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<br />, . <br /> <br />r.; ....... <br /> <br />J. <br />;; <br /> <br />,)" . <br />.... . :~ <br />.-.... ..l <br /> <br />- <br />effectively prevent the vertical movement of water. Changes in flow from an <br />aquifer into an underlying aquifer were simulated using the General-Head <br />Boundary Package described in McDonald Harbaugh (1) which utilizes the <br />equation: <br /> <br />Q = K (Hb - Ha) AIL <br /> <br />where <br /> <br />Q is the flow rate <br /> <br />K is the effective vertical hydraulic conductivity between <br />aquifers <br /> <br />L is the length of the flow path <br /> <br />Hb is the head in the underlying aquifer <br />Ha ;s the head in the aquifer <br />A is the horizontal area of the cell <br /> <br />In the models, 3 x 10-5 ft./day was used for the value of K (Robson, <br />(8)). The length of the flow path was computed at each cell as one-half the <br />sum of the aquifer thickness and the underlying aquifer thickness. Changes <br />in stream system depletion were computed for Lower Dawson window #1 with and <br />without leakage into the Denver aquifer. Nearly identical results were <br />obtained. <br /> <br />The bedrock aquifers receive recharge from precipitation falling <br />directly on the aquifer outcrops. Pumping from the bedrock aquifers will <br />not appreciably change this direct precipitation recharge and was not <br />simulated in the models. <br /> <br />Bedrock aquifers of the Denver Basin discharge water to streams and/or <br />their alluviums. Stream systems also recharge the bedrock aquifers. Any <br />computed change in that discharge or recharge as a result of pumping. is <br />stream depletion. Changes in flow between bedrock aquifers and stream <br />systems were simulated in the models using the River Package described in <br />McDonald Harbaugh (1). The River Package utilizes the equation: <br /> <br />Q = C (Hr - Ha) <br /> <br />where <br /> <br />-19- <br />