Upper Aquifer Remedial Action Plan

Transcription

1 Upper Aquifer Remedial Action Plan Hilmar Cheese Company Hilmar, California Revised February 28, 2013 Prepared for: Hilmar Cheese Company Mr. Burton Fleischer, Environmental Director 9001 Lander Avenue Hilmar, California Prepared by: J A C O B SO N J A M E S & a s s o c i a t e s, i n c 9083 Foothills Blvd., Suite 370 Roseville, California 95747

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3 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page ii TABLE OF CONTENTS PAGE LIST OF FIGURES... iii LIST OF TABLES... iii LIST OF APPENDICES... iv LIST OF ACRONYMS AND ABBREVIATIONS... v 1.0 INTRODUCTION Purpose Organization BACKGROUND Site Location, Land Use, and Operations Facility Waste Water Treatment Operations and Primary Land Use History Regulatory Framework, Prior Investigation and Remedy Evaluation Activities CONCEPTUAL SITE MODEL Environmental Setting Geology and Hydrogeology Water Resources and Beneficial Uses Ambient Water Quality Conditions Potential On Site and Off Site Sources of COCs Migration Pathways and Plume Stability Potential Receptors REMEDIAL ACTION FRAMEWORK Remedial Action Objective Remedial Action Area Remedial Alternative Timeframe Estimates to Achieve the RAOs PERFORMANCE MONITORING PLAN Purpose and Objectives Irrigation Water Applications Groundwater Monitoring, Sampling, and Analyses Monitoring Parameters and Locations Data Evaluation Reporting Performance Monitoring Plan Modifications Contingency Plan Schedule REFERENCES HCC UA RAP_ Final.docx

4 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page iii LIST OF TABLES Table 2 1 HCC Partially Treated Waste Water Analytical Summary Table 2 2 Water Quality Data for Potential Irrigation Sources to S 63, S 64, and S 65 Table 3 1 Ambient Screening Thresholds Table 4 1 Remedial Action Objectives Table 5 1 Performance Monitoring and Sampling Plan Table 5 2 Monitoring Well Network Rationale Figure 2 1 Figure 2 2 Figure 2 3 Figure 2 4 Site Location Figure Land Use Classifications Site and Vicinity Land Use LIST OF FIGURES Site Plan with Upper Aquifer Monitoring Well Locations Figure 2 5 Historic Waste Water and Former Primary Land Use Timeline, 1985 December 2010 Figure 2 6 Former Primary Land Reuse Area Timeline, January 2011 September 2012 Figure 3 1 Physiographic Setting Figure 3 2a Figure 3 2b Figure 3 2c Geologic Cross Section A A Geologic Cross Section B B Geologic Cross Section C C Figure 3 2d Geologic Cross Section D D Figure 3 3a Upper Aquifer Shallow Zone Potentiometric Surface Map (July 23, 2012) Figure 3 3b Upper Aquifer Supply Zone Potentiometric Surface Map (July 23, 2012) Figure 3 4a Figure 3 4b Figure 3 5a Figure 3 5b Figure 3 6a Figure 3 6b Figure 3 7a Figure 3 7b Total Dissolved Solids in 2010 Groundwater Monitoring Well Samples (Upper Aquifer Shallow Zone) Total Dissolved Solids in 2010 Groundwater Monitoring Well Samples (Upper Aquifer Supply Zone) Chloride in 2010 Groundwater Monitoring Well Samples (Upper Aquifer Shallow Zone) Chloride in 2010 Groundwater Monitoring Well Samples (Upper Aquifer Supply Zone) Sodium in 2010 Groundwater Monitoring Well Samples (Upper Aquifer Shallow Zone) Sodium in 2010 Groundwater Monitoring Well Samples (Upper Aquifer Supply Zone) 2012 Total Dissolved Solids in Groundwater Samples (Upper Aquifer Shallow Zone) 2012 Total Dissolved Solids in Groundwater Samples (Upper Aquifer Supply Zone) HCC UA RAP_ Final.docx

5 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page iv LIST OF FIGURES Figure 3 8a 2012 Chloride in Groundwater Samples (Upper Aquifer Shallow Zone) Figure 3 8b 2012 Chloride in Groundwater Samples (Upper Aquifer Supply Zone) Figure 3 9a 2012 Sodium in Groundwater Samples (Upper Aquifer Shallow Zone) Figure 3 9b 2012 Sodium in Groundwater Samples (Upper Aquifer Supply Zone) Figure 3 10 Upper Aquifer Shallow Zone Average Total Dissolved Solids (2006 to 2012) Figure 5 1 Upper Aquifer Performance Monitoring Network Figure 5 2 Construction Details for Upper Aquifer Monitoring Wells LIST OF APPENDICES Appendix A Upper Aquifer Sampling and Analysis Plan HCC UA RAP_ Final.docx

6 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page v LIST OF ACRONYMS AND ABBREVIATIONS AF/y AGR CalEPA CAO COC CSM CVRWQCB EC FS ft bgs HCC ICF J&S IND JJ&A KJ MCL mg/l MNA MUN PRO RAO RAP RI SAP Site TDS TID TSO USEPA WDR Acre feet per year agricultural supply California Environmental Protection Agency Cleanup and Abatement Order constituent of concern Conceptual Site Model Central Valley Regional Water Quality Control Board electrical conductivity Feasibility Study feet below ground surface Hilmar Cheese Company ICF Jones & Stokes industrial service supply Jacobson James & Associates, Inc. Kennedy/Jenks Consultants maximum contaminant level milligrams per liter Monitored Natural Attenuation municipal and domestic supply industrial process supply Remedial Action Objective Remedial Action Plan Remedial Investigation Sampling and Analysis Plan Hilmar Cheese Company Facility (9001 Landers Avenue) and Historical Primary Lands total dissolved solids Turlock Irrigation District Time Schedule Order United States Environmental Protection Agency Waste Discharge Requirement HCC UA RAP_ Final.docx

7 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California Revised February 28, 2013 Page INTRODUCTION This Upper Aquifer Remedial Action Plan (the RAP ) was prepared on behalf of Hilmar Cheese Company (HCC) for the HCC facility located at 9001 Lander Avenue in Hilmar, California and the former HCC Primary Lands (the Site ). The RAP addresses the requirements of Cleanup and Abatement Order (CAO) No. R , issued by the Central Valley Regional Water Quality Control Board (CVRWQCB) to HCC on December 2, In addition, the RAP responds to the following: August 17, 2012 CVRWQCB correspondence which requested that HCC submit a remedial action plan: (1) detailing tasks required for implementation of the preferred alternative, and (2) presenting a monitoring and reporting program to monitor the progress of the preferred alternative in achieving the Site Remedial Action Objectives (RAOs). December 28, 2012 CVRWQCB correspondence transmitting comments on the initial November 2, 2012 RAP submittal. 1.1 Purpose The purpose of this RAP is to describe the methods by which the performance of the remedial alternative will be evaluated relative to achieving the RAOs. The RAP provides Site background information and the Conceptual Site Model (CSM), both of which have been updated to reflect current Site land use, irrigation practices, and groundwater quality conditions as they are relevant to the purpose of the RAP. 1.2 Organization The RAP is organized as follows: Section 1.0 Section 2.0 Section 3.0 Section 4.0 Section 5.0 Section 6.0 Introduction Background Conceptual Site Model Remedial Action Framework Performance Monitoring Plan References HCC UA RAP_Rev 1_2013Feb28.docx

8 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page BACKGROUND 2.1 Site Location, Land Use, and Operations The Site is located slightly north of the town of Hilmar in Merced County, California, as shown on Figure 2 1. As shown on Figure 2 2, agriculture represents the predominant land use both regionally and in the vicinity of the Site. The indicated land use shown within the Site boundaries on Figure 2 3 includes agricultural and industrial (e.g., the HCC milk processing plant). Figure 2 3 also shows the local land use, indicating the prevalence of field crops, orchards, and dairy operations. The Site is comprised of the HCC facility and former Primary Lands. As further described in Section 2.2, the former Primary Lands include those lands that historically received waste water from the HCC facility. Figure 2 4 provides the Site Plan showing the HCC facility and the historic Primary Lands. 2.2 Facility Waste Water Treatment Operations and Primary Land Use History Beginning in 1985, facility waste water was discharged to the former holding/percolation ponds shown on Figure 2 5. Beginning in 1989, facility waste water was discharged to areas identified as the Primary Lands with the discharge of partially treated waste water to the former Primary Lands beginning in The discharge to the former Primary Lands was regulated by Waste Discharge Requirements (WDRs) issued by the CVRWQCB. The most recent WDR was issued as Order No. R , as modified by the Time Schedule Order (TSO) No. R , which required that all discharge to the Primary Lands cease as of February 15, The last discharge to the former Primary Lands was in December The quality and volume of partially treated waste water application to the former Primary Lands varied over time, as did the size and location of the former Primary Lands. Figure 2 5 provides a timeline depicting the changes to the partially treated waste water quality, volumes, and arrangement of the former Primary Lands through December The partially treated waste water applied to the former Primary Lands consisted of water resulting from the cleaning and sanitation of equipment and operations; Table 2 1 provides an analytical summary of key constituents in the partially treated waste water applied to the former Primary Lands between 2001 and December The former Primary Lands are currently used for agricultural purposes. Figure displays a land use timeline for the former Primary Lands beginning with January As shown on Figure 2 6, portions of the former Primary Lands became designated Reuse Areas S 63 and S 64 in March 2011 and Reuse Area S 65 in April Reuse Areas S 1 through S 62 are comprised of off Site properties to the north, west, and southwest. All Reuse Areas can receive HCC Reuse water, Turlock Irrigation District (TID) water and/or Dairy Waste water as regulated by WDR Order No. R Figure 2 6 represents data reported to the CVRWQCB per WDR Order No. R ; as such, it is possible that TID water was applied to former Primary Lands prior to April HCC UA RAP_ Final.docx

