Application of the Regional Simulation Model (RSM) to Simulate Regional Floods and Droughts in the Kissimmee Basin

Government agencies responsible for managing water depend on numerical models to simulate the detailed hydraulics and hydrology over areas under their jurisdiction. These models play a key role in making planning and operational decisions. The regional simulation model (RSM) developed at the South Florida Water Management District (SFWMD) is such a model used for simulating flood control and water supply scenarios. It uses object-oriented design methods to fully integrate 1-D and 2-D surface and groundwater flow features. Fully integration is used for reducing the error in coupling. RSM uses an implicit total variation diminishing Lax-Friedrics (TVDLF) method to solve both full and approximate shallow water equations under extremely flat and steep conditions. Functionality was added recently to the model to simulate wetland hydrology, local hydrologic features, and detailed transitional flow resulting from micro-topography and local drainage. The RSM model is applied to the Kissimmee River Basin in South Florida to capture the dominant hydrologic and hydrologic response features needed for understanding high and low flow regimes in the basin. Following basic physical principles and maintaining parameter parsimony were important considerations during the application. The results show that the ability to simulate transitional flow using physically based representations of micro-topographic features was important for producing the discharge hydrograph correctly using the model. The results also show the overall distribution of flow during flood events, water levels at all locations, and detailed flow vector patterns resulting from surface, sub-surface, and transitional flow.