Ethically meeting electrical demand

Fifty years ago this June, Manitoba Hydro destroyed one of the province’s finest lakes, its fourth-largest, when it began operating a newly constructed control structure at Missi Falls, the outlet where Southern Indian Lake flows into the lower Churchill River.

This raised the water level of the lake, creating a reservoir and diverting the flow southward via the Rat and Burntwood River systems to increase power output at its hydroelectric generating stations along the Nelson River.

More than 3,500 km of shorelines on the lake alone were permanently inundated, and along with its adjacent waterways, an area of 840 square kilometres was flooded. The entire Indigenous community of South Indian Lake had to be moved to higher ground to avoid the flooding, and the island community of Nelson House was irreparably harmed.

The Churchill River diversion project had a disastrous effect on the natural environment and the Indigenous people whose subsistence and way of life depended on the lake.

I know because I spent the summer in 1971 with a forestry crew evaluating the forest resources along the Churchill, Rat and Burntwood Rivers, and around Southern Indian Lake itself. The numerous waterways we traversed that summer are barely recognizable now, owing to extensive flooding.

The rocky shorelines, numerous islands, shrubby riparian areas, adjacent spruce and moss-filled forests and reed-filled inlets and bays were indescribably beautiful. Pristine wilderness at its best.

Fish and wildlife abounded. The waters were clear, clean and productive, providing a stable livelihood for the Cree people who fished there. Watching them live in harmony with nature — canoeing across the lake, negotiating a portage with ease or camping along the wooded shorelines — were sights I will never forget.

Prior to flooding, trees within the flood zones were felled by dragging a cable and heavy ball between two bulldozers. When the water rose, many of these trees washed into the lakes and rivers, along with other vegetation and copious amounts of clay, a predominant substrate in the area. The waters became clogged with woody debris and clouded with clay and silt.

Along with increased water levels on Southern Indian Lake, fluctuations (a characteristic of most hydroelectric reservoirs) added to the severity of impacts, especially on fish, which depend on stable water levels and sediment-free shoals for spawning.

Studies by a scientific team from the Freshwater Institute documented shore erosion, impacts of sediment on incubating whitefish eggs and increases in the mercury concentration in fish.

In 1973, Manitoba Hydro was granted an interim licence that allowed fluctuations in water level of two feet over a 12-month period, similar to fluctuations in nature.

But years later, Manitoba Hydro deviated from the interim licence under a government-approved augmented-flow program, resulting in 4.5 feet of fluctuation. This was the final blow to a once-productive whitefish fishery, and it collapsed soon afterward. In 2021, the augmented flows were cemented into the terms and conditions of the Final Water Power Act Licence. The fishery on Southern Indian Lake is unlikely to ever recover under these conditions.

Manitoba Hydro generates a significant surplus of electricity from its hydroelectric stations, allowing it to export power to neighbouring jurisdictions, including Ontario, Saskatchewan, and even beyond to Nunavut. In April 2025, the Manitoba government directed Manitoba Hydro to stop renewing two major electricity export contracts with the United States.

The Churchill River diversion helped lower rates for Manitobans by more than 20 per cent. However, owing to recent droughts reducing water levels, Manitoba Hydro is seeking rate increases from 2026 to 2028 to cover costs.

A Statement of Hydro Impacts on Southern Indian Lake is contained in a 2023 report by O-Pipon-Na-Piwin Cree Nation, the Community Association of South Indian Lake, and the South Indian Lake Fisherman’s Association.

While the economic benefits of hydroelectric development are relatively easy to quantify, the enormous environmental and socio-economic costs of the Churchill River diversion project are irreversible and impossible to measure.

Canada’s electricity demand is projected to double by 2050. Meeting this demand in an environmentally responsible way will require extensive innovation, application of new technologies and strong political leadership.

With a master’s degree in forest ecology and 35 years of public service, Jan Simonson has made a career in environmental education, forestry, and the stewardship of public lands and water resources.