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TABLE OF CONTENTS 1.0 INTRODUCTION 1.111 INTRODUCTION..................................................................................I..........................1 On behalf of Nu[nen Ag Solutions,Inc.(Nutrient),Rubik is submitting this Monitoring Well Network 1.1 Objecdve.......................................................................................................................................1 Replacement Work Plan forthe facility located at 35100 South Highway 33 in Vernalis,California 1.2 Chemicals of Concern...................................................................................................................1 (site, Figure 1). This work plan was requested by the Central Valley Regional Water Quality 2.0 SITE DESCRIPTION.........................................._...........................................................1 Control Board(RWQCB)during their April 8,2020 meeting with Nutrien. 3.0 GEOLOGY AND HYDROGEOLOGY..............................................................................1 1.1 Objective 4.0 ENVIRONMENTAL BACKGROUND..............................................................................1 The objective of this project is to replace the monitoring well network at the she due to detaining S.D PROPOSED MONITORING WELL DESTRUCTION AND INSTALLATION...................2 groundwater levels in the current wells. i� 5.1 Pemliting......................................................................................................................................2 5.2 Health and Safety Plan.................................................................................................................2 1.2 Chemicals of Concern 5.3 Utility Clearance............................................................-..............................................................2 5.4 Monitoring Well Destruction............................................................................................._......._-2 The primary chemicals of concern (COCs) in groundwater are nitrate, 1,2-tlichloropropane 5.5 Monitoring Well Installation...........................................................................................................3 (1,2-DCP),and 1,2,3-trichloropropane(1,2,3-TCP). 5.6 Well Development..............................................................................................................I..........3 5.7 Well Survey........................................................................--.......................................................3 2.0 SITE DESCRIPTION 5.8 Decontamination and Waste Management...................................................................................3 on Figure 5.9 Scheduling and Reporting-.......---.... .----^•^^--- ^^^•^-.----^"""."""""'3 The site Is used for sales of bulk liquid and dry fertilizers and liquid peril and pre-packaged fertilizers and pesticides.Current and former she features are shown Figure 2. 3.0 GEOLOGY AND HYDROGEOLOGY FIGURES The soil beneath the site consists primarily of day from the ground surface to approximately 25 Figure 1 Site Vicinity Map feet below the ground surface (bgs).The clay is underlain by discontinuous layers of sand, silt, Figure 2 Site Map and clay to at least 75 feet bgs,the maximum depth explored. Cross section path locations are Figure 3 Cross Section Location Map shown on Figure 3 and geologic cross sections are included as Figures 4 and S. Figure Geologic Cross Section A-A' Figure 5 Geologic Cross Section B-B' She monitoring wells are installed to between 45 and 50 feet bgs with between 20 and 24 feet of Figure 6 Groundwater Elevation Contours-February 2020 screen. In February 2020, depth to groundwater in the monitoring wells was approximately 45 Figure 7 Groundwater Analytical Results-February 2020 feet bgs. Groundwater elevations have decreased approximately 15 feet since 2013 and wells Figure 8 Proposed Groundwater Monitoring Well Network MW-4, MW-5, and MW-7 have been dry since 2018. The water column height in the wells that Figure 9 Proposed Well Construction Details contained water in February 2020 ranged from approximately 1 to 6 feet. Groundwater predominantly flows to the east at an average gradient of 0.0006 feet per foot �^ TABLES Monitoring well locations are shown on Figure 2 and construction details are summarized in Table 1 Monitoring Well Construction Details Table 1.Historical groundwater elevation data are provided in Table 2 and groundwater elevation Table 2 Historical Groundwater Elevation Data contours from the February 2020 event are shown on Figure S. Graphs depicting the depth to groundwater over time in the wells are included as Appendix A. Table Historical Groundwater Analytical Data 4.0 ENVIRONMENTAL BACKGROUND APPENDICES Groundwater beneath the site has been monitored and sampled since 1997. Concentrations of Appendix A Depth to Groundwater and COC Concentration vs Time Graphs the COCs in groundwater beneath the she have historically exceeded their respective MCLs in some of the wells,including wells that have gone dry.The February 2020 groundwater analytical Nutran Nvlden vemal*CiulMmia �� MoniWng Well Nea mid 1 T2¢Gili Monitoring Well Nerw rk Replemme ,Work Plan Moniroring Well Nehwrk Replemment Work Plan