FLOOD WARNING: Ottawa River – Arnprior to L’Orignal – Update #2

21-Apr-2019 21-Apr-2019

Weather Forecast:
Significant rainfall has fallen over the Ottawa River basin since Thursday, April 18, 2019. Cooler than forecasted temperatures and less precipitation was received yesterday, with only 6 mm of rain received in the Ottawa area. Some rain is forecasted later in the week in the northern portion of the Ottawa River basin which may impact flows.

Environmental Conditions:
Saturated soils, warm temperatures and precipitation received has melted some of the remaining snowpack in the Ottawa River basin. Some snowpack remains.

All flood-prone areas along the Ottawa River from Lac Coulonge down to the Montreal Archipelago are at risk. Water levels across some areas of the Ottawa River are expected to peak today while others will be closer to the end of the week.

Levels will remain high for several days with ongoing risk of increases depending on snowmelt runoff and precipitation next week. Reservoirs throughout the basin are being used to store runoff and minimize flooding.

MVCA areas of concern: Water levels in the Constance Bay area are projected to rise an additional 0.30 m above the current elevation over the next seven days. Levels are currently forecasted to be about 0.50 m below those experienced at the height of the May 2017 flood.

RVCA areas of concern: Water levels from Britannia to Cumberland are expected to rise an additional 0.40 m above the current elevation over the next seven days. Levels are currently forecast to be about 0.25 m below those experienced at the height of the May 2017 flood.

SNC areas of concern: Water levels are expected to continue to be elevated along the Ottawa River in Clarence-Rockland and Alfred-Plantagenet and are projected to peak today at 42.95 m. Areas previously affected by the May 2017 flood are at greatest risk.

Residents in flood-prone areas are encouraged to closely follow evolving conditions and to take necessary measures. Sandbags are available to residents in flood prone areas. 

Residents are advised to stay away from watercourses where flows are high and where banks might be unstable. Parents are encouraged to explain dangers to children.

This Flood Warning is in effect until Monday, April 22, 2019.

South Nation Conservation (SNC) and its Ottawa partners, the Rideau Valley and Mississippi Valley Conservation Authorities, monitor the water levels and weather forecasts with the Ministry of Natural Resources and Forestry as part of the Flood Forecasting and Warning Program. Updates are provided as conditions change.

The Ottawa River Regulation Planning Board will be reassessing forecast conditions and providing hydrological condition updates on its website daily at

Please visit for more information. To provide feedback with respect to changes in water related conditions please email, post on our Facebook (/SouthNationConservation) or Twitter (@SouthNationCA).

For more information regarding the Ottawa River, visit

FOR MORE INFORMATION: Jason Symington, SNC Environmental Technologist,

FOR MEDIA INQUIRIES: John Mesman, SNC Team Lead of Communications,

FORWARDED TO: All Flood Forecasting and Warning Directory