Water levels expected to rise on Ottawa River through Ottawa this weekend

Sandbags are seen on Armitage Avenue in West Carleton. May 2, 2025. (Peter Szperling/CTV News Ottawa)

Water levels are expected to rise 25-30 centimetres along the Ottawa River in the Britannia and Cumberland areas this weekend, but officials say water levels will remain below flooding levels in 2019 and 2023.

A flood warning has been issued along the Lower Ottawa River for areas from Arnprior to Hawkesbury heading into the weekend.

“A flood warning is always something people should pay attention to,” said Jim Lethbridge, manager with public works, emergency planning and response at the City of Ottawa. “It means we have active water, it could be water near your parks and roadways—you should pay attention to that. You should be taking a look at your plans that you have for your property and executing them as appropriate to the levels you’re seeing and accounting for anything like wind action, which we might see on some of the larger stretches of the Ottawa River.”

The Ottawa River Regulation Planning Board says water levels continue to rise along the Ottawa River following the recent rainfall and due to snowmelt from the “mountainous areas of the basin.”

“Minor flood levels have been reached in most flood prone locations between Mattawa and Lake Deschenes,” the planning board said in a statement Thursday afternoon. “Levels may reach or exceed the major flood level in Mattawa and from Lake Coulonge down to Lake Deschenes depending on the rapidity of snowmelt and precipitation to be received over the next few days.”

• West Carleton, Cumberland residents being advised to monitor Ottawa River levels

Water levels are expected to exceed minor flood levels from the Hull Marina down to Hawkesbury.

Three conservation authorities announced a flood warning for areas along the Lower Ottawa River, including through Ottawa, on Thursday, warning flood prone areas “remain at risk.”

“Water levels and flows have been steadily rising along the Ottawa River due to recent rainfall combined with ongoing snowmelt in the northern basin,” officials said. “Additional increases are expected over the coming days, with further rain and meltwater forecast.”

A statement from the South Nation Conservation Authority, the Rideau Valley Conservation Authority and the Mississippi Valley Conservation Authority said that minor flood levels have been exceeded between Pembroke to Britannia, “with potential for major flooding in some locations starting Friday.”

While minor flood thresholds have been exceeded along the Ottawa River from Gatineau to Hawkesbury, officials say, “peak levels are expected to stay below major flood limits.”

“It’s a year where people need to be paying attention. For sure, it’s more than we see on our normal annual event. We have people that will be using sandbags right now, and some pumps will be running heavily. So, they need to monitor those, make sure they’re running, pay attention to them. But we’re not expecting dramatic flooding across the entire city,” said Lethbridge.

“Currently, our 2025 forecast is that we won’t be approaching what we observed in 2023. It will remain under that upper peak, and we’re certainly not forecasting anywhere near our previous significant flooding years.”

Here is a look at the specific forecasts along the Ottawa River

Constance Bay

The Mississippi Valley Conservation Authority says water levels are expected to rise on the Ottawa River at Constance Bay by up to 25 cm by the weekend.

“Flooding of low-lying properties, roads, and shoreline structures is possible,” the conservation authority said Thursday. ”Residents should monitor shoreline conditions and prepare accordingly.”

Britannia/East of Cumberland

The Rideau Valley Conservation Authority (RVCA) says the Ottawa River is expected to rise up to 30 cm at Britannia by the weekend.

“Low-lying yards, parks, and roads may experience localized flooding,” the RVCA said.

The river is expected to rise up to 25 cm in Cumberland, but officials say it will be 75 cm below the 2023 peak levels.

“Potential access issues along Boisé Lane; residents should prepare for restricted road access,” the RVCA said.

Clarence-Rockland

The Ottawa River is expected to increase up to 30 cm by the weekend in the area of Voisine Road and Old Highway 17, but will be 35 cm below 2023 levels.

“Low-lying areas near the river and some municipal roads may experience water on the roadway; residents should secure property and monitor updates,” the South Nation Conservation said.

The conservation authorities warn the elevated water levels are forecast to continue through Monday.

Gatineau

The City of Gatineau says expected peaks are still forecast to be lower than in 2023, and have been revised slightly downward, as water levels are rising less quickly than expected.

“The situation could persist for several days next week. Data has fluctuated throughout the week, but municipal teams remain mobilized and are ready to intervene at any time,” the city said in a statement, originally in French.

With files from CTV News Ottawa’s Peter Szperling