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were 390 mg/kg and 630 mg/kg, respectively for the eastern (sample 4E) and western (sample 5W) samples. Also on December 15, 2011, three confirmation soil samples (samples 6E, 7M, 8W) were collected in the northern trench beneath the 4 -inch pipeline. The results were non - detect for PCBs, VOCs, TPHg and TPHd. The Cd, Cr III, Cr VI, Pb, Ni, and Zn levels were significantly below RSLs. On December 19, 2011, five (5) confirmation soil samples were collected from pot -holes along the main pipeline trench including where the pipelines turn 90 degrees south toward the building and two where the pipelines enter the building, one at 2 feet below the pipelines and one at 4 feet below the pipelines. The results were non -detect for PCBs, VOCs, and TPHg. The Cd, Cr III, Cr VI, Pb, Ni, and Zn levels were significantly below RSLs. The TPHd results ranged from 19 mg/kg in the easternmost pot -hole to 430 mg/kg in the pot -hole at the building for the sample 2 feet below the pipelines. The TPHd result for the sample at 4 feet below the pipelines at the building was 140 mg/kg. 2.2 Clean -Up Criteria In evaluating the clean-up criteria for the site, the following factors are presented for consideration based on the LUFT Manual Table 2-1 (Leaching Potential Analysis for Gasoline and Diesel using TPH). 1. The depth to groundwater at the site is believed to be between 25 and 50 feet below ground surface (bgs) based on data from GeoTracker for sites in the vicinity (e.g., 800 Main Street E, Stockton, CA, is approximately 3,000 feet to the northwest of the subject site and depth to groundwater is approximately 30 feet bgs). 2. There are no known fractures in the subsurface (applies to foothills or mountain areas). 3. The average annual precipitation in Stockton is approximately 14 inches (falls within the range of 10-25 inches). 4. There are no wells on site and no known man-made conduits which could potentially increase vertical migration of leachate. 5. There are no unique site features such as nearby recharge areas, coarse soils in the excavation areas, or nearby wells. In addition, no VOCs or TPHg were detected in the soil samples beneath the USTs or associated piping. The petroleum product used in the system appears to have been a heavy fuel oil like Bunker C which would have low potential for leaching. The future plans for the former UST site is to cover the area with asphalt for employee parking which will provide a more impervious barrier to stormwater infiltration. Given these factors, a clean-up goal of 1,000 mg/kg for TPHd is proposed for this site. CE Project No. 11 R-120 Work Plan — Cal Water Stockton 3