Although the basin received high rainfall over the last few days, so far inflows have been manageable and lake level are rising within their normal ranges. Most of the basin received 50 to 60 mm on Tuesday evening and Wednesday. This resulted in very rapidly increasing flows in the tributaries and a sudden jump in lake levels (8 cm at Lac Seul and 5 cm at Lake of the Woods). Forecasts are predicting a chance for some moderate rainfall this Friday and Saturday, followed by much drier conditions next week. This means high tributary flows and lake inflows will be temporary.
The current level of Lake of the Woods is 322.74 m (1058.86 ft), a 40th percentile level, within the normal range for this time of year. The average lake level increased by 7 cm (3 in) over the last week and is expected to increase by 5 to 12 cm (2 to 5 in) over the next week, depending on precipitation amounts and upstream flow changes. Lake of the Woods authorized outflow is 400 m3/s with planned outflow increases to 480 m3/s tomorrow May 24th and 550 m3/s Monday May 27th. More outflow increases may be required depending on the amount of the rainfall over the next week.
These flow changes will cause a large and rapid increase in levels along the Winnipeg River. By Tuesday, water levels will have increased by approximately 35 cm, (14 in) directly downstream of the Norman Dam and by 20 cm (8 in) above the Dalles. The level at Minaki will not be affected by these flow changes, but could increase due to local inflow.
The current level of Lac Seul is 355.25 m (1165.5 ft), a 40th percentile level, within the normal range for this time of year. The average lake level increased by 14 cm (5.5 in) over the past week and is expected to increase by 17 to 22 cm (6.5 to 8.5 in) over the next week. Lac Seul authorized outflow is 200 m3/s with a planned increase to 240 m3/s Friday May 24th.
If you have any questions, comments or observations, please contact the Secretariat at secretariat@lwcb.ca or by calling 1-800-661-5922. This Noticeboard will be updated regularly as conditions develop.
For more information on Namakan and Rainy Lakes, visit the Water Level Notices page of the International Rainy-Lake of the Woods Watershed Board.