Lake Winnipeg Regulation

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Lake Winnipeg

In 1970, Manitoba Hydro was granted a licence to regulate Lake Winnipeg outflow. The outflow from Lake Winnipeg is regulated by a control structure at Jenpeg Generating Station on the Nelson River near the outlet of the lake. When the level of Lake Winnipeg is between 216.7 m (711 ft) and 217.9 m (715 ft) above sea level (ASL), the licence allows Manitoba Hydro to set the outflows as required for power production purposes along the Nelson River. During periods when the water level is above 217.9 m, Manitoba Hydro must operate the control structure at Jenpeg in such a manner to effect maximum discharge possible under the circumstances then prevailing, until the water level of Lake Winnipeg recedes to 217.9 m. During periods when the water level is below 216.7 m, Manitoba Hydro must operate the control structure at Jenpeg as ordered by the Minister of Water Stewardship.

In addition to the control structure at Jenpeg, the Lake Winnipeg Regulation Project included the removal of restrictions in existing channels and the excavation of new channels (2-Mile Channel, 8-Mile Channel, and the Ominawin Bypass Channel) to improve outflows from the lake, and a dam at the outlet of Kiskitto Lake to prevent water from backing up into that lake. These works increased the maximum outflow capacity of the lake by up to 50 per cent, meaning that in high water periods, water can be passed out of the lake more quickly than prior to Lake Winnipeg Regulation. The increased ouflow capacity has reduced the occurrence of post-Lake Winnipeg Regulation extreme lake levels (highs and lows) when compared to pre-Lake Winnipeg Regulation lake levels.

Jenpeg Generating Station and Control Structure is located on the Upper Nelson River at the point where the west channel of the Nelson River flows into Cross Lake. Jenpeg's primary purpose is to regulate the water outflow from Lake Winnipeg into the Nelson River. Its secondary function is to take advantage of a 7.3-m operating head (waterfall) at the site to produce electricity. The generating station's powerhouse and spillway provide the means of controlling the outflow from Lake Winnipeg.

2-Mile Channel helps to "unplug" Lake Winnipeg by augmenting the natural outlet at Warren Landing. The channel cuts across the narrowest point of land between the north end of Lake Winnipeg and Playgreen Lake about 10 km northwest of Warren Landing.

8-Mile Channel connects Playgreen Lake with the southernmost end of Kiskittogisu Lake, just north of the 54th parallel. The channel increases the flow of water from Playgreen Lake.

The Ominawin Bypass Channel avoids natural constrictions in the Ominawin Channel, which is the most northerly outlet of Kiskittogisu Lake to the west channel of the Nelson River.

Lake Winnipeg Level Determinations

Weather conditions, such as wind and barometric pressure, can cause water levels to differ substantially at various points on the lake. In order to determine the average level of the lake at a given point in time, a smoothed wind eliminated level is determined. The regulation of the lake is based upon this wind eliminated level. Water levels are recorded continuously at eight water level gauges around the lake and it is from these levels that the wind eliminated level is calculated.

Licences
Supporting Documentation
Historical Reports
Clean Environment Commission Review

On July 5, 2011, the Minister of Conservation at the request of the Minister of Water Stewardship, asked the Manitoba Clean Environment Commission (CEC) to conduct a review regarding the regulation of Lake Winnipeg under The Water Power Act. Please visit the CEC website for more information.

Questions/Comments

Frequently Asked Questions (FAQ)


The comment period for the Churchill River Diversion project is now closed. The province intends to make a final licensing decision in 2021.