Laserfiche WebLink
First Quarter,2002 Quarterly Groundwater Monitoring Report <br /> Canepa's Car Wash,Pacific Avenue,Stockton,CA <br /> Page 2 <br /> FIELD OBSERVATIONS <br /> On January 9 and 10, 2002, Condor representatives made field observations at the 12 site monitor wells <br /> (MW-I through MW-11 and MW-12d). Field observations included water level measurement (Table 1, <br /> below), appearance of samples (color, clarity, and presence of petroleum product sheen or phase in <br /> samples), and collection of water quality field parameters(Attachment D). <br /> GROUNDWATER ELEVATIONS AND GRADIENT <br /> The locations and top of casing elevations of the monitor wells were surveyed on November 26, 2001. <br /> The well locations are referenced to the NAD 83 datum and the well elevations are referenced to the <br /> NAVD 88 vertical datum from NGS benchmark JS1384. <br /> Groundwater elevation contours for the shallow monitor wells are shown on Figure 2, attached. The <br /> groundwater gradient is approximately 0.004 ft/ft to the east-northeast as measured between monitor <br /> wells MW-6 and MW-3. A hydrograph of historic groundwater elevations is attached as Figure 3. <br /> Table 1 <br /> Groundwater Elevation Data (January 9,2001) <br /> WeScrell Casineng well Collar Depth to Groundwater <br /> WELL Elevation Water Elevation <br /> Interval (feet) (feet) (feet) <br /> (feet-bgs) <br /> MWl 50-70 15.48 34.25 -18.57 <br /> MW2 50-70 15.29 33.95 -18.66 <br /> 0 MW3 50-70 15.53 34,71 -19.18 <br /> MW4 50-70 15.83 34.95 -19.12 <br /> MWS 50-70 14.71 34.00 -19.29 <br /> MW6 45-65 14.89 33.30 -18.41 <br /> MW7 45-65 15.80 34.32 -18.52 <br /> MWS 45-65 15.31 34.28 -18.97 <br /> MW9 25-45 14.84 34.12 -19.28 <br /> MW 10 25-45 14.72 33.30 -18.58 <br /> MWII 25-45 15.12 33.69 -18.57 <br /> MW12d 100-110 14.99 33.53 -18.54 <br /> LABORATORY ANALYTICAL RESULTS <br /> The groundwater samples collected from the monitor wells were analyzed for BTEX, TPH-G, and MTBE <br /> by GeoAnalytical Laboratories, Inc. of Modesto, California. The current analytical results included in <br /> Table 2, on the following page, are generally consistent with the historical results (Attachment Q. <br /> Benzene and MTBE iso-concentration contour maps are included as Figure 4 and Figure 5, respectively, <br /> in Attachment A. The groundwater sample analytical results from wells MW-1I and MW-12d indicate <br /> decreases in contaminant concentration since the first sampling event for those wells conducted on <br /> October 25, 2001. Laboratory analytical results indicate a trend of increasing MTBE concentration at well <br /> MW-3 (Figure 6, Attachment A). Laboratory certificates of analysis and chain-of-custody record are <br /> included in Attachment E. <br /> ia CONDOR <br />