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A Modification to the Bouwer and Rice Method of Slug‐Test Analysis for Large‐Diameter, Hand‐Dug Wells
Author(s) -
Rupp David E.,
Selker John S.,
Šimunek Jirka
Publication year - 2001
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.2001.tb02313.x
Subject(s) - slug test , hydraulic conductivity , groundwater recharge , aquifer , geotechnical engineering , soil science , groundwater , range (aeronautics) , geology , vadose zone , hydrology (agriculture) , soil water , mathematics , materials science , composite material
The Bouwer and Rice method of estimating the saturated hydraulic conductivity (K s ) from slug‐test data was evaluated for geometries typical of hand‐dug wells. A two‐dimensional, radially symmetric and variably saturated, ground water transport model was used to simulate well recovery given a range of well and aquifer geometries and unsaturated soil properties, the latter in terms of the van Genuchten parameters. The standard Bouwer and Rice method, when applied to the modeled recharge rates, underestimated K s by factors ranging from 1.3 to 5.6, depending on the well geometry and the soil type. The Bouwer and Rice analytical solution was modified to better explain the recovery rates as predicted by the numerical model, which revealed a significant dependence on the unsaturated soil for the shallow and wide geometries that are typical of traditional wells. The modification introduces a new parameter to the Bouwer and Rice analysis that is a measure of soil capillarity which improves the accuracy of K s estimates by tenfold for the geometries tested.