ARCHIVED REPORTS_2009_14 - Laserfiche WebLink

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1. The pH= conductivity, and turbidity eters will be calibrated ata minimum at the be&nmgof each sampling day using commemially obtalned.staUdards. Calibxatiorn will be checked two to three tunes " g the day to evaluate the potential that the calibration is ddfting throughout the day. -If instrUment drift is detected in the field, the masuremem taken during purXIM and ' be adjusted accordingly. Example calibration logs arc included in Ap ' p and sampling of the wells the instruments will be used in the same manner as during calibration. 2. Depth to water will be measured "or to sampling, in each well as dcstxi'bcd in Section 44,i and recorded on the Purge Characterization,and Sample Log. The volume of groundwater in the well casing will be calcubted using the followingequation(s): 4-inch well- '(Total Well Depth fiom. the mark on the well casing {ft) - DTW (ft)) x 0.653 gaYfL 3.' Prior to purging, the-water,will.be•. , y-using a-d"tsposabW bailer that is Clear- -enough to sex through- Features such as humisdible layers will be noted and measured_ .Tfimmiscible layers-are observed the wa will not be purged prior to sampling. 4_ The well will then be purged using the-purge _-Due to die-fact that thepumps anust I purge water from depths as great as 70 to 80 feet Maw ground surfacr,. ptu$e rates range from 1/4 to 1 gallon per minute. This-purge .rate does not appear to exceed the recharge ratees. of the Vohs. a wares will be discharged to-the ground (sec Sermon 4.4.6)- Depth water ineasurvmcnU will be 'cally dudrig purging. The purpose of these measurements is to numitor-dravdown. If a in puundwater elevation is the purge rate will be d=wsed un (purge rate equals recharge rate) Is achieved- The fivquency of measurement Will be once every five minutes in' ' y dccr=sing to ince evay one,42alfhour once equffibritim has been rwzhedL If equilibrium can=be it wM be necessw to purge the well to dryness. Purge�.Until less than 10•4/a of the original volume of water;=ains in the well Hand Wing be requizvd to meet this objective. Monitor die DTW every 15 minutes to evahwe rechwge. Start sample collection 1when ddW two fed of WzW has filled the well or 1.75 hours has elapsed since dw end of pwging. Collectvolatile organics no later than two - hours after purging. R=rd all actions and measurements associated with pur&g a well. dry on the Purse Chtracterization and Sample Log. 449-n 11?3 i oR325 M7 July l 4,2000 Sac.