9 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page 2 2 Quarterly WDR reports are submitted by HCC to the CVRWQCB which identify the source, volume, and quality of Reuse water, TID water, and Dairy Waste water applied to the Reuse Areas. Water quality data for the Reuse water, TID water, and Dairy Waste water available for irrigation use on Reuse Areas S 63, 64 and 65 for January 2011 through September 2012 are summarized in Table 2 2. The volume of each of these irrigation sources applied to Reuse Areas S 63, 64, and 65 is summarized in Figure 2 6 through September Regulatory Framework, Prior Investigation and Remedy Evaluation Activities The CAO requires delineation of the lateral and vertical extent of potential groundwater impact by historic HCC operations and the evaluation and selection of potential remedial options to address impacts to groundwater resulting from historic HCC operations. The delineation work consisted of a series of work plans, field efforts, and reports. All work plans and reports were submitted to the CVRWQCB for review and approval. The Remedial Investigation (RI) Report (Jacobson James & Associates, Inc. [JJ&A], 2010a) provided a compilation of the data collected to complete the Upper Aquifer characterization and delineation of identified constituents of concern (COCs). As indicated in a letter dated August 19, 2010, the CVRWQCB concurred that impacts in the Upper Aquifer were characterized sufficiently for evaluation of remedial options. The evaluation and selection of remedial options for the Upper Aquifer was performed and presented in the document titled Remedial Action Feasibility Study (FS) and Proposed Remedial Actions for the Upper Aquifer (JJ&A, 2010b). The FS identified and evaluated technologies and four remedial action alternatives using the FS process and criteria established by the United States Environmental Protection Agency (USEPA). The FS also considered environmental sustainability using advisories and guidance developed by the California EPA (CalEPA) and USEPA. The FS recommended selection of the remedial alternative that included institutional and engineering controls, irrigated induced soil flushing, and monitored natural attenuation (MNA) as the most effective option based on the criteria of implementability, short term effectiveness, cost, and sustainability. The FS did not provide relative time estimates for the alternatives to meet the RAOs because the discharge of partially treated waste water to the former Primary Lands was being terminated, which represented a change in land use conditions for which no data were available to support development and calibration of a groundwater model. Therefore, the FS recommended that modeling be performed at a later date to confirm that the recommended alternative was capable of achieving the RAOs in a reasonable period of time as compared to the other alternatives. A Work Plan for Groundwater Modeling (Kennedy/Jenks Consultants (KJ), 2012a) was subsequently submitted and, following CVRWQCB approval, groundwater modeling was performed to provide comparative estimates of the timeframes for the evaluated remedial alternatives to achieve the RAOs. The groundwater modeling report concluded that there was no discernible difference in the relative timeframes for achieving the RAOs for the evaluated remedial alternatives; and, that the remedial alternative including MNA, as recommended in the FS, was the appropriate remedial alternative for achieving the RAOs (KJ, 2012b). The CVRWQCB issued a letter, dated August 17, 2012, which summarized the modeling results HCC UA RAP_ Final.docx

10 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page 2 3 and requested submittal of a remedial action plan detailing tasks required for implementation of the preferred alternative and presenting a monitoring and reporting program to monitor the progress of the preferred alternative in achieving RAOs. HCC UA RAP_ Final.docx

11 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page CONCEPTUAL SITE MODEL The preliminary CSM for the Site (JJ&A, 2008) has been updated throughout the project as new data have been collected. This section of the RAP provides an updated version of the CSM presented in the FS, considering the groundwater quality data collected subsequent to the last discharge of partially treated waste water to the former Primary Lands in Environmental Setting This section presents the environmental setting component of the CSM Geology and Hydrogeology The San Joaquin Valley in the vicinity of the Site is underlain predominantly by unconsolidated fluvial and lacustrine deposits. As shown on Figure 3 1, the Site is located in an area mapped by the United States Geological Survey (Burow, et al, 2004) as the Modesto Formation. The Modesto Formation consists of alluvial sediments including unconfined to semi confined groundwater in the vicinity of the Site (Burow, et al, 2004). The primary source of present day recharge to the Modesto Formation in the vicinity of the Site is irrigation water (Burow, et al, 2004). Irrigation practices combined with extensive groundwater extraction in the area results in a significant downward vertical gradient in the region (Burow, et al, 2004) and in the vicinity of the Site, as measured in Site specific well pairs (JJ&A, 2010a). The aquifer system present in the Modesto Formation is separated from the deeper aquifer system of the Turlock Lake Formation by the Corcoran Clay. The Corcoran Clay is reported to be a laterally extensive, fine grained lacustrine deposit in the upper portion of the Turlock Lake Formation. Figure 3 1 indicates the estimated lateral extent of the Corcoran Clay in the region. The Corcoran Clay is the defining hydrogeologic feature at the Site, separating the aquifer systems into the Upper Aquifer (above the Corcoran Clay) and the Lower Aquifer (below the Corcoran Clay). Figures 3 2a through 3 2d provide hydrogeologic cross sections for the Site. The subsurface has been defined (as indicated in prior reports) to be include nine stratigraphic units as follows: (1) Upper Aquifer Shallow Zone (includes the vadose zone and the upper portion of the saturated zone), (2) A Zone, (3) A Aquitard, (4) B Zone, (5) B Aquitard, (6) C Zone, (7) C Aquitard, (8) D Zone, and (9) E Zone. The A Zone through D Zone units are defined based on data collected to date as presented in the RI Report (JJ&A, 2010a) and the E Zone was defined based on data collected in support of the Lower Aquifer investigation (JJ&A, 2012a). The Shallow Zone, A Zone, A Aquitard, and B Zone comprise the Upper Aquifer; the B Aquitard correlates to the Corcoran Clay unit. The Corcoran Clay has been observed beneath the Site at depths of 110 to 160 feet below ground surface (ft bgs) at a thickness ranging from 10 to 60 feet. The underlying C, D, and E Zone units are within the Lower Aquifer. HCC UA RAP_ Final.docx

12 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page 3 2 A review of water level data from monitoring wells discretely constructed in different portions of the Upper Aquifer indicates the presence of a shallow unconfined aquifer in the upper 20 feet (approximate) of the Upper Aquifer (Upper Aquifer Shallow Zone) with deeper semi confined conditions beneath the shallow zone (approximately ft bgs), from which numerous agricultural supply wells draw water (Upper Aquifer Supply Zone). Site data indicates consistent downward groundwater gradients within the Upper Aquifer and between the Upper Aquifer and Lower Aquifer, although the magnitude of the vertical gradient varies. Years of groundwater monitoring data indicate that the horizontal gradient across the Site is generally consistent with the regional westerly to southwesterly gradient direction, with occasional localized variations at certain times in response to seasonal land use variations (e.g., irrigation and supply well pumping). Figures 3 3a and 3 3b provide groundwater elevation and flow direction figures for the Upper Aquifer Shallow Zone and Upper Aquifer Supply Zone, respectively, for the third quarter 2012 monitoring event Water Resources and Beneficial Uses The Site is located in the Turlock Sub Basin of the San Joaquin Valley Groundwater Basin. The Turlock Sub Basin is bounded to the north, west, and south by the Tuolumne, San Joaquin, and Merced Rivers, respectively. The beneficial uses of the groundwater within the Turlock Sub Basin and underlying the Site are identified in the Basin Plan (CVRWQCB, 2011) as follows: Municipal and Domestic Supply (MUN) Water supply for community, military, or individual use; Agricultural Supply (AGR) Uses of water for farming, horticulture, or ranching including, but not limited to, irrigation (including leaching of salts), stock watering, or support of vegetation for grazing; Industrial Service Supply (IND) Uses of water for industrial activities that do not depend primarily on water quality including, but not limited to, mining, cooling water supply, hydraulic conveyance, gravel washing, fire protection, or oil well re pressurization; and, Industrial Process Supply (PRO) Uses of water for industrial activities that depend primarily on water quality. The Basin Plan sets water quality objectives to protect these beneficial uses, but recognizes that improvement over naturally occurring background conditions is not required (Basin Plan at III , IV 17.00) (CVRWQCB, 2011) Ambient Water Quality Conditions Agricultural land use in the San Joaquin Valley Groundwater Basin and Site vicinity has resulted in groundwater quality degradation. The primary source of degradation for the Turlock Sub basin is through the recharge of applied water (i.e., irrigation) at an estimated rate of 313,000 acre feet per year (AF/yr) (ICF Jones & Stokes (ICF J&S), 2008) to 375,000 AF/yr (Turlock Groundwater Basin Association, 2008). It is HCC UA RAP_ Final.docx

13 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page 3 3 noted that the artificial recharge rate is about 10 times larger than the estimated natural recharge rate of 33,000 AF/yr for the Turlock Sub basin (ICF J&S, 2008). The Site COCs are consistent with those present in the regional groundwater due to agricultural land use. Therefore, detections of the Site COCs in groundwater do not indicate that HCC is the source of the COCs. Ambient screening thresholds were developed as a means of discerning if the presence of a COC is due to an impact from historic HCC discharges of waste water or due to ambient regional groundwater quality as affected by historic and ongoing agricultural land use. Statistical evaluations were performed on data collected from the vicinity of the Site to develop ambient screening thresholds for the COCs as described in the RI Report (JJ&A, 2010a). The ambient screening thresholds are provided in Table 3 1 for COCs in the Upper Aquifer Shallow Zone and the Upper Aquifer Supply Zone. 3.2 Potential On Site and Off Site Sources of COCs The residual COCs in the Site soils and groundwater from past discharges of waste water and partially treated waste water represent the current on Site sources. Since the last discharge of partially treated waste water in December 2010, the former Primary Lands have been irrigated with TID water, HCC Reuse water, and/or Dairy Waste water. The irrigation water provides the flushing component described for each of the remedial alternatives evaluated in the FS (JJ&A, 2010b). The FS indicated an absence of adverse impact from the residual soil conditions on groundwater quality; the post 2010 data are consistent with this aspect of the CSM, as further discussed in Section 3.3. The location and concentration of representative Site COCs (total dissolved solids (TDS), chloride, and sodium) in Upper Aquifer groundwater in December 2010, relative to potential beneficial use levels, are provided on Figures 3 4 through 3 6. Figures 3 7 through 3 9 provide July 2012 TDS, chloride, and sodium concentration data relative to Site RAOs. The December 2010 figures represent water quality at the time of the last discharge of partially treated waste water to the former Primary Lands, and the July 2012 figures represent recent water quality conditions after approximately one and one half years of agricultural land use and related irrigation practices. As indicated in the Section 3.3 discussion below, these data indicate that the expected natural attenuation is occurring. Potential off Site sources of COCs include the local row crop fields, orchards, and dairies in the vicinity of the Site. 3.3 Migration Pathways and Plume Stability Groundwater quality in the Upper Aquifer Shallow Zone had been similar to the quality of the partially treated waste water applied to the former Primary Lands, as presented in the RI Report (JJ&A, 2010a). This similar water quality indicated that the ability of the vadose zone soil and Upper Aquifer Shallow Zone to remove COCs by natural attenuation processes had been diminished while the discharges of the partially treated waste water to the Primary Lands were occurring. The 2012 data indicate that, since discharges of HCC UA RAP_ Final.docx

