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GROUND WATER MONITORING WELL CONSTRUCTION PROTOCOL <br /> Ground water monitoring wells shall be constructed pursuant to <br /> the general specifications established by the State or local <br /> regulatory agencies. <br /> Ground water monitoring wells shall extend to the base of the <br /> upper aquifer, as defined by the first consistent ( >5 feet <br /> thick) clay layer below the upper aquifer. The wells shall not <br /> extend through the laterally extensive clay layer below the upper <br /> aquifer. The well shall be terminated one to two feet into such <br /> a clay layer. <br /> For single-cased wells, groundwater monitoring well casings shall <br /> extend to approximately 6 inches above the bottom of the boring <br /> or the bentonite plug, if one is used at the bottom of the boring <br /> as a hydraulic seal. The casing shall be factory perforated from <br /> a point one foot above the bottom of the casing to at least five <br /> feet above the top of the upper aquifer, as defined by boring <br /> lithology and/or borehole geophysics. <br /> Groundwater monitoring wells shall be constructed as filter- <br /> packed wells that will prevent the migration of the surrounding <br /> formation into the well. Filter pack shall extend at least two <br /> feet above the top of the perforated interval. A layer of <br /> bentonite pellets one to two feet thick shall be placed on top of <br /> the filter pack. Approximately two gallons of water shall be <br /> added to the pellets and allowed to hydrate the bentonite for at <br /> least 30 minutes. The wells shall then be sealed from the top of <br /> the bentonite seal to the surface with cement/bentonite slurry or <br /> neat cement. All sand, bentonite and cement shall be placed in <br /> the well using a tremie pipe. <br /> Well heads shall be installed in a water-tight structure and <br /> provided with a water-tight cap. Well heads shall be enclosed in <br /> a locked well covering device that protects the well from the <br /> entry of surface water, accidental damage, unauthorized access, <br /> and vandalism. <br /> Soil and water sampling equipment and materials used to construct <br /> the wells shall not donate, capture, mask, nor alter the chemical <br /> composition of the soil and ground water. <br /> All well casings, casing fittings, screens, and all other <br /> components that are installed in the well shall be thoroughly <br /> cleaned immediately before starting each well installation. <br /> Applied GeOSystefm <br />