by Erling Friis-Baastad
When Tyler Williams was considering careers, he knew that whatever he decided upon would have to be “impactful.” As there are few natural forces with more impact on our planet than water, and no precious resources more readily influenced by climatic changes, the newly-minted hydrologist obviously chose well. “Everybody needs water,” says Williams.
In January, he began working as hydrology research assistant for the University of Saskatchewan on a collaborative project with McMaster University and the Yukon Department of Environment. Under the supervision of Richard Janowicz of the water resources branch, Williams is studying the Wolf Creek basin to help determine the state of that water source and to predict changes that might occur there as climate changes.
Wolf Creek basin, about 15 kilometres south of Whitehorse, is an especially suitable locale in which to launch research and develop predictive models because there is a rich store of data on the water course, which has been under study for about 20 years, says Williams. Compared with some southern regions, not much long-term water monitoring work has been undertaken in the Yukon, and records like those of Wolf Creek are rare. He and his colleagues are now pulling two decades of historical data, and current research results, into the Cold Regions Hydrological Model that’s been developed by the University of Saskatchewan.
Computers are being used to create possible future scenarios by experimenting with temperatures and precipitation levels. If the basin becomes warmer or cooler, drier or wetter, how will the water flow at Wolf Creek be affected in a given year?
There are three primary aspects of the watershed being monitored in the project. During the winter, snow surveys are conducted about once a month, says Williams. The researchers look at depth and moisture content, “the total water that’s available within the snow.”
Come late spring and summer, attention turns to stream-flow measurements. How much water is moving through Wolf Creek, and how quickly?
There are three meteorological stations out there, as well, measuring such factors as temperature, relative humidity, precipitation and solar radiation.
“Further down the line, once we’re comfortable with how things are working, we’ll adapt (the modeling) and start applying it to other areas of the territory,” says Williams.
Wolf Creek is a good site choice for preliminary models, not only because of the two decades of study that have been done there, but because of the variety of environments within the 179-square-kilometre basin - including boreal forest, areas of low, thick buckbrush and a relatively bare alpine region. Different environments can have characteristic effects on how water is retained or lost. The reverse is also true: changes to water flow can affect changes to environments.
“With warmer temperatures vegetation is obviously changing, the shrub cover starts expanding into areas that didn’t have it before, and that will affect how much snow that area holds,” says Williams. “It’s all interrelated.
“The biggest loss of water during the winter is sublimation from blowing snow. Once snow gets picked up and thrown around in the air, some of it doesn’t come back down. Where you have shrubs, you don’t have as much blowing snow, you have a shield to protect it.”
Trees, however, can have an opposite effect. Trees trap snow in the canopy. Sublimation from the canopy contributes to overall snow loss. Williams recalls an earlier study in which a tree was cut down, lifted by a crane and hung from a tower near Wolf Creek. After a period of snowfall, the tree could be weighed and scientists could get a better idea of how much sublimation from the treetops contributes to water loss.
Researchers can also apply their Wolf Creek discoveries to other water courses that flow through similar environments. It won’t be necessary to establish complex research sites like those at Wolf Creek in all the other basins in order to make educated guesses about their possible futures.
The model is ongoing and flexible, Williams stresses. Any future research on the watersheds by other scientists can be readily added to the data.
“In a sense this model is never fully completed. It’s operational now. There are people who are using this model now,” he says. Far from being relevant only to the territory, these water flow scenarios are being studied in the Alps, Tibet, the Rockies and all over Canada, by governments and academics.
As time goes on, we should get an ever-clearer idea of where variables are taking us. Does a rise in temperature mean more or less snow available for spring river discharge? Does loss of forest cover mean decreased snow sublimation from the canopy? How will temperature increases caused by climate change affect water resources in a colder climate?
“Generally, up here, we’re worried about too much water,” says Williams. But, of course, that could change, hence the value of myriad models.
Who needs the data? All of us, sooner or later. Right now, road infrastructure is especially affected, including bridge design and culvert sizes. Cities might want to reconsider expansion plans, if they involve future flood plains. But city engineers would be wise not to discount the possibility of drinking-water shortages, or an increase in wildfire situations.
When we start combining the variables from buckbrush to blizzards, anything’s possible. Considering the combinations and permutations, it’s difficult to imagine facing the future without a powerful tool like the Cold Regions Hydrological Model. For more information go to www.usask.ca/hydrology/CRHM.php
This column is co-ordinated by the Yukon Research Centre at Yukon College with major financial support from Environment Yukon and Yukon College. The articles are archived at www.yukoncollege.yk.ca/research