14 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page 3 4 partially treated waste water ceased in 2010, natural attenuation of COCs has been occurring in groundwater both laterally and vertically within the Upper Aquifer. The 1,000 milligrams per liter (mg/l) TDS contour has been well defined for several years in the Upper Aquifer Shallow Zone and is a useful metric for evaluating overall plume dynamics as defined in the RI Report (JJ&A, 2010a). A review of the average annual TDS concentrations in this zone indicates that the 1,000 mg/l TDS contour 2 stayed within the same general footprint from 2006 to 2010, as shown on Figure However, the size and shape of the 1,000 mg/l TDS contour has shrunk subsequent to 2010, as indicated by the 2011 contour and the shading that represents the extent in The reduction in the plume footprint since the cessation of discharge of the partially treated waste water to the former Primary Lands is consistent with the CSM expectations as presented in the FS (JJ&A, 2010b) as follows: Despite the potential for future irrigation of the Primary Lands to cause COCs within the soils to migrate to groundwater, the soil and current COC versus data indicate the following: (1) upon cessation of partially treated waste water applications to the Primary Lands concentrations within the plume will diminish further and the plume footprint will reduce, and (2) this reduction in COC concentrations and plume size will occur despite the presence of COCs in the Site soil as the COCs in the soil have been a constant to the system. 3.4 Potential Receptors Potential receptors include supply wells screened within the Upper Aquifer in the immediate vicinity of the Site. Evaluation of impacts to these potential receptors has been performed and an annual supply well monitoring, sampling, and reporting program is in place. Groundwater in the vicinity of the Site does not discharge to natural surface water bodies (i.e., creeks, streams, rivers, wetlands, or lakes). Tile drains, initially installed to lower the water table due to irrigation, were historically present beneath portions of the Site but were removed from service in 2003 with additional work performed in There are operating tile drains located south of the Site, however, the majority of the tile drains are not located within the area of the HCC Site; it is noted that the water quality for the tile drain system near the Site is better than the other TID tile drain systems (JJ&A, 2010b Appendix B,). 2 The 1,000 mg/l TDS contour was used as this TDS concentration has been bounded by monitoring wells allowing for a historical trend review. HCC UA RAP_ Final.docx

15 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California Revised February 28, 2013 Page REMEDIAL ACTION FRAMEWORK 4.1 Remedial Action Objective The RAO for the Site is to attain the identified and applicable groundwater beneficial uses to the extent feasible based on regional water quality conditions. The groundwater beneficial uses are defined in the Basin Plan, (CVRWQCB, 2011) and include MUN, AGR, IND, and PRO. However, the Basin Plan recognizes that improvement over naturally occurring background conditions is not required (Basin Plan: Sections III 9.00, IV 17.00) (CVRWQCB, 2011). Table 4 1 presents RAOs for COCs which can be used to monitor the remedial alternative to determine when the broader RAO described above is achieved. Table 4 1 provides RAOs for COCs that have promulgated maximum contaminant levels (MCLs) with the exception of: (1) electrical conductivity (EC), as TDS is a representative indicator, and (2) sodium, which does not have a MCL but was requested as a key indicator constituent by the CVRWQCB for the Upper Aquifer groundwater modeling of remedial alternatives (CVRWQCB, 2012). The COCs without MCLs are represented by the TDS RAO. The RAOs presented in Table 4 1 are considerate of the respective COC ambient screening thresholds, which were discussed in detail in the FS. As discussed in the FS, the COC specific RAO is the lower of the drinking water or agricultural water quality objective, but not lower than the ambient screening threshold. Section 5 provides a description of how the RAO monitoring and evaluation will be performed to determine when the RAOs have been achieved. 4.2 Remedial Action Area The area evaluated by the FS includes the Site and the portions of the Upper Aquifer historically impacted by HCC COCs above the RAOs, with the exception of the groundwater south of the Site due to potential off Site contributory sources (JJ&A, 2010b). 4.3 Remedial Alternative The components of the recommended Upper Aquifer remedial alternative are as follows: Institutional Controls: o Elimination of the discharges of partially treated waste water to the former Primary Lands in accordance with the TSO Order No. R ; o In kind replacement of water to nearby residences upon notification from the CVRWQCB Executive Officer in accordance with the CAO; o Supply of bottled water to nearby residences to meet drinking water beneficial uses, as needed; and, o Supply of HCC Reuse water to nearby property owners to meet agricultural beneficial uses, as needed. HCC UA RAP_Rev 1_2013Feb28.docx

16 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page 4 2 Engineering Controls: o Maintenance of the existing asphalt and concrete surfaces over the former holding pond and historic Primary Land areas as long as these measures are considered necessary. Irrigation Induced Soil Flushing: o Implementation of routine irrigation practices, using fully treated process waste water (i.e., HCC Reuse water) and/or TID water, associated with agricultural use of the former Primary Lands not covered with asphalt or concrete. Monitored Natural Attenuation: o MNA of the COCs in Upper Aquifer groundwater to document and confirm the reduction in COC concentrations with time. The institutional controls, engineering controls, and irrigation induced soil flushing components of the remedy have been implemented. The discharge source was eliminated with the last discharge of partially treated waste water to the former Primary Lands in Additionally, flushing of the residual source in the soils commenced with the 2011 implementation of irrigation using HCC Reuse water and/or TID water. Recent groundwater quality data provide information relevant to assessing the MNA component of the remedy. Groundwater quality data, collected subsequent to the cessation of partially treated waste water discharges, were used in the groundwater modeling effort to estimate the relative timeframes to achieve the RAOs for the remedial alternatives. The results supported HCC s selection of the remedial alternative with the MNA component. 4.4 Timeframe Estimates to Achieve the RAOs The groundwater model time frame estimates for MNA to achieve the RAOs, on a simulated depth averaged concentration basis 3, were 2016 for the Upper Aquifer Shallow Zone and 2022 for the Upper Aquifer Supply Zone, with an estimated uncertainty of +6/ 4 years (KJ, 2012b). 3 Simulated depth averaged concentrations were calculated at specific model time steps. They reflect the average of the simulated concentrations from each of the model layers within a particular zone, weighted by individual layer thicknesses. Thus, the calculation of the depth averaged concentration for the Upper Aquifer Shallow Zone utilizes different model layers than the calculation for the Upper Aquifer Supply Zone. HCC UA RAP_ Final.docx

17 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California Revised February 28, 2013 Page PERFORMANCE MONITORING PLAN 5.1 Purpose and Objectives Consistent with USEPA guidance for the use of MNA (USEPA, 1999), the performance monitoring plan is to describe the location, frequency, and types of samples and measurements necessary to evaluate if the remedy is performing as expected and if it is capable of attaining the RAO. Accordingly, the performance monitoring plan presented herein has been designed to accomplish the following objectives: Confirm that natural attenuation is progressing as expected and consistent with the timeframe estimates to achieve the RAOs. Monitor for potential changes in environmental conditions at the Site that may increase or decrease the effectiveness of the remedy. 5.2 Irrigation Water Applications The recommended remedial alternative includes irrigation of the former Primary Lands consistent with soil flushing as described in the FS. Irrigation practices for the former Primary Lands are relevant to evaluating and interpreting the Site groundwater quality data. In accordance with the WDRs, HCC reports on the volume and quality of water applied to the Reuse Areas which includes the former Primary Lands. The data from the HCC WDR compliance reports will be reviewed and included in the quarterly reports described in Section Groundwater Monitoring, Sampling, and Analyses Groundwater monitoring, sampling, and analyses will be performed to provide the data necessary to achieve the objectives defined in Section 5.1. This will include the collection of data from monitoring wells up gradient, within, and cross/down gradient of the plume 4. This will allow for the collection of data to: (1) define the quality of groundwater moving into the plume, (2) confirm that natural attenuation is occurring, and (3) monitor potential plume migration Monitoring Parameters and Locations Monitoring parameter data will be collected on a quarterly basis. The RAO and general mineral monitoring parameters are those listed in Table 5 1. In addition, standard field measurements will be collected during sampling events to ensure representative groundwater samples are collected. Standard field measurements include water level, ph, temperature, and EC. 4 For purposes of the performance monitoring plan, plume is defined as the area of groundwater with COCs exceeding their respective RAOs. HCC UA RAP_Rev 1_2013Feb28.docx

18 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California Revised February 28, 2013 Page 5 2 The monitoring well network is comprised of wells at locations suitable to provide water quality data regarding up gradient and cross/down gradient conditions and to confirm that natural attenuation is occurring. The monitoring and sampling plan is presented in Table 5 1 and Table 5 2 provides the rationale for selection of the monitoring well locations. The Upper Aquifer monitoring well locations are shown on Figure 5 1 and monitoring well construction details are graphically illustrated on Figure 5 2. It should be noted that the proposed performance monitoring plan and the rationale for the selected monitoring well locations are based on recent Site conditions (i.e., water quality, flow direction, land use). The monitoring objective for each monitoring well within the performance monitoring plan is subject to change as the groundwater conditions change. For example, as the plume footprint diminishes the wells monitoring natural attenuation at the edges of the plume may transition to a cross/down gradient monitoring role. Similarly, wells currently monitoring cross/down gradient conditions may become unnecessary as the plume footprint diminishes and locations within the interior of the plume become suitable replacements. Modifications will be proposed to the performance monitoring plan, as described in Section 5.6. Appendix A presents the Upper Aquifer Sampling and Analysis Plan (SAP), which describes the methods and procedures for data collection, quality assurance/quality control plan, data management, and reporting. 5.4 Data Evaluation Multiple lines of evidence and analyses will be used to evaluate the data collected to assess the objectives identified in Section 5.1. Statistical and/or graphical analyses will be performed on the data sets for the Upper Aquifer Shallow Zone and Upper Aquifer Supply Zone. Statistical evaluations may include regression analysis, hypothesis tests (e.g., Students T Test or Mann Whitney U Test), and trend analysis (e.g., Mann Kendall Test) in addition to the following potential graphical methods. Well Specific Constituent Trend Graphs. Constituent concentration versus time graphs can be used to determine if COC concentrations are behaving as anticipated or if unexpected conditions are occurring. The trend of decreasing COC concentrations over time can be used to assess the progress of MNA to attain the RAOs. An increasing trend could represent a new source or unanticipated plume behavior, a change in ambient conditions in an up gradient well, or unanticipated plume migration if noted in down or cross gradient monitoring wells. Plume Maps and Cross Sections. Concentrations of constituents plotted for the Upper Aquifer Shallow Zone and the Upper Aquifer Supply Zone, respectively, can be used to define the lateral extent of the plume relative to the RAOs. Comparisons of plume extents through time provide information relevant to the trend of the plume location, size, configuration, and concentrations, allowing for the identification of potential migration patterns and assessment of MNA progress. HCC UA RAP_Rev 1_2013Feb28.docx

