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Depletion of flow in right-angle stream bends by steady wells


  • Mahdi S. Hantush


The flow of a stream that is hydraulically connected to an aquifer can be reduced considerably by nearby pumping wells. Pumping such wells will either increase the infiltration from the nearby streams or decrease the natural groundwater flow that would have discharged into the streams if the wells had not been pumped, or effect both processes at the same time. The depletion of the stream flow is an increase to the perennial yield of the sand. Consequently, greater supplies of water can be obtained than would be available as groundwater alone in such systems. Natural as well as artificial streams meeting at approximately right angles are not uncommon in nature. Irrigation and drainage canals, and streams having a trellis drainage pattern, are examples of such an occurrence. Wells for domestic as well as for irrigation use are often installed near such streams. Rational estimates of the rate of depleting such streams by the nearby pumping wells are therefore of practical interest. Formulas for estimating the rate and volume of stream depletion in such systems are developed in terms of extensively tabulated functions.