thumbnail

Two-dimensional advective transport in ground-water flow parameter estimation

Ground Water

By:
, , and
https://doi.org/10.1111/j.1745-6584.1996.tb02165.x

Links

Abstract

Nonlinear regression is useful in ground-water flow parameter estimation, but problems of parameter insensitivity and correlation often exist given commonly available hydraulic-head and head-dependent flow (for example, stream and lake gain or loss) observations. To address this problem, advective-transport observations are added to the ground-water flow, parameter-estimation model MODFLOWP using particle-tracking methods. The resulting model is used to investigate the importance of advective-transport observations relative to head-dependent flow observations when either or both are used in conjunction with hydraulic-head observations in a simulation of the sewage-discharge plume at Otis Air Force Base, Cape Cod, Massachusetts, USA. The analysis procedure for evaluating the probable effect of new observations on the regression results consists of two steps: (1) parameter sensitivities and correlations calculated at initial parameter values are used to assess the model parameterization and expected relative contributions of different types of observations to the regression; and (2) optimal parameter values are estimated by nonlinear regression and evaluated. In the Cape Cod parameter-estimation model, advective-transport observations did not significantly increase the overall parameter sensitivity; however: (1) inclusion of advective-transport observations decreased parameter correlation enough for more unique parameter values to be estimated by the regression; (2) realistic uncertainties in advective-transport observations had a small effect on parameter estimates relative to the precision with which the parameters were estimated; and (3) the regression results and sensitivity analysis provided insight into the dynamics of the ground-water flow system, especially the importance of accurate boundary conditions. In this work, advective-transport observations improved the calibration of the model and the estimation of ground-water flow parameters, and use of regression and related techniques produced significant insight into the physical system.

Study Area

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Two-dimensional advective transport in ground-water flow parameter estimation
Series title:
Ground Water
DOI:
10.1111/j.1745-6584.1996.tb02165.x
Volume:
34
Issue:
6
Year Published:
1996
Language:
English
Contributing office(s):
Office of Ground Water
Description:
9 p.
Larger Work Title:
National Ground Water Association
First page:
1001
Last page:
1009
Country:
United States
State:
Massachusetts
City:
Boston