Current Situation April 22, 2026:
Flooding Warnings are in place across the province of Ontario. Locally, Minden Hills remains under a State of Emergency, and its Emergency Operations Group is meeting frequently. To learn more about this, follow communications from the Township of Minden Hills and the County of Haliburton.
All reservoirs in the Trent Severn Waterway System are full or above full, many with local flooding. For example Lake Simcoe is only 6 cms below its all time high level based on a record of over 100years. The Kawartha Lakes are all above normal spring levels and flows all the way to Lake Ontario are well above normal for the spring freshet with flood conditions. There has been significant flooding in the down stream Burnt River Basin. The Central Lakes reservoir area is seeing full and overfull levels from April rains but they saw most of the snow melt earlier so the current situation is less severe that I more northern areas.
Reservoir System Overview:
The reservoir system is a complicated, 100+-year-old system the history of which goes back to the logging days of the late 1800s. The attached diagram illustrates how all the water flows including the number of dams within the system. https://www.cewf.ca/map-how-the-water-flows
There are 16 dams above Minden and when the water is as high as it is, TSW’s primary objective is ensuring as little flooding as possible in Minden. To do that, TSW puts logs in and out of its dams above Minden on an almost daily basis to maintain as even a flow as possible across a very large geographic area. There is a significant flow from the Maple Lake chain area that has no control and which is a primary threat from Twelve Mile Lake and downstream through Minden.
Why is there too much water?
Over the past decade, changing weather patterns have been increasingly disruptive to historic spring runoff patterns. As has happened in 2013, 2017, 2019 and 2025, unusual amounts of rain and oddly fluctuating temperatures combined with snow, ice and frozen ground have forced tremendous amounts of water into the ponds, rivers, creeks and lakes. All that water bottlenecks above Minden, resulting in “high water” and flooding.
The combination of factors that lead to flooding can’t be reliably predicted from year to year however, TSW has an entire team continuously observing, measuring, calculating and responding quickly to changing environments.
What happened this year?
According to Environment Canada, we received 75% more rain than usual in March and double the usual rainfall in the first two weeks of April.
In March with an above average snowpack we experienced a period of warm temperatures and significant rainfall events triggering an early melt period. TSW began to store some of that runoff in reservoirs but maintained significant capacity for later spring events.
Then in April with double the normal rainfall onto a significant remaining snowpack in the north and warmer temperatures, we have experienced a major runoff event which has now overfilled the system .
What happens next?
Right now while we are in a relatively dry period, TSW’s priority is flood control. Many property owners have seen the water begin to go down but, in some places, it may go back up again as TSW manages the system as carefully as it can. Once the “rush” of water is finished, TSW will work to stabilize the entire system to attain appropriate levels for the summer season (which brings a whole different set of issues, but that’s for another day!).
Who Are We?
The Coalition for Equitable Water Flow (CEWF) is the organization that watches the water. We are a volunteer organization that represents shoreline property owners on 55 reservoir and flow-through lakes in the Trent River watershed, from Algonquin Highlands all the way through Kawartha Lakes. The CEWF communicates with TSW’s senior staff on a regular basis in order to keep the CEWF membership and other subscribers informed with useful water level information and, in challenging times like these, to provide accurate explanations of current events.
Stay Informed about Water Levels:
You can subscribe to receive notification from CEWF whenever we post new information or links to TSW postings. https://www.cewf.ca/subscribe
Official Flood watches and warnings are posted by MNRF, Conservation Authorities, and local municipalities.