Page 46 - GIS for Science: Technology Showcase

NATIONAL WATER MODEL
A geoscience resource that informs emergency response
In the United States, floodwaters kill more than 80 people a year and cause nearly $8 billion in losses. During the past five years, the National Oceanic and Atmospheric Administration (NOAA), in collaboration with University Corporation for Atmospheric Research (UCAR), Esri, and the academic research community, developed a new stream flow forecasting system, known as the National Water Model. The model, driven by approximately 7,000 observational measurements, hourly precipitation forecasts, and landscape characteristics, estimates water flow on 2.7 million stream reaches across the continental United States. The national model is a collection of models forecasting from hourly to 30 days in the future.
Flooding forecast maps
Emergency management planners and analysts use the hydrologic model to transform stream flow into water depth. An ArcGIS workflow using a digital elevation model and ancillary information turns water depth into flood forecast maps. These maps help users more accurately predict how a given storm might flood different areas, determine when the peak flood will occur, and estimate how long it will take to recede. This information is crucial for first responders and emergency management commanders. Having this predictive capability from hours to days before a flood improves their ability to plan for evacuations, road closures, and rescues.
Exploration in 3D
With this ability to predict when and where flood waters will strike, users can overlay this information with map layers showing buildings, roads, and demographics. Having all this information brought together in a map helps first responders understand the evo- lution of a flood emergency. In this example, an interactive 3D web application allows planners and responders to explore where water may accumulate during the next 24 hours. With this information, responders can set evacuation areas, route evacuees, posi- tion equipment, and visualize the impact of floodwaters on specific buildings and roads.
Modeling the event
The flood map is modeled on a 1-meter resolution, lidar-derived elevation model. The model computes the affected population using the Esri GeoEnrichment Service on the ArcGIS platform for the flooded area. Estimated damage costs are computed for each structure based on square footage and maximum depth of flooding derived from a Fed- eral Emergency Management Agency (FEMA) table.
Estimated Cost: $28,292,020
People, property, and infrastructure affected: 3,169 people
1,242 total structures
987 residential structures
255 commercial structures
85 roads
3D flooding forecast: Steve Kopp, Esri
National Water Model contributors: National Oceanic and Atmospheric Administration, University Corporation for Atmospheric Research, Esri, and numerous academic and federal research partners. Visit water.noaa.gov.
Potential Loss $50,000
$25,000 $5,000
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