HR: 08:55h
AN: CG21B-04    [Abstracts]
TI: Response of River Discharge to Changing Climate Over the Past Millennium in the Upper Mackenzie Basin: Implications for Water Resource Management
AU: * Wolfe, B B
EM: bwolfe@wlu.ca
AF: Department of Geography and Environmental Studies Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2L 3C5, Canada
AU: Hall, R I
EM: rihall@sciborg.uwaterloo.ca
AF: Department of Biology University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
AU: Edwards, T W
EM: twdedwar@sciborg.uwaterloo.ca
AF: Department of Earth and Environmental Sciences University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
AU: Jarvis, S R
EM: sznnjarvis@yahoo.com
AF: Department of Geography and Environmental Studies Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2L 3C5, Canada
AU: Sinnatamby, R N
EM: rn.sinnatamby@gmail.com
AF: Department of Biology University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
AU: YI, Y
EM: yiyi@uvic.ca
AF: Department of Earth and Environmental Sciences University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
AU: Johnston, J W
EM: jjohnston@wlu.ca
AF: Department of Geography and Environmental Studies Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2L 3C5, Canada
AB: Runoff generated from high elevations is the primary source of freshwater for western North America, yet this critical resource is managed on the basis of short instrumental records that encompass an insufficient range of climatic conditions. Like other streams that drain this part of the continent and flow across the northern Great Plains, where seasonal and extended intervals of water deficit are a natural element of the landscape, the Peace and Athabasca rivers provide water that is crucial for societal needs. Climate variability and rapidly increasing industrial development are, however, raising concerns over the future availability of water resources for continued economic growth in these watersheds and to maintain the integrity of aquatic ecosystems, including the Peace-Athabasca Delta (PAD). This is particularly acute for the Athabasca River because the Alberta oil sands industry remains dependent on its water for bitumen extraction. Here we report the effects of climate change over the past 1000 years on river discharge in the upper Mackenzie River system based on paleoenvironmental information from the PAD and Lake Athabasca. The delta landscape responds to hydroclimatic changes with marked variability, capturing systematic changes in ice-jam flood frequency and perched basin water balance. Lake Athabasca level appears to directly monitor overall water availability with the highest levels occurring in concert with maximum glacier extent during the Little Ice Age, and the lowest during the 11th century prior to medieval glacier expansion. Recent climate-driven hydrological change appears to be on a trajectory to even lower levels as high-elevation snow and glacier meltwater contributions both continue to decline. The temporal perspective offered by these paleohydrological reconstructions indicates that climatic changes over the past millennium have led to characteristic responses in the quantity and seasonality of streamflow generated from the hydrographic apex of North America. For water resource managers, a key feature that emerges from these results is that the hydrograph of the 21st century may be evolving towards conditions unprecedented over the past 1000 years, extending beyond the 11th century when reduced glacier meltwater contributions were partly compensated by abundant snowmelt runoff. Continuing reduction in both peak and total discharge clearly underscores the need for stringent allocation of freshwater resources in these watersheds.
DE: 0746 Lakes (9345)
DE: 1800 HYDROLOGY
DE: 1807 Climate impacts
DE: 1820 Floodplain dynamics
DE: 1880 Water management (6334)
SC: Canadian Geophysical Union [CG]
MN: 2009 Joint Assembly