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O1 March 2004 <br /> AGE-NC Project No. 02-0886 <br /> Page 7 of 8 <br /> Following completion of the monitoring wells,well elevations and locations will be surveyed by a <br /> California-licensed surveyor relative to a San Joaquin County elevation benchmark. <br /> 4.3. WELL DEVELOPMENT <br /> Development of the proposed wells will consist of a combination of bailing with a stainless steel <br /> bailer to remove the major portion of fine-grained sediment from inside the well, surging to flush <br /> out or draw in sediment from the filter pack and additional ground water evacuation(purging)with <br /> a Waterra bailing pump to finish the removal of fine-grained sediment. Developmental purging <br /> activities will be continued until field parameter (pH, electrical conductivity, and temperature) <br /> readings have stabilized and purged water is visually sediment-free. <br /> 4.4. GROUND WATER SAMPLING PROCEDURES <br /> Ground water sample collection will be performed in accordance with CRWQCB guidelines (Tri- <br /> Regional Water Quality Control Board Recommendations for Preliminary Investigations and <br /> Evaluation of Underground Storage Tanks) sampling protocols. _ <br /> 4.4.1. Static Water Level Measurements <br /> Before sampling and during groundwater monitoring, static water level will be measured using an <br /> electric water level indicator. Water level data will be recorded to the nearest 0.01-foot from a <br /> reference point marked of the top of the PVC well casing. Before and after each use, the <br /> measurement device will be rinsed with water.6?.rz <br /> 4.4.2. Well Evacuation <br /> Subsequent to measurement of depth to water and prior to sampling,the well will be purged using <br /> an inertia pump or a disposable bailer to ensure that the sample is representative of the formation, <br /> rather than water standing in the well casing. The well will be urged until: 1) a minimum of three <br /> casing-water volumes has been removed from the well; and(614)the field-measured ground water <br /> parameters,pH,temperature and conductivity have stabilized.However,if a well is purged dry prior <br /> to evacuating three casing volumes, a ground water sample will be collected following 80 percent <br /> recovery of ground water within the well or after a minimum of 1 hour but within 8 hours of well <br /> evacuation. <br /> Advanced GeoEnvironniental,Inc. <br />