Projected Climate Impacts on Snow Depths and Discharges In the Lake Winnipeg Watershed

Abstract

A number of studies have documented recent trends toward earlier spring snowmelt (e.g. Brown, 2000) and a decline in snow cover extent (Dery and Brown, 2007) across many regions of the Northern Hemisphere in response to enhanced spring warming. Snow cover is anticipated to decrease in the future due to global warming, as snow cover formation and melt are closely related to a temperature threshold of 0oC. The hydrologic regime of the Lake Winnipeg watershed (LWW), Canada, is dominated by spring snowmelt runoff which accounts for more than 80% of the total annual surface runoff in the region, despite the fact that snowfall only contributes one third of total annual precipitation (Gray and Landine, 1988). Thus, spring snowmelt runoff plays an important role in the agricultural water supply of the region. This study investigated the Canadian regional climate model (CRCM4) future projections of precipitation and temperature as well as maximum snow depth, snow cover duration and snowmelt runoff from the North American Regional Climate Change Assessment Program (NARCCAP) database to assess the potential hydrologic impacts of climate change over the Lake Winnipeg watershed.