| Unsteady flow to wells in layered and fissured aquifer systems |
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A solution has been developed for the calculation of drawdowns in leaky and confined multi-aquifer systems, pumped by a well of constant discharge penetrating one or more of the aquifers. In contrast to earlier solutions the effects of elastic storage in separating and bounding aquitards have now completely been accounted for. The computing technique is based on the numerical inversion of the Laplace transform. Two different methods are used and results are compared with an analytical solution. Both Stehfest’s algorithm and Schapery’s least squares method yield accurate results in a fraction of the computation time required for the analytical evaluation. Selected sets of time-drawdown and distance-drawdown curves are plotted to illustrate multiple-aquifer well flow and to compare new solutions with results which were previously published. The analogy with flow in unconfined and fissured aquifers is demonstrated by multilayer models, representing multiple-porosity formations with linear and diffusive crossflow.
C.J. Hemker and C. Maas (1987) Unsteady flow to wells in layered and fissured aquifer systems; in: Journal of Hydrology, Vol 90, pp 231–249.
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