19 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California Revised February 28, 2013 Page 5 3 Moving Averages. Calculation and comparison of the 4 quarter rolling average for each constituent within each well 5 (Wiedemeier et al, 2000; USEPA, 2011). The methods described above are examples of how the actual COC attenuation data can be evaluated to confirm that natural attenuation is progressing as expected and consistent with the timeframe estimates to achieve the RAOs. 5.5 Reporting Quarterly performance monitoring reports will be submitted to present the collected data and provide data evaluation as per Section 5.4. The quarterly reports will also include a summary of the volume and quality of water applied to the former Primary Lands identified as Reuse Areas, as described in Section 5.2. The fourth quarter report will also be the annual report for the respective year and will include a discussion of the data relative to the objectives defined in Section 5.1 and recommendations for modifications, if determined to be necessary. The quarterly reports will include the data in tabular and graphical format, with appendices for field data sheets, laboratory reports, chain of custody documents, data validation memoranda, and other source information as appropriate. 5.6 Performance Monitoring Plan Modifications The performance monitoring plan will be evaluated annually to ensure that the objectives are being met. Modifications to the plan may be warranted to reflect changing conditions or an improved understanding of the CSM, including the natural attenuation process at the Site. In addition, modifications may be identified for the reporting frequency, format, and content. Any recommendations for modification will be submitted to the CVRWQCB for approval prior to implementation. 5.7 Contingency Plan The data collected through the 2012 third quarter monitoring and sampling event (JJ&A, 2012b) indicate that the plume is shrinking and that natural attenuation is occurring. As such, the need for and implementation of a Contingency Plan is unlikely. However, if the report data indicates that natural attenuation is not progressing as anticipated to achieve the RAOs, then HCC will notify and meet with the CVRWQCB to discuss: (1) evaluation of land uses and modified monitoring in response to anomalous data trends, and (2) an update to the groundwater model to incorporate recent groundwater monitoring data for re calibration of the model. 5 The constituents listed in Table 4 1 are naturally occurring in groundwater with a natural variability in concentration. The 95% UTL has been proposed as a metric to evaluate attainment of the RAOs. By definition, 5% of the naturally occurring data set will exceed the RAOs due to natural variability in the data. As such, a requirement for all sample results to meet the 95% UTL for all constituents at all wells is not statistically feasible. In other words, based purely on the statistical approach proposed, 5% of the data will exceed the UTLs when the RAO s are achieved. HCC UA RAP_Rev 1_2013Feb28.docx

20 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page Schedule Quarterly monitoring and reporting is currently occurring for the Site to provide data pursuant to the CAO. The performance monitoring plan described herein will be implemented upon CVRWQCB approval of this RAP and will replace the current monitoring program. HCC UA RAP_ Final.docx

21 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Page REFERENCES Burow, K.R., Shelton, J.L., Hevesi, J.A., and Weissmann, G.S., Hydrogeologic Characterization of the Modesto Area, San Joaquin Valley, California: U.S. Geological Survey Scientific Investigations Report , pp. 54. California Regional Water Quality Control Board, Central Valley Region (CVRWQCB), The Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins, California Regional Water Quality Control Board Central Valley Region. Fourth Edition October Download October 10, 2012: CVRWQCB, Comments Transmittal Regarding the Work Plan for Groundwater Modeling, Hilmar Cheese Company, Hilmar, Merced County. March 19. ICF Jones & Stokes (ICF J&S), Irrigated Lands Regulatory Program, Existing Conditions Report: Prepared for the Central Valley Regional Water Quality Control Board. December. Jacobson James & Associates, Inc. (JJ&A), Preliminary Conceptual Site Model, Hilmar Cheese Company, Hilmar, California. October 1. JJ&A, 2010a. Remedial Investigation Report, Hilmar Cheese Company, Hilmar, California. June 18. JJ&A, 2010b. Remedial Action Feasibility Study and Proposed Remedial Actions for the Upper Aquifer, Hilmar Cheese Company, Hilmar, California. December 20. JJ&A, 2012a. Lower Aquifer Remediation Investigation Report, Hilmar Cheese Company, Hilmar, California. August 20, JJ&A, 2012b. Groundwater Monitoring and Sampling Report, Third Quarter 2012, Hilmar Cheese Company, Hilmar, California. November 2. Kennedy/Jenks Consultants (KJ), 2012a. Work Plan for Groundwater Modeling, Hilmar Cheese Company, Hilmar, California. January 17. KJ, 2012b. Groundwater Modeling for Remedial Alternatives Evaluation, Hilmar Cheese Company, Hilmar, California. August 9. Turlock Groundwater Basin Association, Management Plan. January 17, Turlock Groundwater Basin, Draft Groundwater United States EPA (USEPA), Use of Monitored Natural Attenuation at Superfund, RCRA Corrective Action, and Underground Storage Tank Sites, OSWER Directive P. USEPA, An Approach for Evaluating the Progress of Natural Attenuation in Groundwater. December. Wiedemeier, Todd H.; Lucas, Mary A.; and Hass, Patrick E, Designing Monitoring Programs to Effectively Evaluate the Performance of Natural Attenuation for Air Force Center For Environmental Excellence. January. HCC UA RAP_ Final.docx

22 TABLES

23 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 LIST OF TABLES Table 2 1 HCC Partially Treated Waste Water Analytical Summary Table 2 2 Water Quality Data for Potential Irrigation Sources to S 63, S 64, and S 65 Table 3 1 Ambient Screening Thresholds Table 4 1 Remedial Action Objectives Table 5 1 Performance Monitoring and Sampling Plan Table 5 2 Monitoring Well Network Rationale HCC UA RAP_ Final.docx

24 TABLE 2 1 HCC PARTIALLY TREATED WASTE WATER ANALYTICAL SUMMARY 1,2,3 Upper Aquifer Remedial Action Plan Hilmar Cheese Company Hilmar, California Compound units Average Alkalinity, bicarbonate (as CaCO 3 ) mg/l , Ammonia as Nitrogen mg/l Biochemical Oxygen Demand mg/l Calcium mg/l Chloride mg/l Chemical Oxygen Demand mg/l Electrical Conductivity us/cm Iron mg/l Magnesium mg/l Nitrate nitrogen mg/l ph standard units Phosphorus, total mg/l Potassium mg/l Sodium mg/l Solids, total dissolved mg/l Sulfate mg/l Sulfide mg/l Total Kjeldahl Nitrogen mg/l Notes: 1 Treated waste water applied to primary lands. 2 Brown and Caldwell, Report of Waste Discharge, Hilmar Cheese Company, Hilmar, California. August HCC, Monthly Water Quality Monitoring Reports. January 2005 through December KennedyJenks, Report of Waste Discharge, Hilmar Cheese Company, Hilmar, California. June The last discharge of partially treated waste water occurred in December Reflects water quality data trhough December CaCO 3 = calcium carbonate mg/l = milligrams per liter us/cm = microsiemens per centimeter Page 1 of 1

25 TABLE 2 2 WATER QUALITY DATA FOR POTENTIAL IRRIGATION SOURCES TO S 63, S 64, AND S 65 1 Upper Aquifer Remedial Action Plan Hilmar Cheese Company Hilmar, California TDS (mg/l) Chloride (mg/l) Sodium (mg/l) Reuse 2 TID 3 Dairy 4 Reuse 2 TID 3 Dairy 4 Reuse 2 TID 3 Dairy 4 Apr May Jul Aug Sep Jan Mar May Jun Jul Aug Sep Notes: 1 S 63, S 64, and S 65 are former Primary Lands now designated as Reuse Areas. Data provided as reported in the HCC Quarterly Monitoring Report submittals dated July 2011, October 2011, January 2012, April 2012, July 2012 and October 2012; submitted per WDR Order No. R TDS is the only parameter reported for all irrigation sources. 2 Reuse data is a monthly averagefrom Table 2a in HCC Quarterly Monitoring Reports. 3 TID water quality based on data from Table 8 in HCC Quarterly Monitoring Reports. 4 Dairy Waste water based on data from Table 10 in HCC Quarterly Monitoring Reports. HCC = Hilmar Cheese Company mg/l = milligrams per liter TDS = total dissolved solids TID = Turlock Irrigation District = not analyzed Page 1 of 1

26 TABLE 3 1 AMBIENT SCREENING THRESHOLDS 1 Upper Aquifer Remedial Action Plan Hilmar Cheese Company Hilmar, California Constituent 95% Upper Tolerance Limit (UTL) Upper Aquifer Shallow Zone Upper Aquifer Supply Zone Alkalinity, Bicarbonate as CaCo 3 (mg/l) Calcium, dissolved (mg/l) Chloride (mg/l) Electrical Conductivity (EC) (umhos/cm) 2 1,096 Iron, dissolved (mg/l) Magnesium, dissolved (mg/l) Manganese, dissolved (mg/l) Nitrate as N (mg/l) Potassium, dissolved (mg/l) Sodium, dissolved (mg/l) Sulfate (mg/l) Total Dissolved Solids (mg/l) Total Kjeldahl Nitrogen (mg/l) 68 RL 4 Notes: 1 Source: Jacobson James & Associates, Inc., Remedial Investigation Report, Hilmar Cheese Company. June No Tolerance Limit calculated. 3 Data set has >50% non detected value; default to non parametric limit using largest detected value in data set that is not an outlier. This is a conservative limit and should be used for informational purposes only. 4 Data set has 100% non detected values; default to limit set at method reporting limit. This is a conservative limit and should be used for informational purposes only. CaCO 3 = calcium carbonate mg/l = milligram per liter RL = reporting limit umhos/cm = micromhos per centimeter Page 1 of 1

27 Constituent TABLE 4 1 REMEDIAL ACTION OBJECTIVES 1 Upper Aquifer Remedial Action Plan Hilmar Cheese Company Hilmar, California Upper Aquifer Shallow Zone Remedial Action Objective 1,2,3 Upper Aquifer Supply Zone Chloride Iron Manganese Nitrate as Nitrogen Sodium Sulfate Solids, total dissolved (TDS) Notes: 1 All units in milligrams per liter. 2 Remedial Action Objectives (RAOs) are provided for Constituents of Concern (COCs) that have MCLs with the exception of: (1) electrical conductivity, as TDS is a representative indicator, and (2) sodium, which does not have a MCL but was requested as a key indicator constituent by the CVRWQCB for the Upper Aquifer groundwater modeling of remedial alternatives. The COCs without MCLs will be represented by the TDS RAO. 3 The RAOs reflect the lower of the MCL or agricultural use level unless lower than the ambient screening threshold in which case the ambient screening threshold was selected as the RAO as described in the FS (JJ&A, 2010b). Page 1 of 1

28 TABLE 5 1 PERFORMANCE MONITORING AND SAMPLING PLAN Rev:1 2013Feb28 Upper Aquifer Remedial Action Plan Hilmar Cheese Company Hilmar, California Monitoring Objective Upper Aquifer Shallow Zone Monitoring Wells Upper Aquifer Supply Zone Monitoring Wells Quarter 1 (January March) Quarter 2 (April June) Analysis Plan 1,2,3,4 Quarter 3 (July September) Quarter 4 (October December) Up Gradient Water Quality 5 MW 21 MW 18 RAO Monitoring General Minerals Field Parameters Water Levels RAO Monitoring General Minerals Field Parameters Water Levels RAO Monitoring General Minerals Field Parameters Water Levels RAO Monitoring General Minerals Field Parameters Water Levels Attenuation Confirmation and Down/Cross Gradient Water Quality 6 MW 01, 02, 03, 04, 05, 06, 07, 08, 09, 12, 13, 15, 17, and 19 MW 22, 25, and 29 RAO Monitoring General Minerals Field Parameters Water Levels RAO Monitoring General Minerals Field Parameters Water Levels RAO Monitoring General Minerals Field Parameters Water Levels RAO Monitoring General Minerals Field Parameters Water Levels Groundwater Gradient Conditions 7 MW 02 and 11 MW 24 Water Levels Only Water Levels Only Water Levels Only Water Levels Only Notes: 1 RAO (Remedial Action Objective) monitoring includes sampling for analysis of constituents defined in Table 4 1: chloride, iron, manganese, nitrate, sodium, sulfate, and total dissolved solids. 2 General Minerals include alkalinity (bicarbonate as calcium carbonate (CaCO 3 )), calcium, magnesium, potassium, and total kjeldahl nitrogen (TKN). 3 Water level measurements and field monitoring for field parameters will be performed on each well sampled. 4 Field parameters include ph, temperature, electrical conductivity. 5 Water quality data representative of upgradient conditions for groundwater moving into the area of water quality exceeding RAOs. 6 Water quality data to confirm attenuation is occurring and to monitor changes in the plume magnitude (concentrations) and extent. 7 Water level data to be used in conjunction with water level data from other monitoring wells to construct potentiometric surface maps. Page 1 of 1

