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Diamond Pet Food&Ripon Energy April 12,2016
<br /> First-Quarter 2016 Groundwater-Monitoring Report Page I of 5
<br /> INTRODUCTION
<br /> This report presents the results of first-quarter 2016 groundwater monitoring performed by
<br /> Lawrence &Associates (L&A) on January 11 and 2, 2016, at Diamond Pet Food Processors of
<br /> Ripon California, LLC (DP) and A1taGas Ripon Energy, Inc. (Ripon Energy), 942 and 944
<br /> South Stockton Avenue, Ripon, California(Figure 1). The work was performed in accordance
<br /> with Waste Discharge Requirements (WDR) Order No. R5-2012-0105 for the DP/Ripon Energy
<br /> site, adopted by the California Regional Water Quality Control Board, Central Valley Region
<br /> (CVRWQCB) on October 4, 2012.
<br /> First-quarter monitoring consisted of measuring the depth to groundwater in monitoring wells
<br /> OB-1, OB-2, OB-4, OB-5, OB-7, OB-8, OB-11, OB-17, OB-19, OB-21, OB-22, OB-24, OB-25,
<br /> OB-26, and OB-28, collecting groundwater samples from the wells and analyzing the samples
<br /> for temperature,pH, electrical conductivity(EC), turbidity, total dissolved solids (TDS), and
<br /> nitrate as nitrogen.
<br /> Table 1 (following text)presents well descriptions including well names, casing diameter,
<br /> reference point elevation, total depth, screened intervals, and aquifer unit(s).
<br /> L&A sampled the wells located on the DP/Ripon Energy site. All offsite monitoring, domestic,
<br /> and municipal wells were sampled by Stantec for the City of Ripon or ECM Consultants for
<br /> Nestl6s. Field and laboratory results provided by Stantec and ECM Consultants were used in
<br /> the preparation of this report and are presented in Attachment A. L&A, however, did not
<br /> review the Stantec or ECM Consultants sampling methods or data for accuracy.
<br /> FIRST-QUARTER 2016 GROUNDWATER MONITORING
<br /> FINDINGS
<br /> On January 11, 2016, the direction of the groundwater across the majority of the DP/Ripon
<br /> Energy site was towards the northwest(309°) at a magnitude of 0.00168 ft/ft. West of the site, a
<br /> mound was present in the uppermost groundwater unit in the vicinity of the City of Ripon's
<br /> waste-water treatment facility(WWTF)ponds and fresh-water infiltration pond. The mound
<br /> extended eastward onto the western portion of DP/Ripon Energy site. A depression also was
<br /> present in the northwestern corner of the site in the vicinity of well OB-1 (Table 2; Figure 2).
<br /> The pH concentrations in all monitoring wells were within the 6.5 to 8.5 standard pH units
<br /> range for DP/Ripon Energy effluent (Table 2).
<br /> TDS concentrations in groundwater samples OB-4, OB-5, OB-24, OB-25, and OB-28 exceeded
<br /> the 800 mg/L limitation for DP/Ripon Energy effluent. The highest TDS concentration was
<br /> measured in well OB-4 (1,600 mg/L) located in the eucalyptus grove in the northeast quadrant
<br /> of the site (Figure 3). The lowest TDS concentration was measured in monitoring well OB-17
<br /> (I 10 mg/L), located in the southeastern corner of the site along the Stanislaus River.
<br /> Nitrate as nitrogen concentrations in wells OB-1, OB-5, OB-19, OB-26, and OB-28 met or
<br /> exceeded the 10 mg/L limitation for DP/Ripon Energy effluent. The highest nitrate
<br /> concentrations were measured in well OB-28 (68 mg/L; Table 2)just offsite of the northeastern
<br /> quadrant of the site.
<br /> 10107.08 Task I Lawrence&Associates
<br /> W.-I CLIENTSIDiamond Pet Foods 1010107.01-Groundwater Monitoring)Groundwater Monitoring12016U Q2016U Q quarter 2016 report.docx
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