HR: 1330h
AN: H13B-09    [Abstracts]
TI: Landfill Gas Effects on Evapotranspirative Landfill Covers
AU: * Plummer, M A
EM: mitchell.plummer@inl.gov
AF: Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 8415-2107 United States
AU: Mattson, E
EM: earl.mattson@inl.gov
AF: Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 8415-2107 United States
AU: Ankeny, M
EM: mark.ankeny@inl.gov
AF: Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 8415-2107 United States
AU: Kelsey, J
EM: jkelsey@dbstephens.com
AF: Daniel B. Stephens and Assoc., 6020 Academy NE, Albuquerque, NM 87109 United States
AB: The performance of an evapotranspirative landfill cover can be adversely affected by transport of landfill gases to the plant root zone. Healthy plant communities are critical to the success and effectiveness of these vegetated landfill covers. Poor vegetative cover can result in reduced transpiration, increased percolation, and increased erosion regardless of the thickness of the cover. Visual inspections of landfill covers indicate that vegetation-free areas are not uncommon at municipal waste landfills. Data from soil profiles beneath these areas suggest that anaerobic conditions in the plant-rooting zone are controlling plant distribution. On the same landfill, aerobic conditions exist at similar depths beneath well-vegetated areas. The movement of methane and carbon dioxide, generated by degradation of organic wastes, into the overlying soil cover displaces oxygen in the root zone. Monitoring data from landfills in semi-arid areas indicate that barometric pumping can result in hours of anaerobic conditions in the root zone. Microbial consumption of oxygen in the root zone reduces the amount of oxygen available for plant root respiration but consumption of oxygen and methane also produce water as a reaction byproduct. This biogenic water production can be on the order of centimeters of water per year which, while increasing water availability, also has a negative feedback on transport of landfill gases through the cover. Accounting for these processes can improve evapotranspirative landfill cover design at other sites.
DE: 1803 Anthropogenic effects
DE: 1851 Plant ecology
DE: 1866 Soil moisture
DE: 1875 Unsaturated zone
DE: 6339 System design
SC: Hydrology [H]
MN: 2005 Joint Assembly