Inundation Mapping Using Hydraulic Models and GIS: Case Studies of Steady and Unsteady Models on the Tar River, NC

The National Weather Service (NWS) recently began providing static inundation maps at selected river forecast points through the Advanced Hydrologic Prediction Service (AHPS) web pages. Positive feedback has motivated efforts to expand the forecast mapping program. In order to expand this mapping program efficiently and effectively, we need a more objective basis for determining where static forecast mapping is acceptable and where real-time, dynamic forecast mapping is required. With the current static forecast mapping approach, we do not have quantitative guidance specifying how far away from forecast points the maps are valid. This pre-print describes a methodology to develop this type of guidance and better understand sources of forecast mapping uncertainty. For this pre-print, we present limited results from an example case study on the Tar River, NC, comparing water surface profiles generated from steady and unsteady flow hydraulic models. Results that are more comprehensive will be presented at the conference.