Laserfiche WebLink
' Cw6gfcal Tedida!fic Page 2 <br /> Groundwater Momtonng Report <br /> Project No 662 2 <br /> August 30,2004 <br /> ' facsimile correspondence The work will be initiated pending receipt of encroachment <br /> permits from San Joaquin County and City of Manteca <br /> 1.0 GROUNDWATER MONITORING <br /> ' 1.1 Hydrogeology of Site <br /> ' The dominant soil type in the upper 40 feet of the subsurface geologic soils investigated is <br /> sand, fine to course grained, interbedded with thinner units of plastic clay The average <br /> groundwater elevation on June 4, 2004 was approximately 1143 feet above MSL, which is <br /> ' about 27 feet below ground surface This represents a decrease of 2 17 feet since the <br /> February 2004 monitoring event <br /> ' A groundwater gradient was calculated for the event and the groundwater was found to flow <br /> S80°E at 0 002 ft/ft Groundwater elevation and gradient data are summarized in Table 1, <br /> Appendix A Gradient direction is shown on Figure 2 Gradient Map, and Figure 3 <br /> ' Groundwater Gradient Rose Diagram <br /> 1.2 Groundwater Sampling Procedure <br /> On June 4, 2004, Don Light of Del-Tech mobilized to the site to conduct groundwater <br /> ' monitoring of the four monitoring wells on site <br /> Before sampling was performed the wells were sounded for depth to water The wells were <br /> ' purged of at least three well volumes of stagnant water using a dedicated Waterra check-ball <br /> assembly and 1/2 inch tubing Purging continued until the temperature, conductivity, and pH <br /> of the groundwater stabilized (<10% variation between three readings) indicating that <br /> ' formation water representative of aquifer conditions was entering the wells These water <br /> quality parameters were measured at intervals of each well volume purged <br /> ' Once purging was complete, a water sample was collected from the Waterra tube Care was <br /> taken to minimize sample agitation Once the sample container was filled and capped, the <br /> bottle was inverted, tapped, and checked for headspace bubbles The sample container was <br /> ' identified and labeled with a unique designation, inserted into foam holders and placed in an <br /> ice chest cooled to 4°C for transport to the laboratory <br /> ' All non-disposable sampling equipment was decontaminated using a hot water washer and <br /> detergent before and between uses Disposable gloves were used by the technician to collect <br /> all samples and were changed with each sample collection <br />