Recent discussion with Manitoba Hydro (MH) regarding their ability to mitigate the fluctuation in lake levels from Nutimik to Lac du Bonnet has confirmed that they already operate their damns on a “run-of-the-river” basis, and do not use the surcharge lakes to increase either the head or volume available for power generation. This means that the fluctuation in level of these lakes is attributable to a combination of the uncontrolled tributaries and the Lake of the Woods Control Board (LWCB), including the attribution from Lac Seul / English River.
Given that MH already uses the run-of-the-river approach, the only additional opportunity for reducing the level fluctuation would be for Hydro to monitor the lake levels more proactively, and adjust their power output (and / or spillage rate) to stem rising lake levels as the increased flow rate works its way down the river.
The WCA’s Lake Levels Committee is working with Manitoba Hydro and the LWCB in an effort to stabilize the water level of the lakes along the river to the maximum extent feasible. The following is an email from Matt Dewolfe of LWCB with updates.
WCA Chair, Lake Levels
From: DeWolfe, Matt [mailto:email@example.com]
Sent: Friday, June 17, 2016 1:42 PM
Subject: Lake of the Woods Control Board Update
First Nations, Resource Advisors and Specific Interest Group representatives,
This morning, heavy, widespread rainfall occurred over Lake of the Woods, the Rainy River and its tributaries and, to a lesser degree, along the Winnipeg River. Initial data shows as much as 3.5 inches (89 mm) of rainfall in 6 hours this morning (at Warroad, MN), though local amounts will vary greatly due to the track of individual storm cells.
Outflow from Lake of the Woods was increased from 450 m³/s to 550 m³/s on Friday morning. The level of the Winnipeg River is expected to rise in response to this increase as follows:
Below Norman Dam 26 cm (10 in)
Above Kimberley Rapids 20 cm (8 in)
Winnipeg River Marina 16 cm (6 in)
Near Locke Bay 16 cm (6 in)
Above Myrtle 16 cm (6 in)
Above the Dalles 14 cm (5 in)
Above Throat Rapids 15 cm (6 in)
Note that this is the minimum rise expected. Local rainfall and runoff will add to this rise and cannot be accurately forecast.
The level of the Winnipeg River in the Whiteshell region of Manitoba will see the results of this flow increase within 3-7 days. At Nutimik Lake, the level is expected to rise by 16 cm (6 in) as a result of today’s increase in outflow from Lake of the Woods. Additional rise is expected due to local rainfall along the Winnipeg River and its other tributaries.
The LWCB is closely monitoring basin conditions and expects further outflow increases in the coming days. Flows into Lake of the Woods from Rainy River had risen sharply before this rainfall, and will continue to rise with the today’s rainfall and any additional rainfall over the weekend.
Please visit the LWCB Notice Board for the latest updates, and contact the Secretariat with any questions.
Matthew DeWolfe, P.Eng.
Lake of the Woods Secretariat
Toll-Free: 1-800-661-5922 Ex 3
LWCB Mission: To regulate the water levels of Lake of the Woods and Lac Seul, and the flows in the Winnipeg and English Rivers downstream of these lakes to their junction, for the benefit of all users and interests.