| Abstract: | Various approaches have been proposed to manage the nonlinearities associated with the unconfined flow equation and to simulate perched groundwater conditions using the MODFLOW family of codes. The approaches comprise a variety of numerical techniques to prevent dry cells from becoming inactive and to achieve a stable solution focused on formulations of the unconfined, partially-saturated, groundwater flow equation. Keeping dry cells active avoids a discontinuous head solution which in turn improves the effectiveness of parameter estimation software that relies on continuous derivatives. Most approaches implement an upstream weighting of intercell conductance and Newton-Raphson linearization to obtain robust convergence. In this study, several published approaches were implemented in a stepwise manner into MODFLOW for comparative analysis. First, a comparative analysis of the methods is presented using synthetic examples that create convergence issues or difficulty in handling perched conditions with the more common dry-cell simulation capabilities of MODFLOW. Next, a field-scale three-dimensional simulation is presented to examine the stability and performance of the discussed approaches in larger, practical, simulation settings. |
| Genre: | Article |
| ProdID: | 70041749 |
| Citation Author: | Bedekar, Vivek; Niswonger, Richard G.; Kipp, Kenneth; Panday, Sorab; Tonkin, Matthew |
| Citation Contributing Office: | Nevada Water Science Center |
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| Citation End Page: | 198 |
| Citation Issue: | 2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Ground Water |
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| Citation Month: | 3/4 |
| Citation No Pagination: | |
| Citation Number Of Pages: | 12 |
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| Citation Phsyical Description: | 12 p. |
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| Citation Publisher: | Wiley |
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| Citation Search Results Text: | Approaches to the simulation of unconfined flow and perched groundwater flow in MODFLOW; 2012; Article; Journal; Ground Water; Bedekar, Vivek; Niswonger, Richard G.; Kipp, Kenneth; Panday, Sorab; Tonkin, Matthew |
| Citation Start Page: | 187 |
| Citation Volume: | 50 |
| Citation Year: | 2012 |
| Type: | citation/reference |
| Text: | Approaches to the simulation of unconfined flow and perched groundwater flow in MODFLOW; 2012; Article; Journal; Ground Water; Bedekar, Vivek; Niswonger, Richard G.; Kipp, Kenneth; Panday, Sorab; Tonkin, Matthew |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1111/j.1745-6584.2011.00829.x |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 12 Dec 2012 00:00 -0600 |
| Publisher: | Wiley |
