April 9, 2020 Press Release from the Ottawa River Regulation Planning Board - EXPECTING MINOR FLOODING ON THE OTTAWA RIVER (Fort-Coulonge to the Montreal Region)

Ottawa River Regulation Planning Board/
Commission de planification de la régularisation de la rivière des Outaouais 

EXPECTING MINOR FLOODING ON THE OTTAWA RIVER (Fort-Coulonge to the Montreal Region) 

OTTAWA/GATINEAU, Thursday, April 9, 2020 — 

— The Ottawa River Regulating Committee cautions that levels and flows on the Ottawa River continue to rise gradually due to on-going snowmelt in the central and northern portions of the basin. Minor flood levels may be exceeded starting this Monday in flood prone areas along the river between Fort-Coulonge and the Montreal region, depending on temperatures and precipitation received over the next few days. The minor flood level is defined as the level at which parts of some streets, lawns and parks are beginning to flood, with no or few houses/buildings affected by water levels. Water levels are currently expected to remain below major flood thresholds in all locations.

River Conditions Forecast / Flooding Risk: The spring thaw started early this year and there is no snow left on the southeast basin portion. April 1st snow measurements indicate that the remaining snow cover still contains a significant amount of water and has generally higher than average water content for this time of the year (refer to figure). With warmer temperatures over the last few days, part of the snow remaining on the central and northern portions of the basin has now melted and is currently flowing in the river system, thereby causing the levels and flows along the river to increase over the last week. With cooler temperatures and only moderate amounts of precipitation forecast to start tonight, levels are expected to stabilize into the weekend. On Monday, a spring storm is expected to bring above average temperatures and a significant amount of rainfall on a large part of the watershed. The Ottawa River Regulating Committee cautions residents that live in areas prone to flooding from Fort-Coulonge down to the Montreal region that starting Monday, levels may rise rapidly at times and may exceed minor flood levels, depending on the temperatures and precipitation amounts received. For the flood prone areas from Fort-Coulonge to the Lake Deschenes area, levels are expected to be similar to or below the peak levels reached in 2018. For the flood prone areas between Gatineau (Hull) and the Montreal region, levels are expected to be similar to or slightly above the maximum levels reached in 2018.  Further bulletins will be published if flood risks increase.

A diagram illustrating the snow water content can be viewed in the attached full copy of the notice which is available for download as a pdf from this website or from http://www.ottawariver.ca

Reservoir Regulation Strategy: Increases in water levels in the spring are caused by increases in flows. The principal storage reservoirs in the northern part of the watershed will store a large portion of runoff from these areas, thereby reducing flows in downstream basin areas. However, dams located in the central and southern portions of the basin are essentially “run of the river” with no significant storage capacity. As such, they do not significantly reduce the flows (and hence the levels) associated with increased spring runoff. During this critical freshet period, the Regulating Committee will take all possible actions to mitigate the amount of flooding and will continuously monitor conditions at all points along the river.


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 Natural Resources and Forestry issue 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 Centre des opérations gouvernementales du Québec and the Sécurité civile collaborate with municipalities to protect residents. Monitoring of flood conditions can be viewed at https://geoegl.msp.gouv.qc.ca/adnv2

If you think that your property may be at risk of flooding, please contact your municipality.


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. www.ottawariver.ca  (English) www.rivieredesoutaouais.ca  (French)

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 the following numbers:

Ottawa-Gatineau: (819) 994-9049 English; (819) 994-8171 French

Outside the Ottawa-Gatineau region: 1-800-778-1246 English; 1-800-778-1243 French

Twitter: Follow us to be notified when news releases are issued, when we begin daily updates or the general four-day forecasts on our website, or when special bulletins are posted on our website.

www.twitter.com/ORRPB (English)                                            www.twitter.com/CPRRO  (French)


The Ottawa River Regulating Committee consists of the following agencies that are responsible for the cooperative flow management of the principal reservoirs within the Ottawa River watershed: HydroQuébec, 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 Natural Resources and Forestry, through its associate membership with the Regulating Committee, contributes important hydrometeorological information and plays a key role in disseminating information in Ontario. 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) could exceed significant flood levels.

Covid-19: For important information by the Planning Board, please refer to a bulletin posted on March 20th on our website Latest News page.

For additional information, please communicate with the Ottawa River Regulation Secretariat using the ‘Contact us’ form on the website, or leave a message at any of the telephone numbers listed above.

Ottawa River Regulating Committee