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<br /> Pile No.2070.: f i it tk:
<br /> 19 December 1991 t•! it' 1
<br /> Pipe 9
<br /> 3.5 Well Pumping Test Results
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<br /> :A continuous, 24-hour well pumping test was conducted for the Rainbo Bakery site utilizing the
<br /> existing onsite monitoring wells. MW-1, located in the ranter of the groundwater contaminant
<br /> r e, was utilized as the pumping well. MW-2, MW-3, MW-4, MW-6 and MW-8 were utilized �y'st '? ,,
<br /> as observation wells. Drawdown of the local groundwater table was continuously measured and' .
<br /> `� •}` recorded in the pumping well and five observation wells during the well pumping test.
<br /> During the well pumping test, MW4 was the first observation well to be influenced by the pumped ?' t ra+`L`i+ r
<br /> ° well at approximately 5 minutes after the start of the test. At approximately 330 minutes'aftcr they .
<br /> YKI;a,° � ,1 start of the,test, all five observationwells were nosed to be influenced by the pumped:well.,Since
<br /> the groundwater contaminant plume extends no farther than any of the five observation wells theme dkt'1r
<br /> full extent of the groundwater contaminant plume was accordingly contained •within the zone of
<br /> r e rt influence of the pumped well at approximately 330'minutes after the start of the well pumping test r L f z> �9RxRIt
<br /> Continued pumping resulted in the local groundwater table lowering even further and the zone of r, , y i,k�u� a '
<br /> a 'influence of the'pumped well expanding farther out laterally. Figure 11 illustrates the approximate
<br /> } 3 a x , drawdown encountered' in the pumping well and the observation wells at 330 minutes, 750 minutes ';It
<br /> 1020 minutes and 1320 minutes after the start of the well pumping test.
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<br /> At the pumping rate of. 6.7 gpm, groundwater inflow !o the pumped well was not..d ' 'a ' `r'
<br /> y^t... �a roximatel equal,the rate of groundwater extraction at approximately 1200 minutes`' 20 ��.
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<br /> x i,-%''d' <, '?',O after the start of the test. At this point, drawdown in the pumped well was approximately
<br /> feet.,,From- e,time of 1200 minutes until the vi:d of the test, drawdown in the pumpW weu
<br /> a fluctuated between 10.36 feet and 11.64 feet.
<br /> Not kl.;
<br /> A,spreadsheet +was created tabulating the field data obtained from the perfotmanca of_tha weal !� ' v �# ,y.l
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<br /> zpumping tele: Data incorporated in the spreadsheet included the distance of each observation well� ': ^",�, 4Y�•`<xH' •�. '
<br /> from the pumped well,the drawdo.m in the pumped well,the drawdown in the observation`wells ' , hi y' b
<br /> {w1 z
<br /> an time at which the drawdown measurements were obtained. A copy of the spreadsheet
<br />'i ,yx _j a4 sri c included in Appendix:X.
<br /> Distance-drawdown graphs for each of the five observation wells were created by plotting the data
<br /> contained in the spreadsheet according to the Jacob Straight-Line Method (see C.W.Fetter 741
<br /> 7 and Driscoll, 1986 for a detailed explanation -of the Jacob Straight-Line Method). Aquifer'-,ranmissivit
<br /> V i r E iThesaquiferyp opert esgare uand storae U izedcienito predwereict theiperforman eo of groundwater
<br /> rextrract onawdown -.ells °:. (>raphsf� I'¢+ < f of
<br /> Copies of the five distance-drawdown graphs are included in Appendix XI.t>.. - 4.,SYx }');,i•en `k' tl!�
<br /> ty is an
<br /> uifer
<br /> rty which
<br /> ts the quantity, of water which can- b I e,
<br /> et", , g r e "P ,transmitted vithrough die aquifer.roIt s determ determined from nthe distance-drawdown graph based on the �..,�
<br /> Fr slope,of the drawdown line and the pump discharge rate. The five values obtained for [he aquifer I i t1x, t 'i
<br /> transmissivity based on the pumping test data for the Rainbo Bakery site were 6551;6206 5340,
<br /> 6206 and 6936 gallons per day per foot of aquifer thickness. The average value was calculated as
<br /> c„! 6248 gallons per day per foot of aquifer thickness.
<br /> ,The storage coefficient represents the volume of water stored in the aquifer which can be released
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