TSW Water Level Management Update – Dec 20/21

Trent-Severn Waterway – Water Level Management Update – Monday, December 20, 2021


The weather forecast for early next week is changing significantly from day to day. A 20 to 30 mm of mixed precipitation event is forecasted across the next 5 days. 


Precipitation amounts for September to December 2021 have contributed to 100-125 % more precipitation relative to normal.  Rainfall and warm temperatures earlier in the month have generated active snowmelt, which, in combination with the above-normal precipitation amounts, resulted in raising the flows and water levels across the watersheds.  With currently forecasted air temperatures below zero, water levels and outflows are expected to crest and slowly recede at all locations. However, there is a measure of uncertainty associated with this.  Depending on the exact amounts of precipitation over the next 5 days, whether it falls as rain or snow and whether air temperature is above or below zero, local snowmelt and snowmelt runoff may occur, impacting the watershed response. Trent Severn Water Management team will be active, and the changing conditions will be closely monitored. Any watershed conditions updates will be released by your Conservation Authority or local Ontario Ministry of Natural Resources district. 

Ice on shorelines

The temperature variations around and above the freezing mark makes ice weak along the shoreline, which is then easily broken and moved by windy conditions. The areas subject to the greatest impact are those facing the primary wind direction. In the event of strong wind conditions, the public should be aware of possible onshore ice movement leading to shoreline damage.

Haliburton and Northern Areas 

All reservoir lakes remain at their respective winter set dam configuration. Water levels on the lakes, in general, are well above average and are beginning to level out. Flows on the Gull River and Burnt River are above average. Central Lakes levels are above average for this time of the year.

Kawartha Lakes and the Otonabee River

After the snowmelt and rainfall of last week, most of the Kawartha Lakes are above average; water levels on the Kawartha Lakes have peaked and are beginning to decline. Flows on the Otonabee River are higher than average for this time of year. 

Rice Lake and the Lower Trent

Rice Lake's water level is above the long-term average and is levelling off. Flows on the Lower Trent River are above average and are beginning to decline. 

Severn River

Lake Simcoe is above the long-term average water level, and outflows have been maximized. Flows on the Black River are above average. Flows on the Severn River are above average.