Flood Warning - Update #2— Lower Ottawa River
April 28, 2023 — This FLOOD WARNING statement is an update to the Flood Warning issued for areas along the Lower Ottawa River (Arnprior to Hawkesbury) on April 20th, 2023.
Water levels are expected to rise again within the Ottawa River Basin due to significant rainfall forecasted Saturday through Tuesday. Runoff from this rain event will bring additional water volumes to the Ottawa River at a time when levels are already near major flood thresholds.
The Ottawa River Regulating Committee is managing principal reservoirs to reduce river flows to downstream areas.
The Ottawa River Regulating Committee anticipates that water levels along the main stem of the Ottawa River will rise again next week, possibly exceeding major flood thresholds.
Rainfall runoff could affect multiple streets, lawns and houses in low-lying areas.
Water levels are currently expected to remain well below historical flood levels of 2019 on the main stem of the Ottawa River.
Affected locations includeflood-prone areas at Chats Lake, Constance Bay area, Britannia / Lac Deschênes, Cumberland, City of Clarence-Rockland, Township of Alfred Plantagenet, and other vulnerable areas down to Montreal.
MVCA areas of concern:
- Water levels in the Constance Bay area are expected to rise early next week by about 0.3 mabove the current elevation*.
RVCA areas of concern:
- Water levels in the Britannia area (Grandview Road and the Belltown Community) are expected to rise early next week by about 0.3 mabove the current elevation*, which is about 0.1 m above the highest water level observed this year.
- Water levels east of Cumberland Village (Boise Village, Morin Road, Leo Lane) are expected to rise early next week by about 0.45 m above the current elevation*, which is about 0.25 m above the highest water level observed this year.
SNC areas of concern:
- Water levels in the Rockland area are expected to rise early next week by about 0.45 mabove the current elevation*, which is about 0.25 m above the highest water level
observed this year.
MNRF areas of concern:
- Water levels in the Hawkesbury area are expected to rise by about 0.4mabove the
current elevation* early next week, which is about 0.20 m above the highest water level observed this year.
* Current elevation as of 10:00 a.m., Friday, April 28, 2023.
Peak river conditions remain dependent on snowmelt in the northern part of the basin and rainfall. There is uncertainty on the rainfall amounts and the areas that could be affected. It should be noted that water level forecasts do not account for wind and wave impacts.
Residents in flood-prone areas are encouraged to closely follow changing 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 and provide appropriate supervision around all waterbodies.
The Mississippi Valley, Rideau Valley, and South Nation Conservation Authorities monitor 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 Regulating Committee will be reassessing forecast conditions and providing hydrological condition updates on its website daily at www.ottawariver.ca/forecasts.
To view current flood warnings across Ontario, visit: www.ontario.ca/law-and-safety/flood-forecasting-and-warning-program.
This FLOOD WARNING STATEMENT is in effect until May 5th, 2023 at 5:00 PM.
Updates will be provided as conditions change.
South Nation Conservation
Erin Thorne, Communications Specialist,
FLOOD DUTY OFFICER:
Katherine Watson, Water Resources Specialist – Monitoring
- Water Conditions Statement: Water Safety: indicates that high flows, melting ice or other factors could be dangerous for such users as boaters, anglers, and swimmers but flooding is not expected.
- Water Conditions Statement: Flood Outlook: gives early notice of the potential for flooding based on weather forecasts calling for heavy rain, snow melt, high winds, or other conditions.
- Flood Watch: potential for flooding exists within specific watercourses and municipalities. Municipalities, emergency services and individual landowners in flood-prone areas should prepare.
- Flood Warning: flooding is imminent/occurring within specific watercourses and municipalities.
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