NUMERICAL MODELING OF HEAT AND SALINITY TRANSPORT FOR WEST INDIAN MANATEE HABITATS IN SOUTHWEST FLORIDA

A heat transport algorithm has been developed and implemented by the USGS within the FTLOADDS coupled variable-density, hydrodynamic surface and groundwater model code to study the ecological effects of proposed restoration scenarios in the southern Florida Everglades. With this algorithm, numerical simulations can be used to predict how environmental changes affect temperature and salinity sensitive species, such as the West Indian manatee. In model development, a heat-budget approach was utilized and several alternative methods were considered for representing the heat fluxes that contribute to changes in temperature within the model cells. The formulation was initially developed and tested within the TIME (Tides and Inflows in the Mangroves of the Everglades) application of FTLOADDS, with the required heat-flux coefficients and parameters estimated using locally-measured evapotranspiration data. The model was calibrated to several temperature monitoring stations, and simulated daily average temperatures correspond closely to coastal and inland measurements. The ability to represent diurnal fluctuations varied by location, however, possibly due to the lack of spatial variation in heat-transport parameters such as soil heat capacity, mass transfer, and surface albedo.

The results reflect the suitability of the new formulation for defining the existing thermohydrologic system and for predicting the effect of proposed changes due to restoration efforts. The heat transport formulation is now being implemented within the Ten Thousand Islands area, which is a primary habitat for manatees in southwestern Florida. Model results currently are being compared with manatee tracking locations to determine how environmental changes affect animal behavior during high thermal stress periods.