Dougherty-Babu Solution for Confined Aquifers
Description
A mathematical solution by Dougherty and Babu (1984) is useful for determining the hydraulic properties (transmissivity, storativity and hydraulic conductivity anisotropy ratio) of nonleaky confined aquifers. Analysis involves matching the solution to drawdown data collected during a pumping test. The Dougherty-Babu solution accounts for wellbore storage effects in a finite-diameter, partially penetrating well with wellbore skin. Moench (1988) extended the method to account for anisotropic conditions.
AQTESOLV provides visual and automatic methods for matching the Dougherty and Babu 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 Dougherty and Babu solution:
- aquifer has infinite areal extent
- aquifer is homogeneous, anisotropic and of uniform thickness
- control well is fully or partially penetrating
- flow to control well is horizontal when the control well is fully penetrating
- aquifer is nonleaky confined
- flow is unsteady
- water is released instantaneously from storage with decline of hydraulic head
Solution Options
AQTESOLV provides the following options for the Dougherty and Babu solution:
- large-diameter pumping wells
- variable pumping rates
- multiple pumping wells
- multiple observation wells
- partially penetrating wells
- boundaries
Benchmark
AQTESOLV benchmark for Dougherty and Babu (1984) type-curve solution using data from a pumping test in a confined aquifer with no wellbore skin. Symbols calculated with a computer program by Barlow and Moench (1999).
References
Dougherty, D.E and D.K. Babu, 1984. Flow to a partially penetrating well in a double-porosity reservoir, Water Resources Research, vol. 20, no. 8, pp. 1116-1122.
Moench, A.F., 1988. The response of partially penetrating wells to pumpage from double-porosity aquifers, Proceedings of the International Conference on Fluid Flow in Fractured Rocks, Atlanta, GA, May 16-18, 1988.
See also: solution methods, pumping tests