Caption title. At head of title: Project summary. Distributed to depository libraries in microfiche. "Sept. 1986." "EPA/600-S2-86-057."

"Hazardous wastes disposed of in landfills may continue to drain for several years after site closure. Leachate sources include waste fluids as well as precipitation trapped in the landfill during construction and operation. Waste fluids may be released via barrel degradation and subsidence and/or compression of waste materials. Water may also continue to enter the landfill through structural faults. Predictions of rates and amounts of leachate produced can be developed if the hydraulic parameters and/or specific-yield values for the hazardous waste and backfill materials are known. A literature search showed that limited hydraulic parameters and specific-yield information are available. Unit-gradient and specific-yield modeling approaches were evaluated for use at hazardous waste landfills. Specific yield was determined for three data sets: one collected by a commercial hazardous waste landfill operator and provided by the state regulatory agency, one collected by the authors at a hazardous waste site located in New York State, and one developed from physical models where drum arrangement, void volume, and soil type were varied."