Conservation authority warns of spring flooding risk along Rideau River watershed

A local conservation authority is warning of the potential of flooding along waterways in the Rideau Valley watershed this spring due to the heavy snowfall this winter.

A total of 308.5 cm of snow has fallen in Ottawa this winter, the second-highest snowfall total over the past 20 years.

The Rideau Valley Conservation Authority says water levels on some lakes in the upper watershed are above normal, including Wolfe Lake and Christie Lake, and could rise further as the snowpack begins to melt.

As spring approaches, officials are urging people to be prepared for possible flooding conditions over the next few weeks.

"Based solely on the fact we have above-average snow water content and above-normal water levels in some upper watershed lakes, there is potential for above-average flooding this spring across the Rideau Valley watershed, especially in low-lying areas which have flooded in the past," the conservation authority said in a statement.

"Precipitation and temperature are two other key factors influencing actual flood conditions as we move through March and into April, which staff will monitor closely."

The conservation authority says the short-term forecast suggests a "slow melt with little precipitation, which is favourable for limited flooding for at least the first half of March."

City of Ottawa crews have begun ice removal operations on the Rideau River, between Rideau Falls and Bronson Avenue.

The last two winters Ottawa saw at least 300 cm of snow, there was record-setting flooding along the Ottawa River.

In 2019, Constance Bay, Fitzroy Harbour, Arnprior, Pembroke, Gatineau and Pontiac experienced flooding. The Canadian military was deployed to Ottawa and Gatineau to assist with flood relief efforts.

In 2017, flooding linked to heavy rains flooded several communities along the Ottawa River.

The Ottawa River Regulation Planning Board said Wednesday that water levels and flows in most locations along the main stem of the Ottawa River are close to seasonal levels and are "expected to be fairly stable over the coming week".

Mississippi and Carp rivers 

The Mississippi Valley Conservation Authority issued a warning last week about the potential for flooding across the Mississippi and Carp River watersheds.

"Well above average snow pack conditions across the Mississippi Valley watershed could lead to above average flooding this spring," the authority said on March 3.

"Current conditions at snow course sites are indicating significantly higher than normal water content amounts in the snow for this time of year. While snow is not the primary driver for spring flooding, it is one of several major contributors, along with rainfall and temperature."

The authority says the levels and flows will remain higher than normal across the Mississippi River as water is pushed through the system.