Laserfiche WebLink
' W <br /> var <br /> PROBLEM ASSES^MENT REPORT <br /> Moore Petroleum, Inc. <br /> 1399 E. Yosemite Avenue, Manteca, CA <br /> NGA Project No. 10-90-480 <br /> Page 14 <br /> 5.2 Ground Water <br /> Because of the very limited areal extent of petroleum constituents <br /> in ground water at this site the most practical ground-water <br /> remediation alternatives are probably limited to variations of <br /> pumping and treating (if needed) ground water containing petroleum <br /> constituents. A cost-effective pumping and treating system for <br /> ground-water remediation at the site should accomplish the <br /> following goals. <br /> • capture the dissolved plume of hydrocarbons in order <br /> to prevent off-site migration. <br /> • Quickly remove ground-water containing dissolved <br /> hydrocarbons from the aquifer. <br /> 0 Rapidly lower concentrations of dissolved hydrocarbons <br /> in recovered ground water to levels suitable for. <br /> disposal. <br /> In order to meet- the goals of ground-water reme.7iatzon, the <br /> computer program DREAM (Lewis Publishers, 1989) was utilized to <br /> model ground-water flow to determine the most efficient arrangement <br /> of extraction and/or injection wells to quickly capture and remove <br /> the dissolved plume of hydrocarbons. The computer program was also <br /> used in estimating the time needed for ground-water remediation <br /> at the site. <br /> DREAM is an analytical (as opposed to numerical) ground-water flaw <br /> model that uses the Theis equation to calculate drawdowns and wzter <br /> level elevations due to pumping and/or injection wells. The <br /> following assumptions are inherent in the Theis equation. <br /> O The aquifer is homogeneous, isotropic, confined, of <br /> uniform thickness, and infinite areal extent. <br /> • Flow to wells is horizontal and laminar. <br /> • Well diameter is infinitesimal so that storage within <br /> the well can be neglected. <br /> 0 Water removed from storage is discharged <br /> instantaneously with decline in head. <br /> While-all-of-the-above-assumptions-are-rarely-satisfied-innature- <br /> use of the Theis equation should provide reasonable approximations <br /> to declines in water levels produced by ground-water pumping at the <br /> site. <br />