ARCHIVED REPORTS_2010_12 - Laserfiche WebLink

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1. The pH, conductivity, and turbidity meters will be calibrated ata minimum at the beginning ofcadp ' day using commercially obtalfied'sumdards. calibration WM be checked two to throe times during the day to evaluate the potential that the calibration is ddfting throughout the day. -If iastrurnent drift is detected in the field, the me=rements taken during purging and sampling wfil be adjusted accoWhWjy. le callibradi2n logs are included in dix•C. During purging and sampling of the wells the insturnents will be used in the same Vilmner as OUring calibration. 2. Depth to water will be meas=ed again, prior to satripling, in each well as-desaribed in Section 4.4.1 and recorded on the Purge Cluncterizatica snd Sample Log. The volume of groundwater in the well casing will be calcubled usingthe following equation(s): 4-Inch wo1L- (notal Well Depth from the nark on the well casing (It) - D?W (ft)) x 0.653 gal/fL .3-, Prior -to pmTft dw water•wiill-be% ' ed-by-using m disposable.bailer that-is clear- ,enough to sec through. Features such as immiscible layers will be noted and mt If n misct•ble layersareobserved the well will not be purged prior to •'` 4. The well will then be pinged using the-purge -Due to the fact that the PUBUM must l purge water from depths as as 70 tea 80 feet below ground surface,purge rates range from 1/4 to f gallon per minute_ This purge razz does not appear to exceed the recharge rites• of the wells. Purge waterwill be discharged to-die grouted ('see Section 4.4.6)- Depth vrater measurctnerits will be tak=periodically during puMin& The purpose of these measuretnents is to r dna If a decrease in gmundwater elevation is the purge rate will be d=eased until equilUbdum(gunge rate equals r=haxge rate) is achieved. ricy of ineasur=ent will be every Eye y d -to once every one-Mf hour once equilibriurn has been reached- If equilibrium cannot be reached,it will be to purge the well to drynem Purge. until less than 104/6 of the origirial volume of water;=a:ms in the well. Hand bailing may be requirtd to med d&ob' • 've. Monitor the DTW every 15 mft.mtes to evaluate rechage. Start sample collection when dtlier two feet of wata has filled the well or 1.75 hours has elapsed since dz end of pm*& Collect Volatile organics no later than two hours after purging. Riecord all actions and measurernests associated with purging a well - dry on the Purge Ch=cwizadon and Sample Log. 23-M449-RIX231OR325 A-7 July 14,2000