Groundwater–Surface Water Interaction: Process Understanding, Conceptualization and Modelling (Proceedings of Symposium HS1002 at IUGG2007, Perugia, July 2007). IAHS Publ. 321, 2008, 61-66.

Importance of seasonal frost to peat water storage: Western Boreal Plains, Canada

R. M. PETRONE¹, K. J. DEVITO², U. SILINS³, C. MENDOZA⁴, S. C. KAUFMAN¹ & J. S. PRICE⁵

1 Cold Regions Research Centre, Wilfrid Laurier University, 75 University Ave West, Waterloo, Ontario N2L 3C5, Canada

rpetrone@wlu.ca

2 Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada

3 Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada

4 Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada

5 Department of Geography, University of Waterloo, Waterloo, Ontario, Canada

Abstract Ponds and peatlands comprise up to 50% of the landscape in the Canadian Western Boreal Plain (WBP) where summer precipitation is often outpaced by evapotranspiration. Further, hillslope groundwater position does not follow topography, therefore groundwater fluxes and stores in riparian peatlands influence pond water levels and root zone moisture sources for forested uplands. To accurately describe the transport and retention properties of water in peat, it is important to quantify the effect of seasonal frost on subsidence and the resulting water movement within a riparian peatland. Results from the Utikuma Lake region in North-Central Alberta, Canada, demonstrate that thick (and persistent) ground frost hinders pore collapse (peat compression) above the water table until late summer when the ground has thawed, after which true compression is still limited to the top 50 cm and not well related to changes in peatland water table or pond water level.

Key words boreal; peatlands; subsidence; ground frost; wetlands; disturbance; water storage; seismic lines