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1 <br /> MM <br /> Working to Restore Nature <br /> 1 <br /> Monitoring Well Construction <br /> The monitonng well was constructed 1n the bonng with thread-,jointed, 2-inch-inner- <br /> diameter, Schedule 40 PVC casing No chemical cements, glues, or solvents were used in <br /> well construction The screened portion of the well consisted of factory-perforated casing <br /> with 0020-inch-wide slots The well screen extends from the total depth of the well to <br /> approximately 5 to 10 feet above the groundwater surface. This screened interval allows <br /> sampling at the air-water interface during seasonal fluctuations of the groundwater level <br /> The annular space in the well was packed with number 3 sand to approximately 1 to 2 feet <br /> above the slotted interval A 3-foot thick bentonite plug was added above the sand pack to <br /> prevent the cement from entering the well pack The remaining annulus was backfilled to <br /> grade with a bentonite cement slurry <br /> The well was protected with a traffic-rated, cast-aluminum utility box equipped with a PVC <br /> skirt The box has a watertight seal to protect against surface-water infiltration and must <br /> be opened with a special wrench. The design of this box discourages vandalism and reduces <br /> the possibility of accidental disturbance of the well <br /> Well Development <br /> . We waited a minimum of 24 hours after well installation before developing the groundwater <br /> monitoring well to allow the grout to seal Before developing the monitoring well, a water <br /> sample was collected for subjective analysis from near the water surface in the well with a <br /> Teflon bailer cleaned with a laboratory-grade detergent and deionized water Floating <br /> product was not encountered The well was developed with a surge block and pump Well <br /> development continued until the discharge water was clear of silt and sand Clay-size <br /> sediments derived from the screened portion of the formation cannot be entirely eliminated <br /> by well development <br /> After the wells stabilized for a minimum of 24 hours, the well was purged of stagnant water <br /> and a sample was collected for laboratory analysis. The well was purged of approximately <br /> 3 to 5 well volumes of water with a submersible pump, or until pH, conductivity, and <br /> temperature of the purged water have stabilized Water purged from the well was stored <br /> in labeled, 55-gallon, steel drums approved for this use by the Department of Transportation <br /> until suitable disposal options were selected based on laboratory analysis <br /> 1130ccar/31009-9 <br />