A FIRST GENERATION ECOSYSTEM MODEL OF THE DES-PLAINES RIVER EXPERIMENTAL WETLANDS

A first-generation wetland ecosystem model is developed from first-year field data for four constructed freshwater marshes at the Des Plaines River Wetland Demonstration Project in northeastern Illinois, USA. The model, which includes hydrology, sediment and phosphorus algorithms common for all four wetlands, was used for the integration of data collected as part of the many different aspects of the demonstration project and for prediction of wetland function under varying hydrologic and chemical loadings. Stepwise calibration was completed on the model for the hydrology, sediment, productivity, and phosphorus submodels. Separate sedimentation coefficients were necessary for each wetland and each season. Preliminary simulations investigate the role of changing now conditions in the wetlands on phosphorus retention. As simulated inflow increased from 34 to 136 cm/wk, phosphorus retention increased from 1.5 to 3.3 g P m(-2) yr(-1) while retention efficiency decreased from 67 to 37%.