables the cost effective refinement of approximate floodplains as well as more affordable detailed modeling

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

Value of Enhanced Approximate Studies

► Replace outdated effective Zone A boundaries


► Replace outdated effective Zone A boundaries ► Used as best available data for floodplain management and

permitting



permitting ► AFHs can support LOMA determinations § BFEs are higher level of quality than FEMA LOMA WSEL

determination approaches




determination approaches ► Cost effective technology to develop high volume of

improved floodplains





improved floodplains ► Can be updated/enhanced to limited detailed or detailed

studies





improved floodplains ► Can be updated/enhanced to limited detailed or detailed

studies ► Accessible via the WV Flood Determination Tool – unique

to West Virginia

Data Updates

Effective DFIRM:11 counties added to Flood Tool Preliminary DFIRM: 5 counties added Digital floodplains for all counties – No data gaps Advisory Flood Height (AFH): 5 counties added Parcels: Cabell, Hampshire, Kanawha, Monongalia, Wood

Viewing purposes only New Data Layers Added to Flood Tool:

Community Rating System (CRS) Mitigated Properties

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New Data: New Effective & Preliminary DFIRM, and AFH data Added CRS communities, Mitigated Properties, Parcels (5 counties total)

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Status Map, Public View; Few changes overall, but… - DFIRM, Preliminary or Effective, for all counties - CRS: - City and county locations - Active polygon layer underneath for queries - Query results displayed in retractable side panel

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CRS: Countywide

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CRS: Municipality

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More changes to Expert View (And of greater interest to FPMs), including: CRS (same as with Public View) Advisory Flood Height (AFH) data (18 counties, 2 more pending completion) Profile Viewer AFH model data download

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Expert View, including: Advisory Flood Height (AFH) data incorporated into Flood Tool

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Expert View: Profile Viewer (select counties) AFH model data download (select counties)

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Functional Improvements: - AFH / Depth Grid / Water Surface Elevation in Expert View

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Functional Improvements: Profile Viewer Stream Name at top of results panel

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Functional Improvements: - Model engineering data package download link for AFH counties.

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Functional Improvements: Tool Tips associated with Basemap layers Default Basemap switches from Esri Street to Sherrifs’ Association orthoimagery at ~1:4k

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Functional Improvements: Zoom To graphics improved, dropped “urban” tint, other changes Zoom To Coordinates now available (Demo)

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Functional Improvements: - Simplified Draw and Measure with line and text color options

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Query results panel (1): Community Rating System (CRS), if applicable Example: Philippi, Barbour County

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Mitigated Properties point data Plans in place to correlate with parcels

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Query results panel (2): - Parcel information

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Parcel data service for viewing purposes only (no download)

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HEC-RAS Model Data Dpwnload Link in Query Results

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Progress map for stream name / profile viewer / model download query layer.

Future Development

Mobile App: Proof Of Concept Spring 2013 Agreement pending

Migration to Javascript from Flex API Mitigated Property / Parcel Correlation

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Future Development

Data Sharing Request

High Resolution Orthoimagery Elevation:

Lidar 2-foot contours

Digital Parcels

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If you have data to share please contact us.

GIS Training

► Scheduled Training Courses (WVGISTC) § Foundational Training

► ArcGIS I & II (June 10-14)

§ Specialized Training ► ArcGIS Advanced Editing (June 19) ► ArcGIS Python (July 16-18)

► Training Resources § WV Association of Geospatial Professionals (www.wvagp.org)

► Mapper ListServe - [email protected]

§ WV Property Tax Division § WV Office of GIS Coordination § Academic & Research Institutions § Software companies § Other assessor offices

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GIS Training Resources

http://www.wvagp.org/

User Feedback/Questions?

http://MapWV.gov/flood

http://MapWV.gov/flood

west virginia flood hazard determination tool update · west virginia flood hazard determination...

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