South Atlantic Water Science Center - North Carolina Office
Period of Project
USGS IN YOUR STATE
USGS Water Science Centers are located in each state.
Flood Inundation Mapping
This project was completed in 2004. These pages are for historical purposes only.
Edgecombe County, N.C., September 19, 1999—Aerial photo of severe flooding engulfing populated areas as a result of Hurricane Floyd. Picture by David Saville/FEMA News Photo.
North Carolina is subject to flooding from land-falling hurricanes, storm surge, intense thunderstorms, and slow-moving frontal systems. The existing flood information and flood forecasting system has served the State of North Carolina and the Nation well. However, as indicated by experiences during Hurricanes Fran and Floyd, as well as other flood events across the State and Nation, there is a growing demand and need for more and better flood information and flood forecasting. In 1999, Governor Hunt and the North Carolina General Assembly tasked the North Carolina Floodplain Mapping Program to improve the flood information and flood-forecasting system. Following a 2 - year period of program planning and negotiations, a multiagency group was formed to develop the flood-information and flood-forecasting system (see list of cooperative agencies). The primary U.S. Geological Survey (USGS) role in this project is to develop and implement a real-time flood information and inundation mapping component for the flood-information and flood-forecasting system.
The objective of this study is to produce maps in real-time that depict the current area of inundation and depth of inundation near gaged locations in the Tar River basin. A secondary objective is to provide additional stream and rainfall data to the National Weather Service to enhance flow forecasts.
The four key elements of the project include data collection, hydraulic modeling, inundation map preparation, and software development and implementation. The USGS will continue data-collection activities at current and new streamgage and raingage sites in the Tar River basin. After models are calibrated and regions for mapping are defined around each streamgage site, a library of inundation maps will be prepared for each site. For a given stage at a particular site, each inundation map will show water depth and lateral extent of inundation over the mapped reach. Software will be developed jointly by the USGS and the N.C. Floodplain Mapping Program to link real-time stage information to the map library.