ARCHIVED REPORTS XR0001801 - Laserfiche WebLink

Home Browse Search

1 ' �uAM t�"/VA Monitoring Well Construction Working to Restore Nature 1 The monitoring well was constructed 1n the boring with thread-jointed, 2-inch-inner- diameter, Schedule 40 PVC casing No chemical cements, glues, or solvents were used in well construction The screened portion of the well consisted of factory-perforated casing with 0 020-inch-wide slots The well screen extends from the total depth of the well to approximately 5 to 10 feet above the groundwater surface This screened interval allows sampling at the air-water interface during seasonal fluctuations of the groundwater level The annular space in the well was packed with number 3 sand to approximately 1 to 2 feet above the slotted interval A 3-foot thick bentonite plug was added above the sand pack to prevent the cement from entering the well pack The remaining annulus was backfilled to grade with a bentonite cement slurry I The well was protected with a traffic-rated, cast-aluminum utility box equipped with a PVC skirt. The box has a watertight seal to protect against surface-water infiltration and must be opened with a special wrench The design of this box discourages vandalism and reduces the possibility of accidental disturbance of the well Well Development We waited a minimum of 24 hours after well installation before developing the groundwater monitoring well to allow the grout to seal Before developing the monitoring well, a water ` . sample was collected for subjective analysis from near the water surface in the well with a Teflon bailer cleaned with a laboratory-grade detergent and deionized water Floating product was not encountered The well was developed with a surge block and pump Well development continued until the discharge water was clear of silt and sand Clay-size sediments derived from the screened portion of the formation cannot be entirely eliminated by well development After the wells stabilized for a minimum of 24 hours, the well was purged of stagnant water and a sample was collected for laboratory analysis The well was purged of approximately 3 to 5 well volumes of water with a submersible pump, or until pH, conductivity, and temperature of the purged water have stabilized Water purged from the well was stored in labeled, 55-gallon,steel drums approved for this use by the Department of Transportation until suitable disposal options were selected based on laboratory analysis 0 0319ccar/38048-11