29 Well ID Zone Monitored Screened interval (ft bgs) TABLE 5 2 MONITORING WELL NETWORK RATIONALE 1 Upper Aquifer Remedial Action Plan Hilmar Cheese Company Hilmar, California Rationale for Sampling and Analysis MW 1 Upper Aquifer Shallow Zone Attenuation Monitoring: Location within central portion of plume; analytical data to be used to evaluate decreasing magnitude of impact. MW 2 Upper Aquifer Shallow Zone Not Sampled: bounded by four monitoring wells that provide representative water quality data for this area; water level data to be collected quarterly to evaluate flow regimes. MW 3 Upper Aquifer Shallow Zone Attenuation and Cross/Down Gradient Monitoring: Location at edge of plume where attenuation process are occurring/have occurred and COC concentrations are subject to fluctuations. MW 4 Upper Aquifer Shallow Zone Attenuation and Cross/Down Gradient Monitoring: Location at edge of plume where attenuation process are occurring/have occurred and COC concentrations are subject to fluctuations. MW 5 Upper Aquifer Shallow Zone Attenuation Monitoring: Location within southern portion of plume; analytical data to be used to evaluate decreasing magnitude of impact. MW 6 Upper Aquifer Shallow Zone Attenuation Monitoring: Location within central portion of plume; analytical data to be used to evaluate decreasing magnitude of impact. MW 7 Upper Aquifer Shallow Zone Attenuation/Cross or Down Gradient Monitoring: Water quality samples will be used to evaluate attenuation and cross/down gradient conditions. MW 8 Upper Aquifer Shallow Zone Attenuation Monitoring: Location within southern portion of plume; analytical data to be used to evaluate decreasing magnitude of impact. MW 9 Upper Aquifer Shallow Zone Attenuation Monitoring: Location on down gradient edge of plume; monitor water quality to evaluate decreasing magnitude and extent of impact. MW 11 Upper Aquifer Shallow Zone Not Sampled: Location up gradient of impacted area; water level data to be collected quarterly to evaluate flow regimes. Note: MW 21 serves as the Shallow Zone Up Gradient monitoring location. MW 12 Upper Aquifer Shallow Zone Cross/Down Gradient Monitoring: Location is down gradient of plume in Upper Aquifer Shallow zone; intended to monitor change in plume dimensions. MW 13 Upper Aquifer Shallow Zone Attenuation Monitoring: Location within up gradient portion of plume; monitor water quality to evaluate decreasing magnitude and extent of impact. Page 1 of 2

30 Well ID Zone Monitored Screened interval (ft bgs) TABLE 5 2 MONITORING WELL NETWORK RATIONALE 1 Upper Aquifer Remedial Action Plan Hilmar Cheese Company Hilmar, California Rationale for Sampling and Analysis MW 15 Upper Aquifer Shallow Zone Cross/Down Gradient Monitoring: Location is cross gradient of plume in Upper Aquifer Shallow zone; intended to monitor any changes in plume dimensions and or alternative Cross/Down Gradient directions due to changes in groundwater flow. MW 17 Upper Aquifer Shallow Zone Cross/Down Gradient Monitoring: Location is down gradient of plume in Upper Aquifer Shallow zone; intended to monitor changes in plume dimension. Useful for evaluation of potential off site source and impact to monitoring well MW 29. MW 19 Upper Aquifer Supply Zone Cross/Down Gradient Monitoring: Location is down gradient of plume in Upper aquifer supply well zone; intended to monitor change in plume dimension. MW 21 Upper Aquifer Shallow Zone Up Gradient Monitoring: Intended to provide reference data for groundwater migrating onto the Site. MW 22 Upper Aquifer Supply Zone Attenuation and Up Gradient Monitoring: Location up gradient of plume where attenuation process are occurring/have occurred; data used to evaluate the up gradient area within the central portion of the Site. MW 24 Upper Aquifer Supply Zone Not Sampled: Location up gradient of impacted area; water level data to be collected quarterly to evaluate flow regimes. MW 25 Upper Aquifer Supply Zone Cross/Down Gradient Monitoring: Location is cross and down gradient of plume in the supply well zone; intended to monitor changes in plume dimensions and or alternative Cross/Down Gradient directions due to changes in groundwater flow. MW 29 Upper Aquifer Supply Zone Cross/Down Gradient Monitoring: Location is down and cross gradient of plume in Upper aquifer supply well zone; intended to monitor any changes in plume dimensions and or alternative Cross/Down Gradient directions due to changes in groundwater flow. May be affected by off site sources. Notes: 1 This performance monitoring plan presents the proposed rationale for selected monitoring well locations based on recent Site conditions (i.e., water quality, flow direction, land use). The monitoring objective for each monitoring well within the performance monitoring program is subject to change as the groundwater conditions change. For example, Attenuation Monitoring wells currently located within the plume may become Up, Cross or Down Gradient Monitoring wells as water quality improves and the plume diminishes in size. COC = constituent of concern ft bgs = feet below ground surface Page 2 of 2

31 FIGURES

32 Upper Aquifer Remedial Action Plan, Hilmar Cheese Company, Hilmar California November 2, 2012 Figure 2 1 Figure 2 2 Figure 2 3 Figure 2 4 Site Location Figure Land Use Classifications Site and Vicinity Land Use LIST OF FIGURES Site Plan with Upper Aquifer Monitoring Well Locations Figure 2 5 Historic Waste Water and Former Primary Land Use Timeline, 1985 December 2010 Figure 2 6 Former Primary Land Reuse Area Timeline, January 2011 September 2012 Figure 3 1 Physiographic Setting Figure 3 2a Figure 3 2b Figure 3 2c Figure 3 2d Geologic Cross Section A A Geologic Cross Section B B Geologic Cross Section C C Geologic Cross Section D D Figure 3 3a Upper Aquifer Shallow Zone Potentiometric Surface Map (July 23, 2012) Figure 3 3b Upper Aquifer Supply Zone Potentiometric Surface Map (July 23, 2012) Figure 3 4a Figure 3 4b Figure 3 5a Figure 3 5b Figure 3 6a Figure 3 6b Figure 3 7a Figure 3 7b Figure 3 8a Figure 3 8b Figure 3 9a Figure 3 9b Total Dissolved Solids in 2010 Groundwater Monitoring Well Samples (Upper Aquifer Shallow Zone) Total Dissolved Solids in 2010 Groundwater Monitoring Well Samples (Upper Aquifer Supply Zone) Chloride in 2010 Groundwater Monitoring Well Samples (Upper Aquifer Shallow Zone) Chloride in 2010 Groundwater Monitoring Well Samples (Upper Aquifer Supply Zone) Sodium in 2010 Groundwater Monitoring Well Samples (Upper Aquifer Shallow Zone) Sodium in 2010 Groundwater Monitoring Well Samples (Upper Aquifer Supply Zone) 2012 Total Dissolved Solids in Groundwater Samples (Upper Aquifer Shallow Zone) 2012 Total Dissolved Solids in Groundwater Samples (Upper Aquifer Supply Zone) 2012 Chloride in Groundwater Samples (Upper Aquifer Shallow Zone) 2012 Chloride in Groundwater Samples (Upper Aquifer Supply Zone) 2012 Sodium in Groundwater Samples (Upper Aquifer Shallow Zone) 2012 Sodium in Groundwater Samples (Upper Aquifer Supply Zone) Figure 3 10 Upper Aquifer Shallow Zone Average Total Dissolved Solids (2006 to 2012) Figure 5 1 Figure 5 2 Upper Aquifer Performance Monitoring Network Construction Details for Upper Aquifer Monitoring Wells HCC UA RAP_ Final.docx

33 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 2-1 Hilmar Site Location Map.mxd SOURCE:NATIONAL GEOGRAPHIC CALIFORNIA TOPO VERSION 4.2 ^_ SITE LOCATION Miles LOCATION HILMAR CHEESE COMPANY HILMAR, CALIFORNIA DATE DRAWN BY APPR. BY 11/1/12 DPG TJ FIGURE 2-1 SITE LOCATION FIGURE

34 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 2-2 LandUseClassifications.mxd SCALE IN MILES Turlock STANISLAUS COUNTY MERCED COUNTY San Joaquin River Hilmar LEGEND Merced River Livingston Atwater SITE BOUNDARY LAND USE CLASSIFICATION AGRICULTURAL LAND NATIVE CLASSES NON-IRRIGATED AGRICULTURAL LAND NOT SURVEYED PASTURE URBAN WATER SOURCE: 2002 MERCED COUNTY AND 2004 STANISLAUS COUNTY LAND USE SURVEY DATA; CALIFORNIA DEPARTMENT OF WATER RESOURCES. LOCATION HILMAR CHEESE COMPANY HILMAR, CALIFORNIA DATE DRAWN BY APPR. BY 6/17/10 SM JJ FIGURE 2-2 LAND USE CLASSIFICATIONS

35 LEGEND JOHNSON AVENUE POTENTIAL OFFSITE SOURCE POTENTIAL ONSITE SOURCE EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS YES HISTORIC HCC PRIMARY LANDS NO HCC FACILITY NO HCC RO AND STORMWATER PONDS YES CURRENT OFFSITE POND OSLO ROAD YES NO NO YES YES YES YES YES YES YES YES YES YES YES YES YES HISTORIC POND INDUSTRIAL RESIDENTIAL DAIRY HISTORIC DAIRY POULTRY FARM HISTORIC POULTRY FARM FIELD CROPS ORCHARD (ALMONDS) VINEYARDS LIVESTOCK OR HORSES HISTORIC LIVESTOCK OR HORSES OSLO STREET LANDER AVENUE LATERAL NO. 6 LATERAL No. 7 AUGUST AVENUE Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 2-3 Land Use.mxd ENUE LOCATION HILMAR CHEESE COMPANY HILMAR, CALIFORNIA DATE DRAWN BY APPR. BY 11/1/12 DPG JJ 0 1,000 SCALE IN FEET FIGURE 2-3 SITE AND VICINITY LAND USE

