Theis Recovery Solution for Nonleaky Confined Aquifers
Description
A mathematical solution by Theis (1935) is useful for determining the hydraulic properties (transmissivity) of nonleaky confined aquifers from recovery tests. Analysis involves matching the Theis recovery solution to water-level recovery (residual drawdown) data collected after a pumping test.
AQTESOLV provides visual and automatic methods for matching the Theis residual drawdown solution to recovery test data. This easy-to-use and intuitive software promotes rapid and accurate determination of aquifer properties.
Assumptions
The following assumptions apply to the use of the Theis recovery solution:
- aquifer has infinite areal extent
- aquifer is homogeneous, isotropic and of uniform thickness
- control well is fully penetrating
- flow to control well is horizontal
- aquifer is confined
- flow is unsteady
- water is released instantaneously from storage with decline of hydraulic head
- diameter of control well is very small so that storage in the well can be neglected
- values of u are small (i.e., r is small and t is large)
Solution Options
AQTESOLV provides the following options for the Theis recovery solution:
- variable pumping rates
Benchmark
AQTESOLV benchmark for Theis (1935) residual drawdown solution matched to a recovery test in a confined aquifer. Driscoll (1986) reported T=10,200 gal/day/ft for these data.
References
Theis, C.V., 1935. The relation between the lowering of the piezometric surface and the rate and duration of discharge of a well using groundwater storage, Am. Geophys. Union Trans., vol. 16, pp. 519-524.
See also: solution methods, pumping tests