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Chapter six Groundwater remediation - 193 <br /> ti <br /> Y <br /> Stagnation 40 <br /> Point <br /> 2 Pumping Well _ Gronndwaber Flow " <br /> x <br /> -40 40 80 720 760 200 <br /> -401 <br /> y 4 <br /> Figure E VI 124 Capture zone of a single well <br /> Example VI 12B Determine the downstream and sidestream <br /> distances of a capture zone <br /> A groundwater extraction well is installed it an aquifer (hydraulic conduc- <br /> #ivtty = 1000 gpd/ft2, gradient = 0 015, and aquifer thtclaness = 80 ft) , 01 <br /> The design pumping rate is 50 gpm. Delineate the capture zone of this -� <br /> recovery well by specifying the following charactenshc distances of the <br /> capture zone <br /> a The sidestream distance from the well to the envelope of the capture <br /> zone at the line of the pumping well <br /> b The downstream distance from the well to the stagnation point of the <br /> envelope <br /> c The well <br /> sidestream distance of the envelope far upstream of the pumping Y j= <br /> Solution <br /> a Determine the groundwater velocity, u <br /> f <br /> u = (K)(i) _ [(1000 gal/d/ft2)(1 d/1440 nun)(1 ft3/748 gal)](0015) , <br /> 139 x 10-3 ft/mut r, <br /> b Determine the sidestream distance from the well to the envelope of <br /> x,1 SC Com`+ <br /> the capture zone at the line of the pumping well, Q/4Bu <br /> r P'. <br /> Q _ (50 gal/mun)(1ft3/7 48 gal) T 15 Oft <br /> 4Bu (4)(80 ft)(139 x 10-3 ft/mut) <br /> c Determine the downstream distance from the well to the stagnation <br /> point of thep , Q <br /> envelo a /2nBu <br /> � y <br />