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Nonlinear-regression groundwater flow modeling of a deep regional aquifer system

Water Resources Research

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, ORCID iD , and
https://doi.org/10.1029/WR022i013p01759

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Abstract

A nonlinear regression groundwater flow model, based on a Galerkin finite-element discretization, was used to analyze steady state two-dimensional groundwater flow in the areally extensive Madison aquifer in a 75,000 mi2 area of the Northern Great Plains. Regression parameters estimated include intrinsic permeabilities of the main aquifer and separate lineament zones, discharges from eight major springs surrounding the Black Hills, and specified heads on the model boundaries. Aquifer thickness and temperature variations were included as specified functions. The regression model was applied using sequential F testing so that the fewest number and simplest zonation of intrinsic permeabilities, combined with the simplest overall model, were evaluated initially; additional complexities (such as subdivisions of zones and variations in temperature and thickness) were added in stages to evaluate the subsequent degree of improvement in the model results. It was found that only the eight major springs, a single main aquifer intrinsic permeability, two separate lineament intrinsic permeabilities of much smaller values, and temperature variations are warranted by the observed data (hydraulic heads and prior information on some parameters) for inclusion in a model that attempts to explain significant controls on groundwater flow. Addition of thickness variations did not significantly improve model results; however, thickness variations were included in the final model because they are fairly well defined. Effects on the observed head distribution from other features, such as vertical leakage and regional variations in intrinsic permeability, apparently were overshadowed by measurement errors in the observed heads. Estimates of the parameters correspond well to estimates obtained from other independent sources.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Nonlinear-regression groundwater flow modeling of a deep regional aquifer system
Series title:
Water Resources Research
DOI:
10.1029/WR022i013p01759
Volume:
22
Issue:
13
Year Published:
1986
Language:
English
Publisher:
American Geophysical Union
Description:
20 p.
First page:
1759
Last page:
1778
Country:
United States
Other Geospatial:
Great Plains, Madison aquifer