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• • <br />1 APTIM <br />180 Promenade Circle, Suite 320 <br />APTIM Sacramento, CA 95834 <br />Telephone: 925-457-1130 <br />December 8, 2017 <br />Project 149265 <br />Taj M. Bahadori, P.E. <br />Senior Civil Engineer <br />San Joaquin County Department of Public Works <br />Solid Waste Division <br />1810 E. Hazelton Avenue <br />Stockton, CA 95201 <br />Re: Work Plan for Well Installation and Landfill Gas Control, North County Sanitary <br />Landfill, San Joaquin County <br />Dear Mr. Bahadori: <br />This letter is in response to the North County Sanitary Landfill (NCSL) Notice of Violation, <br />Review of the First Half 2017 Groundwater Monitoring Report from the Regional Water Quality <br />Control Board (RWQCB) dated October 17, 2017. The letter requests San Joaquin County <br />(County) to submit a brief letter that includes the following scope of work: <br />• Reconstruct or deepen groundwater monitoring wells G-313, G-6, and background well <br />G -IA. Submit a brief letter with location map and well construction details. <br />Install new landfill gas (LFG) extraction wells to address the LFG release detected at soil <br />gas probe SG -6. <br />The following is the proposed work plan for the installation of replacement groundwater wells <br />and expansion of the LFG extraction system at the NCSL. <br />Installation of Replacement Groundwater Monitoring Wells <br />Due to falling groundwater levels in the Great Central Valley of California over the past several <br />years, many of the existing monitoring wells at the NCSL do not produce enough groundwater to <br />collect groundwater samples. This work plan proposes to install replacement wells for existing <br />wells G -IA, G-313, and G-6. The replacement wells will be identified as G -1B, G -3E, and G -6A. <br />This will be the third replacement at the background G-1 location, and at the downgradient G-3 <br />location. The general procedures for the well installations will follow the well G-9 work plan <br />previously approved by the RWQCB at the NCSL. Based on the latest depth to water survey at <br />the existing wells, tabularized below, the proposed depth of replacement wells are shown below: <br />North County 2017 NOV Final 120817.docx <br />