FINITE DIFFERENCE MODELING OF THE EFFECTS OF INFILTRATION REDUCTION ON LEACHATE PRODUCTION

Aging landfill covers tend to become permeable with age resulting in infiltration into the refuse. This infiltration contributes to the formation and discharge of leachate. The Univ. of Toledo, Dept. of Environmental Sciences is involved in designing evapotranspirative covers to reduce infiltration using special vegetation, targeted grading, and drainage modifications. In order to aid in the design, this portion of the project uses a series of linked hydrological models including a finite difference (FD) groundwater model of leachate production and discharge. This FD model is then used to predict the response of leachate levels to the landfill cover modifications mentioned above. The site conceptual model, regional groundwater model, and hydrogeological characterizations are use in the design and setup of the FD model. Discharge from leachate springs, water levels in ponded areas, and stream discharges from the landfill provide estimates of boundary conditions that are used to calibrate the model. Finite difference modeling provides an effective method of predicting the results of various landfill cover modifications, and will be used to design the most cost-effective method of reducing the production of leachate.