The purpose of this study was to quantify the potential of available storm water to mitigate the adverse impacts of impounded saline water within a 1,336-ha, forested coastal ecosystem. A site-specific hydrodynamic model was constructed to predict the spatial influence of reduced salinity resulting from the continuous discharge of storm water, at a volume of 2.83 cubic meters per second (cms), directly and indirectly into the study area. These results were then incorporated into the Wetlands Value Assessment (WVA) model to quantify wetland benefits to specific habitats.
The results show that the discharge of 2.83 cms of storm water can significantly enhance wetland functions within the 1,336-ha coastal ecosystem. The most benefit occurs when the storm water is discharged directly into the swamp via dedicated channel or pipeline, in contrast to discharging into an existing bayou within the subbasin and directing flow into the adjacent wetlands. Utilizing the WVA methodology, direct discharge is predicted to result in a net wetland benefit of 725.97 Average Annual Habitat Units (AAHUs). This benefit is largely attributed to reductions in salinity and an improved water regime (mixing) within the declining baldcypress swamp.