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Monitoring Well Installation and Destruction Report <br /> 6. City of Stockton RWCF <br /> Page 5 <br /> 1r 3.6 MONITORING WELL DEVELOPMENT <br /> Monitoring well development activities were conducted between April 26 and May, 10, 2010. Monitoring <br /> ` wells MW-1S and MW-2S were initially developed on April 26, 2010, using a surge block and <br /> disposable,polyethylene bailer. The water purged from the wells was brown in color with poor clarity. A <br /> total of 10 well casing volumes were removed from MW-1S. MW-2S purged dry after removing <br /> Lapproximately 3.5 gallons(slightly less than two casing volumes). <br /> Monitoring wells MW-19 and MW-19S were initially developed on April 27, 2010, using a surge block <br /> and disposable, polyethylene bailer. The water purged from the wells was brown in color with poor <br /> L clarity. MW-19 purged dry after removing approximately 87 gallons (six casing volumes); MW-19S <br /> purged dry after removing approximately five gallons(approximately two casing volumes). <br /> L Poor hydraulic recharge of monitoring wells MW-1S, MW-2S, and MW-19S limited the efficacy of <br /> development by surging and bailing. Additional well development was achieved on the low-yielding <br /> wells with an air-lift pump system. A one-inch diameter PVC pipe(eductor casing)was inserted into each <br /> well to approximately one foot above total well depth. Polyethylene tubing attached to an oil-less air <br /> compressor was inserted into the eductor casing below the static groundwater level. Compressed air <br /> applied at sufficient pressure to overcome the head of water lifted groundwater to the surface. Discharged <br /> ` groundwater was diverted through a pipe fitting and hose away from the wellhead. Surging was <br /> accomplished by injecting air below the bottom of the eductor casing and forcing groundwater out of the <br /> well screen into the soil. <br /> LAir development methods were used at MW-1 S and MW-19 on May 7, 2010. Approximately 8.25 gallons <br /> (slightly less than three casing volumes)were removed from MW-1S, and no groundwater was removed <br /> L from MW-19. <br /> Air development methods were again employed at MWAS, MW-2S, MW-19, and MW-19S on May 10, <br /> 2010. Approximately 59 gallons (approximately four casing volumes) were removed from MW-19; less <br /> L. than one casing volume (approximately two gallons) was removed at MW-2S. No groundwater was <br /> removed from MW-IS or MW-19S. <br /> L No odors were noted in the groundwater purged from the monitoring wells during well development. <br /> All well-development equipment was cleaned prior to use by washing in a solution of laboratory-grade, <br /> Lnon-phosphate detergent and deionized water, double rinsing with deionized water, and wiping with <br /> alcohol. The purge water removed from the wells during development was discharged to the land surface <br /> - near each well. Depth to groundwater measurements are provided in Table 3, below, and on the <br /> LGroundwater Well Development Field Forms included in Attachment D. <br /> TABLE 3-DEPTH TO GROUNDWATER(APRIL 26 AND 27,2010) <br /> b Monitoring Well ID Date Screened Interval(bgs) Depth to Groundwater <br /> MW-1S 4/26/2010 4-9 4.92 <br /> ` MW-2S 4/26/2010 4-9 5.26 <br /> MW-19 4/27/2010 17-27 4.29 <br /> MW-19S 4/27/2010 4-9 4.02 <br /> All measurements are in feet. bgs—below ground surface <br /> A <br /> ti 1� CONDOR <br />