Simulating the impact of glaciations on continental groundwater flow systems: 1. Relevant processes and model formulation

[1] In the recent literature, it has been shown that Pleistocene glaciations had a large impact on North American regional groundwater flow systems. Because of the myriad of complex processes and large spatial scales involved during periods of glaciation, numerical models have become powerful tools to examine how ice sheets control subsurface flow systems. In this paper, the key processes that must be represented in a continental-scale 3-D numerical model of groundwater flow during a glaciation are reviewed, including subglacial infiltration, density-dependent (i.e., high-salinity) groundwater flow, permafrost evolution, isostasy, sea level changes, and ice sheet loading. One-dimensional hydromechanical coupling associated with ice loading and brine generation were included in the numerical model HydroGeoSphere and tested against newly developed exact analytical solutions to verify their implementation. Other processes such as subglacial infiltration, permafrost evolution, and isostasy were explicitly added to HydroGeoSphere. A specified flux constrained by the ice sheet thickness was found to be the most appropriate boundary condition in the subglacial environment. For the permafrost, frozen and unfrozen elements can be selected at every time step with specified hydraulic conductivities. For the isostatic adjustment, the elevations of all the grid nodes in each vertical grid column below the ice sheet are adjusted uniformly to account for the Earth's crust depression and rebound. In a companion paper, the model is applied to the Wisconsinian glaciation over the Canadian landscape in order to illustrate the concepts developed in this paper and to better understand the impact of glaciation on 3-D continental groundwater flow systems.

[1]  E. C. Childs.  Dynamics of fluids in Porous Media , 1973 .

[2]  N. R. Morgenstern,et al.  Physics, chemistry, and mechanics of frozen ground. A review : Conference. In Permafrost - North American contribution to the 2nd Internat. Conference. 11F, 182R. NAT. ACAD. SCI. WASHINGTON, 1973, P257–288 , 1974 .

[3]  Tim Burt,et al.  Hydraulic conductivity in frozen soils , 1976 .

[4]  R. Armstrong,et al.  The Physics of Glaciers , 1981 .

[5]  E. Frind.  Simulation of long-term transient density-dependent transport in groundwater , 1982 .

[6]  A. N. Stokes,et al.  An Improved Method for Numerical Inversion of Laplace Transforms , 1982 .

[7]  D. Kane,et al.  Water movement into seasonally frozen soils , 1983 .

[8]  D. Siegel,et al.  Isotopic Evidence for Glacial Meltwater Recharge to the Cambrian-Ordovician Aquifer, North-Central United States , 1984, Quaternary Research.

[9]  J. Teller.  Proglacial lakes and the southern margin of the Laurentide Ice Sheet , 1987 .

[10]  D. Siegel.  Geochemistry of the Cambrian-Ordivician aquifer system in the northern Midwest, United States , 1989 .

[11]  J. Teller.  Volume and Routing of Late-Glacial Runoff from the Southern Laurentide Ice Sheet , 1990, Quaternary Research.

[12]  D. Siegel.  Evidence for dilution of deep, confined ground water by vertical recharge of isotopically heavy Pleistocene water , 1991 .

[13]  P. Glasbergen,et al.  Deep circulation of groundwater in overpressured subglacial aquifers and its geological consequences , 1993 .

[14]  W. Peltier,et al.  Ice Age Paleotopography , 1994, Science.

[15]  M. I. Sheppard,et al.  Continental glaciation and nuclear fuel waste disposal: Canada's approach and assessment of the impact on nuclide transport through the biosphere , 1995 .

[16]  G. Boulton,et al.  Groundwater flow beneath ice sheets: Part I — Large scale patterns , 1995 .

[17]  J. Cherry,et al.  Recent cross-formational fluid flow and mixing in the shallow Michigan Basin , 1995 .

[18]  C. Forsberg.  Possible consequences of glacially induced groundwater flow , 1996 .

[19]  E. Sudicky,et al.  Three-dimensional analysis of variably-saturated flow and solute transport in discretely-fractured porous media , 1996 .

[20]  G. Boulton,et al.  The impact of glaciation on the groundwater regime of Northwest Europe , 1996 .

[21]  G. Boulton,et al.  The effects of Pleistocene glaciations on the geohydrological system of Northwest Europe , 1997 .

[22]  J. Piotrowski,et al.  Response of sediment to ice-sheet loading in northwestern Germany: effective stresses and glacier-bed stability , 1997, Journal of Glaciology.

[23]  J. Piotrowski.  Subglacial hydrology in north-western germany during the last glaciation: groundwater flow, tunnel valleys and hydrological cycles , 1997 .

[24]  J. Piotrowski.  Subglacial groundwater flow during the last glaciation in northwestern Germany , 1997 .

[25]  C. Neuzil,et al.  Glaciation and regional ground-water flow in the Fennoscandian Shield: Site 94 , 1998 .

[26]  C. Talbot.  Ice ages and nuclear waste isolation , 1999 .

[27]  W. Peltier,et al.  Impact of thermomechanical ice sheet coupling on a model of the 100 kyr ice age cycle , 1999 .

[28]  Herbert F. Wang.  Theory of Linear Poroelasticity with Applications to Geomechanics and Hydrogeology , 2000 .

[29]  K. Raven,et al.  Groundwater mixing dynamics at a Canadian Shield mine , 2000 .

[30]  M. Gascoyne.  A review of published literature on the effects of permafrost on the hydrogeochemistry of bedrock , 2000 .

