Project summary:
The coastal margin of the US has been in the focus of various USGS activities due to its tremendous economic and recreational values. Currently, the USGS is developing a GIS based inventory of scientific data that includes variables that are known to contribute to coastal changes, such as erosion and accretion. The database is intended to provide a quantitative basis for monitoring, modeling, assessing, and ultimately predicting coastal change in response to hurricanes and northeasters. This project will be an integral part of the USGS national coastal erosion assessment as it will use SURGE a hydrodynamic model of ocean circulation for coastal areas that simulates and predicts storm surge, flooding, overwash, water recession, and associated horizontal currents. The model will be verified for four category 4 hurricanes (Hugo, 1989; Gracie, 1959; Connie, 1954; Hazel, 1954) and several severe northeasters using the data available from NOAA and USGS WRD surge maps for those storms. SURGE has become a powerful tool capable of addressing a variety of storm surge and flood issues.
Project objectives and strategy:
The ultimate objective of the project is to obtain quantitative measures of hydrodynamic coastal processes necessary for near real time and long term predictions of erosion changes in coastal topography and bathymetry, and assessment of the past and present rates of coastal change. Implementation of SURGE involves several steps. First, a curvilinear orthogonal grid for the South Carolina coastal zone needs to be developed. The grid should extend inland sufficiently to accommodate hurricane and northeasters related flooding and overwash. NOAA/NOS bathymetry data for the grid has been obtained and high resolution topography data will be available from USGS/NOAA Lidar surveys. Second, a data base of forcing boundary conditions (time dependent horizontal fields of surface wind stress generated by each of the 4 hurricanes) will be compiled in order to perform computer simulations of coastal circulation caused by each storm. The results of these simulations will be verified against USGS WRD surge maps. The results will be animated and made available via the Internet.
The major outcome of the project is: