Laserfiche WebLink
r <br /> 15 May 92 7 <br /> APPENDIX A RRR�.'✓ ` r Y v <br /> ANNEX A OR, M1 1 <br /> u <br /> GROUNDWATER TREATMENT REMEDIAL DESIGN <br /> DEFENSE DISTRIBUTION REGION WEST-SHARPE ' " 4W Lo <br /> STATEMENT OF WORK JUN. 5 1592 <br /> ENVIRONMENTAL HEAL'I H <br /> 1.0 BACKGROUND PERMIT/SERVICES <br /> 1.1 The Defense Distribution Region West-Sharpe (DDRWS) located north- <br /> east of Lathrop, California in San Joaquin County, has an existing ground <br /> water problem. The primary contaminants of concern are listed on Table 1 in <br /> the Record of Decision (ROD) dated 16 March 1992, (Reference 10.15) . DDRWS is <br /> a NPL site and a Federal Facilities Agreement (FFA, Reference 10.11) contain- <br /> ing conditions and schedules that must be followed, is in effect. DDRWS has <br /> constructed two interim ground water treatment systems, one in the north <br /> (Reference 10. 13) and one in the south areas of the installation. The interim <br /> treatment systems allowed testing of some of the aquifer's hydrogeological <br /> properties, evaluation of the effectiveness of the treatment system, and col- <br /> lection of data for supporting the proposed final remedial action. All of <br /> this information is detailed in a comprehensive Remedial <br /> Investigation/Feasibility Study Report (RI/FS, Reference 10.9) . In the in- <br /> terim treatment systems, contaminated groundwater is withdrawn from the <br /> aquifers via extraction wells, treated in an air stripper, and discharged. <br /> Currently, water is discharged to a collection system and reused in a nearby <br /> plant for steam or the water is discharged to surface drainage when the <br /> plant's demand is met. <br /> 1.2 The U.S. Army Toxic and Hazardous Materials Agency (THAMA) has con- <br /> ducted numerous environmental investigations at DDRWS over the years. Cur- <br /> rently THAMA is investigating the extraction and injection characteristics of <br /> the groundwater aquifers that are the targets of this remedial design. THAMA <br /> has scheduled the installation and testing of the extraction network. They <br /> have also installed one injection well in each aquifer zone (three wells) and <br /> conducted injection tests for each zone. THAMA will use the results in a <br /> groundwater model that will assist them in a tentative model design for an in- <br /> jection network. The final engineering report and design for this latest ef- <br /> fort will be available in August or September, 1992. <br /> AA-1 <br />