The South Florida Water Management District (SFWMD) is responsible for the operation and management of the engineered hydrologic system in south Florida. For the past decade or more, SFWMD has used the regional hydrologic model SFWMM (South Florida Water Management Model) to evaluate strategies for managing the engineered system, evaluate proposed changes to the system, and provide boundary conditions for local models. More recently, SFWMD has been developing a new model, the South Florida Regional Simulation Model (SFRSM). SFRSM is intended to ultimately replace the SFWMM. It is an object-oriented finite-volume code, based on an unstructured mesh of triangles. In SFRSM, levee seepage is simulated as three flow components, that exchange water between: (1) a “marsh” cell and a borrow canal; (2) a “marsh” cell and a "dry" finite-volume cell; and (3) the borrow canal and “dry” cell. The authors have developed seepage coefficients for the three levee seepage water movers at 20 levee reaches in south Florida using an analytic element cross-sectional model and PEST. The model simulates steady flow under the levee, based on estimates of aquifer properties and the local hydrostratigraphy at the levee. PEST was used to determine the range of possible seepage rates, based on the uncertainty of the hydraulic conductivity distribution in the aquifer. The simulated seepage rates were then used to determine seepage coefficients that can be incorporated in the regional model.