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1 <br /> Monitoring Well Installation <br /> 1 <br /> Monitoring wells in cemented non-cobble matrix will be completed by installing 2- <br /> to 6-inch-diameter schedule 40 polyvinyl chloride (PVC) casing The 2-inch- <br /> diameter flush-threaded casing is generally used for wells dedicated for <br /> groundwater monitoring purposes Larger diameter casings will be used for <br /> ' monitoring wells which will potentially be used for hydraulic testing and <br /> groundwater extraction The screened sections of casing are factory machine <br /> slotted and will be installed approximately 5 feet above and up to 15 feet below <br /> ' first-encountered water level The screened interval will allow for seasonal <br /> fluctuation in water level and for monitoring floating product A filter pack of graded <br /> sand will be placed in the annular space between the PVC casing and the <br /> borehole wall Sand will be added to the borehole through the hollow stem of the <br /> augers to provide a uniform filter pack around the casing and to stabilize the <br /> borehole The sand pack will be placed to a maximum of 2 feet above the screens <br /> ' followed by a minimum 1-foot seal consisting of bentonite pellets <br /> Cement grout containing 5 percent bentonite or concrete will be placed above the <br /> ' bentonite seal to the ground surface Monitoring well will be protected from traffic <br /> by concrete pipe or a concrete traffic-rated vault box will be installed over the <br /> monitoring well(s) A watertight locking cap will be installed over the top of the well <br /> casing Reference elevations for each monitoring well will be surveyed when more <br /> than two wells will be located on site Monitoring well elevations will be surveyed <br /> by a State of California registered civil engineer or licensed surveyor or a <br /> ' subcontractor to the nearest 0 01 foot relative to mean sea level or a site datum <br /> Exploratory boring logs and well construction details will be prepared for the final <br /> ' written report <br /> Well installation will be tamed out by a properly licensed contractor A permit for <br /> ' the well will be required from Contra Costa County Environmental Health <br /> Department <br /> ' Probe Sampling Well Installation <br /> Wells may be completed by direct push technology In the event inflow rate into <br /> the sampling hole requires casing a 2 inch or less diameter polyvinyl chloride <br /> (PVC) casing will be installed The 314-inch-diameter flush-threaded casing is <br /> ' generally used for direct push wells dedicated for groundwater sampling purposes <br /> Larger diameter casings will be used for monitoring wells which will potentially be <br /> used for hydraulic testing and groundwater extraction The screened sections of <br /> ' B B-3 <br /> 1 <br />