| Abstract: | Many ground water modeling efforts use a finite-difference method to solve the ground water flow equation, and many of these models require a relatively fine-grid discretization to accurately represent the selected process in limited areas of interest. Use of a fine grid over the entire domain can be computationally prohibitive; using a variably spaced grid can lead to cells with a large aspect ratio and refinement in areas where detail is not needed. One solution is to use local-grid refinement (LGR) whereby the grid is only refined in the area of interest. This work reviews some LGR methods and identifies advantages and drawbacks in test cases using MODFLOW-2000. The first test case is two dimensional and heterogeneous; the second is three dimensional and includes interaction with a meandering river. Results include simulations using a uniform fine grid, a variably spaced grid, a traditional method of LGR without feedback, and a new shared node method with feedback. Discrepancies from the solution obtained with the uniform fine grid are investigated. For the models tested, the traditional one-way coupled approaches produced discrepancies in head up to 6.8% and discrepancies in cell-to-cell fluxes up to 7.1%, while the new method has head and cell-to-cell flux discrepancies of 0.089% and 0.14%, respectively. Additional results highlight the accuracy, flexibility, and CPU time trade-off of these methods and demonstrate how the new method can be successfully implemented to model surface water-ground water interactions. Copyright ?? 2006 The Author(s). |
| Genre: | Conference Paper |
| ProdID: | 70028885 |
| Citation Author: | Mehl, S.; Hill, M. C.; Leake, S. A. |
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| Citation End Page: | 796 |
| Citation Issue: | 6 |
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| Citation Language: | English |
| Citation Larger Work Title: | Ground Water |
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| Citation Number Of Pages: | 5 |
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| Citation Search Results Text: | Comparison of local grid refinement methods for MODFLOW; 2006; Conference Paper; Ground Water; Mehl, S.; Hill, M. C.; Leake, S. A. |
| Citation Start Page: | 792 |
| Citation Volume: | 44 |
| Citation Year: | 2006 |
| Type: | citation/reference |
| Text: | Comparison of local grid refinement methods for MODFLOW; 2006; Conference Paper; Ground Water; Mehl, S.; Hill, M. C.; Leake, S. A. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1111/j.1745-6584.2006.00192.x |
| Date Other: | Sun, 1 Jan 2006 00:00 -0600 |
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