# Barker Solution for Constant-Head Tests in Confined and Fractured Aquifers

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A mathematical solution by Barker (1988) is useful for determining the hydraulic properties (hydraulic conductivity and specific storage of the aquifer or fractures; hydraulic conductivity and specific storage of matrix; and flow dimension) of **confined** (single porosity) and **fractured** (double porosity) aquifers. Analysis involves matching the Barker solution to discharge data collected during a constant-head (constant-drawdown) test. The so-called **generalized radial flow model **simulates unsteady, n-dimensional flow to a fully penetrating source in an isotropic, single-porosity confined aquifer or a double-porosity fractured aquifer. AQTESOLV includes options for slab and spherical matrix blocks in the double-porosity case.

AQTESOLV provides visual and automatic methods for matching the generalized radial flow model to constant-head 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 Barker generalized radial flow model:

- 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

## Solution

Options

AQTESOLV provides the following options for the Barker generalized radial flow model:

- recovery

## References

Barker, J.A., 1988. A generalized radial flow model for hydraulic tests in fractured rock, Water Resources Research, vol. 24, no. 10, pp. 1796-1804.

Moench, A.F., 1984. Double-porosity models for a fissured groundwater reservoir with fracture skin, Water Resources Research, vol. 20, no. 7, pp. 831-846.