Monday, March 31, 2008 : 1:20 p.m.
Karst Landfill Ground Water Assessments In the Valley and Ridge Geologic Province of Tennessee and Virginia
Three landfill gas assessment case studies are presented to illustrate offsite impacts resulting from the transport of landfill gas via the karst void network. Direct-push gas monitoring techniques were employed to actively map and track the distribution and migration of landfill gas in the soil overburden. Characterizing the extent of offsite impact in the soil overburden allowed the identification of gas transport mechanisms and flow paths existing deep within voids in the bedrock. Offsite gas impacts were remediated at each site by accessing the bedrock voids and redirecting the flow to the surface with vents installed at the property line.
Three groundwater assessment case studies are presented to illustrate radial groundwater flow from karst landfills and resulting offsite impacts. Misinterpretations of groundwater flow directions and contaminant transport often result from information that is confined to the landfill property. Monitoring techniques utilizing existing offsite spring and well networks enables a better understanding of the distribution and migration of landfill groundwater impacts.
Jeff Smith, Draper Aden Associates Jeff Smith is a project geologist with Draper Aden Associates in Blacksburg, Virginia. He has 20 years of experience conducting geotechnical and hydrogeologic investigations at a variety of proposed, existing, and closed landfill sites in the Valley and Ridge, Blue Ridge, and Piedmont geologic provinces of Virginia and North Carolina, and the Valley and Ridge, Eastern Highland Rim, Central Basin, and Western Highland Rim geologic provinces of Tennessee.