Laserfiche WebLink
Working To Restore Nature <br /> feet below grade, the total depth explored A zone of fat clay exists from approximately 7 to <br /> 10 feet below grade which apparently significantly limits the potential for vertical migration of <br /> contaminants <br /> Regional groundwater within the shallow water-bearing zone occurs from less than 10 feet below <br /> grade to as deep as 50 feet below grade Regional groundwater gradient is to the northeast <br /> The flood basin deposits of the shallow water bearing zone have well developed soil profiles <br /> consisting of interbedded layers of clays, silts, and sands, and consequently poor permeability <br /> The quality of the shallow groundwater in the Stockton area is generally poor The Stockton <br /> area has long been recognized as having water quality problems Deeper wells routinely exceed <br /> the secondary drinking water standards for chloride, iron, manganese, and TDS Shallower <br /> wells have even poorer quality due to the additional affects of infiltrating surface water (DWR, <br /> 1967) A recent groundwater quality investigation conducted by the San Joaquin County Flood <br /> Control District determined that very high levels of TDS (up to 6120 mg/Q) and chloride (up <br /> to 1959 mg/f) exist in the Stockton area (W 7) <br /> ' During the period of investigation the depth to groundwater at the subject site has ranged from <br /> ' 38 feet to 47 feet below grade When groundwater levels were last measured in March 1994 <br /> the depth to water was 43 04 feet <br /> 3.0 BACKGROUND <br /> IThe past and present use of the site is the City of Stockton Police facility Three underground <br /> storage tanks were formerly located on the site (Figure 2) These tanks were used to fuel <br /> 1 facility vehicles <br /> OW01481REPORTSICR-0694 FNL 2 <br />