83rd Annual

Tuesday, 11 February 2003: 2:15 PM
Enhanced flood forecasting and real-time inundation mapping in the Tar River Basin, North Carolina, USA
Douglas C. Marcy, NOAA/NWS, Charleston, SC; and G. Austin, J. Feldt, and S. Harned
Hurricane Floyd (1999) produced devastating flooding across eastern North Carolina that destroyed more than 4,000 homes and businesses.  As a result, the state’s governor requested a program to address flood hazard mapping deficiencies.  In 2000, NOAA formally agreed to participate in the North Carolina Flood Mapping Project by proposing enhancements to National Weather Service (NWS) flood predictions.  These enhancements will include real-time flood forecast maps.  This presentation highlights the objectives and activities of a demonstration project being conducted by the NWS Advanced Hydrologic Prediction Service (AHPS) that focuses on the Tar River Basin in eastern North Carolina.  It also highlights new partnerships between federal, state, and local governments that make these hydrologic prediction enhancements possible.

The AHPS project will be a collaborative effort between NWS, the U.S. Geological Survey, the Federal Emergency Management Agency (FEMA), the National Oceanic and Atmospheric Administration (NOAA) Coastal Services Center, and the state of North Carolina.  NWS will provide enhanced flood forecasts in the Tar Basin through the integration of scientific and technological advances in operational river forecast procedures.  Enhanced modeling will be used to produce Internet-based graphical representations of river and flood forecasts.  Ensemble Streamflow Prediction (ESP) will be used to generate probabilistic river forecasts for risk management decision making.  A key feature of this new approach to river forecasting and flood warning will be the incorporation of an unsteady-state dynamic hydraulic model that uses highly accurate terrain elevation data.  These data were created by the state of North Carolina in the process of completing new and updated flood insurance studies under FEMA's National Flood Insurance Program.

A new partnership with the NOAA Coastal Services Center will bring geographic information system (GIS) and modeling expertise to this project to develop real-time flood forecast mapping capabilities that will be incorporated into NWS operational forecasts.  The flood maps will provide a graphical aerial depiction of the forecasted flooding areas that will supplement the traditional text products.  Using LIDAR-derived elevation data collected by the State of North Carolina, accurate flood forecast maps will be provided via the Internet by the NWS and the State Of North Carolina’s Flood Mapping Information System (FMIS).  The successful demonstration of this project in the Tar Basin and several other basins in North Carolina will lead to nationwide implementation.

Real-time flood forecast mapping using unsteady-state hydraulic model and LIDAR derived elevation data  

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