A precipitation system will impact southern portions of the Winnipeg River basin this Friday, April 21. Snow is expected, with amounts ranging from 10 to 15 cm (4 to 6 in) and in some locations as high as 25 cm (10 in). This precipitation will, in the short term, cause increased flows and levels in the rivers and lakes. In the long-term, this added snowpack will increase the snow water content and as it melts will cause river flows and lake inflows to remain at above normal levels. Additional larger outflow increases are scheduled at Lake of the Woods to help slow the rate of level rise. The ice cover is no longer in place on the Winnipeg River, minimizing the impact of river level rise due to these outflow increases.

The current level of Lake of the Woods is 322.57 m (1058.3 ft), a 50^th percentile level for this time of year. The average lake level increased by 14 cm (5 in) over the past week and is expected to increase by 13 to 16 cm (5 to 6 in) over the next week. Lake of the Woods authorized outflow will increase to 575 m³/s on Friday, April 21 (slightly higher than planned) and again to 625 m³/s on Monday, April 24.

Each of these outflow changes will cause levels along the Winnipeg River to increase by 14 cm (5 in) directly below the Norman Dam and by 8 cm (3 in) above the Dalles for a total rise of 28 cm (11 in) and 16 cm (6 in) respectively at each location. These flow changes will not affect the level at Minaki.

Less precipitation is forecast to impact the English River basin on April 21st. In this basin, freshet is slow to begin and river flows and lake inflows are at low-normal conditions. As such, an outflow reduction was scheduled at Lac Seul to allow for the lake level to start rising gradually in anticipation of higher spring inflows.

The current level of Lac Seul is 354.84 m (1164.2 ft), a 50^th percentile level for this time of year. The lake level increased by 3 cm (1 in) over the past week and is expected to increase by 6 to 8 cm (2 to 3 in) over the next week. Lac Seul authorized outflow was reduced to 100 m³/s on April 20.

Inflow to Lake of the Woods continues to rise and is expected to remain high over the next week. Another round of precipitation is forecast to impact the southern portion of the Winnpeg River basin at the end of the week and flows on the Rainy River are expected to increase.

To slow the rate of level rise on Lake of the Woods and achieve a gradual refill of the lake, staged outflow increases will continue with increases of 25 m³/s per day to minimize impacts downstream on the Winnipeg River. Authorized outflow will increase to 500 m³/s on April 19, to 525 m³/s on April 20 and to 550 m³/s on April 21.

Each of these outflow changes will cause levels along the Winnipeg River to increase by 6 cm (2 in) directly below the Norman Dam and by 3 cm (1 in) above the Dalles for a total rise of 20 cm (8 in) and 11 cm (4 in) respectively at each location by Friday. These flow changes will not affect the level at Minaki.

Inflow to Lake of the Woods increased over the weekend due to precipitation and increased flows from the Rainy River. As a result, the level of Lake of the Woods increased by 7 cm (2.5 in) over the last three days.

To slow the rate of level rise and achieve a gradual refill of the lake, staged outflow increases are planned this week starting with an increase to 450 m³/s today, April 17, and another increase to 475 m³/s tomorrow, April 18. Each of these outflow changes will cause levels along the Winnipeg River to increase by 6 cm (2 in) directly below the Norman Dam and by 3 cm (1 in) above the Dalles. These flow changes will not affect the level at Minaki.

As inflow stabilizes and the accuracy of this week’s precipitation forecast improves, the need for additional outflow increases will be assessed.

A low pressure system will impact the Winnipeg River basin this Friday, April 14 and into Saturday, April 15. The heaviest precipitation is expected to occur over the Northern half of the basin, resulting in additional snow or freezing rain on top of the current snowpack. Warmer temperatures during the day, and on Saturday, will result in moderate amounts of rain basin wide.

This event will accelerate the freshet that has already begun with snow melting rapidly over the last week due to the warm and sunny conditions. Runoff from the precipitation is expected to cause river flows and lake inflows to increase temporarily. Lake levels are expected to start increasing gradually starting the refill period.

The current level of Lake of the Woods is 322.43 m (1057.8 ft), a 30^th percentile level for this time of year. The average lake level remained stable over the past week and is expected to increase by 2 to 6 cm (1 to 2 in) over the next week. Lake of the Woods authorized outflow is 425 m³/s with no changes scheduled.

The current level of Lac Seul is 354.81 m (1164.1 ft), a 50^th percentile level for this time of year. The lake level changed little over the past week and is expected to increase by 3 to 8 cm (2 to 3 in) over the next week. Lac Seul authorized outflow is 150 m³/s with no changes scheduled.

Due to a power outage in the National Capital region, the Basin Data page could not be updated today. It will also not be updated over the Easter long weekend. Daily data updates will resume on Tuesday, April 11.

Flow and level data is available at the source websites:

• Water Survey of Canada
• United States Geological Survey

The following level forecast was produced on April 5:

The current level of Lake of the Woods is 322.42 m (1057.8 ft), a 35^th percentile level for this time of year. The average lake level declined by 1 cm (0.5 in) over the past week and is expected to decline by up to 2 cm (1 in) over the next week. Lake of the Woods authorized outflow is 425 m³/s with no changes scheduled.

The current level of Lac Seul is 354.80 m (1164.0 ft), a 45^th percentile level for this time of year. The lake level declined by 2 cm (1 in) over the past week and is expected to remain stable over the next week. Lac Seul authorized outflow is 150 m³/s with no changes scheduled.

