Laserfiche WebLink
17 July 1992 <br /> (GeoAudit CV 42F5-1. 26) <br /> Page 5 of 6 <br /> Relative Relative <br /> Casing Depth to Ground Water <br /> Well No. Elevation Water Elevation <br /> MW-1 100.31 10. 95 89 . 36 <br /> MW-2 99.77 10. 95 88 . 82 <br /> CMW-3 100. 13 10. 72 89 . 41 <br /> The data indicate that groundwater is shallowest on the <br /> northwestern part of the property, and the water table slopes to <br /> the southeast, away from the Stockton deep water channel . The data <br /> are contoured in Figure 4 . The average hydraulic gradient is 0. 009 . <br /> ISOIL DISPOSAL <br /> A Soil Remediation Plan (SRP) was prepared by GeoAudit and <br /> submitted to the SJ PHS/EHD on 5 June 1992. After the soil was <br /> sampled and analyzed according to the SRP, approximately 600 cubic <br /> yards of soil (about 3/4 of the total) was transported under non- <br /> hazardous manifest to Forward, Inc. in Stockton. The remaining soil <br /> was transported to BFI Waste Management Systems in Livermore. The <br /> segregation, loading and transport of the soil was supervised by <br /> Mr. Ronald K. Rinehart of Rino Environmental. The non-hazardous <br /> waste manifests are attached in Appendix D. <br /> CONCLUSIONS AND RECOMMENDATIONS <br /> Confirmatory soil samples collected after excavation of the tank <br /> cavity demonstrate that the contaminated soil has been successfully <br /> removed from this site. Approximately 1, 000 cubic yards were <br /> removed and hauled to BFI landfill and Forward landfill for <br /> disposal. <br /> A water sample was collected from the bottom of the cavity after <br /> excavation was completed. Three on-site monitoring wells were <br /> sampled four months later on 9 June 1992 . All samples were <br /> contaminated with diesel fuel. Contaminant levels exceed 100 ppm in <br /> both MW-1 and MW-3 , but are slightly lower in MW-2 . These results <br /> are inconsistent with the present northwest-southeast gradient, and <br /> suggest that either the groundwater gradient has reversed or that <br /> contaminated groundwater has migrated to the site from a source to <br /> the west and/or northwest. An off-site contaminant source is more <br /> consistent with the fact that the lowest TPH value was obtained <br />