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GESS <br /> GENESIS ENGINEERING&REDEVELOPMENT <br /> 4.0 EXTRACTION WELL AND AQUIFER TEST <br /> 4.1 Aquifer Test Well Construction <br /> Construction of the Aquifer Test well will be similar to that of the other new shallow monitoring <br /> wells. The 6-inch diameter well casing will be set inside the hollow stem auger. Sand pack <br /> material will be placed through the auger using a tremie pipe, as the auger is removed. The sand <br /> pack will extend at least 2 feet above the top of the well screen interval. The well will be surged <br /> to settle the sand pack. Additional sand will be placed as necessary until at least two feet of sand <br /> are above the top of the well screen. A minimum of two feet of bentonite chips will be placed <br /> above the sand pack,through the tremie pipe. After the bentonite has been allowed to hydrate, a <br /> grout seal will be placed. The grout will extend to approximately two feet below grade. The <br /> upper two feet of the annulus will be sealed with concrete. The top of the well will be protected <br /> with a flush mounted traffic rated vault, set in the concrete. Well construction procedures will be <br /> consistent with SJCDEH guidelines. <br /> 4.2 Observation Wells <br /> During the aquifer test,the three shallow monitoring wells closest to the test well (MW-104, <br /> MW-103,and CRW-4)and the proposed deep monitoring well near the liquid containment <br /> areas/surface water sump will be utilized as observation wells. This will allow the potential <br /> communication between the shallow and deep water bearing intervals to be assessed, as well as <br /> determine the aquifer properties of the shallow aquifer. The proposed location of the aquifer test <br /> well and observation wells are shown on Figure 2. <br /> 4.3 Disposal of Discharge Water <br /> Prior to commencement of the aquifer test,arrangements will be made for disposal of water <br /> generated during the test. At the present time, it is anticipated this water can be discharged <br /> through the City of Ripon Non-Potable water distribution system. GE&R will commence <br /> discussions with City of Ripon personnel regarding disposal options for the aquifer test <br /> generated water,once final approval of the Work Plan has been received, and authorization to <br /> proceed is received from Defense Counsel. It is anticipated the purge water will be temporarily <br /> stored at the site in Baker Tanks, or similar tanks, pending disposal. Samples of purge water will <br /> be collected to characterize the nitrate concentration in the water for the purpose of disposal. <br /> If the purge water is disposed of through the City's Non-Potable water distribution system,the <br /> location where water can be added to the system will be determined, and a schedule for disposal <br /> of the water will be negotiated. <br /> Ripon Farm Services 3 of 5 <br /> Site Characterization Work Plan—Phase[I <br /> November 2009 <br />