ARCHIVED REPORTS_XR0012391 - Laserfiche WebLink

Home Browse Search

i 4 ' Work Plan For Monitoring Well installation—Former Unocal Service Station#2859 June 24 1999 PROPOSED SCOPE OF WORK To delineate the vertical and lateral extent of petroleum hydrocarbons in soil and groundwater in the downgradient direction (northeast), GR proposes to install two off-site groundwater monitoring wells (Figure 2) Field Methods and Procedures are included in Appendix A To complete installation of the two groundwater monitoring wells GR proposes the following six tasks Task I Pre-Field Activities GR will generate a site-specific safety plan and obtain the necessary well installation permit from the SICPHS-EHD Underground Service Alert (USA) will be notified a minimum of 48 hours prior to drilling An encroachment permit will be obtained from the SCPW Task 2.Well Installation GR will install two groundwater monitoring wells (MW-11 and MW-12) at the locations shown on Figure 2 The wells will be installed by a California licensed well driller A GR geologist will monitor the drilling activities and prepare a log of each boring The wells will be drilled using 8-inch-diameter hollow-stem augers The wells will be constructed of 2-inch-diameter Schedule 40 polyvinyl chloride (PVC) well casing and 0 02-inch machine-slotted well screen Well MW-I 1 will be installed in a 60-foot deep boring with a screened interval from 50 to 60 feet below ground surface (bgs) Well MW-12 will be installed in a 90-foot deep boring with a screened interval from 85 to 90 feet bgs Proposed well construction details are presented in Figure 3 Because wells MW-11 and MW-12 will be installed within 5 feet of each other, GR will only log encountered lithologies and collect soil samples from the 90-foot deep well boring (MW- 12) Soil samples for description and possible chemical analysis will be obtained from the boring at five-foot intervals, as a minimum Soil samples will be collected with a split-spoon sampler fitted with clean brass sample rings The actual number of samples submitted for chemical analysis will depend on site conditions and field screening data As a minimum, it is expected that two unsaturated soil samples and four saturated samples from boring MW-12 will be submitted for chemical analysis as described in Task 5 Soil from each sampled interval will be screened in the field for the presence of volatile organic compounds using a photoionization detector (PID) These data will be collected for reconnaissance purposes only, and will not be used as verification of the presence or absence of petroleum hydrocarbons Drill cuttings will be stockpiled at the site pending receipt of chemical analytical data The drill cuttings will be stockpiled on and covered with plastic sheeting pending disposal Four soil samples of the drill cuttings will be collected for disposal characterization These samples will be submitted to the laboratory for compositing into one sample, and then analyzed as described in Task 5 Steam cleaning ansate waste water will be transported to the Tosco Refinery in Rodeo, California,for disposal 24007202-1 2