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4.0 GROUNDWATER MONITORING WELL INSTALLATION <br /> 4.1 Installation and Construction <br /> Following the completion of the borehole drilling and sampling activities, four of the five <br /> boreholes were converted to groundwater monitoring wells Murray & Associates <br /> completed the necessary workplans and obtained the appropriate permits to install the <br /> groundwater monitoring wells from the San Joaquin County Environmental Health Division <br /> The four groundwater monitoring wells were completed to a depth of 30 feet below grade <br /> ' or approximately 15 feet below the water table <br /> ' Materials used for the construction of the groundwater monitoring well included 2-inch LD <br /> interior/exterior flush threaded PVC Schedule 40 casing and well screen. Well screen <br /> ' perforations were precision machine slotted with screen slot sizes of 0 02 inches Fifteen <br /> feet of well screen was installed into each boring, followed by 15-feet of blank casing A <br /> sand pack consisting of #3 Lonestar sand was placed in the well annulus until it extended <br /> to about 3 feet above the uppermost perforations (a depth of 12 feet) The well was then <br /> ' sealed with a 3 foot bentonite pellet plug and grouted to the surface with a Portland <br /> cement slurry. Each well was completed nearly flush with the surface and enclosed within <br /> a subsurface locking Christy box Each well was also equipped with a locking water-tight <br /> ' pressure cap to avoid the possibility of vandalism Well completion details areP resented <br /> in Appendix 2 <br /> 1 <br /> 4 2 Well Development <br /> The new wells were developed prior to their completion by swabbing the inside of the well <br />' casing with a surge block bailer in a plunger-like fashion and then removing the <br /> water/silt/sand slurry mixture until the discharge water began to clear This procedure was <br /> over a 20 to 40 minute cycle Each well was swabbed approximately 30 to 40 times at a <br /> slow speed over the entire length of the well screen followed by bailing of the well until <br /> the discharge water began to clear All discharge water was emptied into DOT approved <br /> 9 <br /> 1 <br />