USEFUL DEFINITIONS LEACHATE-Leachate is a combination of infiltrated precipitation and any liquids squeezed from the waste as it naturally compacts. Leachate will percolate to the base of land disposal sites due to the influence of gravity.Leachate can carry particulate matter, pollutants,biological contaminants and other constituents with it. Leachate will travel through the subsurface following the same flow direction as groundwater.All land based disposal facilities must incorporate a leachate collection and disposal system into their designs.Liners and covers must be added so as to minimize infiltration into the waste site thereby minimizing leachate production or escape LINER-Generally there are several layers of liners at the base of a land disposal site.Layers consist of compacted clay alternating with plastic.The purpose of the liner is to prevent leachate from escaping into the subsurface. CAP/COVER-Caps and covers are constructed(starting at the waste and working outward)of compacted,low permeability clay. This is followed by a flexible plastic liner(theoretically impermeable).Next comes a drainage layer designed to transport surface water away from the waste disposal site.Finally,this is followed by a layer of earth and then some type of vegetative cover.USEFUL DEFINITIONS  LEACHATE - Leachate is a combination of infiltrated precipitation and any liquids squeezed from the waste as it naturally compacts. Leachate will percolate to the base of land disposal sites due to the influence of gravity. Leachate can carry particulate matter, pollutants, biological contaminants and other constituents with it. Leachate will travel through the subsurface following the same flow direction as groundwater. All land based disposal facilities must incorporate a leachate collection and disposal system into their designs. Liners and covers must be added so as to minimize infiltration into the waste site thereby minimizing leachate production or escape.  LINER - Generally there are several layers of liners at the base of a land disposal site. Layers consist of compacted clay alternating with plastic. The purpose of the liner is to prevent leachate from escaping into the subsurface.  CAP/COVER - Caps and covers are constructed (starting at the waste and working outward) of compacted, low permeability clay. This is followed by a flexible plastic liner (theoretically impermeable). Next comes a drainage layer designed to transport surface water away from the waste disposal site. Finally, this is followed by a layer of earth and then some type of vegetative cover