Important Press Release from the Ottawa River Regulating Committee Issued on May 3 2019

ONGOING FLOOD RISK ON THE OTTAWA RIVER Mattawa down to the Montreal Archipelago 

OTTAWA/GATINEAU, Friday May 3, 2019 — The Ottawa River Regulating Committee warns that levels and flows on the Ottawa River from Mattawa down to Lac Coulonge are expected to increase again and reach another peak over the next week. Reservoirs in the Abitibi-Timiskaming area are filling rapidly with snowmelt and runoff from precipitation in that part of the watershed. Water released from the reservoirs is increasing and will cause water levels on the Ottawa River downstream between Mattawa and Lac Coulonge to increase. Flows and levels could rise rapidly at times between Mattawa and Lac Coulonge and will possibly exceed flood levels experienced earlier last month.

River Conditions Forecast / Flooding Risk:

The rate of snowmelt in northern regions is quickly increasing with warming temperatures. Over the next few days, flows released from the reservoirs in the Abitibi-Timiskaming area will increase significantly. Sharp increases in water levels downstream of Lake Timiskaming from Mattawa to Lac Coulonge are expected with amounts dependent on actual temperatures, rate of snowmelt, and precipitation. People living along the Ottawa River in these sectors are advised to closely follow changing conditions and to take necessary measures. The Regulating Committee will be reassessing forecast conditions and providing hydrological condition updates on its website daily at If you think that your property may be at risk of flooding, please contact your municipality.

The Regulating Committee cautions residents that during the next two weeks, all areas between Mattawa and Lac Coulonge are at risk of additional flooding, depending on weather conditions. Furthermore, the Regulating Committee also cautions residents from Lac Coulonge down to the Montreal Archipelago that water levels and flows will remain high and will also be susceptible to any significant additional precipitation.

Reservoir Regulation Strategy:

This year in the Abitibi-Timiskaming region, the volume of spring runoff exceeds the holding capacity of most reservoirs. The reservoirs in this region have been retaining the major part of the spring runoff from these areas over the last two weeks. The operational strategy has been to release as little water as possible downstream while local uncontrolled tributary rivers from the central-west part of the basin reached their peak and started to recede. Now that the natural runoff from these rivers has peaked and is in decline, the rapidly filling reservoirs located in the Abitibi-Timiskaming region will begin to release water. Other reservoirs located further to the north will be gradually filling over the next two to three weeks as snow melt runoff continues.

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 cannot reduce the flows and levels associated with increased spring runoff. During this critical freshet period, the Regulating Committee will undertake actions to limit the amount of flooding and will continuously monitor conditions at all points along the river. 


The Ottawa River 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 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: 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 .


Website: Current and forecast conditions on the Ottawa River along with conditions at the major 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. (English) (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 (613) 995-3443 English (613) 995-3455 French

Outside the Ottawa-Gatineau 1-800-778-1246 English region 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. (English) (French)

The Ottawa River Regulating Committee consists of the following agencies that are responsible for the integrated 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. For additional information, please contact Manon Lalonde (613) 996-8639 or Michael Sarich (613) 996-8643 of the Ottawa River Regulation Secretariat, or write to (English) or to (French).

Ottawa River Regulating Committee