The LWCB has published an updated version of its “Before You Build” page. This document provides guidance on hazard land levels for construction of docks, boathouses and cottages and has been updated to reflect the high water levels of 2022.

New hazard land levels have been established for:

• Winnipeg River in Manitoba – Nutimik Lake
• English River – Below Ear Falls/Pakwash Lake

Statistics and reference water levels have also been updated to reflect more recent data.

For questions or comments, please email secretariat@lwcb.ca

The current level of Lake of the Woods is 322.43 m (1057.8 ft), a 40^th percentile level for this time of year. The average lake level remained stable over the past week and is expected to decline by up to 4 cm (1.5 in) over the next week. Lake of the Woods authorized outflow will return to 425 m³/s following today’s outage and there are no further changes scheduled.

The current level of Lac Seul is 354.82 m (1164.1 ft), a 40^th percentile level for this time of year. The lake level declined by 3 cm (1 in) over the past week and is expected to decline by less than 2 cm (1 in) over the next week. Lac Seul authorized outflow decreased to 150 m³/s today, Thursday March 30^th with no further changes scheduled.

Below is an update to the planned outage of the Norman and Kenora Powerhouses, originally posted on March 23.

On Wednesday, March 30 (one day earlier than previous noted), Hydro One will be conducting a full day outage that will result in temporary disconnection of the Norman Generating Station and Kenora Generating Station from the grid. During the outage, neither facility will be able to pass flow through turbines and this will result in a temporary drop in the level of the Winnipeg River near Kenora. To limit the effect of the outage on river levels, the LWCB has directed the dam operators to add flow through the log sluices at the Norman Dam (currently all log sluices are fully closed).

River levels will fluctuate before, during and after the outage as dam operations are adjusted and this may cause the ice on the river to shift. The LWCB recommends taking precautions when on or near the Winnipeg River between March 29 and March 31.

Minor fluctuations in the river level are expected the day before and the day after the outage as flow is adjusted between the Norman powerhouse and the log sluices.

On March 30, river levels are expected to decrease as follows.

Below the Norman Dam: 15- 17 cm (6-7 in)

Above Kimberly Rapids: 12-13 cm (5 in)

Winnipeg River Marina: 10 (4 in)

Near Locke Bay and Above Myrtle Rapids: 10 cm (4 in)

Above the Dalles and Throat Rapids: 8 cm (3 in)

Minaki: no change

Following the outage at the end of the afternoon on March 30, flow will return to the authorized rate of 425 m³/s and the river will rise back to the pre-outage level range.

On Thursday, March 31, Hydro One will be conducting a full day outage that will result in temporary disconnection of the Norman Generating Station and Kenora Generating Station from the grid. During the outage, neither facility will be able to pass flow through turbines and this will result in a temporary drop in the level of the Winnipeg River near Kenora. To limit the effect of the outage on river levels, the LWCB has directed the dam operators to add flow through the log sluices at the Norman Dam (currently all log sluices are fully closed).

River levels will fluctuate before, during and after the outage as dam operations are adjusted and this may cause the ice on the river to shift. The LWCB recommends taking precautions when on or near the Winnipeg River between March 30 and April 1.

On March 31, river levels are expected to decrease as follows.

Below the Norman Dam: 55 cm (22 in)

Above Kimberly Rapids: 39 cm (15 in)

Winnipeg River Marina: 26 cm (10 in)

Near Locke Bay and Above Myrtle Rapids: 26 cm (10 in)

Above the Dalles and Throat Rapids: 22 cm (9 in)

Minaki: no change

Following the outage, flow will return to the authorized rate of 425 m³/s and the river will rise back to the pre-outage level range.

The current level of Lake of the Woods is 322.43 m (1057.8 ft), a 40^th percentile level for this time of year. The average lake level changed little over the past week and is expected to remain stable over the next week. The last of the gradual increases to Lake of the Woods authorized outflow continue this week as follows:

March 21: from 375 to 390 m³/s

March 22: 405 m³/s

March 23: 425 m³/s

Each flow adjustment will result in the Winnipeg River near Kenora rising by roughly 3 cm ( 1 in). The Winnipeg River level at Minaki will not be affected by these adjustments.

The current level of Lac Seul is 354.86 m (1164.2 ft), a 35^th percentile level for this time of year. The lake level declined by 4.3 cm (1.5 in) over the past week and is expected to decline by 3 to 5 cm (2 in) over the next week. Lac Seul authorized outflow is 200 m³/s with no scheduled changes.

Spring Strategy

On March 7, the LWCB held its spring Regulation Meeting, attended by specific interest groups and resource agencies, and adopted its Spring Regulation Strategy. The strategy outlines regulation targets for various inflow conditions for the period of March to the end of June. Winter conditions were also reviewed at the meeting, with measured snow depth close to normal throughout the basin and other factors resulting in a winter severity that was less than normal.

For Lake of the Woods, the strategy targets a lower end of March level to assist with property repairs following the 2022 flood. Summer level targets are also set slightly lower than typical for this same purpose. With higher snow depth in the headwaters of the larger Lake of the Woods basin, the risk of insufficient inflow for lake refill is reduced this spring.

For Lac Seul, the strategy targets mid-April levels that meet preferences for fish spawning and are slightly higher than the typical range. Inflows to Lac Seul have been below normal over the course of the winter and with the snowpack close to normal, there is no elevated risk of high spring inflows.