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Homespun knowledge
Oct 05, 2007

Scientists if willing, have a wealth of first-hand information or folklore to aid them in their investigations and research.

Whether it is knowledge from Inuit of the Arctic or fishermen on Lake Winnipeg, scientists are coming to appreciate information about conditions that existed in the past in order to come to a greater understanding of what is now occurring.

Inuit hunters are able to tell scientists investigating climate change about the prior extent and composition of the Arctic ice pack, while Lake Winnipeg fishermen can relate information to scientists on the growth of algae blooms observed while plying their trade on  the lake over the years.

Lake Winnipeg fishermen often come to understand the nuances of the lake, an invaluable tool for the scientists researching how pollution is contributing to the massive algae blooms that have become such a concern in recent years. 

Algae has always been present during the summer months on Lake Winnipeg. Although the extent of the blooms have varied considerably over time, only in recent years have the blooms increased in size and persistence. The causes are varied — from agricultural chemical run-off to municipal waste — but scientists are now paying greater attention to people with an intimate knowledge.

Recent articles in the Winnipeg Free Press by Kevin  Rollason and the Interlake Spectator by John Coward, reported on the observations of Halli Jonasson, a long-time Riverton-area trapper and fisherman, who has developed an interesting theory about modern-day changes that have affected the water flow between the north and south basins of Lake Winnipeg.

Jonasson has argued that the Hecla Island causeway, completed by the provincial government in 1972, has adversely affected currents between the basins, contributing to both soil erosion in the south basin and the algae accumulation.

During a recent public forum to discuss the impact of the causeway on shorelines and water quality as reported by the Spectator, Jonasson said algae “as thick as a mat are being trapped by the causeway.”

“They’ve changed the complete cycle of Mother Nature,” he said. “It’s a disgrace.”

Jonasson said the causeway has turned Hecla island into a giant dam causing eddies that are eroding the  shoreline south of Hecla. Compounding the erosion is Manitoba Hydro’s regulation of  the lake water level — this by damming the north’s great rivers. At Grand Rapids, a dam holds back the Saskatchewan River, while an outlet into the Nelson River prevents the natural northward flushing of the lake. Manitoba Hydro blocks the natural flow of water out of the lake during the summer to create a giant reservoir (all of Lake Winnipeg) for the generation of electricity during the winter.

Research, compiled using core samples taken in 1994 of lake sediment, was used to confirm there had been a deterioration in the quality of the water used by the communities of Norway House, Nelson House, Split Lake, Cross Lake and York Landing which resulted in Manitoba Hydro being obliged to pay as much as $70 million in compensation.

Quite troubling is that clearer water and trapped nutrients have aided algae growth, which thrives as more sunlight penetrates the lake surface enabling it to use photosynthesis to convert inorganic matter, such as phosphates, into organic matter. While certain types of algae are toxic, decaying algae perhaps poses a greater threat due to oxygen consumption — essential to maintain commercially-viable fish species such as pickerel and whitefish. It was decaying algae which nearly killed Lake Erie — only strong intervention prevented the complete collapse of the lake’s ecosystem.

Many cottagers and residents living along Lake Winnipeg have noticed increasing shoreline erosion since water level regulation began. Enough people would seem to be making the same observation that there must be some kernel of truth in their conclusion.

Jonasson’s observations fall into the same category as anecdotal, but Lake Winnipeg Research Consortium  managing director and biologist, Al Kristofferson of Gimli, is still paying attention. He said that Jonasson’s theory undoubtedly has enough merit that it requires investigation.

Kristofferson told the Free Press he is sure that the causeway has affected the natural flow of water around Hecla Island.

There may not be any data, but water from the south end can only go between Hecla and Black islands and Black Island, and the east shore of the lake, while the former route in the Grassy Narrows  (Hecla-Grindstone channel) has been primarily blocked and only a 70-metre bridge allows the free flow of water under the causeway, Kristofferson said. 

Most of the area now dedicated to the 3.2-kilometre causeway had previously been open to the flow of water. The impact of the causeway is that one-third of the flow between the north and south basins of the lake has essentially been cut off — 70 metres of open area cannot replace the kilometres of open area that existed until 1971-72.

Take a look at a map of the region and it becomes evident that the causeway presents a severe impediment to the free flow of water in a major channel. 

Algae is naturally occurring in Lake Winnipeg and essential to the lake’s health; small organisms are part of the food chain that has predators such as pickerel and whitefish as its last link. What sets the recent algae outbreaks apart is the proliferation of toxic blue-green algae and the sheer size of the green algae blooms. 

Satellite photos show outbreaks in recent years that appear to fill the north basin. The same images show blooms in the south basin that are less extensive — it’s substantially smaller in size than the north basin — but no less disconcerting. In fact, south basin commercial fishermen have in recent years periodically reported the presence of so much algae that it clogs their gill nets and prevents them from catching fish.

Those who have lived, hunted and fished in diverse regions from the Arctic to Manitoba’s Interlake are proving the benefit of anecdotal evidence to the scientific community.