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Kennedy/Jenlcs Consultants <br /> wetted portion of the monitoring well filter pack in addition to the casing/screen. If this is a <br /> requirement, it should be defined in the project-specific sampling requirements. <br /> d. Peristaltic pump: place the pump intake at a depth equal to the approximate middle or just <br /> slightly above the middle of the well screen interval or water column unless another position <br /> is justified based on site-specific conditions. Note: If degassing of water is occurring when <br /> sampling with a peristaltic pump, alternative types of sampling equipment should be used for <br /> volatile organic compound (VOC) or volatile petroleum hydrocarbon (VPH) sample <br /> collection. <br /> e. Inertial pump: place the pump intake at a depth approximate to the middle or just slightly <br /> below the middle of the well screen interval or water column unless another position is <br /> justified based on site-specific conditions. Note: Some studies suggest that the use of <br /> inertial pumps for purging and/or sampling may produce a low bias when collecting samples <br /> for VOC and VPH analyses. This should be considered along with regulatory requirements <br /> when selecting an inertial pump for purging and/or sampling. <br /> f. Submersible pump: place the pump intake at a depth approximate to the middle or just <br /> slightly below the middle of the well screen interval unless another position is justified based <br /> on site-specific conditions. <br /> g. Pre-cleaned or disposable bailers. Note: The use of bailers for low-flow purging/sampling <br /> is not appropriate. <br /> h. Another suitable purging/sampling device may be selected for use depending upon project <br /> requirements. <br /> 2. Monitoring Well Purging and Sampling. When purging of a monitoring well prior to sampling <br /> is appropriate and/or required, purge the well using either (a) wetted-casing-volume-based <br /> purging or (b) low-flow purging as described in the following sections. If a well exhibits evidence <br /> of slow recharge, or produces excessively silty water, etc., the well may need to be <br /> redeveloped. <br /> a. Wetted-casing-volume-based purging. <br /> (1) Establish a purging rate to pump or bail approximately three wetted-casing volumes of <br /> groundwater without dewatering the well. <br /> (2) If using a pump, set-up the discharge tubing, flow-through cell, water quality meter, and <br /> purge water collection container. If turbidity is measured, collect the sample for turbidity <br /> measurement after groundwater passes through the flow-through cell in the vial <br /> provided with the turbidity meter. If using a bailer, maintain a clean plastic container <br /> next to the well for collecting observation samples. Begin purging the well. <br /> (3) At the beginning of purging and periodically thereafter, record the following information <br /> and water quality parameters/observations on the groundwater purge and sample form: <br /> As guidance, field parameters may be measured after one purge volume is removed <br /> and every '/ purge volume thereafter. <br /> , <br /> - Date and time <br /> - Purge volume and/or flow rate <br /> - Water depth <br /> Hydrogeologic Investigation and Groundwater Sampling and Analysis Work Plan SOG 4 <br /> Sutter Home Lodi Winery, Lodi, California Page 3 of 7 <br /> gtisyrpupbdminya618B�8865865 g63utlerliame189reportslwdrtaskslfGhy±Ao wak piwappeod8es1eppb_sap14 yvsamp revel <br />