April 23, 2019 — The Rideau Valley Conservation Authority (RVCA), in conjunction with Mississippi Valley Conservation Authority (MVCA) and South Nation Conservation Authority (SNC) is maintaining our FLOOD WARNING issued on April 19, 2019 for the areas under our jurisdiction along the Ottawa River.

Significant rainfall has fallen over the Ottawa River basin since Thursday, April 18, 2019. 

Warmer than forecasted temperatures were received Sunday and Monday. Additional rainfall of 15 to 50 mm is anticipated today and tomorrow in northern and central areas of the Ottawa River basin. Saturated soils, warm temperatures and precipitation received continues to increase snowmelt in the Ottawa River basin. Some snowpack remains in the western and northern areas of the basin.

All flood-prone areas along the Ottawa River from Lac Coulonge down to the Montreal Archipelago are at risk. Peak water levels across some areas of the Ottawa River are expected to be similar to those experienced in May 2017.

Levels will remain high for several days and will increase later this week due to forecasted precipitation and snowmelt runoff. Reservoirs throughout the basin are being used to store runoff and minimize flooding.

MVCA areas of concern: 

Based on the most recent model outputs from the Ottawa River Regulation Committee (ORRC) and rainfall in the forecast, water levels in the Constance Bay area are projected to rise an additional 0.50 m to 0.60 m above the current elevation of 59.83 m over the next four days. Levels are currently forecast to be very close to those experienced at the height of the May 2017 flood. Updates to this projection will be provided as they become available.

RVCA areas of concern:

In Britannia (Grandview Road and the Belltown Community) water levels expected to increase an additional 0.50 m to 0.60 m above the current elevation of 59.83 m over the next four days.  Levels are currently forecast to be very close to those experienced at the height of the May 2017 flood. 

East of Cumberland Village (Boise Village, Morin Road, Leo Lane) water levels expected to increase an additional 0.40 m to 0.60 m above the current elevation over the next four days.  Levels are currently forecast to be just below those experienced at the height of the May 2017 flood.  Updates to this projection will be provided as they become available.

SNC areas of concern: 

Water levels are expected to remain high along the Ottawa River for the next few days in Clarence-Rockland and Alfred-Plantagenet; current water elevation has peaked at 43.02m. Water levels are expected to increase rapidly later this week due to forecasted precipitation. Levels are expected to peak again on Monday, April 29, 2019 at 43.30m, slightly below peak levels observed during May 2017.

Due to the forecast uncertainty it is difficult to accurately predict how quickly water levels will rise and when river conditions may peak.

Residents in flood-prone areas are encouraged to closely follow evolving conditions and to take necessary measures. 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 Thursday, April 25, 2019.

The Rideau Valley Conservation Authority and its Ottawa partners, Mississippi Valley Conservation Authority and South Nation Conservation, 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 www.ottawariver.ca/forecast.php. 

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"Rideau Valley Conservation Authority is a partnership of municipalities within the Rideau Valley watershed created under the Conservation Authorities Act to deliver a range of programs in watershed management and natural resource conservation."

RVCA Watershed Conditions Statements:

• Water Safety – High flows, unstable banks, melting ice or other factors that could be dangerous for recreational users such as anglers, canoeists, hikers, children, pets, etc. Flooding is not expected.
• Flood Outlook – Early notice of the potential for flooding based on weather forecasts, calling for heavy rain, snow melt, high winds or other conditions that could lead to high runoff, cause ice jams and/or lakeshore flooding or erosion.
• Flood Watch – Flooding is possible in specific watercourses or municipalities. Municipalities, emergency services and individuals in flood-prone areas should prepare.
• Flood Warning – Flooding is imminent or already occurring in area watercourses.