Hydraulic Gradient Comparison Method to Estimate Aquifer Hydraulic Parameters Under Steady-State Conditions

The hydraulic gradient comparison method is an inverse method for estimation of aquifer hydraulic conductivity (or trans‐missivity) and boundary conductance for a ground water flow model under steady‐state conditions. This method, following formal optimization techniques, defines its objective funct...

Full description

Saved in:
Bibliographic Details
Published in:Ground water 2000-11, Vol.38 (6), p.815-826
Main Authors: Guo, Xiaoniu, Zhang, Chuan-Mian
Format: Article
Language:English
Subjects:
Aquifers
Boundaries
Calibration
Computation
Conductivity
Domains
Estimating techniques
Groundwater
Hydraulics
Hydrology
Iterative methods
Mathematical models
Minimization
Mountains
Optimization
Transmissivity
USA, Colorado
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The hydraulic gradient comparison method is an inverse method for estimation of aquifer hydraulic conductivity (or trans‐missivity) and boundary conductance for a ground water flow model under steady‐state conditions. This method, following formal optimization techniques, defines its objective function to minimize differences between interpreted (observed) and simulated hydraulic gradients, which results in minimization of differences between observed and simulated hydraulic heads. The key features of this method are that (1) the derived optimality conditions have an explicit form with a clear hydrology concept that is con‐sistent with Darcy's law, and (2) the derived optimality conditions are spatially independent as they are a function of only local hydraulic conductivity and local hydraulic gradient. This second feature allows a multidimensional optimization problem to be solved by many one‐dimensional optimization procedures simultaneously, which results in a substantial reduction in computation time. The results of the numerical performance testing on a heterogeneous hypothetical case confirm that minimizing gradient residuals in the entire model domain leads to minimizing head residuals. Application of the method in real‐world projects requires rigorous conceptual model development, use of a global calibration target, and an iterative calibration proess. The conceptual model development includes interpretation of a potentiometric surface and estimation of other hydrologic parameters. This method has been applied to a wide range of real‐world modeling projects, including the Rocky Mountain Arsenal and Rocky Flats sites in Colorado, which demonstrates that the method is efficient and practical.
ISSN:0017-467X
1745-6584
DOI:10.1111/j.1745-6584.2000.tb00679.x