[31]  K. Raven,et al.  Recharge and Preservation of Laurentide Glacial Melt Water in the Canadian Shield , 2000 .

[32]  D. Macayeal,et al.  A numerical investigation of ice-lobe-permafrost interaction around the southern Laurentide ice sheet , 2000 .

[33]  R. Betcher,et al.  Reversal of the regional-scale flow system of the Williston basin in response to Pleistocene glaciation , 2000 .

[34]  L. Hinzman,et al.  Non-conductive heat transfer associated with frozen soils , 2001 .

[35]  Analysis of groundwater flow beneath ice sheets , 2001 .

[36]  W. Edmunds.  Palaeowaters in European coastal aquifers — the goals and main conclusions of the PALAEAUX project , 2001, Geological Society, London, Special Publications.

[37]  G. Clarke,et al.  A multicomponent coupled model of glacier hydrology 2. Application to Trapridge Glacier, Yukon, Canada , 2002 .

[38]  S. Bachu,et al.  Equations of state for basin geofluids: algorithm review and intercomparison for brines , 2002 .

[39]  W. Peltier,et al.  Greenland glacial history and local geodynamic consequences , 2002 .

[40]  M M Burgess,et al.  A digital database of permafrost thickness in Canada , 2002 .

[41]  G. Clarke,et al.  A multicomponent coupled model of glacier hydrology 1. Theory and synthetic examples , 2002 .

[42]  R. Haggerty,et al.  Modeling the subglacial hydrology of the late Pleistocene Lake Michigan Lobe, Laurentide Ice Sheet , 2002 .

[43]  J. McIntosh,et al.  Pleistocene recharge to midcontinent basins: effects on salinity structure and microbial gas generation , 2002 .

[44]  P. Vidstrand.  Surface and subsurface conditions in permafrost areas – a literature review , 2003 .

[45]  B. Dugan,et al.  Pleistocene hydrogeology of the Atlantic continental shelf, New England , 2003 .

[46]  C. E. Neuzil,et al.  Hydromechanical coupling in geologic processes , 2003 .

[47]  Alain Dassargues,et al.  Climate change impacts on groundwater resources: modelled deficits in a chalky aquifer, Geer basin, Belgium , 2004 .

[48]  Kes Heffer,et al.  Theory of linear poroelasticity with applications to geomechanics and hydrogeology , 2004 .

[49]  Lev Tarasov,et al.  A geophysically constrained large ensemble analysis of the deglacial history of the North American ice-sheet complex , 2004 .

[50]  U. Michie,et al.  Estimating hydrogeological conditions over the last 120 ka: an example from the Sellafield area, UK , 2004, Journal of the Geological Society.

[51]  D. T. Long,et al.  Analysis of modern and Pleistocene hydrologic exchange between Saginaw Bay (Lake Huron) and the Saginaw Lowlands area , 2004 .

[52]  J. McIntosh,et al.  Volumetrically significant recharge of Pleistocene glacial meltwaters into epicratonic basins: Constraints imposed by solute mass balances , 2005 .

[53]  R. Christiansson,et al.  DECOVALEX III BMT3/BENCHPAR WP4: The thermo-hydro-mechanical responses to a glacial cycle and their potential implications for deep geological disposal of nuclear fuel waste in a fractured crystalline rock mass , 2005 .

[54]  D. D. Griffin,et al.  NMR measurements of permafrost : unfrozen water assay, pore-scale distribution of ice, and hydraulic permeability of sediments , 2005 .

[55]  S. Grasby,et al.  Subglacial recharge into the Western Canada Sedimentary Basin—Impact of Pleistocene glaciation on basin hydrodynamics , 2005 .

[56]  G. Garven,et al.  Modeling Variable-Density Fluid Flow and Solute Transport in Glaciated Sedimentary Basins , 2005 .

[57]  T. Chan,et al.  Subsurface hydro-mechanical (HM) impacts of glaciation: Sensitivity to transient analysis, HM coupling, fracture zone connectivity and model dimensionality , 2005 .

[58]  W. Peltier,et al.  A calibrated deglacial drainage chronology for the North American continent: evidence of an Arctic trigger for the Younger Dryas , 2006 .

[59]  Thomas Graf,et al.  Modeling coupled thermohaline flow and reactive solute transport in discretely-fractured porous media , 2006 .

[60]  Grant Ferguson,et al.  Hydrogeology of the Winnipeg Formation in Manitoba, Canada , 2007 .

[61]  W. Peltier,et al.  Coevolution of continental ice cover and permafrost extent over the last glacial‐interglacial cycle in North America , 2007 .

[62]  J. McIntosh,et al.  Pleistocene hydrology of North America: The role of ice sheets in reorganizing groundwater flow systems , 2007 .

[63]  J. Lemieux.  Impact of the Wisconsinian Glaciation on Canadian Continental Groundwater Flow , 2007 .

[64]  C. Voss,et al.  Groundwater flow with energy transport and water-ice phase change: Numerical simulations, benchmarks, and application to freezing in peat bogs , 2007 .

[65]  E. A. Sudicky,et al.  Simulating the impact of glaciations on continental groundwater flow systems: 2. Model application to the Wisconsinian glaciation over the Canadian landscape , 2008 .

[66]  E. Sudicky,et al.  Dynamics of groundwater recharge and seepage over the Canadian landscape during the Wisconsinian glaciation , 2008 .