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between 39 feet bgs and 109 feet bgs. Total purgeable gasoline range petroleum hydrocarbons (TPPH) were detected in grab groundwater samples collected from CPT9, CPT10 and CPT12 locations at concentrations ranging from 800 ug/l (CPT12-105) to 7,000 ug/l (CPT9-70). Petroleum hydrocarbons were not detected in grab groundwater samples collected from the CPT 11 hydropunch boring location (FREY, 2023). Hydropunch groundwater sample analytical results are summarized in Table 2. GROUNDWATER MONITORING AND SAMPLING(2004—2023) Quarterly or semi-annual groundwater monitoring and sampling was conducted by AGE from the first quarter 2004 through the third quarter 2018. FREY resumed semi-annual groundwater monitoring and sampling in the first quarter 2021. Based on groundwater monitoring data collected by FREY between the third quarter 2021 and the first quarter 2023, the direction of groundwater in the shallower-screened monitoring wells has ranged between south-south westerly and southeasterly. The direction of groundwater flow in the deeper-screened wells (75- 80 feet) has been east-northeasterly. Sketches showing groundwater elevations and estimated directions of groundwater flow in shallower screened (20' - 55') and deeper screened (75' — 80' and 95' — 105') wells measured during the first quarter 2023 groundwater monitoring and sampling event are presented in Figures 4 and 5, respectively. A rose diagram incorporating shallow screened and deeper screened wells for flow direction estimates are presented on Figures 6 and 7, respectively. Sketches showing TPPH and benzene in groundwater from the first quarter 2023 groundwater monitoring and sampling event are presented in Figures 8 through 11. Historical groundwater analytical data is summarized in Table 3. OBJECTIVE The objective of the scope of work outlined below is to further assess the lateral and vertical extent of petroleum hydrocarbons in groundwater to the north and northeast of groundwater monitoring well MW-14 and CPT12, and south of groundwater monitoring well MW-12 and CPT-9. SCOPE OF WORK The scope of work designed to meet the objective will include the following tasks: • Acquire an encroachment permit from the City of Stockton. • Acquire drilling permits from the San Joaquin County Environmental Health Department (SJCEHD). • Mark boring locations for Underground Service Alert (USA) notification and retain a licensed utility location contractor to identify and mark detectable utilities. • Prepare a Site-Specific Health and Safety Plan. • Schedule a drilling subcontractor and notification of the Agencies having jurisdiction to inspect work. • Advance one hydropunch boring (HP I) and collect a groundwater sample at approximately 120 feet bgs, approximately 200 feet northeast of CPT12. FREY Environmental,Inc. 7 Project No. 1095-01