Rideau Canal - Water Level Management Update – August 6, 2025

Rideau Canal - Water Level Management Update – August 6, 2025

Parks Canada's water management team continues to actively monitor water levels, flows, and weather forecasts across the Rideau Canal National Historic Site. These factors are used to determine dam operations on a daily basis for the Rideau Canal National Historic Site.

Parks Canada maintains the Ontario Waterways Water Management InfoNet on the Rideau Canal website at https://parks.canada.ca/lhn-nhs/on/rideau/info/infonet.

The InfoNet provides background information on water management practices, updates on water management, frequently asked questions about water management, various reports on water management, and the most recent water levels of lakes along both the Rideau Canal and the Trent-Severn Waterway. The information comes from hydrometric gauges located at key points along both waterways and is vetted by trained and experienced Parks Canada water management staff.

This information is intended as supplemental information only. Your respective Conservation Authority continues to serve as the primary source for relevant flood forecasting information specific to your area. These are the Rideau Valley Conservation Authority and the Cataraqui Conservation Authority.

Weather
Rainfall amounts for June and July have been 50% below normal, and until last week, the same was true for August. The 14-day forecast suggests high temperatures and low precipitation. Most of the forecasted rainfall is expected to be associated with thunderstorms, which could cause highly variable amounts from one location to another.

Outlook
The ongoing hot and dry conditions over an extended period have resulted in lower-than-normal local inflows and increased evaporation rates. Consequently, the system has transitioned from summer-like conditions to a deficit state. Water management and operational activities are being conducted to appropriately respond to these changes and may result in fluctuations in water levels across the system.
The Rideau Canal Water Management team will remain active, and changing conditions will be closely monitored. Any updates regarding watershed conditions will be released by your Conservation Authority.

Cataraqui River
The Cataraqui River lake levels are below average and below standard navigation draft levels, declining due to continued hot weather and lack of rainfall. If current weather conditions persist, this will result in a more gradual draft reduction on the Cataraqui Lakes. All draft reductions will be posted via Notice to Shipping as well as on the water management webpage.

Tay River
Bobs Lake is below average for this time of year. Outflows from Bobs Lake are lower than normal, resulting in below-average water levels in Christie Lake and a low flow rate downstream along the Tay River. If dry weather persists, outflows from Bobs Lake will be increased, which will accelerate the rate of water level decline.

Rideau River
Water levels for Wolfe Lake and Upper Rideau Lake are below average, as is the level of Big Rideau Lake for this time of year. However, levels in the river from Smiths Falls to Ottawa remain within navigation range.