DRAWDOWNS FOR LEAKY-AQUIFER FLOW WITH STORAGE IN FINITE-WIDTH SINK

One-dimensional horizontal flow in a semi-infinite confined aquifer can be described in terms of mathematical solutions that relate the drawdown to aquifer parameters and the aquifer flow rate. A new solution that considers the effects of storage in a finite-width sink into which flow occurs from the aquifer was developed for the leaky-aquifer case. The solution was obtained by inverting the Laplace-space solution using the Stehfest numerical algorithm, and a drain function D(u, x/B, A/x)q was defined based on the solution. Type curves for the drain function were plotted, and aquifer parameters can be determined by matching drawdown data from observation wells to the type curves. This drain function and its type curves could be used to analyze aquifer drawdowns resulting from a canal pumping test in which a significant part of the discharge from the canal was derived from water stored in the canal and from flow from a leaky aquifer into the canal.