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' Draft: Aprrl 5, 1999 Page C-4 <br />' C.3..3.1 Preparation for Purging <br />Before well purging begins, the following procedures aze to be performed at each well: <br />Note the condition of the outer well casing, concrete well pad, protective posts (if <br />present), and any other unusual conditions of the area around the well. <br />Open the well. <br />Note the condition of the inner well cap and size of outside diameter of casing. <br />Measure (to neazest O.OI foot) and record depth of static water level from the <br />measuring point on the well casing and indicate time. Record what the measuring <br />' point is (i.e., notch on north side, top of PVC well casing). <br />Measure and record total depth (if possible) of well from the same measuring point <br />' on the casing. <br />' ~ Calculate volume ofwater in the well casing in gallons based on feet of water in well <br />and casing diameter. (For micropurging, calculate the tubing volume.) <br />' C.3.3.2 Purge Volume Calculations <br />The volume ofwater purged from the well should be adequate to remove all stored water <br />' from the well casing prior to sampling. <br />Two exceptions to this approach may be encountered: wells which aze very low-yield or <br />wells which are extremely deep or large diameter. Inlow-yielding wells, the casing may be purged <br />dry. This will effectively remove all stored water in the casing, and the sample can be collected <br />' when the water level recovers sufficiently to allow for sample collection. Indeep or large-diameter <br />wells having a volume so large as to make removal of all water impractical, micropurge techniques <br />should be employed. <br />C.3.4 Groundwater Sample Collection <br />' Obtain samples for chemical analysis within 2 hours after purging is completed. For slow <br />recovering wells, the sample will be collected immediately after a sufficient volume of water is <br />t available. The water quality samples may be collected using bailers or submersible downhole <br />pumps. The following sampling procedure should be used at each well: <br />Assemble decontaminated sampling equipment. If bailers are using for sampling, <br />clean cable or rope should be used for each well for each sampling event. Assemble <br />the manual filtering apparatus. <br />' Agapito Associates, Inc. <br />