Update #2 Flood Watch - Lower Ottawa River
This FLOOD WATCH statement is an update to the Flood Watch Statement issued for areas along the Lower Ottawa River (Arnprior to Hawkesbury) on April 25th, 2025.
The Ottawa River Regulation Planning Board (ORRPB) advises that weather events, particularly those bringing warmer temperatures and heavy rainfall, could cause water levels and flows to exceed minor flood thresholds in some areas along the Lower Ottawa River beginning Saturday, April 26th, 2025.
Water levels and flows have been gradually increasing along the main stem of the Ottawa River. Levels and flows are expected to increase over the next week due to forecasted rainfall Friday into Saturday, combined with increased spring runoff from snow melt in the northern region of the Ottawa River Basin.
From Pembroke to Britannia, minor flood levels will likely be exceeded starting Saturday with major flood levels being exceeded in some locations
Monday to Friday.
From Gatineau (Hull Marina) to Hawkesbury, minor flood levels will likely be exceeded starting Monday to Tuesday, with peak levels likely exceeding minor flood levels Thursday to Friday and expected to remain below major flood levels.
The minor flood level is defined as the level at which parts of some streets, lawns and parks are beginning to flood, with no or few houses/buildings being affected.
The major flood level is defined as the level at which one or several streets are beginning to flood, with several houses/buildings or neighbourhoods being affected.
Water levels are currently expected to remain well below historical flood levels on the main stem of the Ottawa River.
This advisory includes flood-prone areas at Lake Coulonge, Chats Lake, Britannia / Lac Deschênes, Pointe-Gatineau, Cumberland, City of Clarence-Rockland, and other vulnerable areas down to Hawkesbury.
These results are dependent on the amount of rainfall received. Residents in flood-prone areas are encouraged to closely follow changing conditions by consulting the Ottawa River Regulation Planning Board Current Conditions page (https://ottawariver.ca/conditions/) and to take necessary measures.
Residents in flood prone or low-lying areas, historically susceptible to flooding, should take the necessary precautions to protect their property. Please ensure:
- Sump pump is clear, in good working condition and has a backwater valve on it.
- Easy access to portable backup generator and pump.
- Downspouts are clear and the outlet is at least 3 m from the dwelling.
- Driveway culverts are clear of debris and drain well.
- Securing items that might float away as flows increase.
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 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 WATCH STATEMENT is in effect until April 28th, 2025 at 5:00 PM.
South Nation Conservation
Kat Watson, Coordinator, Early Warning Systems and Watershed Plans
kwatson@nation.on.ca,1-877-984-2948.
Definitions:
- 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 or occurring within specific watercourses and municipalities.
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