Laserfiche WebLink
Clayton <br /> AoP SERv, rs � <br /> monitoring, the site status is to be reevaluated The following sections detail the <br /> procedures to be employed to install and monitor these wells <br /> 3 0 GROUNDWATER MONITORING WELL INSTALLATION <br /> Groundwater at the site was encountered at ranging depths between 10 and 16 feet below <br /> p g g <br /> ground surface during the October 2000 investigation and is assumed to flow to the <br /> southeast with an estimated gradient of 0 003 (Kleinfelder, 2001) Subsequent <br /> discussions with Mr Marty Hartzell of the California Regional Water Quality Control <br /> Board indicated that local groundwater flows to the east-northeast <br /> Prior to drilling, Underground Service Alert (USA) will be notified to mark the surface <br /> traces of utilities in the area Site personnel and engineering drawings will also be <br /> consulted All work will be conducted in accordance with the site-specific health and <br /> safety plan (Appendix A) Well installation permits will be obtained from the PHS/EHD <br /> Three groundwater-monrtonng wells are to be installed at the site The proposed <br /> locations for these wells are presented on Figure 3 MW-1 will be located upgradient of <br /> the UST area and MW-2 and MW-3 will bracket the assumed downgradient flow <br /> direction The pilot borings for the wells will be advanced using 8-inch diameter <br /> continuous flight hollow stem augers The pilot borings will each be advanced to a total <br /> depth of approximately 30 feet The soil cuttings produced during drilling will be <br /> containerized and appropriately managed <br /> The pilot borings will be completed as groundwater monitoring wells using 2-inch <br /> diameter polyvinyl chloride (PVC) well casing, as shown on Figure 4 The lower 20 feet <br /> of the casings will be perforated with machined slots with 0 010-inch openings The <br /> annular space between the casing and the boring wall will be filled with 2/16 filter sand <br /> Each well will have an above ground surface completion <br /> Soil samples will be collected during drilling to determine the elevation of the water <br /> table No soil samples will be submitted for laboratory analysis <br /> 4.0 QUARTERLY MONITORING <br /> Following installation, the wells will be allowed to stand for a minimum of 48 hours <br /> Prior to sampling, the depth to water will be gauged in each of the wells using an <br /> electronic water level meter, recorded, and the volume of water standing in the well will <br /> be calculated The water level meter will be decontaminated before each use as described <br /> below <br /> During sampling activities, each well will be purged using an electric well pump that has <br /> been decontaminated using a three-step process Decontamination will consist of <br /> washing the pump and hosing in a solution of water and a phosphate-free detergent, such <br /> 5 1ProjAP02263\2263 workplan_Oct02 doc <br />