ARCHIVED REPORTS XR0010467 - Laserfiche WebLink

Home Browse Search

CALIFORNIA GEOPHYSICAL GROUP, INC, P O Box 691 , Poway, CA 92074 -TOF,'(619) 486-1323 FAX' (619) 486-4936 November 29 , 1993 - ; ` • �"u Public Health Services San Joaquin County P.O. Box 2009 Stockton, Ca 95307 RE: Quarterly Report October 1993 Darpetro Service Station 749 E. Charter Way Stockton, Ca. Site # 1060 The site was sampled on November 1, 1993 and the laboratory analyses of the water samples were done by Sherwood Labs of Hilmar, California. The water table measurements, sampling sheets and chain of custody are attached. Table I lists the history of the water analyses taken at the site since Jan. 26, 1990. Table II is the history of the water table measurements, and Table III list the history of hydraulic gradients. The water samples were obtained by using a pre-cleaned stainless steel bailer and a new section of rope. This was performed after the measured field parameters had stabilized during the purging operation. See protocols. Water samples were placed in appropriate glass containers with teflon-lined lids. FINDINGS The ground water flow remains to the east at a gradient of 0.0068 Ft/Ft. We resurveyed the elevations of wells 7 and 8 this quarter. We found a slight but significant difference in both wells. The revised and corrected elevations for these two wells are included in Table II of this report. The corrected elevations have changed the gradient bearing for ' the quarterly report of Aug. 8, 1993 and a revised Water Table Elevations plot is shown in Fig. 1 . The present gradient bearing is to the east (Fig. 2) as it has been since April 1992. We have never found a gradient to the west or southwest as would be necessary for our site to contaminate the area around well MW- 7, however, this well has contaminant in the groundwater. Well 7 was drilled on the west side of the site to define the contamination Plume. California Geophysical Group believes that the