NOAA AHPS Flood Inundation Mapping

1. Southeast Regional Flood Mapping Meeting October 29, 2009 NOAA AHPS Flood Inundation Mapping Victor Hom National Inundation Mapping Services Leader National Weather Service Office of Climate, Water, and Weather Services Hydrologic Services Division Silver Spring, MD

2. NOAA NWS AHPS Flood Mapping Presentation Outline • Enhancing the Communication of Flood Risk • Current AHPS Flood Mapping Projects • The MappingWeb Interface • Flood Inundation Mapping Challenges

3. Socioeconomic Impacts • On average, over the past 20 years in the U.S., flooding has claimed over 90 lives and caused damages in excess of $7 billion annually. • Flooding is responsible for more fatalities than any other severe weather related phenomenon. • More than half of all flood-related deaths result from motorists being swept away in their vehicles.

4. Enhancing the Communication of Flood Risk • • For over 30 years, the NWS has utilized a 3-tier, impact based, flood severity scale with the categories minor, moderate, and major flooding • For each NWS river forecast location, flood stage and the stage associated with each of the NWS flood severity categories are established in cooperation with local • public officials • NCC049-107-070200- • /O.NEW.KMHX.FL.W.0001.010407T1300Z-000000T0000Z/ /KINN7.1.ER.010407T1300Z.010412T0100Z.000000T0000Z.NO/ • 200 PM EDT FRI APR 6 2001 • THE NATIONAL WEATHER SERVICE IN NEWPORT HAS ISSUED A • FLOOD WARNING FOR NEUSE RIVER AT KINSTON • FROM SATURDAY MORNING UNTIL FURTHER NOTICE • AT 9 AM EDT FRIDAY THE STAGE WAS... 13.5 FEET • MINOR FLOODING IS FORECAST * FLOOD STAGE IS...14.0 FEET • FORECAST...FLOOD STAGE WILL BE REACHED AT 900 AM SATURDAY. MAXIMUM STAGE WILL BE 15.0 FEET AT 900 PM EDT WEDNESDAY. THE RIVER MAY REMAIN ABOVE FLOOD STAGE FOR SEVERAL WEEKS. THE EXACT FLOOD DURATION IS DIFFICULT TO PREDICT DUE TO THE VERY SLOW RISE AND FALL TIMES FOR THIS RIVER. • AT 14 FEET...WATER WILL BEGIN TO OVERFLOW INTO LOWLANDS ADJACENT TO THE NEUSE RIVER. $$ http://www.weather.gov/ahps/

5. Enhancing the Communication of Flood Risk • • The Inland Flood Forecasting and Warning System Act of 2002, Pub. Law No. 107-253 • Championed by Representative Bob Etheridge (2nd District NC) • Authorized NOAA to conduct activities to improve inland flood forecasting, develop a new flood warning index, train and educate officials regarding improved forecasting techniques and the inland flood warning index

6. Enhancing the Communication of Flood Risk • Since 2002, NWS has conducted extensive outreach to determine whether our current flood severity index satisfies user needs • Partnered with Claes Fornell International (CFI) Group to survey users of NOAA’s hydrologic information via the American Customer Satisfaction Index (ACSI) • Conducted user forums with State and Local Officials in North Carolina • Partnered with David Ford Consulting Engineers, Inc to conduct a national survey of emergency managers • Conducted additional local and regional user outreach

7. Enhancing the Communication of Flood Risk • Partners and Users are telling us that they…. • are familiar with NWS flood severity categories • find them useful • do not want changes to the existing flood severity indices • need the communication of flood risk to be enhanced by use of inundation graphics (maps)

8. Enhancing the Communication of Flood Risk "The problem for our emergency responders during flooding is that we rush over our floodplain maps but they are basically a 100 year storm event that rarely informs the expected flooding from a particular storm event." Floodplain Manager Baltimore Area

9. Advanced Hydrologic Prediction Service (AHPS) • Provide enhanced water availability and flood warning information by leveraging NOAA’s infrastructure and expertise • Modernize services through infusion of new science and technology • - Flash-flood to seasonal freshwater forecasts • - Quantification of forecast certainty • - More accurate and timely forecasts and warnings • - Partnered flood inundation mapping • - Visually-oriented products • Provide consistent access to standardized graphics via web interface

