Neuman Solution for Unconfined Aquifers

Description

Well configuration for pumping test in unconfined aquifer

A mathematical solution by Neuman (1974) and enhanced by Moench (1993, 1996) is useful for determining the hydraulic properties (transmissivity, elastic storage coefficient, specific yield and vertical hydraulic conductivity) of unconfined (water-table or phreatic) aquifers. Analysis involves matching the solution to drawdown data collected during a pumping test. The Neuman solution accounts for delayed gravity response (delayed yield) and partial penetration.

AQTESOLV provides visual and automatic methods for matching the Neuman solution to pumping test and recovery test data. This easy-to-use and intuitive software promotes rapid and accurate determination of aquifer properties. uses the latest algorithms by Moench (1993, 1996) to compute the well function for the Neuman solution.

Assumptions

The following assumptions apply to the use of the Neuman pumping test solution for phreatic aquifers:

  • aquifer has infinite areal extent
  • aquifer is homogeneous, isotropic and of uniform thickness
  • aquifer is unconfined
  • flow is unsteady
  • diameter of control well is very small so that storage in the well can be neglected

Solution Options

provides the following options for the Neuman pumping test solution for unconfined aquifers:

  • variable pumping rates
  • multiple pumping wells
  • multiple observation wells
  • partially penetrating pumping and observation wells
  • boundaries

Benchmark

Comparison of AQTESOLV (blue and red lines) and Neuman (1974) drawdown (symbols) for fully penetrating wells (FP) and piezometers (PZ) simulated by WTAQ, a computer program by Barlow and Moench (1999).

Example

Neuman (1974) solution matched to observation well data collected during a constant-rate pumping test in an anisotropic water-table aquifer near Fairborn, OH (Lohman 1972).

References

Neuman, S.P., 1974. Effect of partial penetration on flow in unconfined aquifers considering delayed gravity response, Water Resources Research, vol. 10, no. 2, pp. 303-312.

See also: solution methods, pumping tests

top