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L & M OPERABLE UNIT-THIRD QUARTER 2014 SITE STATUS, REMEDIAL SUMMARY, AND GROUNDWATER MONITORING REPORT Introduction October 31, 2014 The UOU was established to direct investigations from West Weber Street south to the former Main Street and from the midline of the former Harrison Street east to Lincoln Street. The UOU includes monitoring wells MW-3, MW-7, MW-37 and MW-38 and environmental monitoring of the UOU is the responsibility of the City of Stockton under a separate MRP. The MOU was established to direct investigations from the middle of the former Main Street down to the southern boundary of Parcel 2A and from the midline of the former Harrison Street east to Lincoln Street. The MOU includes monitoring well 2AMW-15 and environmental monitoring of the MOU wells is the responsibility of the City of Stockton under a separate MRP. Currently, oversight of environmental management responsibilities of the L&M OU is retained by Stantec on behalf of CEMC and P66, and oversight of the UOU and MOU is performed by Wallace Kuhl Associates (Wallace-Kuhl) on behalf of the City of Stockton. Environmental investigations began at the Site in 1989 and quarterly monitoring and sampling activities were initiated in 2002. SECOR International Inc. (now Stantec) was retained in late 2002 for environmental consulting services at the Site. A summary of previous investigations is included in Appendix B. 1.2 REGIONAL GEOLOGY/HYDROGEOLOGY The shallow groundwater bearing zone (A-Zone) primarily extends from the ground surface to depths ranging from approximately 25 ft below ground surface (bgs) to 40 ft bgs. Subsurface material in the shallow zone predominantly consists of silt, silty sand, and silty gravel from 4 to 10 ft bgs, and then organic clay, clay, high permeability silt, and lenses of silty sand and poorly graded sand to depths ranging from 25 to 40 ft bgs. The shallow zone is generally underlain by low permeability silt and clay (with an occasional, thin, silty sand or poorly graded sand lens) of highly variable thickness. A deeper groundwater bearing zone (B-Zone) is encountered at a depth of approximately 42 ft bgs and extends to approximately 50 ft bgs. Subsurface material in the B-zone consists of poorly graded sand and silty sand. Below 50 ft bgs, clay and silt with some imbedded sand is encountered and extends to a depth of approximately 64 ft bgs, underlain by sand and silty sand of varying moisture extending to a depth of approximately 73 ft bgs. Clay is encountered below the sands to an approximate depth of 84 ft bgs, underlain by a sand/silty sand layer extending to approximately 92 ft bgs. This stratum is a water-bearing zone identified as the C-Zone. Below this sand layer, imbedded clay and silt are encountered to a depth of approximately 115 ft bgs, underlain by a sand/silty sand layer with some imbedded clay to a depth of approximately 130 ft bgs. This stratum is designated as the D-Zone. Clay and silt are encountered below this sand layer to a total depth explored of 140 ft bgs. Groundwater beneath the Site is influenced by the Stockton Channel to the north and the Mormon Slough to the south. The groundwater flow direction for the shallow and deeper groundwater bearing zones is generally to the east-northeast across the Site. 5ta ntec 1.2