A fully coupled physically-based spatially-distributed model for evaluating surface/subsurface flow

Panday, Sorab; Huyakorn, Peter S.

doi:10.1016/j.advwatres.2004.02.016

Cited by 440 publications

(409 citation statements)

References 27 publications

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“…3D surface/vadose zone/groundwater models. MODHMS is a 3D water flow model based on the 3D Richards equation (Panday and Huyakorn, 2004). Areal overland flow and flow through a network of streams and channels is described by diffusion wave equations.…”

Section: Capacity Approachesmentioning

confidence: 99%

“…MODHMS (Panday and Huyakorn, 2004) was applied with global inverse parameter optimization to simulate spatially distributed tile drainage for a 2-year period in the Broadview Water District (38.8 km 2 ), San Joaquin Valley, California (Vrugt et al, 2004). The domain was horizontally discretized into 200 m × 200 m square cells, which were vertically subdivided into 14 layers of 0.3 m (top) to 0.9 m (bottom).…”

Section: Hillslope Scalementioning

confidence: 99%

See 1 more Smart Citation

A review of model applications for structured soils: a) Water flow and tracer transport

Köhne

Šimůnek

2009

Journal of Contaminant Hydrology

292

224

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Section: Capacity Approachesmentioning

confidence: 99%

Section: Hillslope Scalementioning

confidence: 99%

A review of model applications for structured soils: a) Water flow and tracer transport

Köhne

Šimůnek

2009

Journal of Contaminant Hydrology

292

224

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“…The Newton method is a commonly used method in the earth sciences to solve nonlinear equations, such as for solving the multiphase-flow and variably-saturated flow equations (Huyakorn and others, 1986;Pruess, and others, 1999;Panday and Huyakorn, 2004;Maxwell and Miller, 2005). Because many recently developed packages for MODFLOW-2005 apply nonlinear boundary conditions to the groundwater-flow equation (Merritt and Konikow, 2000;Halford and Hanson, 2002;Niswonger and Prudic, 2005;Niswonger and others, 2006;Konikow and others, 2009), the Newton method may improve convergence and computational efficiency when using these packages.…”

Section: Introductionmentioning

confidence: 99%

MODFLOW-NWT, a Newton formulation for MODFLOW-2005

Niswonger¹,

Panday²,

Ibaraki³

2011

Techniques and Methods

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328

257

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For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprodTo order this and other USGS information products, visit http://store.usgs.gov Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Altitude, as used in this report, refers to distance above the vertical datum.*Transmissivity: The standard unit for transmissivity is cubic foot per day per square foot times foot of aquifer thickness [(ft 3 /d)/ft 2 ]ft. In this report, the mathematically reduced form, foot squared per day (ft 2 /d), is used for convenience. The UPW Package treats nonlinearities of cell drying and rewetting by use of a continuous function of groundwater head, rather than the discrete approach of drying and rewetting that is used by the BCF, LPF, and HUF Packages. This further enables application of the Newton formulation for unconfined groundwater-flow problems because conductance derivatives required by the Newton method are smooth over the full range of head for a model cell. TablesThe NWT linearization approach generates an asymmetric matrix, which is different from the standard MODFLOW formulation that generates a symmetric matrix. Because all linear solvers presently available for use with MODFLOW-2005 solve only symmetric matrices, MODFLOW-NWT includes two previously developed asymmetric matrix-solver options. The matrix-solver options include a generalized-minimum-residual (GMRES) Solver and an Orthomin / stabilized conjugate-gradient (CGSTAB) Solver. The GMRES Solver is documented in a previously published report, such that only a brief description and input instructions are provided in this report. However, the CGSTAB Solver (called χMD) is documented in this report.Flow-property input for the UPW Package is designed based on the LPF Package and material-property input is identical to that for the LPF Package except that the rewetting and vertical-conductance correction options of the LPF Package are not available with the UPW Package. Input files constructed for the LPF Package can be used with slight modification as input for the UPW Package. This report presents the theory and methods used by MODFLOW-NWT, including the UPW Package. Additionally, this report provides comparisons of the new methodology to analytical solutions of groundwater flow and to standard MODFLOW-2005 results by use of an unconfined aquifer MODFLOW example problem. The standard MODFLOW-2005 simulation uses the LPF Package with the wet/dry option active. A new example problem also is presented to demonstrate MODFLOW-NWT's ability to provide a sol...

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“…New concepts for process-based models have been put forward in recent years, but more testing is required to assess whether previous limitations of physically-based models have yet been overcome (e.g. Reggiani et al 1998Reggiani et al , 1999Reggiani et al , 2000Reggiani et al , 2001Panday & Huyakorn 2004;Qu & Duffy 2007;Kollet & Maxwell 2006, 2008.…”

Section: Introductionmentioning

confidence: 99%

Advances in the identification and evaluation of complex environmental systems models

Wagener

Reed

Werkhoven

et al. 2009

Journal of Hydroinformatics

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Advances in our ability to model complex environmental systems are currently driven by at least four needs: (1) the need for the inclusion of uncertainty in monitoring, modelling and decisionmaking; (2) the need to provide environmental predictions everywhere; (3) the need to predict the impacts of environmental change; and (4) the need to adaptively evolve observation networks to better resolve environmental systems and embrace sensing innovations. Satisfying these needs will require improved theory, improved models and improved frameworks for making and evaluating predictions. All of these improvements should result in the long-term evolution and improvement of observation systems. In the context of this paper we discuss current bottlenecks and opportunities for advancing environmental modelling with and without local observations of system response. More realistic representations of real-world thresholds, nonlinearities and feedbacks motivates the use of more complex models as well as the consequent need for more rigorous evaluations of model performance. In the case of gauged systems, we find that global sensitivity analysis provides a widely underused tool for evaluating models' assumptions and estimating the information content of data. In the case of ungauged systems, including the modelling of environmental change impacts, we propose that the definition of constraints on the expected system response provides a promising way forward. Examples of our own work are included to support the conclusions of this discussion paper. Overall, we conclude that an important bottleneck currently limiting environmental predictions lies in how our model evaluation and identification approaches are extracting, using and evolving the information available for environmental systems at the watershed scale.

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A fully coupled physically-based spatially-distributed model for evaluating surface/subsurface flow

Cited by 440 publications

References 27 publications

A review of model applications for structured soils: a) Water flow and tracer transport

A review of model applications for structured soils: a) Water flow and tracer transport

MODFLOW-NWT, a Newton formulation for MODFLOW-2005

Advances in the identification and evaluation of complex environmental systems models

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