The development of a coupled hurricane storm surge forecasting Model for the Pascagoula River

The scope of this analysis is to dynamically model the effects of storm surge or elevated astronomical tides on the Pascagoula River watershed that incorporate rainfall and flows from upstream and to develop stage forecasts and inundation maps showing the depths and extents of flooding produced by rainfall, storm surge, or a combination of the two. The study area consists of the Pascagoula River, and estuary area from Merrill, MS to the Gulf of Mexico. The major tributaries included in the analysis have upstream boundaries at the following locations: Black Creek near Wiggins, MS, Red Creek at Vestry, MS, Escatawpa River near Agricola, MS, and Big Creek at Big Creek Dam, AL.

A model is being developed for the lower Pascagoula River using the U.S. Army Corps of Engineer's Hydrologic Engineering Center River Analysis System, an unsteady state, one-dimensional hydraulic model. The upstream boundaries and lateral inputs of the river model will be generated from the National Weather Service River Forecast System a hydrologic model that produces stream flow and stage hydrographs, using the continuous Sacramento soil moisture accounting model. The downstream boundaries will be stage hydrographs consisting of observed tide blended with National Ocean Service astronomical tide forecasts and the NWS Meteorological Development Laboratory's extratropical storm surge forecasts. Stage hydrographs generated from either the Advanced Circulation Model for Oceanic, Coastal, and Estuarine Waters developed by the Coastal Hydroscience Analysis, Modeling & Predictive Simulations Laboratory at the University of Central Florida or NOAA's Sea, Lake, Overland Surge Heights Model will be incorporated into the downstream boundary during tropical events.

Geometry data for the hydraulic model and inundation maps come from channel survey data from the United States Geological Survey and the U.S. Army Corps of Engineers Mobile District. Using these channel survey data, the University of Central Florida Coastal Hydroscience Analysis, Modeling & Predictive Simulations Laboratory developed a localized bathymetric mesh for the Lower Pascagoula and Escatwapa Rivers and estuary area needed to complete the coastal modeling. A digital elevation model was merged with the CHAMPS bathymetric grid merely to produce a continuous surface to represent the full river channel and floodplain. This topographic surface for the lower river reaches and estuary is merged with another digital elevation model to complete the upstream tributary reaches and will be used to build the cross sections needed for the hydraulic model.