Calibration and Testing of Simulation Models for Evaluation of Trench Cap Designs

Abstract

AbstractA prototype decision support system (PDSS) using multi‐objective decision theory and embedded simulation models is being developed to evaluate landfill cover designs for low‐level radioactive waste disposal sites. To evaluate the performance of the PDSS, the simulation models, which are used to parameterize the decision model when data are not available, must be calibrated and tested. The two linked simulation models embedded in the PDSS are the HELP (hydrologic evaluation of landfill performance) and CREAMS (chemicals, runoff, and erosion from agricultural management systems) models. Data from a field demonstration study at Hill Air Force Base were used to calibrate the simulation models. The models were calibrated using water balance and erosion parameters for two alternative designs, a control soil cover and a modified USEPA Resource Conservation and Recovery Act design. Simulations were run using the calibrated model parameters for a 200‐yr period to evaluate the long‐term performance of the models. The progressive annual average for all of the output parameters was within the 95% confidence limits of the long‐term mean by Year 60 for both of the cover designs evaluated. The results of the calibration and long‐term evaluation of the simulation models were reasonable for the length of the data set. To fully validate and test the simulation models, other data sets of landfill covers in a variety of climates are needed.