Calibration of seepage from steady state simulation for water budget estimation

Water gain/loss through seepage in the Everglades Nutrient Removal (ENR) project is a major component of the water budget. Seepage is the most difficult component to evaluate because most of its constituents cannot be directly measured. For this reason simulations from models or equations are the common procedure to estimate seepage. These procedures involve a series of assumptions and simplifications (i.e., geometry, soil parameters), which can be validated with a calibration-verification process. The accuracy of the water budget for this wetland treatment is very important because it will help to clarify and quantify, together with the nutrient mass budgets, the system efficiency in removing nutrients. Two seepage components into the project site from WCA1 are pertinent to this study: levee seepage, and subsurface seepage. This thesis addresses the quantification of the subsurface seepage by finding a set of parameters (hydraulic conductivities), which minimizes the deviations between observed and calculated values of levee seepage. Thus, the subsurface seepage is estimated with the use of a finite element, steady state seepage model. Levee and subsurface seepage account for 16 percent of the inflow pump for the two year period from August 19, 1994 through August 19, 1996.