This article first appeared in the Fall 2014 issue of the U of S alumni magazine The Green and White
Fresh water: we can’t live without it. The human body is made up of 65 per cent water - roughly the same proportion of Saskatchewan’s population that relies on the Lake Diefenbaker reservoir for fresh water - including local lake communities and those further downstream, such as Saskatoon, and Moose Jaw and Regina via Buffalo Pound Lake.
Water from Diefenbaker is also a source for agricultural irrigation, mining and industrial use, fish farm operations, and recreation. And all of these stakeholders are looking to the reservoir more and more: a growing population needs more fresh drinking water; potash and other mines want more water for increased production; farmers want to double irrigation; fish farms are expanding to meet consumer demand; and developers are seeking the ever-attractive lakefront property.
“Lake Diefenbaker is called Saskatchewan’s prairie jewel, and it really is; it’s an oasis,” noted biologist Jeff Hudson, lead limnology (fresh water) researcher at the University of Saskatchewan’s Global Institute for Water Security. But we could be in danger of losing our oasis if we do not better understand how to manage it. “The World Wildlife Fund considers the South Saskatchewan one of two Canadian rivers most endangered for flow due to heavy development. So there are many reasons to show regard and proper planning. When we have a rapidly growing province, [fresh water] must be a consideration, thinking longterm with this non-renewable resource.”
The lake is the result of the Gardiner Dam, finished in 1967 to both control water levels and provide hydroelectricity. But the dam also has some negative side effects: it draws water from the mid-section to release back into the river system, causing cooler overall temperatures in summer and warmer temperatures in winter, which affects seasonal ice formation and the lake’s habitat and inhabitants - large and small - year-round.
We also need to realize the human risk if a water source so much of our population depends upon were to be compromised, either from a shortage or contamination.
“There are all types of reasons to be prepared, and to minimize our use.” Hudson said. “Most cities are done in a matter of weeks without water. If we don’t take it more seriously, we may find ourselves without the water we need to survive, and this is what limits population size.”
Jania Chilima (MES’11), a graduate student in the School of Environment and Sustainability running research focus groups on water use and management, echoed Hudson’s concerns. She grew up in a large city in Tanzania where water rations were in place, boil water advisories were constant and it wasn’t guaranteed that turning a tap would result in water coming out.
“Here, you just open your tap, get your glass and drink the water,” she said. “You don’t think about it if you live in cities. It doesn’t always cross my mind that I shouldn’t let the water run too long so it doesn’t run out for another person.”
Hudson explained that beyond basic drinking water, water shortages affect basic hygiene “because we don’t have outhouses anymore”— along with many industrial processes, from agriculture and irrigation, to potash and mining, to water-cooled chambers at the university, to steam-powered turbines at coal-powered electricity plants, and the Gardiner Dam hydroelectric plant which cannot generate power at low water levels.
Water shortages are already occurring in the United States because demand is outstripping fresh water supplies. Reservoirs are not being replenished, and some river systems, such as the Colorado, are in severe distress, noted Hudson.
“The [global] water situation is pretty dire, but people are still not realizing how dire. We have to set an example. We want to be able to exercise conservation, because we may have to, and it’s better to have those practices already in place.”
Part of the challenge is sharing our river system with Alberta and Manitoba. Urban growth and heavy agricultural and industrial use in southern Alberta impacts the entire waterway. During the 1998-2000 drought, Alberta used up more than its agreed upon 50 per cent base flow, which could happen again. And we need to be aware of the quantity and quality of water we are passing to our neighbours to the east.
Understanding what goes into the water is just as important as understanding how we use it. The past four years have seen surplus water from Alberta’s heavy glacier melt, snowmelt and precipitation.
“Living with a continental climate, you never know what kind of year you’re going to have, and all these weather conditions change the properties of the reservoir,” Hudson explained. “It’s a privilege to work on the system and make that contribution to the province. It’s a very dynamic system so we have to sample frequently to capture the constant changes going on.”
With funding secured for two more years, Hudson hopes to gather valuable data from lower water levels to balance the extreme conditions of the past four years. Both heavy and minimal flows impact the oxygen and temperature levels of the reservoir, which in turn can impact algal blooms and nutrient storage. Phosphorus enters the reservoir and settles on the bottom. But when oxygen levels are too low—and they are becoming quite low near the lake bottom—the phosphorus that has entered the system is released, providing conditions for heavy algae growth. When the algae dies, it settles to the bottom, further depleting the oxygen levels in a negative cycle. Hudson’s research, along with modelling from fellow U of S researcher Karl-Erich Lindenschmidt and his team, is examining what water levels are optimal to maintain water quality, especially with factors such as climate change and competing demands for water use.
“The goal is to first of all capture the status quo and make sure we can mimic the key processes responsible for the quality of the lake right now, and then incorporate some climate change and land use change scenarios and see how the quality of the lake may change in coming years,” explained Lindenschmidt. “Meteorological climate change data and land use: trends, how things change in the catchment upstream of Lake Diefenbaker with trends to intensification of agriculture, population growth, urbanization, all of which increase the loadings into the lake from the upper South Saskatchewan River.”
Lindenschmidt emphasized the importance of identifying and reducing negative nutrient inputs through better management of landscapes.
“Waste-water treatment plants and lagoons, agriculture” contribute to the nutrient load according to Lindenschmidt. “Blackstrap has stopped using sewage fields, and now the sewage is being pumped away, but is everybody doing that? Anybody close to a river or lake, are they still using fields? Then there’s industry. Everybody’s in some way or form inputting nutrients into the catchment.”
Hudson agreed, noting that the reservoir has been under-studied for a long time, but it’s an essential part of the economy and social fabric of the province.
“Ecosystems have an incredible ability to take our abuse and purify the water, but if we disturb those, there is a point of no return.”
With ongoing research guiding our use of this precious resource, it’s becoming apparent we all play a role in preserving our prairie jewel.