A Salinity Management Model for Restoration of a Coastal Riverine Ecosystem

The Northwest Fork of the Loxahatchee River contains one of the last examples of a pristine subtropical riverine cypress swamp in South Florida. The permanent opening of the Jupiter Inlet along with sea level rise and reduced dry season freshwater flows in the Northwest Fork has allowed salt water to migrate upriver causing the introduction of mangroves into areas once dominated by freshwater floodplain swamp vegetation, particularly bald cypress. Restoration of this natural resource requires reducing or reversing the current condition of saltwater intrusion and maintaining the freshwater habitats in the upper reaches of the Northwest Fork to protect existing populations and distribution of wildlife that require freshwater habitat. A computer program was developed to predict salinity and calculate other performance parameters under various ecosystem restoration scenarios. Field data, regression analysis and results of multi-dimensional hydrodynamic computer models were integrated into a system simulation and management tool. Salinity prediction and other computations were conducted over a 39-year period. Such long-term simulations are required to investigate ecosystem response and assess the effectiveness of the proposed restoration approach. The model also contains system management functions such as the calculation of additional freshwater demand for salinity management under various restoration alternatives.