Federal, state, and local regulations govern the location, construction, content, and maintenance of landfill sites built to accommodate the vast quantities of garbage produced every day in America. A landfill is an enormous hole, either excavated for the purpose of waste disposal or left over from surface mining operations. The hole is lined with clay or a synthetic liner to prevent leakage of waste material into the water supply. A system of underground drainage pipes permits the monitoring of leaks and leaching. Waste is laid on the liner at the bottom of the excavation, and a layer of topsoil is then compacted onto the waste. The layering procedure is repeated until the landfill is full, with the layers mounded up sometimes as high as several hundred feet.
