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Nitrate Loading Study Page 3 Proposed Warehouse 26550 South Banta Road Tracy, California April 15, 2014 CTE Job No. 20-2463G 3.0 GROUNDWATER 3.1 Hydrology Groundwater information presented in this section was collected from groundwater monitoring and sampling reports obtained from the State Water Resources Control Board's "Geotracker" website. The most applicable report used for reference was for a former clean-up program adjacent to and southwest of the subject site at the Olin Chlor Alkali Products property, located at 26700 Banta Road (Stantec Consulting Services Inc; "2013 Annual Monitoring and Sampling Report", Olin Chlor Alkali, dated January 30, 2014). Based on above, water level data obtained from monitoring well levels in the vicinity of the site (MW-1, MW-6 & MW-9, Stantec, 2014) indicate groundwater level at 12.5± to 16± feet depth (elev. 59.4± to 61.2±) during 2013. Well water level data in the vicinity (Local Well ID: 02S06E3IN001, approx. 1 mile northwest of site) indicates groundwater to have been as high as 8.5 feet below grade (elev. 57.9, on 4/17/13) and as low as 53.7 feet below grade (elev. 12.7, on 6/28/60). Based on data from that well, groundwater has not fluctuated more than 5 feet during the period 2007 to 2013. Groundwater encountered during our study was at a depth of 22.0 feet (elev. 53.0, on 12/18/13). This level appears to be generally consistent with groundwater levels in the vicinity. Differences in water levels are attributed to seasonal fluctuations combined with agricultural influences such as varying amounts of crop irrigation in the vicinity. Groundwater is indicated (Stantec, 2014) to flow northeast in the vicinity of the subject site which is consistent with per San Joaquin County Flood Control and Water Conservation District "Fall 1999 — Spring 2007 Groundwater Report". Regional trends generally indicate flow to be similar and in the downslope direction of surface topography. Based on the Stantec report, groundwater gradients are as follows: • 0.0024 feet/feet (ft/ft) in March 2012 • 0.0023 ft/ft in August 2012. Based on information provided within a letter from SJCEHD "Revised PA-1300183 (SA), SU0009811, 266550 S. Banta Rd, Tracy", it is understood that there is a potential for groundwater contamination from the chloroform and carbon tetrachloride contamination plume from the Olin Alkali Plant located at 26700 South Banta Road, Tracy (located within 1000 feet of the subject site). 3.2 Groundwater Contamination Discussion Based on information provided by the State Water Resources Control Board "Geotracker" (httu://¢eotracker.waterboards.ca.eov), there are no open LUST sites within 4000 feet of the subject site. There are three open sites which exist within 4000 feet of the site. Two of the open sites are up gradient (southwest) and one to the northwest of the subject property. All other sites listed within 4000 feet of the site have been closed.