Wednesday, 10 July 2013 13:39

Study investigates environmental challenges facing Lake Diefenbaker

Written by  Matthew Liebenberg
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The pressures on one of Saskatchewan’s main water sources are being studied by an interdisciplinary team of scientists from the University of Saskatchewan’s Global Institute for Water Security (GIWS).

The institute is carrying out one of the first long-term research programs at Lake Diefenbaker to get a better understanding of nutrient loading and its impact on the lake’s water quality and aquatic ecosystems.
The institute’s work at the lake is part of a larger seven-year-long project to study water security challenges across the entire Saskatchewan River basin at experimental sites that are located in Alberta, Saskatchewan and Manitoba.
The study involves 80 scientists and 85 research staff and students from various disciplines. GIWS Director Dr. Howard Wheater is the project leader. He is an international expert in hydrological science and sustainable water resource management.
“We’re really trying to understand the water issues in the basin, how the environment is changing, how people are changing the environment and what effects that’s having on water quantity and water quality,” he said.
The project recently received a financial boost of $800,000 from the Canada Foundation for Innovation (CFI). The funds are being invested in research equipment and infrastructure at four key sites, including Lake Diefenbaker.
Research data will be used to build a computer model of the lake’s hydro dynamics, including information about lake flows, temperature profiles during different seasons, oxygen levels and water chemistry. The model will allow scientist to look at future scenarios, for example the impact of a warming climate on toxic algae blooms.
“There’s a generic problem around the world that people and agriculture are putting a lot of nutrients in the water environment and everybody is really struggling as to how we can manage this problem,” he said. “It’s certainly the case in the South Saskatchewan that there’s really a large load of both phosphorus and nitrogen coming down the river into Lake Diefenbaker.”
According to Wheater, there was little knowledge available about the nutrient levels in the lake until this study started two years ago. So far, the data is already indicating high nitrogen levels and that phosphorus is retained in the sediments on the lake floor.
“That’s almost certainly not a sustainable situation and of course people living around the lake have had concerns about the increasing occurrence of algal blooms and with this nutrient loading that problem is set to get worse,” he said. “One of the issues about algae is it’s not only unsightly and it can harm the ecosystem, but under certain conditions it can generate blue-green algae, which is toxic and they can kill animals and be harmful to human health too.”
The Saskatchewan River basin covers 336,000 square kilometres and about three million people are living in the area. The World Wildlife Fund has described the South Saskatchewan River as the most threatened river in Canada.
“It’s an interesting river,” he said. “It’s got most of the problems that we see around the world.”
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According to Wheater there are severe pressures on the river in Alberta, where 86 per cent of water use from the South Saskatchewan River is for irrigation purposes. An interprovincial water agreement requires that 50 per cent of the natural flow must pass on to Saskatchewan.
“In a drought year it struggles, but it maintains the 50 per cent,” he said. “The big concern is at some point we will face a severe multi-year drought and then the question is how can we manage our way through that.”
At the moment the 50 per cent required water flow from Alberta is enough to give Saskatchewan a spare water resource in the South Saskatchewan River, but the province is facing some difficult decisions on how to allocate that water. For example, does it want to expand irrigated agriculture or preserve water resources for future mining development.
A water quality issue of concern to Wheater is the lack of an agreed limit for phosphorus at the Saskatchewan-Alberta border. Such an agreement exists between Saskatchewan and Manitoba to regulate the phosphorus discharge as the Saskatchewan River flows across that provincial border.
Some of the research work at the GIWS is also focused on the Swift Current Creek, which is the only really significant water flow into Lake Diefenbaker that is not coming from the South Saskatchewan River.
“It’s got this problem of very episodic flows, so almost no flow a lot of the year but then major flows in the spring,” he said about the creek.
For this reason the current focus is on aspects of water quality in relation to episodic stream flow in the creek. Researchers have been looking at nutrient loads and exotic chemical levels in the stream.
“The new (Swift Current) sewage treatment works had a major effect in improving water quality but the old sewage lagoons are still being used and we are seeing some leachate of some of these pharmaceutical products into the water course,” he said. “So that’s an issue that we’re going to look at further.”
This GIWS study of the Saskatchewan River basin is currently the only active regional hydroclimate study project of the World Climate Research Program in North America.
“That’s aiming to really improve our capability to model regional and global climate,” he said. “One of the ways we can do that is working with large basins as experimental test beds ... We can understand various aspects of how the land interacts with the atmosphere, how environmental change might affect climate, the feedbacks between the land and the climate, and then of course we can look at the ability of the models to predict extreme events.”
The recent floods in Alberta caused a setback for the project in that province. A major flow monitoring station in Marmot Creek was washed out and at least $40,000 worth of equipment was lost.

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