ARCHIVED REPORTS_2008_14 - Laserfiche WebLink

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I• The pH, conductivity, and turbidity meters will be calibrated at a minimum at the beginning of each sampling day using commercially obtain standards. Calibiati oa will be checked two to three times during the day to evaluate the potential that the calibration is driffing throughout the day. -If insIzUrnent drift is detected in the field, the measurements taken during pu%*and sampling wtli be adjusted accordirigly. Example calibration logs are included in ApliendbcC. During purging and sampling of the wells the instruments will be used in the a manner as druingcollbration. 2. Depth to water will be measured again, prior to sampling, in each well as described in Section 4.4.1 and recorded on the Purge 'on.and Sample Log. The volume of groundwater in the well casing will be ed using the following equation(s): 4-inch well: {Total Well Depth from the mark on the well casing (ft) - DTW (ft)) x 0.653 gallft. .3-, Prior to purging, the-water,will.be. dry-using-a,disposable!bailer that is clear- enough to see through. Features such as immiscible layers will be noted and-mimed_ "If immisciible layers-arc observed the well wifl not be purged prior to sampling. 4_ The well will their be purged using the-purge ImmIme Due to the-fact that the pumps must � •purge waren from depths as great as-7t3 tci 80 feet below ground suufacey Purge rates range from 114 to I gallon per minute. This-.purzc • e docs not appear to exceed the recharge rates_ of the wells. Purge water will be discharged to-the ground (sec Section 4.4.6)_ Depth to water measuremerits wM be taken pedodicaffy during p The purpose of these measuacments is to monitor-drawdown. If.ain groundwater cicvafion is noted, the purge rage will be decreased unto equffibriurn(purge rate+tea Is recharge rate) is achieved. The frulu7ency of measurement will be encs every $ve minutes initially deamsing to once every onc—halfhou.r once equilibrium has been reached. If equilibrium cannot be reached,it will be necessaxy to purge the well to drynem Furgc. until less than 104% of the otiginalvolume of water remains in the well, Hand baing Pay be required to meet thus ob,ecdve. Monitor the DTW every 15 minutes to evaluate recharge. Start sample collection when Ci o feat of water has filled the well or 1.75 hours has elapsed since d= end of purging. Collect volatile organics no later than two hams after purging. R=rd all actions and measurements associated with purging a well dry on the Purge Characterization and Sample Log. 42348344940 IX23 I OR325 A-7kitty 14 2400 ?A40 Y.kial�etdec,tic