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Department of Geography



Supraglacial, Englacial and Subglacial Hydrology of Glaciers and Ice Sheets

This work is concerned with modelling the water movement through: i) supraglacial snowpacks (unsaturated / saturated; isothermal / non-isothermal) and across ice surfaces; ii) englacial pipes and channels; and iii) subglacial distributed and channelised drainage systems. Data to develop and test the model have been collected at Haut Glacier d'Arolla, Switzerland and Midre Lovénbreen, Svalbard. The model uses the output of a distributed surface energy balance melt model (described in other projects). An early version of the snowpack model used simple equations (Colbeck, 1978) to account for the delay associated with vertical routing through an unsaturated layer and lateral movement through a saturated zone (Arnold et al, 1998; Willis et al, 2002). The most recent snowpack model uses a distributed version of the 1-D (vertical) snow energy and mass balance model SNTHERM (Jordon, 1991) to calculate vertical routing of water. Output from this component has been tested against measurements of snowpack temperature and density profiles (Figure 1) and lysimeter measurements of water outflow from the base of the unsaturated snowpack (Figure 2). This model component can be used to calculate the influence of the unsaturated snowpack on the spatial and temporal patterns of water flow on the glacier surface (Figure 3). The second component uses the 3-D groundwater model MODFLOW (Harbaugh et al, 2000) to route the water laterally through the saturated layer at the base of the snowpack. This component of the model is tested against measurements of water table depth within the saturated layer. The full snowpack model can be used to calculate spatial and temporal patterns of water storage in the unsaturated and saturated parts of the snowpack (Figure 4), and temporal patterns of runoff across the glacier surface and into crevasses and moulins (Figure 5). Application of the model to Haut Glacier d’Arolla in 2000 showed that up to 400,000 m3, of water may be stored within the snowpack during the early summer before being released. This represents approximately 10% of all water input during the early summer.

The englacial / subglacial water routing is simulated using an adaptation of part of the US Environmental Protection Agency Storm Water Management Model (SWMM) (Roesner et al, 1988). This model component has been adapted to account for growth and shrinkage of ice walled channels. A range of empirical data can be used to test the full model, notably moulin to snout travel times (from dye tracing experiments), subglacial water pressure fluctuations (measured in boreholes), and proglacial stream hydrographs.

So far, the model has been implemented mostly on Haut Glacier d’Arolla, Switzerland in collaboration with our former PhD student, Andrew Fox (University of Sheffield) but we are currently adapting and applying the model to the Paakitsoq, Ilulissat area of Western Greenland in collaboration with our Masters student, Sylvan Long, and our colleague Andreas Ahlstrom (Greenland Geological Survey).


  • Colbeck SC. 1978. The physical aspects of water flow through snow. In Advances in Hydrosciences, Vol. 11, Chow VT (ed.). Academic Press: New York; 165-206.
  • Harbaugh, A. W., E. R. Banta, M. C. Hill and M. G. McDonald. 2000. MODFLOW-2000, The U.S. Geological Survey modular ground-water model - User guide to modularization concepts and the ground-water flow process, U.S. Geological Survey. Open-File Report 00-92.
  • Jordan, R. E. 1991. A one-dimensional temperature model for a snow cover: Technical documentation for SNTHERM.89. Hanover, New Hampshire, US Army Corps of Engineers.
  • Roesner, L.A., Aldrich, J.A. and R.E. Dickinson. 1988. Storm Water Management Model, Version 4, User's Manual: Extran Addendum. Athens, GA, 188pp.

Papers relating to this project

  • Arnold, N., Richards, K, Willis, I. and Sharp, M. 1998. Initial results from a semi-distributed, physically-based model of glacier hydrology. Hydrological Processes, 12, 191-219.
  • Fox, A.M., Willis, I.C. and Arnold, N.S. 2008. Modification and testing of a one-dimensional energy and mass balance model for supraglacial snowpacks. Hydrological Processes. DOI: 10.1002/hyp.6908.
  • Willis, I., Arnold, N. and Brock, B. 2002. Effect of snowpack removal on energy balance, melt and runoff in a small supraglacial catchment. Hydrological Processes, 16, 2721-2749.


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Figure 1. Observed (blue) and modelled (orange) snowpack density profiles on Day 134 (a), Day 150 (b), Day 170 (c), Day 172 (d), Day 178 (e) and Day 181. Haut Glacier d’Arolla, 2000.

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Figure 2 Observed and modelled outflow from the base of the snowpack.

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Figure 3 Modelled melt hydrograph peak to base of snowpack hydrograph peak: (a) Day 141, (b) Day 161, (c) Day 181. Haut Glacier d’Arolla 2000.

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Figure 4. Modelled saturated layer thickness across the glacier at 1800hrs on: (a) Day 141, (b) 161, (c) 181.

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Figure 5. Time series of input discharge for (a) moulin 7, (b) moulin 9, (c) moulin 25 and (d) moulin 26 which are progressively closer and closer to the glacier snout. Note change in scale on y-axis. The effects on the hydrographs of the depletion and removal of the snowpack can be seen.