Laserfiche WebLink
i <br /> Project 113-13 <br /> February 7,1995 <br /> Page 2 <br /> In a November 12, 1990 report, Dames and Moore documented that groundwater <br /> samples were collected on October 24, 1990. All samples were ND. Depth to <br /> groundwater was 25 3 feet BGS. <br /> A fourth monitoring well (MW-4) was installed by Parker Environmental Services <br /> at the site on September 6, 1991 Soil samples analyzed from the boring were all ND <br /> for TPH-g and BTEX. Groundwater samples obtained on September 11, 1991 from all <br /> four morutonng wells were also ND for TPH-g and BTEX. Depth to groundwater <br /> was 28 to 29 feet BGS. <br /> A pump discharge test was done by Parker Environmental Services at the site <br /> October 15-16, 1991. The drawdown between wells indicated that all four monitoring <br /> wells are probably in the same aquifer. <br /> Quarterly monitoring was performed by Parker Environmental Services during 1993 <br /> In March, 1993, during the first quarter of monitoring, xylenes were measured at 1.2, <br /> 1.1, and 0 96 ppb in three of the wells (MW-1, MW 2, and MW-3). Toluene was <br /> present (1 2 ppb) in MW4. All 4 wells were ND for 1,2-dibromoethane (ethylene <br /> dibromide) and for lead. <br /> All wells were ND for both TPH-g and BTEX in July, September, and December, <br /> 1993, and in April and July, 1994 Monitoring was not performed in October, 1994, <br /> because of the low water table. <br /> II. Current Activities <br /> Groundwater samples were obtained on January 25, 1995 Prior to sampling, <br /> groundwater elevation measurements were obtained with an electronic water level <br /> meter. Results are presented in the table below. <br /> Table 1 <br /> Cheaper! #76, 890 North Main Street, Manteca, California <br /> Groundwater Measurement Results* <br /> Measured on January 25, 1995 <br /> MW-1 MW-2 MW-3 MW-4 <br /> Well Elevation 33.12 33.22 33.55 33.66 <br /> Depth to GW 21.74 21.75 22.09 22,29 <br /> GW Elevation 11.38 11.47 1146 11.37 <br /> * elevation above mean sea level, in feet <br /> Shallow groundwater measurements indicate the water table is approximately 2.4 <br /> feet higher than measurements taken in July, 1994. The flow direction is toward the <br /> south-southwest, with a gradient of about 0 002 (2 feet / 1,000 feet), as shown in <br /> Figure 2, the Groundwater Elevation Map. <br /> Parker Environmental Services 190 East 7th Street Pittsburg CA 94565-6116 <br /> Phone (510) 439-1024 Fax (510) 439-2566 <br />