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July 6, 2017 Monitoring Well Installation Workplan the Lathrop area (i.e., unconsolidated sediment), a hollow-stem auger has successfully been used to drill monitoring well boreholes. 2.2. Borehole Logging and Soil Sampling California Department of Water Resources and San Joaquin County require completion and submittal of Water Well Drillers Reports. In the Lathrop area, the near surface deposits are composed of discontinuous inter-bedded silty sand, sandy silt, silty clay, clay, and sand. Continuous-core samples will be collected using a split-spoon sampler driven ahead of the drilling tool. Core samples will be removed from the split-spoon sampler and examined to describe their texture, moisture content, grain size, and color using the Unified Soil Classification System. The core samples will be bagged and kept chilled for pore-water extraction. Pore water from select core samples shall be extracted using a vacuum pump and filter, and the electrical conductivity of the pore water measured. In addition to core sample descriptions, the borehole log will also report any changes in the drilling rate, caving of the borehole, or changes in water temperature or water levels. All observations will be recorded and reported on a well boring and construction form (an example boring and construction form is provided in Appendix B). 3. Monitoring Well Design As stated in the WDRs, replacement wells should ensure representative monitoring of the specified Use Area. Groundwater monitoring wells are to be designed and sited to ensure that water quality at storage pond sites and land application areas is adequately characterized and any potential water quality impacts from the discharge are detected. The wells shall yield samples representative of the uppermost portion of the first encountered groundwater underlying the proposed monitoring site. General monitoring well design is illustrated in Figure 3a (below ground completion) and Figure 3b (above ground completion). This design is consistent with SJCEHD and State of California Monitoring Well Standards. A description of the monitoring well design includes: (1) the well casing, perforated over the targeted depth interval for monitoring; (2) the annular spacing between the perforated well screen and borehole, filled with a filter pack; (3) a transition seal placed on top of the filter pack; and, (4) a sanitary seal which extends upwards from the top of the transition seal to land surface. Additional details on monitoring well casing, filter pack, seals, and completions are described below. 3.1. Well Casing The well casing will be ASTM, API and/or AWWA approved. The casing diameter will be 4 inches to provide adequate clearance for water-level measuring instrumentation, either electronic sounders or pressure transducers, and submersible pumps to collect water HydroFocus, Inc. 5