Modeling the Hydrology and Hydrodynamics in Loxahatchee River and Estuary, Florida during Hurricanes Frances and Jeanne

Over the past several years, the South Florida Water Management District has initiated several projects for data collection and model development to simulate freshwater inflows and salinity conditions in the Loxahatchee River and Estuary. These models include a watershed hydrologic model (WaSh) simulating long term freshwater inflows from all tributaries into the Loxahatchee River, and a two-dimensional estuarine hydrodynamic and salinity model (RMA) that simulates the influence of the freshwater inflows and tide on salinity conditions within the Loxahatchee River and Estuary. The estuary model and the watershed model combined became an integrated modeling tool that was used extensively to evaluate ecosystem restoration scenarios (Wan and Hu, 2006). While the estuary model was tested against the tide and salinity data that had been collected in 2003, the data collected during the 2004 hurricane season provided another opportunity to further test the model performance with storm surge and large amount of storm water runoff from the watershed. The integrated model simulation of the 2004 hurricane season focused on two major hurricanes (Frances and Jeanne) that made landfall near the Loxahatchee River in September 2004. This paper describes the preliminary results of the model simulation. The description of model output in this paper is focused on the water level only. The preliminary results seem to indicate that for simulations that involves storm surge and large amount of freshwater inflow it is necessary for the Loxahatchee estuary model to include floodplain in the model domain. Since the current mode became numerically unstable in shallow areas on the floodplain, in the next phase of our study we will use a newer model in our modeling tool box that was specifically formulated for simulations of wetland and floodplain.