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��Vater-Bearing Zone Current Schedule Proposed Schedule ��[-Zone Semi-Annual Annual, 1st Quarter ��[-Zone Semi-Annual Annual, 1It Quarter ��[-Zone Semi-Annual No Change ��F-Zone Semi-Annual No Change B'-Zone Semi-Annual Annual, 1It Quarter • B'-Zone Semi-Annual Annual, 1st Quarter B'-Zone Semi-Annual Annual, 1st Quarter B'-Zone Semi-Annual Annual, 1st Quarter ��F-Zone Semi-Annual Annual, 1It Quarter B'-Zone Semi-Annual Annual, 1st Quarter GHD proposes changing the GWM&S schedules for all A-zone and B'-Zone wells from semi-annual to annual in the first quarter of each year, with the exception of A-zone wells MW-3 and MW-4. 4. Domestic Well 10 Domestic Well 10 is a domestic supply well located on North Hunter St., approximately 1,200 feet from the center of the site property. GHD successfully contacted Mr. Mark Schafer, the property owner of record for 1821 N Hunter Street, Stockton, California, via telephone on October 3, 2022 at approximately 12:45pm. Mr. Schafer indicated that the dwelling on the property is not connected to water provided by Cal Water, and that the dwelling receives all water from Domestic Well 10. Mr. Schafer told GHD that Well 10 is approximately 100 feet deep, but also said that he thought that the well might have been re-drilled deeper to approximately 180 feet. He indicated that the well construction information is physically located at the well or perhaps printed on it somewhere, but that he would not be able to get over to it for about a month or so. GHD followed up the telephone conversation via email on October 3, 2022 summarizing the well construction information that we would like to confirm about the well. GHD sent a follow up email on October 21, 2022 and a follow up phone call on November 11, 2022. No response to either email or a return phone call has been received as of the writing of this report. 5. Offsite Investigation GHD proposes to install three offsite groundwater monitoring wells to provide additional vertical and lateral plume delineation and further define the extent of dissolved petroleum hydrocarbons in the B- and C-zones. MTBE and 1,2-DCA concentrations exceeding Water Quality Objectives (WQOs)extend offsite to the north and northeast. The three new monitoring wells will consist of one (1) B-zone monitoring well and one (1) C-zone monitoring well co-located to the east-northeast of MW-23 on North Hunter Street, and one (1) C-zone sentry well located on East Alder Street to monitor groundwater between the plume boundary and Domestic Well 10. Proposed wells MW-27 and MW-28 will be installed to the northeast of the site in the City of Stockton's right-of-way on North Hunter Street, to define the extent of 1,2-DCA and MTBE in the B-zone and 1,2-DCA in the C-zone. Proposed well MW- 29 will be located to the north of the site and installed in the C-zone to define the offsite extent of TPHg and 1,2- DCA and act as a sentry well for Domestic Well 10. The locations of the proposed monitoring wells are shown on Figure 3. B-zone hydrocarbon isoconcentration contour maps and rose diagram from the second semi-annual GHD I Phillips 66 112594700 1 Offsite Investigation Work Plan 3