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Kennedy,'Jenks Consultants d. Peristaltic pump: place the pump intake at a depth equal to the approximate middle or just slightly above the middle of the well screen interval or water column unless another position is justified based on site-specific conditions. Note: If degassing of water is occurring when sampling with a peristaltic pump, alternative types of sampling equipment should be used for volatile organic compound (VOC) or volatile petroleum hydrocarbon (VPH) sample collection. e. Inertial pump: place the pump intake at a depth approximate to the middle or just slightly below the middle of the well screen interval or water column unless another position is justified based on site-specific conditions. Note: Some studies suggest that the use of inertial pumps for purging and/or sampling may produce a low bias when collecting samples for VOC and VPH analyses. This should be considered along with regulatory requirements when selecting an inertial pump for purging and/or sampling. f. Submersible pump: place the pump intake at a depth approximate to the middle or just slightly below the middle of the well screen interval unless another position is justified based on site-specific conditions. g. Pre-cleaned or disposable bailers. Note: The use of bailers for low-flow purging/sampling is not appropriate. h. Another suitable purging/sampling device may be selected for use depending upon project requirements. 2. Monitoring Well Purging and Sampling. When purging of a monitoring well prior to sampling is appropriate and/or required, purge the well using either(a)wetted-casing-volume-based purging or(b) low-flow purging as described in the following sections. If a well exhibits evidence of slow recharge, or produces excessively silty water, etc., the well may need to be redeveloped. a. Wetted-casing-volume-based purging. (1) Establish a purging rate to pump or bail approximately three wetted-casing volumes of groundwater without dewatering the well. (2) If using a pump, set-up the discharge tubing, flow-through cell, water quality meter, and purge water collection container. If turbidity is measured, collect the sample for turbidity measurement after groundwater passes through the flow-through cell in the vial provided with the turbidity meter. If using a bailer, maintain a clean plastic container next to the well for collecting observation samples. Begin purging the well. (3) At the beginning of purging and periodically thereafter, record the following information and water quality parameters/observations on the groundwater purge and sample form: As guidance, field parameters may be measured after one purge volume is removed and every % purge volume thereafter. - Date and time - Purge volume and/or flow rate - Water depth - Temperature - pH Monitoring Well Replacement Work Plan, SOG 4 Sutter Home Lodi Winery, Lodi, California Page 3 of 7 ptiapwyatnv/,bbNTA965005.15 sM®homa�D4repahMw hotel wplyOW1e9�P_rev_mm.Lx