Dagan Slug Test Solution for Unconfined Aquifers
Description
A mathematical solution by Dagan (1978) is useful for determining the hydraulic conductivity of unconfined aquifers when the control well is screened across the water table. Analysis involves matching a straight-line solution to water-level displacement data collected during an overdamped slug test.
AQTESOLV provides visual and automatic methods for matching the Dagan solution to slug 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 Dagan slug test solution:
- aquifer has infinite areal extent
- aquifer is homogeneous and of uniform thickness
- aquifer potentiometric surface is initially horizontal
- control well is screened across the water table
- a volume of water, V, is injected or discharged instantaneously from the control well
- aquifer is unconfined
- flow is steady
Solution Options
AQTESOLV provides the following options for the Dagan method:
- partially penetrating wells
Benchmark
AQTESOLV benchmark for Dagan (1978) solution matched to an overdamped slug test in an unconfined aquifer using recommended head range (Butler 1998). Butler (1998) reported K=0.56 m/day for these data.
References
Dagan, G., 1978. A note on packer, slug, and recovery tests in unconfined aquifers, Water Resources Research, vol. 14, no. 5. pp. 929-934.
See also: solution methods, slug tests