ARCHIVED REPORTS_2007_18 - Laserfiche WebLink

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1. The pH, conductivity. and turbidity meters will be calibrated ata rninimurn at the beginning of each sampling day using commercially obtained.standards, Ga1c'bratiou will be checked two to 6=times during the day to evaluate the potential that the cah`bration is ' g throughout the day. 'If instrument delft is detected in the field, the memuremeigs taken during purgiing and sampling wM be 4justed accordingly. Example calibration logs are included in ApoendbcC. During purging and sampling of the wells the instrurnents will be used in the same mmmer as&ring calibration. 2. Depth to water will be measured again,prior to sampling, in each wellas descn'bed in Section 4.4.1 and recorded on the Purge C haracxerbmtion.and Sample Log. the volume of groundwater in the well casing will be calculated using the following equation(s): 4-inch well: {Total Well Depth front the mark on the well casing DTW (ft)) 0.653 gal/fL 3.' Prior to purging, tete-orate r,wrll be-_cx.aminc -by-usingm d'isposable:baner,that is clear- -enough to see through. Fres such as immiscible layers will be noted and measured.. -If immiscible layers-are observed the well will not be purged prior to sampling. 4_ The well w�then be ed using the-purge Due to the-fact tont the pumps,mast i f� - P�8 g PTu'g �Pz� - pw'g�water from depths as great as•70 t6 80 feet below ground surface;pcirge rates range from 1!4 to I gallon per minute. This-purge Tate docs not appear to exceed the recharge - rates of the wells. Purge water will be discharged to-'the ground (see Section 4.4.6)_ Depth to water measurements well be taken periodically du deg purgin& The purpose of these measurements is to monitor-draweiown. If a decrease in groundwater elevation is the purge rate will be dccreased until equg%rium(purge raze equals recharge tate) _ is achieved. The frequency of measurement will be-once every five minutes initially decreasing to once every orne-halfhour once equilibrium has been reached. If equilibrium cannot be reached,it will be nCCC=iy to purge the well to dryness_ Purge. uatil less than 100% of the original volume of water remains in the well, Hand baling raay be required to meci this obiictive. Monitor the DTW every 15 minutes to evaluate e. Start sample collection when cidw two feet of water has filled the welt or 1.75 boors has the end of purging. Collect volatile organics no later than two hours after purging. Record all actions and mCs uretne=associated with Pig a well. - dry on the Purge CWractctization and Sample Log. 949-n 1123 I oR325 A-7 hely 14,2000 tae. _ •