We soon might be referring to Lake Winnipeg as the “sick old man of Manitoba.”
The 11th largest freshwater lake in the world has been under constant stress for decades, but never so greatly as in recent years. And, despite the best intentions of the provincial government through its Water Stewardship department, the stress seems to be steadily increasing.
There’s the potential threat of the invasion of foreign biota via the diversion of Devils Lake, North Dakota, water into the Sheyenne River and thus into the Red River and from there into Lake Winnipeg, but there’s also another threat that has only recently come to light.
Just this week, Manitobans have been informed that the regulation of the lake’s water level for the production of hydro-electric power has adversely effected Lake Winnipeg. According to a Winnipeg Free Press article, Manitoba Hydro’s northern dams at Grand Rapids and Jenpeg are spurring the growth of algae in the lake’s northern basin.
Without the natural flow of sediment into the lake, its water becomes clearer and the clarity and the accompanying penetration of sunlight helps to create algae blooms — algae being sun-loving plants.
The report was compiled by Ottawa to help resolve a dispute between First Nations communities and Manitoba Hydro. The research, compiled by using core samples taken in 1994 from the lake’s sediment, was used by Ottawa to determine that there had been a deterioration in water quality for the communities of Norway House, Nelson House, Split Lake, Cross Lake and York Landing with the result that Manitoba Hydro had the obligation to pay as much as $70 million in compensation.
What the researchers found was that sediment had been piling up behind the Grand Rapids dam, which holds back the Saskatchewan River. Strangely, holding back Saskatchewan River water may also help the lake by preventing nutrient-rich agricultural run-off from entering the lake, but how much help is attained by this action can only be determined by further research. For the moment, all that is truly known is that water clarity is improving in the northern basin and this does not help the lake.
Another problem is that the outlet from the Lake into the Nelson River traps nutrients in the lake that had previously been flushed down the river. Since Manitoba Hydro blocks the natural flow of water out of the lake during the summer to create one giant reservoir for the generation of electricity during the winter, nutrients have no place to go and the algae have a readily available food source to fuel their reproduction.
Toxic algae blooms are swept by waves onto beaches and mats of them collect in commercial fishermen’s nets, making the nets useless for catching fish.
But, the most insidious threat is that algae die off and when decaying consume oxygen which is absolutely essential for the welfare of the lake — without oxygen, fish and other organisms native to the lake themselves die off. This was the case in Lake Erie, which at one time was classified as a dead lake, but strong environmental measures — still continuing — on both sides of the border brought the lake back to life.
Phosphorous and nitrogen, which promote algae growth, had been constantly fed by agricultural practices and sewage spills from communities along the many rivers that feed the lake, but this new revelation shows that holding back water running either into or out of the lake has compounded the problem.
It demonstrates quite clearly that whenever man interrupts a natural cycle, regardless of how well-intentioned, there are consequences.
Manitoba Hydro’s dams won’t be removed, and has not been suggested, but the Crown corporation can aid the cause of restoring the health of Lake Winnipeg by using the federal government’s research to at least investigate what they can do to lessen the impact of its northern dams.
And, by no means has damming northern rivers been the sole culprit in the death spiral of the lake — agricultural communities and municipal governments on both sides of the U.S.-Canada border also share in the guilt.
But, before Manitoba Hydro’s northern hydro-electric projects came into existence, sediment naturally flowed into the lake, ensuring its murkiness, while hindering profuse growth of algae. Lake Winnipeg is derived from the two aboriginal words winni and peg, which when translated into English mean “muddy water,” but with the change to greater water clarity, the name of the lake may eventually have to be rethought, although Ottawa’s research shows us that this is no cause for celebration.