Residents living along flooding rivers in Ottawa are bracing for water levels to rise even higher Monday and into Tuesday, as an unseasonably warm Monday is followed by a mix of rain, snow and freezing rain Tuesday.

The Rideau Valley Conservation Authority said in an update to its flood warning that water levels can be expected to rise to levels not seen in six years.

"The Rideau Canal reservoir lakes are above their storage capacities; accordingly, additional flow releases will be necessary over the next several days to get water levels to targets and relieve the stress on infrastructure downstream," the conservation authority said in a statement Monday afternoon.

Brantwood Park near Saint Paul University

Water levels have risen to close to the seats of the picnic tables at Brantwood Park near Saint Paul University. (CBC)

Areas at risk along the Rideau River include:

  • Rideau River Drive in Old Ottawa South.
  • Communities on the Long Reach upstream of Manotick including around the Carleton Golf and Yacht Club, upstream of Kars Bridge including Commodore Drive.
  •  Low lying properties in the Village of Kars, Lorne Bridge Road.
  • Fennell Lane, Little Chesterville, Lannin Lane and neighbouring private roads.
  • Greenline, Fairmile Road, Hilly Lane, Rideau Glen and Becketts Landing.
  • Below the Poonamlie Dam near Smiths Falls, riverside properties on Salter’s Lane and Rivers Edge Road.

Areas at risk along other watercourses include:

  • On the Jock River, parts of Richmond in the King Street to Fowler Street vicinity are at risk. Low lying properties in North Gower on Steven Creek could be inundated.
  • On Kemptville Creek, Cedar Beach to Riverview Roads.
  • In the Town of Perth, low laying areas along the Tay River (Stewart and Last Duel Parks).    

Summer, followed by winter

Temperatures at Ottawa Airport reached 25.3 degrees Celsius on Monday, but as Environment Canada warned in a special weather statement, "after a long awaited taste of summer, winter returns with a snowy vengeance."

The national weather agency says a sharp Arctic cold front will bring showers, high winds, and, as temperatures drop below zero Tuesday, snow and freezing rain.

The city is advising residents in a number of Ottawa neighbourhoods along the Rideau River to move valuables out of basements, make sure sump pumps are working and even place sandbags around homes.

In Old Ottawa South, the end of Belmont Avenue near Windsor Park is flooded, and home-owners like Susan Vail are ready with sandbags if the water creeps further down the street.

"Oh gosh. This is the highest the river has been in the 20 years we've lived here. So it's very concerning because a lot of houses must have flooding in the basements," said Vail.

Campbell Laidlaw used to live in the area in the 1950s when he was a child. He remembers paddling around in rafts when water levels got this high.

"This is not typical of recent years but it certainly was typical of years well by gone," said Laidlaw.

The Mississippi Valley Conservation authority has also issued a flood warning for the Clyde River, Fall River, and Mississippi River from Dalhousie Lake through to the outlet at Galetta. The South Nation Conservation authority in eastern Ottawa is currently under a flood watch.