Multi-scale studies of Permafrost Thaw Impacts on Eco-Hydrology in the Southern Fringe of Permafrost, Northwestern Canada.

English Abstract:

The southern Taiga Plains ecoregion is one of the most rapidly warming regions on Earth, and is experiencing unprecedented rates of industrial expansion and related human disturbance. The permafrost in this region is relatively warm, thin and discontinuous. As a result, permafrost thaw is widespread and often leads to the transformation of forested permafrost terrains to permafrost-free, tree-less wetlands. Such permafrost thaw-induced landcover change has the potential to disrupt the hydrological cycle at local and regional scales. However, the hydrological implications of this permafrost-thaw induced land cover transformation remain poorly understood despite its demonstrated pan-arctic occurrence. As a result, there is an urgent need for an improved understanding of, and ability to predict permafrost thaw and its hydrological consequences. This paper presents the results of a long term field study on permafrost thaw-induced land-cover change and the resulting hydrological impact; and demonstrates how this new knowledge is applied to improve predictive capacities. Field measurements were conducted between 1999 and 2014 at Scotty Creek in the peatland-dominated southern fringe of discontinuous permafrost near Fort Simpson, Northwest Territories. Field studies at Scotty Creek have focussed on 1) improving the understanding of the volume and timing of runoff for different ground thaw and moisture conditions; 2) simulating the major water flux and storage processes controlling runoff; 3) characterising permafrost impacts at larger scales through field investigation and subsequent adaptation of a regional-scale permafrost model; and 4) estimating future quantities of runoff and surface water storage under possible scenarios of climate warming and human disturbance. Progress on each of these areas of will be the described.