Hyder et al. (KGS Model) Slug Test Solution for Confined and Unconfined Aquifers

Slug test configuration for KGS Model in confined aquifer
KGS Model for nonleaky confined aquifer.
Slug test configuration for KGS Model in unconfined aquifer
KGS Model for unconfined aquifer.

A mathematical solution by Hyder et al. (1994), also known as the KGS (Kansas Geological Survey) Model, is useful for determining the hydraulic conductivity of unconfined and nonleaky confined aquifers. Analysis involves matching a type curve solution to water-level displacement data collected during an overdamped slug test.

AQTESOLV provides visual and automatic methods for matching the KGS Model 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 KGS Model:

  • aquifer has infinite areal extent
  • aquifer is homogeneous and of uniform thickness
  • aquifer potentiometric surface is initially horizontal
  • control well is fully or partially penetrating
  • a volume of water, V, is injected or discharged instantaneously from the control well
  • aquifer is confined or unconfined
  • flow is unsteady

Solution
Options

provides the following options for the KGS Model:

  • partially penetrating wells
  • hydraulic conductivity anisotropy
  • wellbore skin effect
  • observation wells

Benchmarks

AQTESOLV benchmark for KGS Model in confined aquifer
AQTESOLV benchmark for KGS Model (Hyder et al. 1994) type-curve solution using data from an overdamped slug test in a confined aquifer with wellbore skin. Symbols calculated with a computer program by Liu and Butler (1995) available from KGS.
AQTESOLV benchmark for KGS Model in unconfined aquifer
AQTESOLV benchmark for KGS Model (Hyder et al. 1994) type-curve solution matched to an overdamped slug test in an unconfined aquifer. Butler 1998 reported K=4.21 m/day for these data.

References

Hyder, Z., J.J. Butler, Jr., C.D. McElwee and W. Liu, 1994. Slug tests in partially penetrating wells, Water Resources Research, vol. 30, no. 11, pp. 2945-2957.