10. Blanchard River at Findlay, OH NOAA AHPS Flood Mapping Partnerships In the Southeastern U.S. • North Carolina Flood Mapping Program In the Southern U.S. • Gulf Coast States (Katrina Supplemental) • Lower Colorado River Authority • San Antonio River Authority In the Northeastern U.S. • Susquehanna River Basin (Upper/Lower) • Delaware River Basin Commission In the Midwestern U.S. • Indiana DHS, Indiana University Purdue University POLIS Center • State of Kansas, University of Kansas • City of Findlay Ohio, Killbuck Township of Ohio ~50 new Flood Map Libraries since Oct 2007 10 new Flood Map Libraries added in September 2009

11. AHPS Flood Mapping Partnership Benefits • From NC Partnership • Established Flood Mapping Techniques in cooperation with USGS North Carolina Water Science Center, NCFMP Office • Added Flood Categories and Depths to the AHPS Flood Mapping Interface • From Gulf Coast Partnerships • Refined Quality Assurance, Instituted Quality Checks, Field Review Procedures • From Midwest Partnerships • Improved Spatial Analysis for Display of Inundation and Generation of Depth Grids • From Northeastern Partnerships • Enhanced Guidelines, Statement of Work Templates, and Procedural Development

12. Partnering to Reduce Costs and Improve Efficiency Costs go down Efficiency goes up • Additional cost to complete one inundation map library as part of a detailed FEMA FIS: 5 – 10 K • Cost doubles and time increases if inundation map library is created after the FIS is completed: 10 – 20 K • Developing inundation libraries in conjunction with the detailed FIS yields significant user benefit for small incremental cost. • AHPS Web Implementation: ~7 K

13. AHPS Flood Mapping Interface Target Goals • Information to make risk based decisions • Easy product access • Visually oriented products • Link to other AHPS Products • Flood severity categories: minor, moderate, and majorflooding • FEMA 1%, 0.2% Annual Chance Flood Maps • Flood Depth Grids, Floodway • KML and Shapefile Downloads

14. AHPS Flood Mapping Interface www.weather.gov

15. AHPS Flood Mapping Interface www.weather.gov/ahps/inundation.php

16. AHPS Flood Mapping Interface www.weather.gov/ahps/inundation.php

17. AHPS Flood Mapping Interface • 1% Annual Chance Flood • 0.2% Annual Chance Flood • Floodway www.weather.gov/ahps/inundation/inundation_mapping_user_guide.pdf

18. AHPS Flood Mapping Challenges • Data Collection • Hydrology & Hydraulics • Inundation Mapping • Procedural • Quality Assurance http://www.weather.gov/os/water/

19. Data Collection Challenges • Topographic • Need for Bare Earth – Correction for Lidar returns from trees, cornfields, buildings, elevated structures, bridges, parklands. • Hydrographic • Bathymetric Needs - Soundings, Cross-sections, Acoustic Doppler Current Profiler, Graduated Rods • Stream Centerline • Control Structures • Top of levees, embankments, drainage control • Data Management Issues • Ground Control, Spatial Referencing, Datum, Projection, Vertical/Horizontal Accuracy, Costs http://www.csc.noaa.gov/crs/rs_apps/sensors/lidar.htm

20. H&H Modeling Challenges • AHPS Flood Mapping Suitability Analysis • USGS Gages, NWS Forecast Locations • Hydraulic Model Techniques • Adapting Existing Flood Studies • Flood Studies normally developed for higher flows than NWS Flood Categories • Calibration and Verification • Hydrologic and Flood Data • Funding https://ocwws.weather.gov/intranet/floodmap/Outreach.shtml

21. Inundation Mapping Challenges • Hydro and Hydraulic connections • Mapping Domain and Extents • Uncertainties near model boundaries • Flood Mapping Overlay • Orthophotos and Road Network • Topology, Line thickness • Tin to Raster Depth Grids http://pubs.usgs.gov/sir/2007/5032/

22. Procedural Challenges • NOAA NWS Guidelines • AHPS Flood Mapping • H&H/Spatial Analyses • AHPS Implementation • AHPS Map Library • Project Tracking, Milestones, Oversight Checks • Quality Assurance Measures • NOAA NWS Statement of Work Templates https://ocwws.weather.gov/intranet/floodmap/Docs.shtml

23. Quality Assurance and Maintenance Challenges • Quality Assurance • From start to finish • Quality control checks • Maintenance • Land use changes • Topographic changes • Mapping Reprocessing • AHPS Web Evolution http://www.weather.gov/oh/ahps/

24. National Weather Service … working with partners to improve the communication of flood risk