Cooley-Case Solution for Leaky Aquifers

Description

A mathematical solution by Cooley and Case (1973) is useful for determining the hydraulic properties (transmissivity, storativity and leakage parameters) of a leaky confined aquifer with a water-table aquitard. Analysis involves matching the Cooley and Case solution to drawdown data collected during a constant- or variable-rate pumping test.

AQTESOLV provides visual and automatic methods for matching the Cooley and Case solution to pumping 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 Cooley and Case solution:

• aquifer has infinite areal extent
• aquifer is homogeneous, isotropic and of uniform thickness
• potentiometric surface is initially horizontal
• aquifer is confined
• flow is unsteady
• wells are fully penetrating
• 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
• confining bed has infinite areal extent, uniform vertical hydraulic conductivity, storage coefficient, specific yield and thickness
• flow is vertical in the aquitard

Solution Options

AQTESOLV provides the following options for the Cooley and Case solution:

• constant or variable pumping rate with recovery
• multiple pumping wells
• multiple observation wells
• boundaries

References

Cooley, R.L. and C.M. Case, 1973. Effect of a water table aquitard on drawdown in an underlying pumped aquifer, Water Resources Research, vol. 9, no. 2, pp. 434-447.

See also: solution methods, pumping tests