36 LEGEND m " UPPER AQUIFER SHALLOW ZONE MONITORING WELL UPPER AQUIFER SUPPLY ZONE MONITORING WELL TURLOCK IRRIGATION DISTRICT LATERAL CANAL JOHNSON AVENUE EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS CURRENT REUSE LAND AREA; FORMER PRIMARY LAND S-2 REUSE AREA HCC FACILITY S-33 S-31 S-23 S-24 S-34 MW-24 " m S-22 S-10 S-39 S-38 S-09 S-28 MW-34 & < S-48 S-11 S-45 TEGNER AVENUE MW-35 & < S-50 S-52 S-21 S-51 MW-37 & < S-30 S-43 S-44 LATERAL No. 6 S-29 S-08 S-07 MW-16 & < MW-12 & < MW-19 " m S-13 S-25 MW-09 & < S-65 MW-10 & < S-63 MW-08 & < OSLO STREET MW-15 & < MW-06 MW-22 MW-07 & < & < MW-01 & < MW-11 & < S-64 " m OSLO ROAD MW-03 MW-02 & < & < & < MW-05 & < MW-04 MW-13 & < LANDER AVENUE " m MW-18 MW-21 & < FORMER HOLDING/PERCOLATION POND AUGUST AVENUE LATERAL No. 7 S-46 S-53 MW-36 & < S-54 S-58 S-06 S-26 S-40 " m MW-25 MW-20 & < Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 2-4 Site Plan.mxd S-57 S-47 AMERICAN AVENUE S-60 S-61 S-62 S-55 S-59 S-56 COLUMBUS AVENUE MW-17 & < " m MW-29 S-41 LOCATION MW-14 & < HILMAR CHEESE COMPANY HILMAR, CALIFORNIA DATE DRAWN BY APPR. BY 11/1/12 RAL JJ FIGURE ,000 SCALE IN FEET SITE PLAN WITH UPPER AQUIFER MONITORING WELL LOCATIONS

37 WASTE WATER QUALITY Total Dissolved Solids Yearly Average (milligrams per liter) NO DATA WASTE WATER TREATMENT STATUS 0 NO TREATMENT VSEP (NF Membranes) REMOVED Equalization IN SERVICE VSEP (RO Membranes) REMOVED VSEP (UF Membranes) REMOVED RO Unit #1 IN SERVICE Ponds IN SERVICE VSEP (UF Membranes) REMOVED RO Units #2 & #3 REPLACED IN 2005 Evaporator IN SERVICE IN SERVICE 2005 Filter Press NOT USED PCDAF IN SERVICE Sand Filters NOT USED EGSB IN SERVICE Enclosed Flare IN SERVICE Spill Tank IN SERVICE Pre Aeration IN SERVICE SBR IN SERVICE Surge Tank IN SERVICE Submerged Hollow Fiber UF IN SERVICE Replacement RO Units #2 & #3 IN SERVICE Deep Well Injection (RO concentrate) IN SERVICE Granule Catcher IN SERVICE 0 DISCHARGE HISTORY PRIMARY LAND APPLICATION HISTORY 1 Waste Water Discharge Yearly Average (mgd) NO DATA Waste Water to Primary Areas (mgd) Waste Water to RO Ponds (mgd) Total Waste Water Discharge (mgd) TID tile drain operation in HCC vicinity. Facility operations began. Discharge to holding/ percolation pond. Waste water application began to 29 acres of Primary Lands (areas A and B). First WDR issued. Waste water application to areas A and B gradually increasing. Waste water application shifted to area C and smaller amounts applied to areas A and B. Waste water application to area D began in December. Waste water application to areas F and G began in December. Application to area E began, Increase in facility operations. Removed 16 acres of Primary Lands (area B). Store RO permeate to 2 clay lined ponds (RO ponds). Tile drain plugged (in area H); application to area H began. RO permeate application to secondary lands began; reduction in waste water application to Primary Lands. Tile drain plugged (area A). Removed 6 acres of Primary Lands (part of area H). Removed 10 acres of Primary Lands (area H). Wickstrom tile drain plugged (area C). Removed 52 acres of Primary Lands (areas E, F, G). Application to area C and H from January through March. Application to area H in August. Application to Area C in December C E E F G HOLDING/ C D C D PERCOLATION C D POND A B A B A B LANDER AVE LANDER AVE LANDER AVE LANDER AVE G A F LANDER AVE E C D G A F H LANDER AVE E C D F G A H LANDER AVE E C D F G A H LANDER AVE C D A H LANDER AVE C H LANDER AVE AUGUST AVE AUGUST AVE 1995 AUGUST AVE AUGUST AVE AUGUST AVE AUGUST AVE AUGUST AVE AUGUST AVE 2009 AUGUST AVE 2010 AUGUST AVE Notes: Figure excludes Reuse Land application which began receiving treated waste water in Waste water and Primary Land history is based on the Report of Waste Discharge (August 2004) and the Groundwater Characterization Report (September 2004) by Brown and Caldwell; Monthly and Quarterly Water Quality Monitoring Reports by HCC; and the Report of Waste Discharge (June 2008) by Kennedy Jenks. EGSB = expanded granular sludge bed HCC = Hilmar Cheese Company mgd = million gallons per day NF = nanofiltration PCDAF = physico chemical dissolved air flotation RO = reverse osmosis SBR = sequencing bath reactor TID = Turlock Irrigation District UF = ultrafiltration VSEP = vibratory sheer enhancement process WDR = Waste Discharge Requirement LOCATION HILMAR CHEESE COMPANY HILMAR, CALIFORNIA DATE DRAWN BY APPR. BY 11/2/12 SYC JJ FIGURE 2-5 HISTORIC WASTE WATER AND FORMER PRIMARY LAND USE TIMELINE 1985 to DECEMBER 2010

38

39 SCALE IN MILES Turlock STANISLAUS COUNTY MERCED COUNTY San Joaquin River Hilmar LEGEND Merced River Livingston Atwater PHYSIOGRAPHY BOUNDARY OF CORCORAN CLAY SITE BOUNDARY WATER RIVER FLOODPLAINS, CHANNELS, & OVERFLOW LANDS LOW ALLUVIAL PLAINS AND FANS CONSOLIDATED ROCKS AND DEPOSITS DATA UNAVAILABLE SOURCE: USGS SCIENTIFIC INVESTIGATIONS REPORT (HYDROGEOLOGIC CHARACTERIZATION OF THE MODESTO AREA, SAN JOAQUIN VALLEY, CA) (MODIFIED FROM CALIFORNIA DIVISION OF MINES AND GEOLOGY, 1966). LOCATION HILMAR CHEESE COMPANY HILMAR, CALIFORNIA DATE DRAWN BY APPR. BY 6/17/10 SM JJ FIGURE 3-1 PHYSIOGRAPHIC SETTING

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43

44 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-3a POT Q UAShallow.mxd 0 1,600 SCALE IN FEET SOURCE: HILMAR CHEESE COMPANY QUARTERLY MONITORING REPORT PROJECT NO. HILMAR CHEESE COMPANY HILMAR, CALIFORNIA 01.HCC /1/12 DATE DRAWN BY APPR. BY RAL TJ FIGURE 3-3a UPPER AQUIFER SHALLOW ZONE POTENTIOMETRIC SURFACE MAP (JULY 23, 2012)

45 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-3b POT Q UASupply.mxd LEGEND " m EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL UPPER AQUIFER SUPPLY ZONE MONITORING WELL POTENTIOMETRIC SURFACE ELEVATION (FT. MSL) POTENTIOMETRIC SURFACE CONTOUR (DASHED WHERE APPROXIMATE) COLUMBUS AVENUE OSLO ROAD 0 MW " m GROUNDWATER FLOW DIRECTION FT/FT APPROXIMATE HORIZONTAL GROUNDWATER GRADIENT MW " m 84 OSLO STREET MW " m MW FT/FT FT/FT m " 82 " m MW LANDER AVENUE AUGUST AVENUE " m MW ,200 AMERICAN AVENUE SCALE IN FEET PROJECT NO. HILMAR CHEESE COMPANY HILMAR, CALIFORNIA 01.HCC /1/12 DATE DRAWN BY APPR. BY RAL TJ FIGURE 3-3b UPPER AQUIFER SUPPLY ZONE POTENTIOMETRIC SURFACE MAP (JULY 23, 2012)

46 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-4a TDS in Upper Aq Shallow Zone.mxd LEGEND!( 12' 6.3 MONITORING WELL (DATA COLLECTED IN JULY 2010) GRAB GROUNDWATER SAMPLE LOCATION (DATA COLLECTED IN ) 25 TOTAL DISSOLVED SOLIDS (mg/l) TOTAL DISSOLVED SOLIDS (mg/l) GRAB GROUNDWATER SAMPLE DEPTH (FT-BGS) ESTIMATED AREA IN GROUNDWATER EXCEEDING THE COC SPECIFIC RAO OF 912 mg/l (AMBIENT SCREENING THRESHOLD) EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL WELL COLOR DEFINITIONS "!()!(!(!(!(!( NOTES: RAO MCL mg/l COC MONITORING WELL RAO EXCEEDED FT-BGS NON DETECT NO BENEFICIAL USE EXCEEDANCE PRIMARY MCL EXCEEDED (N/A) SECONDARY MCL EXCEEDED (500 mg/l) AGRICULTURAL LEVEL EXCEEDED (450 mg/l) REMEDIAL ACTION OBJECTIVE MAXIMUM CONTAMINANT LEVEL MILLIGRAMS PER LITER CONSTITUENT OF CONCERN FEET BELOW GROUND SURFACE 12' 2000 HP-07 8' 1500 CPT5 HP-06 10' 630 CPT2 12' 1500 COLUMBUS AVENUE MW ' 1100 MW CPT1 CPT6 14' 1900 HP-05 10' 440 ") MW HP-04 MW MW LATERAL No. 6 ") AUGUST AVENUE 10' 2100 OSLO ROAD OSLO STREET RETENTION POND MW-06 ") ") 2300 MW ' 2600 ") ") CPT8 MW ' 2000 CPT9 MW ' 2400 MW MW REVERSE OSMOSIS PONDS STORM WATER HP-03 HP-01 ") CPT10 12' ' ' ' 460 MW MW AB-01 MW MW ") LANDER AVENUE AB-02 AB-04 AB-06 AB-05 AB-03 AB-05a 14' ' 510 AB-09 AB-07 10' ' ' 580 CPT11 10' ' 370 MW ' ' ' ' ' ' 600 AB-08 JOHNSON AVENUE 12' ' ' ' ' ' ,200 MW CPT3 12' 790 ") MW MW AB-10 10' ' 660 SCALE IN FEET DATE HILMAR CHEESE COMPANY HILMAR, CALIFORNIA DRAWN BY APPR. BY 12/13/2010 DPG TJ FIGURE 3-4a TOTAL DISSOLVED SOLIDS IN 2010 GROUNDWATER MONITORING WELL SAMPLES (UPPER AQUIFER SHALLOW ZONE)

