Laserfiche WebLink
Stockton Avenue GmundwatePExtraction System Shut-down Request <br /> November 5, 2009 <br /> three wells would be screened in the Upper Aquifer and located on the property at 519 <br /> South Stockton Avenue to confirm that concentrations of TCE and other constituents of <br /> concern in the Upper Aquifer have been sufficiently remediated. A third well would be <br /> installed within the Intermediate Aquifer to confirm the current understanding that VOCs <br /> detected in this area are predominately related to migration from the City of Ripon <br /> sewage treatment ponds near the Stanislaus River. ECM has submitted an addendum <br /> dated November 2, 2009 to the June 19, 2009 work plan reflecting the above <br /> modifications. <br /> ECM will continue to monitor the Intermediate Aquifer zone near the Stockton Avenue <br /> System using data from monitoring wells M-8C1, M-1801, M-2501, and E-6. The Upper <br /> Aquifer would continue to be monitored with data from wells M-8A, M-813, M-9A, M-913, <br /> and E-2. ECM proposed to monitor these wells monthly for three months. After three <br /> months, ECM would monitor according to the monitoring frequency required by the <br /> Monitoring and Reporting Program for Nestle. ECM anticipates using data from the <br /> monitoring to conduct an assessment of COC concentrations and the impact of the <br /> functioning of wells E-2 and E-6. The three proposed new monitoring wells will be <br /> initially monitored after installation on a quarterly basis for the first year. Based on the <br /> initial sampling results from theses wells, sampling frequency will then be established or <br /> discontinued depending on the results. <br /> ECM appreciates your review and approval of this request. Please do not hesitate to <br /> contact Brent Searcy (415-282-1979) or Binayak Acharya (661-255-1693) with any <br /> questions or concerns. <br /> Best regards, <br /> Environmental Cost Management, Inc. <br /> pPCfF3S1t).,._ <br /> _ <br /> J 7/ <br /> Jam—/ � �mNo.f66N»Ta <br /> oT C,vry <br /> Brent Searcy, P.E. Binayak Acharya <br /> CC: Mike Desso— NUSA <br /> Distribution List <br /> Attachments: Figure 1 — Site Location Map <br /> Figure 2— Upper Aquifer TCE Trend Graph: M-8A, M-813, M-9A, M-913, and E-2 <br /> Figure 3— Upper Aquifer 1,2-DCE Trend Graph: M-8C1, M-18C1, and E-2 <br /> Figure 4— Intermediate Aquifer TCE Trend Graph: M-8C1, M-18C, and E-6 <br /> Figure 5— Intermediate Aquifer 1,2-DCE Trend Graph: M-8C1, M-18C, and E-6 <br /> Figure 6— MODFLOW/RT3D Outputs, Stockton E2/E6 Alternatives <br /> Figure 7— MODFLOW/RT3D Outputs, Stockton E2/E6 Alternatives <br /> Figure 8— MODFLOW/RT3D Outputs, Stockton E2/E6 Alternatives <br /> Figure 9— MODFLOW/RT3D Outputs, Stockton E2/E6 Alternatives <br /> Table 1 — VOC Data (2003-2009) for Stockton Area Wells <br /> 4 <br />