OTTAWA/GATINEAU, Friday April 8, 2022 — The Ottawa River Regulating Committee would like to inform watershed residents (see Note) that levels and flows along the Ottawa River are expected to begin increasing as a result of the onset of the spring freshet period in the Ottawa River basin. The Committee cautions residents along the shores of the Ottawa River from Mattawa down to the Montreal region that throughout the spring freshet period water levels can rise rapidly at times and cause minor flooding in low-lying areas.
There are currently no flooding indicators of concern. There was a partial melt of the snow earlier in March. A large part of the snow cover in the basin had near-average water content at the end of March, and the freshet is beginning at the normal time of year. However, it is too early to forecast peak river conditions. The Committee will be closely monitoring the effects of precipitation and temperature increases throughout the spring freshet period as they may cause levels and flows to change rapidly. Further bulletins will be published if flood risks increase.
River Conditions Forecast / Flooding Risk: A large low-pressure system is expected to bring 15 to 30 mm of precipitation over much of the Ottawa River basin from early Thursday through to late Friday, with precipitation amounts of up to 40 mm possible locally on the southeastern part of the basin. At the same time, warmer temperatures will melt a large portion of the remaining snowpack in the central and southwest areas of the basin. Combined rainfall and snowmelt is expected to produce high runoff, causing levels to rise on the Ottawa River between Mattawa and the Montreal region starting today.
The spring melt has begun early in the southern part of the basin. A warm spell combined with rain in the third week of March caused most of the snowpack to melt in that area and the water levels and flows on the main stem of the Ottawa River between Pembroke and the Montreal region increased temporarily. There is currently no or close to no snow left on the ground over much of the southeastern part of the basin. Following the return of seasonal weather near the end of March, water levels and flows have decreased and are near average values for this time of year. As seen in the figure, the snow water content (that is the amount of water held in the snow cover) at the end of March was near average in the central and northwest sections of the basin, and above average in the headwater areas of the Ottawa, Gatineau and Lièvre rivers. At that time, there was significantly less snow water content compared to 2019 in most areas, except for the northernmost area of the basin. However, snow water content is only one of several factors impacting the magnitude of the spring freshet.
The Regulating Committee works closely at all times, with provincial agencies responsible for issuing flood- related messages. In Ontario, Conservation Authorities and District Offices of the Ministry of Northern Development, Mines, Natural Resources and Forestry issue local flood-related messages and information to municipalities, Indigenous communities and other key agencies involved in flood preparedness and response. Current flood-related messages can be viewed on-line on the individual conservation authority websites and on the provincial flood webpage: https://www.ontario.ca/flooding. In Quebec, the Ministère de la Sécurité publique through the Centre des opérations gouvernementales and the Regional Directorates of Sécurité civile collaborate with municipalities to protect residents. Monitoring of flood conditions can be viewed at https://geoegl.msp.gouv.qc.ca/adnv2/ .
FOR MORE INFORMATION
Website: Current and forecast conditions on the Ottawa River along with conditions at the principal reservoirs in the system may be obtained by consulting our website. A general four-day forecast is also provided at key locations within the basin during the spring freshet period.
Telephone: The river conditions forecast and information on current river levels may be obtained for the following locations: Lake Timiskaming, Mattawa, Pembroke, Lake Coulonge, Chats Lake, Ottawa (Britannia), Gatineau (Hull wharf), Grenville and Maniwaki, by calling 1-888-621-0059.
Twitter: Follow us to be notified when press releases are issued, when we begin daily updates of the River Conditions Forecast message or the four-day forecasts at reference locations on our website, or when news bulletins are posted on our website.
The Ottawa River Regulating Committee consists of the following agencies that are responsible for the collaborative flow management of the principal reservoirs within the Ottawa River watershed: Hydro-Québec, Ministère de l’Environnement et de la Lutte contre les changements climatiques du Québec, Ontario Power Generation, and Public Services and Procurement Canada. In Ontario, the Ministry of Northern Development, Mines, Natural Resources and Forestry, as an associate member of the Regulating Committee, contributes important hydrometeorological information and plays a key role in disseminating information in Ontario.
Note: The Regulating Committee issues a press release when the spring freshet season is starting on the Ottawa River and when it anticipates that river conditions on the main stem of the Ottawa River (between the Lake Timiskaming outlet down to the Montreal region) may exceed significant flood levels. This press release does not apply to residents of the Abitibi- Timiskaming area or tributaries of the Ottawa River.
For additional information, please communicate with the Ottawa River Regulation Secretariat using the ‘Contact us’ form on the website or leave a message at 819-303-5886 or 1-888-621-0059.
-Ottawa River Regulating Committee