SITE INFORMATION AND CORRESPONDENCE

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California Stop September 2013 2224 Manthey Road, Stockton Claim No: 18428 ATTACHMENT 2: SUMMARY OF BASIC CASE INFORMATION (Conceptual Site Model) Site Location/History • This case is an active commercial petroleum fueling facility and is bounded by Highway 5 to the east, a business to the north and South Manthey Road to the west and south. The surrounding land use is mixed residential and commercial. • Site map showing the location of the USTs, monitoring wells and groundwater level contours is provided at the end of this review summary (Advanced Geo Environmental, Inc., 2013). • Nature of Contaminants of Concern: Petroleum hydrocarbons only. • Source: UST system. • Date reported: February 2002. • Status of Release: UST system upgraded. Tank Information Tank No. Size in Contents Closed in Place/ Gallons Removed/Active 1 10,000 Gasoline Active 2 10,000 Gasoline Active 3 10,000 Gasoline Active Receptors • GW Basin: San Joaquin Valley. • Beneficial Uses: Central Valley Regional Water Quality Control Board (Regional Water Board) lists agricultural, municipal, domestic, industrial service and process supply. • Land Use Designation: Aerial photograph available on GeoTracker indicates mixed residential and commercial land use in the vicinity of the Site. • Public Water System: California Water Service Company and Stockton East Water District. • Distance to Nearest Supply Well: According to data available in GeoTracker, there are no public supply wells regulated by the California Department of Public Health within 1,000 feet of the defined plume boundary. Several irrigation wells were identified (although never observed in the field) and the closest well was located approximately 370 feet northeast of the Site. • Distance to Nearest Surface Water: There is no identified surface water within 1,000 feet of the defined plume boundary. Geology/Hydrogeology • Stratigraphy: The Site is underlain by interbedded and intermixed sand, silt and clay. • Maximum Sample Depth: 80 feet below ground surface (bgs). • Minimum Groundwater Depth: 16.00 feet bgs at monitoring well MW-3. • Maximum Groundwater Depth: 22.06 feet bgs at monitoring well MW-6. • Current Average Depth to Groundwater: Approximately 17 feet bgs. • Saturated Zones(s) Studied: Approximately 16 - 80 feet bgs. • Appropriate Screen Interval: Yes, with the exception of MW-4 and MW-11. • Groundwater Flow Direction: To north, east and southeast with hydraulic gradient from 0.006 to 0.01 feet/foot (May 2013). Page 7 of 13