Hydrologic modeling as a tool for land management and contingency planning in the Calcasieu Sabine Basin. Volume 1

The Calcasieu-Sabine Basin in southwest Louisiana contains approximately 126,518 hectares of wetlands, consisting of fresh marsh, intermediate marsh, brackish marsh and saline marsh. The hydrodynamics of the basin involves a combination of estuarine processes such as saltwater intrusion, response to water level fluctuations at an open boundary and lake dynamics. The basin is also affected by deep ship channels. As such, a robust, flexible and efficient numerical model is needed to incorporate all of these processes in an operational program. This study developed a hydrodynamic and salinity model for a portion of the basin that includes the lakes and marshes for the purpose of land management and contingency planning. The newly developed finite-difference hydrodynamic and salinity model is a combination of 1 and 2 dimensional computations and is intended for land, wildlife and habitat management. It can be used as a coastal restoration tool to evaluate the effectiveness of future and ongoing coastal restoration projects. The model was calibrated and validated against field measurements. It was shown to produce accurate simulations of the complex flow patterns of the Calcasieu-Sabine Basin along with information on salinity, water level fluctuations, velocities and discharges throughout the main channels and open water bodies within the area. It was concluded that the model provides a very useful planning and adaptive management tool to improve the understanding of the complex hydrology and salinity circulation pattern within the system. 5 refs., 4 tabs., 9 figs