Mountain Hydrology Research in Yukon
by Sean Carey and John Pomeroy
The Wolf Creek Research Basin and Coal Lake in the fall.Photo: Sean Carey
Map of Wolf Creek and its infrastructure, Yukon Territory
Rapid climate and hydrological changes are detrimentally impacting Canada’s western mountains, and communities are struggling to understand and adapt to this new reality. Sparse observations and limited scientific capacity hamper our ability to forecast changes across Canada’s northwest. As part of the Global Water Futures program, the largest university-led water-focussed initiative in the world, the Mountain Water Futures (MWF) project worked to provide Canadians with tools and techniques to manage water futures in Canada’s western mountains. This region is undergoing rapid change as glaciers recede, snowpacks diminish, permafrost thaws, and vegetation shifts. By working with a host of partners, MWF maintains several observatories where mountain hydrometeorological processes are studied and long-term data is collected. Work at these observatories helps guide the development of numerical models that can be used to predict future scenarios, which supports stakeholders in decision-making and policy development. Here, we selectively highlight the ongoing partnership MWF has forged with the Government of Yukon, and the development of a next-generation flow forecast system.
Dr. Erin Nicholls checking on one of several climate stations within the basin. Photo: Sean Carey
Forest meteorological tower. Photo: Sean Carey
In 1992, the Wolf Creek Research Basin (WCRB) was established in the sub-arctic mountainous headwaters of the Yukon River, near Whitehorse, Yukon.1 The site was selected to represent many headwater basins along the far northern reaches of the North American Cordillera. At the time, the role of WCRB was to provide science-based evidence for decision-making about water, climate, and the biosphere, and to provide a testbed to help resolve deficiencies in hydrological models that performed very poorly in cold climates. Careful measurements of climate, the water cycle, and ecological change across its different elevation-based biomes provided the foundation to support large-scale scientific programs and have attracted scientists and students from across Canada and the world. In the face of steep declines in federal government monitoring capacity, these programs have positioned WCRB as a sentinel observatory that is part of several global environmental monitoring programs. In 2022, WCRB celebrated its thirtieth anniversary and deepened its partnership with the Government of Yukon through a formal agreement to share physical space and resources, and to continue to collaborate in tackling emerging scientific issues. While the past thirty years have produced a considerable scientific legacy, maintaining and diversifying WCRB becomes increasingly important to help understand environmental change and provide guidance for adaptation initiatives.
The Yukon River Basin (YRB) is one of the main mountain rivers of North America and is shared between Canada and the US. The Canadian part covers almost half of the Yukon and a small portion of the province of British Columbia, while the US part falls entirely within the state of Alaska. Prior to 2018, there was no predictive hydrological model for the Canadian portion of the YRB, despite the severe flood damages to the many Yukon communities that lie on its main river and tributaries from high streamflow and river ice breakup events. Global Water Futures, working with Yukon’s Department of Environment and Environment and Climate Change Canada, set up a streamflow forecasting system for the YRB. This project developed, calibrated, validated, and operationalized a physically based streamflow discharge forecasting system for the Yukon River and several of its tributary rivers within the territory. There were several challenges in doing so due to the cold regions hydrology of the basin. The southern part of the YRB is characterized by large glaciers at high elevations (up to 4,700 metres above sea level) with steep slopes, thus generating considerable runoff. There are also mountain ranges on the eastern and northern boundaries of the basin, while the western areas are milder in slope and partially forested. Snow redistribution, snowmelt, glacier melt, and frozen soil processes in winter and spring, along with summertime rainfall-runoff and evapotranspiration processes, are key to the simulation of streamflow in the basin.
The Yukon River Basin streamflow forecasting system uses the MESH (Modélisation Environmentale Communautaire - Surface and Hydrology) hydrological land surface model. MESH is a state-of-the-art semi-distributed cold regions hydrological land surface model, which models both the vertical exchanges of heat and moisture between the land surface and the atmosphere, as well as the horizontal transfer of water to streams that is routed hydrologically to the outlet of the basin. MESH relies on meteorological forecasts from Environment and Climate Change Canada (ECCC) to run the model across Yukon, with the system running on Amazon cloud services for reliability, and sends automated daily reports to the Government of Yukon.
View of upper forest climate station. Photo: David Barrett
The Wolf Creek Research Basin in winter. Photo: Sean Carey
As the surging waters of the Klondike River near Dawson City subsided late in the spring of 2023, Yukon government officials reflected on how these hydrological modelling efforts helped them better forecast flood events and issue flood advisories. This is the third year in a row that Yukon communities have seen record flooding in at least one area. Anthony Bier, acting senior hydrologist at the Yukon government, stated: “In my experience, over the past two years especially, we use the reports on a daily basis.” Bier added that the model outputs help forecasters gauge the warning level for the advisories they release to the public, and in turn help emergency response officials understand the level of risk an event presents to communities. “We rely on this relationship triad between the [Government of] Yukon, the University of Saskatchewan, and McMaster University,” he said. “One day we hope to run the forecasts ourselves, but we are not quite there yet.”
Dr. Sean Carey is a Professor in the School of Earth, Environment & Society and heads the Watershed Hydrology Group at McMaster University. His research interests include hydrological, biogeochemical, and land surface processes in cold environments and has been working in Wolf Creek since 1995.
Dr. John Pomeroy is the Canada Research Chair in Water Resources and Climate Change at the University of Saskatchewan. His research interests are on the impact of land use and climate change on cold regions hydrology and water quality, and improved prediction of climate change impacts, especially floods and droughts. Dr. Pomeroy has been working in Wolf Creek since 1992.
Further resources:
Global Water Futures: http://gwf.usask.ca
Mountain Water Futures: http://www.mountainwaterfutures.ca
Wolf creek Research Basin: http://wolfcreekresearchbasin.ca
References
1 See Kabir Rasouli, John W. Pomeroy, J. Richard Janowicz, Tyler J. Williams, and Sean K. Carey, “A long-term hydrometeorological dataset (1993-2014) of a northern mountain basin: Wolf Creek Research Basin, Yukon Territory, Canada. Earth System Science Data 11,1 (2019) 89-100, https://essd.copernicus.org/articles/11/89/2019/.