April 29, 2019 — Rideau Valley Conservation Authority (RVCA), in conjunction with the Mississippi Valley Conservation Authority (MVCA) and South Nation Conservation (SNC) is maintaining the FLOOD WARNING issued on April 19, 2019 for the areas under our jurisdiction along the Ottawa River.
The most recent model outputs from the Ottawa River Regulation Committee (ORRC) indicate that runoff from snowmelt and precipitation is decreasing from Mattawa to Lac Coulonge with levels stabilizing in Mattawa and Pembroke.
The Lower Ottawa River water levels are increasing due to upstream spring runoff caused by rainfall, saturated soil and snowmelt over the central part of the basin. Runoff from ongoing snowmelt and recent rainfall has swollen most of its tributaries.
Rainfall amounts of 20 – 40 mm are forecast for Wednesday and into Thursday. An additional 10 – 20 mm of rain is possible Friday.
All flood-prone areas along the Ottawa River from Lac Coulonge down to the Montreal Archipelago are at risk.
Peak water levels across many areas of the Ottawa River will exceed those experienced in May 2017 over the next couple of days. Levels are forecasted to peak between Tuesday and Wednesday; however, water levels will remain high. Risk is highly dependent on the amount of precipitation that is received.
MVCA areas of concern:
Water levels in the Constance Bay area have exceeded those levels reached in May 2017. The ORRC currently forecasts water levels to rise an additional 0.30 m to 0.50 m above the 2017 levels. Updates to this projection will be provided as they become available.
RVCA areas of concern:
Water levels in the Britannia area (Grandview Road, Britannia Village, and the Belltown Community) have exceeded those levels reached in May 2017. The ORRC currently forecasts water levels to rise an additional 0.30 m to 0.50 m above the 2017 levels. Updates to this projection will be provided as they become available.
Water levels east of Cumberland Village (Boise Village, Morin Road, Leo Lane) are slightly below those levels reached in May 2017. The ORRC currently forecasts water levels to rise an additional 0.20 m to 0.40 m above the 2017 levels. Updates to this projection will be provided as they become available.
SNC areas of concern:
Water levels in the Clarence-Rockland and Alfred-Plantagenet area have risen 0.12 m over the last 48 hours and are near the levels observed during the May 2017 flood. The ORRC currently forecasts that water levels are projected to rise an additional 0.05 m to 0.25 m above the May 2017 levels over the next two days.
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 Wednesday, May 1, 2019.
RVCA and its Ottawa partners, MVCA and SNC 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.
To view current flood warnings across Ontario, visit https://www.ontario.ca/law-and-safety/flood-forecasting-and-warning-program.
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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.
