Stream Depletion for Streams and Aquifers with Finite Widths

Abstract

Stream-depletion and drawdown solutions are obtained for pumping from a well beside a stream. The stream has a finite width, and the pumped aquifer has a finite width and is overlain by an aquitard that contains both a free surface and the streambed. Comparison of this solution with an earlier solution that assumes an infinitely wide aquifer and a stream with zero width shows that the zero stream-width assumption gives an accurate approximation for drawdown calculations when the pumped well is at least five stream widths from the nearest stream edge and a reasonably accurate approximation for stream depletion when the pumped well is at least one stream width from the nearest stream edge. At larger values of time the stream-depletion solution becomes relatively sensitive to spacing between lateral aquifer boundaries, which are assumed to be impermeable. It is also shown that this solution, for particular choices of its different parameters, is general enough to reproduce several other well-known stream-depletion solutions.