47 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-4b TDS in Upper Aq Supply Zone.mxd LEGEND!( 12' 6.3 MONITORING WELL (DATA COLLECTED IN JULY 2010) GRAB GROUNDWATER SAMPLE LOCATION (DATA COLLECTED IN ) 25 TOTAL DISSOLVED SOLIDS (mg/l) 0 1,200 SCALE IN FEET TOTAL DISSOLVED SOLIDS (mg/l) GRAB GROUNDWATER SAMPLE DEPTH (FT-BGS) ESTIMATED AREA IN GROUNDWATER EXCEEDING THE COC SPECIFIC RAO OF 713 mg/l (AMBIENT SCREENING THRESHOLD) EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL WELL COLOR DEFINITIONS "!()!(!(!(!(!( NOTES: RAO MCL mg/l COC MONITORING WELL RAO EXCEEDED FT-BGS NON DETECT NO BENEFICIAL USE EXCEEDANCE PRIMARY MCL EXCEEDED (N/A) SECONDARY MCL EXCEEDED (500 mg/l) AGRICULTURAL LEVEL EXCEEDED (450 mg/l) REMEDIAL ACTION OBJECTIVE MAXIMUM CONTAMINANT LEVEL MILLIGRAMS PER LITER CONSTITUENT OF CONCERN FEET BELOW GROUND SURFACE? EXTENT UNCERTAIN HP-07 56' ' 530 CPT2 34' ' ' 860 HP-06 54' ' 690 SB-09 92' ' 260 HP-05 54' ' ' 260 MW COLUMBUS AVENUE CPT6 34' ' 2300 CPT1 34' ' 1700 MW SB ' ' 280 JOHNSON AVENUE 35' ' ' 1600 CPT5 31' ' 1400 CPT3 LATERAL No. 6?? SB-03 35' ' ' 660 SB-07 CPT9 90' ' 270 OSLO STREET HP ' ' 240 HP-04 78' ' 660 SB-06 37' ' ' 1800 CPT8 OSLO ROAD 94' ' 560 MW ' ' ' 360 HP-01 MW REVERSE OSMOSIS PONDS 88' ' 410 MW STORM WATER RETENTION POND MW CPT10 38' ' 1600 HP-03 60' ' 370 SB-05 ") LANDER AVENUE 48' ' 450 CPT11 AUGUST AVENUE DATE HILMAR CHEESE COMPANY HILMAR, CALIFORNIA DRAWN BY APPR. BY 12/13/2010 DPG TJ FIGURE 3-4b TOTAL DISSOLVED SOLIDS IN 2010 GROUNDWATER MONITORING WELL SAMPLES (UPPER AQUIFER SUPPLY ZONE)

48 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-5a Chloride in Upper Aq Shallow Zone.mxd LEGEND!( 12' 6.3 MONITORING WELL (DATA COLLECTED IN JULY 2010) GRAB GROUNDWATER SAMPLE LOCATION (DATA COLLECTED IN ) 25 CHLORIDE (mg/l) 0 1,200 SCALE IN FEET CHLORIDE (mg/l) GRAB GROUNDWATER SAMPLE DEPTH (FT-BGS) ESTIMATED AREA IN GROUNDWATER EXCEEDING THE COC SPECIFIC RAO OF 239 mg/l (AMBIENT SCREENING THRESHOLD) EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL WELL COLOR DEFINITIONS "!()!(!(!(!(!( NOTES: RAO MCL mg/l COC MONITORING WELL RAO EXCEEDED FT-BGS NON DETECT NO BENEFICIAL USE EXCEEDANCE PRIMARY MCL EXCEEDED (N/A) SECONDARY MCL EXCEEDED (250 mg/l) AGRICULTURAL LEVEL EXCEEDED (106 mg/l) REMEDIAL ACTION OBJECTIVE MAXIMUM CONTAMINANT LEVEL MILLIGRAMS PER LITER CONSTITUENT OF CONCERN FEET BELOW GROUND SURFACE 12' 380 8' 260 CPT5 HP-07 10' 95 HP-06 12' 260 CPT2 COLUMBUS AVENUE MW MW ' 210 CPT1 14' 360 CPT6 10' 44 HP-05 MW ") MW ' 90 CPT3 HP-04 MW LATERAL No. 6 MW ") OSLO STREET ") CPT9 MW AUGUST AVENUE 10' 330 MW-01 ") ") 98 ") 12' 58 CPT10 MW JOHNSON AVENUE MW ' ' 300 MW CPT8 OSLO ROAD MW ") AB-02 12' 340 HP-01 REVERSE OSMOSIS PONDS ") 10' 130 HP-03 AB-01 STORM WATER RETENTION POND MW MW MW ' 48 25' 35 10' 48 25' 35 MW MW ") LANDER AVENUE MW AB-04 AB-03 12' 85 AB-06 25' 100 AB-05 12' 80 25' 100 AB-05a 10' 24 AB-07 25' ' 13 AB-10 25' 47 12' 13 25' 17 CPT11 MW-21 12' ' 18 14' 10 12' 94 25' ' 84 25' AB ' 8 25' AB DATE HILMAR CHEESE COMPANY HILMAR, CALIFORNIA DRAWN BY APPR. BY 12/13/2010 DPG TJ FIGURE 3-5a CHLORIDE IN 2010 GROUNDWATER MONITORING WELL SAMPLES (UPPER AQUIFER SHALLOW ZONE)

49 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-5b Chloride in Upper Aq Supply Zone.mxd LEGEND!( 12' 6.3 MONITORING WELL (DATA COLLECTED IN JULY 2010) GRAB GROUNDWATER SAMPLE LOCATION (DATA COLLECTED IN ) 25 CHLORIDE (mg/l) CHRLORIDE (mg/l) GRAB GROUNDWATER SAMPLE DEPTH (FT-BGS) ESTIMATED AREA IN GROUNDWATER EXCEEDING THE COC SPECIFIC RAO OF 106 mg/l (AGRICULTURAL) COLUMBUS AVENUE CPT8 78' ' 96 37' ' ' 470 HP-01 88' ' 38 SB-05 MW JOHNSON AVENUE EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL WELL COLOR DEFINITIONS "!()!(!(!(!(!( NOTES: RAO MCL mg/l COC FT-BGS MONITORING WELL RAO EXCEEDED NON DETECT NO BENEFICIAL USE EXCEEDANCE PRIMARY MCL EXCEEDED (N/A) SECONDARY MCL EXCEEDED (250 mg/l) AGRICULTURAL LEVEL EXCEEDED (106 mg/l) REMEDIAL ACTION OBJECTIVE MAXIMUM CONTAMINANT LEVEL MILLIGRAMS PER LITER CONSTITUENT OF CONCERN FEET BELOW GROUND SURFACE? EXTENT UNCERTAIN 0 1,200 SCALE IN FEET HP-07 56' 27 96' 42 HP-06 54' 24 88' 12 35' ' ' 290 HP-05 CPT5 92' ' 44 54' 51 98' ' 35 MW SB-09 34' ' 260 LATERAL No. 6 MW CPT1 CPT2 34' 67 55' 28 84' 120 SB ' ' 37 CPT3 31' ' 340 SB-03? 34' ' 250 CPT6 128' 83 SB-07 90' ' 35 OSLO STREET? 35' ' 210 CPT9 HP-04 OSLO ROAD 107' ' 39 94' ' 81 SB-06 60' ' ' 31 HP-02 MW MW-25 32? REVERSE OSMOSIS PONDS STORM WATER RETENTION POND HP-03 MW CPT10 38' ' ' ' 61 LANDER AVENUE 48' 19 60' 16 CPT11 AUGUST AVENUE DATE HILMAR CHEESE COMPANY HILMAR, CALIFORNIA DRAWN BY APPR. BY 12/13/2010 DPG TJ FIGURE 3-5b CHLORIDE IN 2010 GROUNDWATER MONITORING WELL SAMPLES (UPPER AQUIFER SUPPLY ZONE)

50 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-6a Sodium in Upper Aq Shallow Zone.mxd LEGEND!( 12' 6.3 MONITORING WELL (DATA COLLECTED IN JULY 2010) GRAB GROUNDWATER SAMPLE LOCATION (DATA COLLECTED IN ) 25 SODIUM (mg/l) SODIUM (mg/l) GRAB GROUNDWATER SAMPLE DEPTH (FT-BGS) ESTIMATED AREA IN GROUNDWATER EXCEEDING THE COC SPECIFIC RAO OF 346 mg/l (AMBIENT SCREENING THRESHOLD) EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL WELL COLOR DEFINITIONS "!()!(!(!(!(!( NOTES: RAO MCL mg/l COC MONITORING WELL RAO EXCEEDED FT-BGS NON DETECT NO BENEFICIAL USE EXCEEDANCE PRIMARY MCL EXCEEDED (N/A) SECONDARY MCL EXCEEDED (N/A mg/l) AGRICULTURAL LEVEL EXCEEDED (69 mg/l) REMEDIAL ACTION OBJECTIVE MAXIMUM CONTAMINANT LEVEL MILLIGRAMS PER LITER CONSTITUENT OF CONCERN FEET BELOW GROUND SURFACE 0 1,200 12' 530 HP-07 CPT5 8' 82 HP-06 10' 130 CPT2 12' 39 HP-05 10' 58 COLUMBUS AVENUE MW MW ' 36 CPT1 CPT6 14' 480 MW JOHNSON AVENUE ") CPT3 12' 180 MW MW HP-04 10' 220 MW LATERAL No. 6 ") OSLO STREET 12' 640 MW CPT8 AUGUST AVENUE CPT9 MW ") 14' 480 ") ") CPT10 HP-01 REVERSE OSMOSIS PONDS STORM WATER RETENTION POND MW MW MW ' 39 12' 620 OSLO ROAD MW MW HP-03 10' ' ' 64 MW MW AB-01 MW MW ") MW LANDER AVENUE AB-04 AB-02 AB-03 AB-05 AB-05a AB-09 AB-07 AB-10 10' ' 19 10' 38 25' 45 MW ' 19 25' 30 10' 15 25' 76 AB-08 12' 13 25' 16 CPT11 12' ' ' 37 25' 150 AB-06 12' ' 74 12' 88 25' 48 14' 25 14' 11 25' 33 SCALE IN FEET DATE HILMAR CHEESE COMPANY HILMAR, CALIFORNIA DRAWN BY APPR. BY 12/13/2010 DPG TJ FIGURE 3-6a SODIUM IN 2010 GROUNDWATER MONITORING WELL SAMPLES (UPPER AQUIFER SHALLOW ZONE)

