Table of Contents

ParFlow is a three-dimensional variably saturated groundwater flow code that was originally developed at the Lawrence Livermore National Laboratory, USA, and has been recently extended to accommodate overland flow and river routing. ParFlow can be applied in coupled mode with the Common Land Model, CLM, which has been implemented modularly into ParFlow and allows to simulate the integrated hydrologic and energy cycles from the deeper subsurface across the landsurface. The modular version of ParFlow including CLM is called ParFlow[CLM]. ParFlow[CLM] is designed for high-performance computing and thus affords large-scale high-resolution simulations. The usefulness of the coupled approach has been shown in a number of studies including the characterization of groundwater dynamics and land-energy feedbacks under climate change conditions at the decadal time scale.

ParFlow is an open-source effort under the terms of the GNU license and can be downloaded for free.

This is an example animation of a ParFlow simulation using the parallel rendering software VisIt.

Ashby S.F. and R.D. Falgout, 1996, A Parallel Multigrid Preconditioned Conjugate Gr~dient Algorithm for Groundwater Flow Simulations, Nuclear Science and Engineering 124:145-159

Dai, X.P., Zeng, X. and Dickinson, C.D., 2001. The Common Land Model (CLM): Technical documentation and user's guide.

Frei S., Fleckenstein J., Kollet S.J., Maxwell R.M., 2009, Patterns and dynamics of river aquifer exchange with variably saturated flow, J. of Hydrology, (in press).

Jones, J.E. and Woodward, C.S., 2001. Newton-Krylov-multigrid solvers for large-scale, highly heterogeneous, variably saturated flow problems. Advances in Water Resources, 24(7): 763-774.

Maxwell, R.M. and N.L. Miller. Development of a coupled land surface and groundwater model. Journal of Hydrometeorology,6(3), 233-247, 2005.

Maxwell R.M., Chow F.K., Kollet S.J., 2007. The groundwater-land-surface-atmosphere connection: Soil moisture effects on the atmospheric boundary layer in coupled simulations, Advances in Water Resour, 30(12), 2447-2466.

Maxwell R.M., Kollet S.J., 2008, The interdependence of groundwater dynamics and land-energy feedbacks under climate change, Nature Geoscience, 1, 665-669.

Maxwell R.M., Kollet S.J., 2008. Quantifying the effects of three-dimensional subsurface heterogeneity on Hortonian runoff processes using a numerical, stochastic approach, Advances in Water Resour. 31(5), 807-817.

Maxwell R.M., Tompson A.F.B., Kollet S.J., 2009, A serendipitous, long-term infiltration experiment: Water and tritium circulation beneath the CAMBRIC Trench at the Nevada Test Site, J. Cont. Hydrology., 108, 12-28.

Kollet S.J., Maxwell R.M., 2006. Integrated surface-groundwater flow modeling: a free-surface overland flow boundary condition in a parallel groundwater flow model, Advances in Water Resour., 29, 945-958.

Kollet, S.J., and R. M. Maxwell, 2008, Capturing the influence of groundwater dynamics on land surface processes using an integrated, distributed watershed model, Water Resour. Res., 44(W02402), doi:10.1029/2007WR006004.

Kollet S.J., Maxwell R.M., 2008, Demonstrating fractal scaling of baseflow residence time distributions using a fully coupled groundwater and land surface model, Geophys. Res. Letter, 35, 07402, doi:10.1029/2008GL033215.

Kollet, S.J., 2009 (invited), Influence of soil heterogeneity on evapotranspiration under shallow water table conditions: transient, stochastic simulations, Environ. Res. Letters, (in review).

Kollet S.J., Cvijanovic I., SchÃ¼ttemeyer D., Maxwell R.M., Moene A.F., Bayer P., 2009, The influence of rain sensible heat, subsurface heat convection and the lower temperature boundary condition on the energy balance at the land surface, Vadose Zone J., (in press).