Final covers for landfills are used to reduce the quantity of water that percolates into closed landfills and contaminated soils. Reducing the volume of percolating water reduces both the rate of leachate generation and the risk of groundwater contamination. EPA regulations prescribe a final cover design based on resistive principles (e.g., low-permeability clay, geomembranes). These covers are commonly used in most landfills and are generally referred to as "conventional" covers. Alternative covers are also permitted provided the alternative cover is equivalent to conventional cover.

There is a growing interest in alternative landfill cover designs because these covers are perceived to be less expensive to construct and maintain than conventional covers while providing long-term protection of human health and the environment. USEPA has initiated an Alternative Cover Assessment Program (ACAP) to address growing interest in innovative technology. ACAP is currently focusing on an evapotranspiration cover (ET) that utilizes plants to cycle water from the soil profile to the atmosphere.

Under ACAP, test facilities have been constructed at 12 sites across the United States to assess the hydrological performance of alternative and conventional covers. This presentation will focus on the ACAP program and its preliminary findings.

End_of_Record - Last_Page 11---------------