Customizing Hydrologic Basin Shapefiles to Improve National Weather Service Flash Flood Warnings and Statements
The current shapefile used in FFMP to monitor and diagnose flash flooding in the NWS Nashville County Warning Area makes it difficult for forecasters to quickly identify well-known areas that would be impacted by flooding. We determined that reconfiguring the basins around the Nashville Metropolitan area would improve forecaster situational awareness and shorten the flash flood warning process.
The basin reconfiguration process involved reshaping drainage basins based on their relative location to streams, lakes, and other topographical features, and renaming them to include recognizable names of cities, neighborhoods, and creeks. This was accomplished by altering several basin attributes using a combination of GIS applications. In addition to better-worded warnings and statements, these changes will allow for customized Flash Flood Guidance values to be assigned to the new basins. This poster will show how this process will lead to an increased quality and usefulness of the Flash Flood Warnings issued, and an improved understanding of the specific areas impacted.