Collaborative Research: Evaluating Long-Term Impacts on Final Covers--Exhumation of the ACAP Test Sections

Affiliation(s)PIProject periodFunded by
DHS Albright, William H 09/15/2006 - 08/31/2009 National Science Foundation

Project Description

In 1998, the US Environmental Protection Agency recognized the scarcity of data describing the hydrologic performance of final covers for waste containment, and initiated the Alternative Cover Assessment Program (ACAP) to fill the information gap. ACAP is a network of 28 large-scale test sections for monitoring the hydrologic performance of final covers in a broad range of environments. Each test section includes an instrumented pan lysimeter for direct monitoring of the water balance, soil state variables, and meteorological conditions. Percolation data from the test sections show that some of the covers functioned as anticipated. However, others transmitted more percolation than expected, with preferential flow occurring in some cases. Ancillary data suggest that changes in the cover materials (soils, geosynthetics) and/or the vegetation may be responsible for the unanticipated behavior. Providing rigorous explanations for these observations requires an understanding of how the cover materials and vegetation changed. To this end, exhumations of the test sections are being planned where soil structure, soil hydraulic properties, geosynthetic properties, and vegetative species will be studied in detail and compared to those at the time of construction. A consortium of entities, including NSF, is being organized to support exhumation of the ACAP test sections. This proposal has been submitted to include NSF in the consortium.