51 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-6b Sodium in Upper Aq Supply Zone.mxd LEGEND!( 12' 6.3 MONITORING WELL (DATA COLLECTED IN JULY 2010) GRAB GROUNDWATER SAMPLE LOCATION (DATA COLLECTED IN ) 25 SODIUM (mg/l) 0 1,200 SCALE IN FEET SODIUM (mg/l) GRAB GROUNDWATER SAMPLE DEPTH (FT-BGS) ESTIMATED AREA IN GROUNDWATER EXCEEDING THE COC SPECIFIC RAO OF 133 mg/l (AMBIENT SCREENING THRESHOLD) EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL WELL COLOR DEFINITIONS "!()!(!(!(!(!( NOTES: RAO MCL mg/l COC MONITORING WELL RAO EXCEEDED FT-BGS NON DETECT NO BENEFICIAL USE EXCEEDANCE PRIMARY MCL EXCEEDED (N/A) SECONDARY MCL EXCEEDED (N/A mg/l) AGRICULTURAL LEVEL EXCEEDED (69 mg/l) REMEDIAL ACTION OBJECTIVE MAXIMUM CONTAMINANT LEVEL MILLIGRAMS PER LITER CONSTITUENT OF CONCERN FEET BELOW GROUND SURFACE? EXTENT UNCERTAIN CPT2 34' 33 55' 27 84' 87 HP-07 56' 42 96' 69 HP-06 54' 33 88' 54 HP-05 CPT5 MW ' ' 43 54' 69 98' ' 61 DATE 35' ' ' 230 SB-09 COLUMBUS AVENUE CPT6 34' ' ' ' 330 MW SB-08 CPT ' ' 63 JOHNSON AVENUE? CPT3 LATERAL No. 6 SB-03? 128' ' ' 350 HILMAR CHEESE COMPANY HILMAR, CALIFORNIA DRAWN BY 35' ' 110 APPR. BY CPT9 SB-07 90' ' 60 12/13/2010 DPG TJ 37' ' ' 350 CPT8 OSLO STREET OSLO ROAD HP-04 HP-02 SB ' ' 53 60' ' ' 97 94' ' 98 MW ' ' 70 MW HP-01 REVERSE OSMOSIS PONDS SB-05 MW STORM WATER RETENTION POND CPT10 88' ' 72 MW ' ' 230 HP-03 60' ' 73 LANDER AVENUE 48' 36 60' 44 CPT11 AUGUST AVENUE FIGURE 3-6b SODIUM IN 2010 GROUNDWATER MONITORING WELL SAMPLES (UPPER AQUIFER SUPPLY ZONE)

52 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-7a TDS Q UAShallow.mxd LEGEND EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL UPPER AQUIFER SHALLOW ZONE MONITORING WELL 1200 TOTAL DISSOLVED SOLIDS (mg/l) TOTAL DISSOLVED SOLIDS CONCENTRATION CONTOUR (mg/l) COLUMBUS AVENUE OSLO ROAD MW REMEDIAL ACTION OBJECTIVE FOR TOTAL DISSOLVED SOLIDS IN THE SHALLOW ZONE IS 912 mg/l MW MW MW OSLO STREET 1000 MW MW MW MW MW MW MW MW MW MW MW LANDER AVENUE AUGUST AVENUE MW ,200 AMERICAN AVENUE SCALE IN FEET PROJECT NO. HILMAR CHEESE COMPANY HILMAR, CALIFORNIA 01.HCC /1/12 DATE DRAWN BY APPR. BY RAL TJ FIGURE 3-7a 2012 TOTAL DISSOLVED SOLIDS IN GROUNDWATER SAMPLES (UPPER AQUIFER SHALLOW ZONE)

53 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-7b TDS Q UASupply.mxd LEGEND " m EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL UPPER AQUIFER SUPPLY ZONE MONITORING WELL 407 TOTAL DISSOLVED SOLIDS (mg/l) COLUMBUS AVENUE MW " m 1000 TOTAL DISSOLVED SOLIDS CONCENTRATION CONTOUR (mg/l) REMEDIAL ACTION OBJECTIVE FOR TOTAL DISSOLVED SOLIDS IN THE SUPPLY ZONE IS 713 mg/l OSLO ROAD OSLO STREET " m MW MW m " " m MW " m MW LANDER AVENUE AUGUST AVENUE " m MW ,200 AMERICAN AVENUE SCALE IN FEET PROJECT NO. HILMAR CHEESE COMPANY HILMAR, CALIFORNIA 01.HCC /1/12 DATE DRAWN BY APPR. BY RAL TJ FIGURE 3-7b 2012 TOTAL DISSOLVED SOILDS IN GROUNDWATER SAMPLES (UPPER AQUIFER SUPPLY ZONE)

54 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-8a Chloride Q UAShallow.mxd LEGEND EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL UPPER AQUIFER SHALLOW ZONE MONITORING WELL 90 CHLORIDE (mg/l) CHLORIDE CONCENTRATION CONTOUR (mg/l) REMEDIAL ACTION OBJECTIVE FOR CHLORIDE IN THE SHALLOW ZONE IS 239 mg/l COLUMBUS AVENUE MW MW OSLO ROAD MW MW MW OSLO STREET MW MW MW MW MW MW MW MW MW MW LANDER AVENUE AUGUST AVENUE MW ,200 AMERICAN AVENUE SCALE IN FEET PROJECT NO. HILMAR CHEESE COMPANY HILMAR, CALIFORNIA 01.HCC /1/12 DATE DRAWN BY APPR. BY RAL TJ FIGURE 3-8a 2012 CHLORIDE IN GROUNDWATER SAMPLES (UPPER AQUIFER SHALLOW ZONE)

55 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-8b Chloride Q UASupply.mxd LEGEND " m EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL UPPER AQUIFER SUPPLY ZONE MONITORING WELL 90 CHLORIDE (mg/l) COLUMBUS AVENUE MW " m CHLORIDE CONCENTRATION CONTOUR (mg/l) REMEDIAL ACTION OBJECTIVE FOR CHLORIDE IN THE SUPPLY ZONE IS 106 mg/l OSLO ROAD OSLO STREET MW " m MW m " " m MW " m MW LANDER AVENUE AUGUST AVENUE " m MW ,200 AMERICAN AVENUE SCALE IN FEET PROJECT NO. HILMAR CHEESE COMPANY HILMAR, CALIFORNIA 01.HCC /1/12 DATE DRAWN BY APPR. BY RAL TJ FIGURE 3-8b 2012 CHLORIDE IN GROUNDWATER SAMPLES (UPPER AQUIFER SUPPLY ZONE)

56 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-9a Sodium Q UAShallow.mxd LEGEND EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL UPPER AQUIFER SHALLOW ZONE MONITORING WELL 120 SODIUM (mg/l) SODIUM CONCENTRATION CONTOUR (mg/l) REMEDIAL ACTION OBJECTIVE FOR SODIUM IN THE SHALLOW ZONE IS 346 mg/l COLUMBUS AVENUE MW MW OSLO ROAD MW MW MW MW MW OSLO STREET MW MW MW MW MW MW MW MW LANDER AVENUE AUGUST AVENUE MW ,200 AMERICAN AVENUE SCALE IN FEET PROJECT NO. HILMAR CHEESE COMPANY HILMAR, CALIFORNIA 01.HCC /1/12 DATE DRAWN BY APPR. BY RAL TJ FIGURE 3-9a 2012 SODIUM IN GROUNDWATER SAMPLES (UPPER AQUIFER SHALLOW ZONE)

57 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-9b Sodium Q UASupply.mxd LEGEND " m EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL UPPER AQUIFER SUPPLY ZONE MONITORING WELL 68.3 SODIUM (mg/l) COLUMBUS AVENUE MW " m SODIUM CONCENTRATION CONTOUR (mg/l) REMEDIAL ACTION OBJECTIVE FOR SODIUM IN THE SUPPLY ZONE IS 133 mg/l OSLO ROAD OSLO STREET " m MW MW m " " m MW " m MW LANDER AVENUE AUGUST AVENUE " m MW ,200 AMERICAN AVENUE SCALE IN FEET PROJECT NO. HILMAR CHEESE COMPANY HILMAR, CALIFORNIA 01.HCC /1/12 DATE DRAWN BY APPR. BY RAL TJ FIGURE 3-9b 2012 SODIUM IN GROUNDWATER SAMPLES (UPPER AQUIFER SUPPLY ZONE)

58 Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 3-10 TDS Avg UAShallow.mxd LEGEND EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS TURLOCK IRRIGATION DISTRICT LATERAL CANAL UPPER AQUIFER SHALLOW ZONE MONITORING WELL REMEDIAL ACTION OBJECTIVE FOR TOTAL DISSOLVED SOLIDS IN THE SHALLOW ZONE IS 912 mg/l TOTAL DISSOLVED SOLIDS CONCENTRATION CONTOURS (1000 mg/l) 2006 COLUMBUS AVENUE MW-16 MW-15 OSLO ROAD MW-13 MW OSLO STREET MW (THROUGH JULY) NOTE: BASED ON AVERAGE TDS CONCENTRATION AT EACH WELL FOR THE RESPECTIVE YEAR *MW-14 NOT SAMPLED SUBSEQUENT TO 2011; REPRESENTS OFF-SITE SOURCE UNRELATED TO HCC MW-12 MW-17 MW-09 MW-08 MW-14 * MW-05 MW-06 MW-04 MW-01 MW-02 MW-11 MW-03 LANDER AVENUE AUGUST AVENUE 0 1,200 AMERICAN AVENUE SCALE IN FEET PROJECT NO. HILMAR CHEESE COMPANY HILMAR, CALIFORNIA 01.HCC /1/12 DATE DRAWN BY APPR. BY RAL TJ FIGURE 3-10 UPPER AQUIFER SHALLOW ZONE AVERAGE TOTAL DISSOLVED SOLIDS ( )

59 S-23 S-24 MW-24 " m LEGEND " m UPPER AQUIFER SHALLOW ZONE MONITORING WELL UPPER AQUIFER SUPPLY ZONE MONITORING WELL S-13 HCC FACILITY S-29 MW-13 & < CURRENT REUSE LAND AREA (FORMER PRIMARY LAND) EXTENT OF HCC FACILITY AND HISTORICAL PRIMARY LANDS MW-16 & < MW-10 & < & < MW-15 OSLO ROAD MW-21 & < S-2 CURRENT REUSE AREA (NOT FORMER PRIMARY LAND) TURLOCK IRRIGATION DISTRICT LATERAL CANAL AMBIENT MONITORING WELLS ATTENUATION CONFIRMATION AND DOWN/CROSS GRADIENT MONITORING WELLS S-08 COLUMBUS AVENUE S-65 REVERSE OSMOSIS PONDS ") GROUNDWATER ELEVATION MONITORING ONLY NOTE: WELLS NOT OTHERWISE IDENTIFIED ARE NOT PART OF THE PROPOSED PERFORMACE MONITORING NETWORK. (MW-10, MW-14, MW-16 & MW-20) S-25 MW-09& < S-63 OSLO STREET MW-06 & < MW-22 " m & < MW-01 MW-07 & < MW-11 " m & < MW-18 S-07 MW-12 & < " m MW-19 S-64 MW-05& < MW-02 & < MW-03 & < AUGUST AVENUE MW-08 & < MW-04 & < Path: J:\GIS\Hilmar\Reports\UprAqRAP\Figure 5-1 Well Newtwork.mxd S-06 S-26 S-40 MW-17 & < " m MW-29 S-41 MW-14 & < " m MW-25 LOCATION MW-20& < HILMAR CHEESE COMPANY HILMAR, CALIFORNIA DATE DRAWN BY APPR. BY 11/1/12 DPG JJ FIGURE SCALE IN FEET UPPER AQUIFER PERFORMANCE MONITORING NETWORK