| 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. |
| Genre: | Article |
| ProdID: | 70018199 |
| Citation Author: | Anderman, E. R.; Hill, M. C.; Poeter, E. P. |
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| Citation End Page: | 1009 |
| Citation Issue: | 6 |
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| Citation Language: | English |
| Citation Larger Work Title: | Ground Water |
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| Citation Number Of Pages: | 9 |
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| Citation Search Results Text: | Two-Dimensional Advective Transport in Ground-Water Flow Parameter Estimation; 1996; Article; Journal; Ground Water; Anderman, E. R.; Hill, M. C.; Poeter, E. P. |
| Citation Start Page: | 1001 |
| Citation Volume: | 34 |
| Citation Year: | 1996 |
| Type: | citation/reference |
| Text: | Two-Dimensional Advective Transport in Ground-Water Flow Parameter Estimation; 1996; Article; Journal; Ground Water; Anderman, E. R.; Hill, M. C.; Poeter, E. P. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Mon, 1 Jan 1996 00:00 -0600 |
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