Laserfiche WebLink
r. <br /> 641 +t <br /> Chevron Products Company 3 <br /> Chevron Station#9-2033. 08 Wet Charter Way,Stockton California March 19 2001 <br /> The following specific goals are outlined to meet the objective of the Site Assessment <br /> • CPT investigation to collect stratigraphy and discrete groundwater samples, <br /> • Review of CPT data, <br /> • Possible destruction of MW-1 and MW-2, <br /> • Installation four pairs of monitoring wells, <br /> • Hydraulic evaluation <br /> The details of the proposed scope of work are discussed in the following sections <br /> CPT Investigation: <br /> CPT boreholes will be advancelt the four corners of the site to investigate site <br /> stratigraphy A second direct-push borehole, immediately adjacent to each CPT <br /> borehole, will be advanced specifically to collect two to three discrete groundwater <br /> samples Depths of the discrete groundwater samples will be determined from the CPT <br /> logs in the field <br /> Groundwater samples will be analyzed for TPHg, BTEX, and the fuel oxygenates <br /> MtBE, di-isopropyl ether (DIPE), tertiary amyl methyl ether(TAME), ethyl tertiary <br /> butyl ether (EtBE), tertiary butyl alcohol (TBA), ethyl dibromide (EDB), 1,2 <br /> dichloroethane (1,2-DCA), ethanol, and methanol by EPA Method 8260B <br /> CPT Data Review: <br /> CPT logs and analytical data from the groundwater samples will be used to determine <br /> well depths and screen intervals for the four pairs of monitoring wells to be installed in <br /> the shallow and intermediate water-bearing zones The CPT logs will also be used <br /> along with previous stratigraphic information to determine if monitoring wells MW-1 <br /> and MW-2 need to be destroyed <br /> Well Destruction: <br /> If further stratigraphic data suggest that monitoring wells MW-1 and MW-2 are <br /> screened across two water-bearing zones, the wells will be destroyed by pressure <br /> grouting and then drilling out the top five feet of each well The well boxes will be <br /> removed and the wells finished to grade with cement <br /> Installation of Groundwater Monitoring Wells: <br /> Up to eight ground water monitoring wells are proposed for installation at the site to <br /> assess the groundwater quality interactions between the upper and intermediate water- <br /> bearing zones <br /> Four groundwater monitoring wells will be advanced into the upper water-bearing <br /> zones, taking care to not penetrate the confining layer between the upper and <br /> I 1Chevron1920331REPORTSIfurther site assessment WP_RevA doc <br />