WORK PLANS - Laserfiche WebLink

Home Browse Search

N.01 2400 Airport Way, Stockton, California April 13, 1994 Chevron U.S.A. Products Company Page 3 cleaned between each sampling interval. Each soil sample will be screened for hydrocarbon vapors using a portable photoionization detector (PID). Soils encountered during drilling will be logged using the Unified Soil Classification System by a Groundwater Technology field geologist, working under the direction and supervision of a California registered geologist. One sample tube from each sampling interval will be sealed with aluminum foil, capped, taped, labeled, and placed on ice in an insulated container pending laboratory analysis. All soil generated through drilling will be stored on and covered with plastic sheeting on Chevron property pending characterization and disposal. All water generated during steam cleaning will be temporarily stored on site in Department of Transportation (DOT)-approved 55-gallon drums pending transportation for recycling at the Chevron refinery in Richmond, California. Based on field observations, selected soil samples from the soil boring will be analyzed by a State-certified laboratory for BTEX using EPA method 8020, and for TPH-G by EPA method modified 8015. TASK 5: GROUNDWATER MONITORING WELL INSTALLATION/DEVELOPMENT The groundwater monitoring well will be constructed of 2-inch-diameter PVC blank casing and 0.020-inch-slot well screen. The well screen will be installed approximately 10 feet above and 10 feet below current water levels. A sand filter pack will be placed within the annulus of the well from the bottom of the boring to approximately 2 feet above the top of the well screen. The annulus of the well will be sealed with approximately 2 feet of bentonite on top of the sand, and a portland cement/bentonite slurry to the surface. The well head will be protected by a locking cap and a traffic-rated, watertight street box. Typical groundwater monitoring well construction is illustrated in Figure 2. The new groundwater monitoring well will be developed by surging and pumping to remove fines from the well and sand pack. Approximately four casing volumes of water will be removed to insure stability of pH, conductivity, and temperature. Top of casing (TOC) and horizontal position of the new well will be surveyed relative to mean sea level using an established bench mark. The survey data will be used together with depth-to-water measurements to determine water table elevation in each monitoring well and the local groundwater flow direction. J-7�JQ��GROUNDWATER TECHNOLOGY