SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

• Mr. Gerald Djuth January 20, 2006 Page 2 it The RWQCB (Djuth 2003) accepted the findings and recommendations of the report. The additional offsite well (1\4W-15) was installed in August 2004. Rationale MW -15 has been sampled in six consecutive quarterly events. The data from MW -5R continued tcentrations show evidence of offsite migration of contaminants at low and MW -15 have concon of TCE and 1,1-DCE at MW -5R cycled within concentrations. In 2005 -15 contaminants were detected ereporting the typical historical range. At MWµ11 lg limit of 0.5 µg/L in all sampling events; maximums of 12 µg/L TCE and 2.3 DCE were detected in November 2004. In view of this condition, the Semiannual (Parsons 2005) proposed the following: "A plan will be developed for remedial action in the vicinity of MW -5R. The objective will be to interrupt nmigration use grMW 5RMW-15 aand contaminants for across the property line and con confirmation groundwater monitoring. It is proposed to drill and install one groundwater extraction well approximately 50 feet northwest of monitoring well MW -5R. The well will be located in a breezeway between Buildings #1 and #2 as indicated on Figure 1.. Progress Report and Annual Summary Planning and Installation Procedure Planning logistics include obtaining a permit for well installation from the San Joaquin County Public Health Service, Environmental Health Division (SJC/EHD) and clearance for utilities. The boring will be started by vacuum excavation of at least 110% of the hole diameter to a depth of 5 feet. The well boring will be drilled using a rubber track mounted limited access, hollow -stem auger rig with 10 -inch diameter augers. The subsurface soil will be sampled at approximately 5 -foot intervals using a standard 18 -inch split -spoon drive sampler. Soil samples and auger cuttings will be logged and identified by visual/manual examination ver per ASTM D-2487 (equivalent to USCS soil classification system) . Percent photographedrco nythf drive samples will be recorded and representative samples will field. Exact placement of the screened length and pump depth placement will be selected ging. A 4 -inch diameter extraction well will be based on the results of drill hole log constructed with a 15- to 20 -foot long screened as indicated on the well interval construction diagram (Figure 2). 7) will The discharge water piping and control conduits from o#2 and hung from the celiing beams be installed through the foundation wall of Building to the in Buildings #4 and #6 on overhead hangers. wFl be buriedrtn a trench. m the noh wall of BuThe n� w6p ping groundwater treatment compound, the pipes