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A method for estimating effective porosity and ground-water velocity

Journal Article · · Ground Water; (United States)
; ;  [1]
  1. Pacific Northwest Lab., Richland, WA (United States). Earth and Environmental Sciences Center

Estimates of ground-water velocity, based either on Darcy's law or on the single-well drift and pumpback tracer method, require prior knowledge of effective porosity. That is, after field data have been collected, the equation for ground-water velocity, using either method, still contains the two unknowns, velocity and porosity. If the local hydraulic gradient is known and if a drift and pumpback tracer test is conducted at a well whose hydraulic conductivity has been determined, two independent functional relationships between velocity and porosity are established. By treating these functions as nonlinear simultaneous equations, a unique solution for the local velocity and porosity can be obtained. This paper is based on data gathered during an aquifer characterization project conducted for the purpose of designing an efficient well field for an aquifer thermal energy storage system. In this application, the velocity determines the rate of downgradient displacement of chilled or heated water that has been injected into the aquifer, and the effective porosity determines the volume of aquifer required to contain a given volume of the water.

DOE Contract Number:
AC06-76RL01830
OSTI ID:
6958401
Journal Information:
Ground Water; (United States), Journal Name: Ground Water; (United States) Vol. 29:2; ISSN GRWAAP; ISSN 0017-467X
Country of Publication:
United States
Language:
English