3 D Flood Risk Visualization Beth Norton December

3 -D Flood Risk Visualization Beth Norton December 21, 2011

Background § Floods are one of the most common hazards in the US § FEMA provides flood risk data to community officials through flood mapping products § Participating communities in the NFIP regulate and enforce the flood maps 2

Problem § Risky decisions are made • Communities allowing development in the floodplain • Developers buying land building homes in the floodplain § The impacts of these decisions aren’t borne by those making them • Homeowners purchase the risk • Federal government insures the risk • First responders risk their lives to rescue people at risk § Flood maps are 2 -D and don’t portray immediate risk • The forces of flood damage can’t be shown on a 2 -D map. § Homeowners and potential homebuyers need tailored information 3

2 -D Flood Map 4

Flooding Damage Forces § Hydrodynamic Forces • Moving water • The faster the water, the greater the pressure and erosion. § Hydrostatic Forces • Standing water • The deeper the water, the more it weighs and greater the pressure. • 3 feet of standing water can collapse a standard frame house § Debris • Ice floes • Large objects • Sediment § Soaking • Damages building materials and household goods *Source: FEMA: Managing Floodplain Development through the NFIP, 2/15/2010 5

Proposal (Solution) 500 year 100 year 50 year 6

Proposal (Solution) 500 year 100 year 50 year 7

Process § Software • Sketch Up § 3 -D Buildings • 3 D Analyst § 3 -D flood hazard data • Arc. Scene § Visualization 8

Data § Provided by the NCFMP § Base Data • 2010 Orthoimagery • Street Centerlines • Streams • Tax Assessor Data • Li. DAR § Built-Environment Data • Digitized Building Footprints • Building Photos § Raster Datasets • Water Surface Elevation (WSEL) and Depth Rasters (Multi-Return Periods) § 10, 25, 50, 100, and 500 years 9

Data (cont) § Risk Data • Building Footprints attributed with § First Floor Elevations § Lowest and Highest Adjacent Grade § Number of stories § Estimated building and content loss § Flood Depths § Flood Elevations § Annualized Damages § Regulatory Data • FIRM • FIS • Database 10

Project Area § Tarboro, Edgecombe County, NC* • Population – 13, 121 • Land Area – 9. 8 square miles • Flood History § July 1919 flood § Exceeded the 100 -year flood § Hurricane Floyd, 1999 § Exceeded the 500 -year flood § $5 Billion in damages to NC § Hurricane Irene, 2011 * Source: 11/3/2004 FEMA Flood Insurance Study, Edgecombe County, NC 11