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Drilling Work Plan Project No.: 1086 March 16, 2022 Two Borings will be drilled on the North Side of E. Lafayette Street Right -of -Way: • Five borings at location CPT -15 will be installed to close data gaps in the 1,2 -DCA plume immediately north of the Site. • Five borings at location CPT -16 will be installed to close data gaps in the 1,2 -DCA plume immediately north of the Site. Three Borings will be drilled within the Cal Trans Right -of -Way: • Five borings at location CPT -12 will be installed approximately 450 feet northeast of CPT -8 and approximately 800 feet down -gradient of the furthest up -gradient end of the former UST pit (source) and beyond the expected edge of the groundwater plume. • Five borings at location CPT -13 will be installed approximately 650 feet northeast of CPT -9 and approximately 850 feet down -gradient of the furthest up -gradient end of the former UST pit (source). CPT -13 would be the furthest down -gradient boring installed to date. • Five borings at location CPT -14 will be installed approximately 150 feet north- northeast of CPT -9 and approximately 325 feet down -gradient of the furthest up - gradient end of the former UST pit (source). Note: CPT -12 & CPT -13 were moved further east from the original plan, which was approved in the November 8, 2021 Regional Board Correspondence. However, due to a homeless encampment in the original vicinity of the CPT -12 & CPT -13, on March 4, 2022, Vera Fischer, RWQCB regulator, verbally approved moving these two boreholes to the location as shown on Figure 2. At each location the CPT rig will drill one boring to approximately 125 feet below ground surface (bgs) and provide a CPT log. A CPT rig will also drill four (4) discrete boreholes to each aquifer unit and collect a discrete groundwater sample from the desired depth. Samples will be collected from the middle of the aquifer units. The depth will be refined based on the initial CPT boring's log. The approximate aquifer depths are as follows: • Aquifer Horizon A = 30 to 46 ft bgs • Aquifer Horizon B = 50 to 56 ft bgs • Aquifer Horizon C = 72 to 86 ft bgs • Aquifer Horizon D = 95 to 110 ft bgs After sampling, the boreholes will be backfilled to grade with neat cement and capped with soil in accordance with SJCEHD requirements. Traffic Control will be performed by Safe -T -Lite using the enclosed Traffic Control Plan for CPT -15 & CPT -16 boreholes.