SITE INFORMATION AND CORRESPONDENCE

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GEZ GENESIS ENGINEERING&REDEVELOPMENT 3.0 DEEP MONITORING WELLS To monitor water quality in the deep water bearing zone,two on-site deep monitoring wells will be installed. The anticipated depth interval of these wells is 190-195 feet,consistent with the bottom depth of the former on-site production well and the upper-most screened interval in the City of Ripon Municipal Well MW-12. One of these wells will be installed adjacent to the surface water sump/liquid containment area; replacing a proposed shallow boring as indicated above. The second deep monitoring well will be installed in the proposed deep exploratory boring located on the eastern portion of the Site, near monitoring well CRW-5. This deep well will double as the proposed deep exploratory boring at this location(see Figure 2). The boreholes for the deep monitoring wells will be advanced utilizing sonic drilling technology, — as discussed in the Work Plan. This technology utilizes a 4-inch diameter core barrel and a 6- inch diameter outer casing. Typically,the core barrel is advanced ahead of the outer barrel into undisturbed soil. The outer casing is then advanced, sealing off the formation. This process is repeated until the target depth is reached. The outer casing acts as a temporary conductor casing as the borehole is advanced. Continuous soil core will be collected for lithologic purposes. Soil samples for chemical analyses will be collected at 20 foot depth intervals. When the target depth is achieved,the core barrel is removed from the outer casing,and the monitoring well will be constructed inside of the outer casing, as the casing is removed from the borehole. The monitoring wells will be constructed of 2-inch diameter schedule 80 PVC. The well screen interval will be 10 feet in length. The well screen slot size and sand pack size will be determined, based on the material encountered as the borehole is advanced. Sand pack material will extend at least two feet above the top of the well screen. After the sand has been placed,the well will be surged to settle the sand pack. Additional sand will be added to the annulus,as appropriate, until at least two feet of sand extend above the top of the well screen. A minimum of two feet of bentonite chips will be placed above the sand pack, and allowed to hydrate. A grout seal consistent with SJCDEH guidelines will be placed using a tremie pipe. The grout will extend to approximately two feet below grade. Cement will be placed above the grout seal. The top of the well will be secured with a flush-mounted traffic rated vault, set into the concrete. Upon completion,the deep monitoring wells will be developed using procedures similar to those used to develop the shallow monitoring wells, as described in the Work Plan. These proposed changes will result in a reconnaissance boring program consisting of 9 shallow borings and 5 deep borings(two of these borings being completed as monitoring wells). ' I Ripon Farm Services 2 of 5 Site Characterization Work Plan—Phase II November 2009