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City of Ripon Well#12 <br /> -- Nitrate Study Report May 31,2006 <br /> 1.0 INTRODUCTION <br /> The Source Group, Inc. (SGI) has prepared this report to document an evaluation of potential sources of <br /> nitrate contamination in wells near City of Ripon Well#12 (Well 12). These activities were carried out in <br /> accordance with SGI's proposal to Herum Crabtree Brown entitled Proposal for Evaluating Potential <br /> Sources of Nitrate Contamination to City of Ripon Well 12 dated June 28, 2005. <br /> 1.1 Background <br /> Well 12 was installed in the northwest part of the city in 1997 and began operation in 2001 (Figure 1). <br /> Nitrate concentrations have been reported in this well since it was put into operation. Nitrate <br /> concentrations in the well have increased from the high 20 milligrams per liter (mg/1) range to <br /> approximately 60 mg/I during the period from 2001 to 2004 (Table 1). As a result of the elevated nitrate <br /> concentrations,the well was taken offline in 2004. The City plans to design, install and begin operation of <br /> a treatment system for-Well 12. The proposed treatment system may also receive water from Well 10 for <br /> removal of arsenic. <br /> Potential sources of nitrate contamination include local agricultural activities and the Ripon Farm Service <br /> (RFS) site- The westem edge of the RFS site is located approximately 700 feet east of Well 12 (Figure <br /> 1)- Historical and current operations at this site included fertilizer formulation. Because of the RFS site <br /> operations and the proximity of RFS to Well 12, this site was considered to be a potential source of <br /> nitrate in Well 12. <br /> 1.2 Purpose <br /> The purpose of this investigation was to evaluate groundwater conditions near Well 12 in order to <br /> evaluate potential sources of the nitrate in that well and provide data to aid the City in designing a <br /> treatment system. SGI carried out five tasks in order to gather the necessary information: 1) obtaining <br /> Califomia Department of Water Resources (DWR) logs and other available information on wells and <br /> properties near Well 12; 2) acquiring data regarding the RFS site from both the California Regional Water <br /> Quality Control Board (CRWQCB) and RFS; 3) developing sampling recommendations; 4) implementing <br /> the sampling recommendations, and 5) analyzing the collected data. <br /> R,p ~12Reron.� <br />