ARCHIVED REPORTS XR0003045 - Laserfiche WebLink

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Chevron Products Company 5 • Chevron Station #9-5775 301 W Kcttleman Lane Lodi CA AuRust 25 2000 On July 3, 2000, operation of interim SVE and GWE remediation was initiated at the site The interim SVE system consists of four SVE wells (VEW-I through VEW-4) and 100 cfm catalytic oxidizer The interim GWE system consists of one extraction well (EX -1) and 3-2,000 pound carbon vessels in series In their document dated August 10, 2000 (Attachment E), G -R reported that the GWE system had pumped 6,661 gallons of water during the first 20 days of system operation at extraction rates of 0 12 to 0 24 gallon per minute (gpm) Based upon the extraction rates and analytical data, G -R estimated that GWE system had removed approximately 0 37 lb TPHg, 0 0042 lb benzene, and 9 40 lb MtBE, as of July 26, 2000 In tables faxed by G -R to SECOR on August 24, 2000 (Attachment E), G -R reported that the SVE system has removed approximately 574 3 lb TPHg, 63 6 lb benzene, and 246 7 Ib MtBE, as of August 3, 2000 SITE GEOLOGY AND HYDROGEOLOGY The site is relatively flat and is situated approximately 42 feet above mean sea level (MSL) Soil in the vicinity of the site consists of Pliocene to Holocene continental rocks and deposits consisting of heterogeneous mix of generally poorly sorted clay, silt, sand, and gravel (R W Page, 1986) The nearest surface water is South Main Canal, located approximately 0 75 miles west of the site Pixley Slough is located approximately 2 5 miles north of the subject site Based on observations during drilling activities, the site vicinity is underlain primarily by silty sands and sandy silts in varying amounts Soil encountered in the borings for MW - 8B, MW -5B, MW -3, SB -1, and MW -4 consists primarily of near sue face sandy silts, extending in some locations to 35 feet bgs, with discontinuous sand and clay lenses A cross-section location map and geologic ci oss-section for the site are provided as Figures 2 and 3A and B, respectively The sandy silt layer is underlain by a silty sand layer, which in some locations extends to 43 feet bgs A sandy silt to clayey silt layer was encountered in some locations extending to the shallow water -bearing zone at a depth of approximately 55 feet bgs Based on the assessment activities performed to date and as summarized in the recently submitted Problem Assessnierlt Reporl, dated July 24, 2000, two water -bearing zones have been identified beneath the site A shallow water-beai ing zone was reported within an approximate 5 -foot layer of primarily coarser -grained soils (silts and sands) at depths of approximately 55 to 65 feet bgs A deeper water -bearing zone of unknown thickness was reported within primarily fine-grained soils at depths of approximately 60 to 70 feet bgs and was encountered to the bottom of some of the borings at approximately 90 feet bgs A coarser -grained unit was encountered directly below the finer -grained unit in • boring MW -12B This coarser -grained unit was also saturated and was encountered to the bottom of the boring at a depth of 90 feet bgs 07141991 041/FRP