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City of Pleasanton December 21, 1988 <br />,~ Quote No. 7097G Page 3-2 <br /> <br />_] <br />~ laboratory. A log of the subsurface conditions er~countered during the drilling <br />' process will be prepared by an EES geologist in the field during the drilling <br /> process. All drill cuttings will be placed on visqueen and left at the site. It <br /> shall be the responsibility of the client to properly dispose of any <br /> contaminated soil. EES can assist the client in arranging for transportation and <br /> disposal of any contaminated soil on a time and material cost basis. <br /> <br /> Task 3.3 - Monitorinq Well Construction <br /> <br /> ~ndwater monitoring wells will be constructed in the exploration <br /> borings. All monitoring wells will" be built under permit requirements of the <br /> Alameda County Flood Control and Water Conservation District (ACFCWCD). The <br /> wells will be constructed of 2-inch Schedule 40 flush-threaded PVC pipe; no <br /> glues or solvents will be used. The PVC well screen will have three rows of <br /> slots sized at 0.020 inches. After drilling the boring to the desired depth, the <br /> PVC casing will be installed through the hollow stem. The sand pack (No. 2/12 <br /> aquarium sand) will be installed in the borehole annulus to a level <br /> approximately 2 feet above the slotted screen section where bentonite will be <br /> used as a seal. The remaining portion of the annular space will be sealed with <br /> a neat cement and bentonite grout. The top of the well will be set in a traffic- <br /> rated box at grade with an internal locking cover to provide security. A locking <br /> steel vault will be used for wells placed in open fields. <br /> <br /> Task 3.4 - Monitorino Well DeveloDment <br /> <br /> After construction, the wells will be developed to improve the hydraulic <br /> conductivity between the wells and the natural formation. The development <br /> will consist of manually bailing or mechanically pumping to remove residual <br /> silts and clays left from the drilling operations. At least ten well volumes of <br /> groundwater will be removed. After development, the wells will be allowed to <br /> recharge for approximately 72 hours, enabling EES to collect a representative <br /> water sample and to measure the thickness of any floating product, if <br /> encountered. Any contaminated water resulting from the development of the <br /> wells will be placed in drums. It shall be the responsibility of the client to <br /> <br /> <br />