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Water Conditions Statement Update #3: Flood Warning — Lower Ottawa River

May 2, 2023Alert level: Flood Warning (4 of 4)

This FLOOD WARNING statement is an update to the Flood Warning issued for areas along the Lower Ottawa River (Arnprior to Hawkesbury) on April 28th, 2023.

Water levels are expected to rise again within the Ottawa River Basin due to significant rainfall received over the past few days. 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.

Based on Ottawa River Regulating Committee forecasts, flood prone areas along the main stem of the Ottawa River from Arnprior to Hawkesbury are at risk. Water levels are currently expected to remain 45 cm to 70 cm below historical flood levels of 2019 on the main stem of the Ottawa River.

Affected locations include flood-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 Carillion Dam. Potential water level increases forecasted by the Ottawa River Regulating Committee are provided below.

MVCA areas of concern:

  • Water levels in the Constance Bay area are expected to rise about 20 cm above the current elevation* over the next week. The water levels are expected to exceed peak levels observed April 21, 2023, by about 20 cm.

RVCA areas of concern:

  • Water levels in the Britannia area (Grandview Road and the Belltown Community) are projected to rise about 30 cm above the current elevation* over the next week. The water levels are expected to exceed peak levels observed April 21, 2023, by about 30 cm.
  • Water levels east of Cumberland Village (Boise Village, Morin Road, Leo Lane) are projected to rise about 35 cm above the current elevation* over the next week.  The water levels are expected to exceed peak levels observed April 22, 2023, by about 60 cm.         

SNC areas of concern:

  • Water levels in the Rockland area are expected to rise about 30 cm above the current elevation* over the next week. The water levels are expected to exceed peak levels observed
    April 22, 2023, by about 60 cm.

MNRF areas of concern:

  • Water levels in the Hawkesbury area are expected to rise about 30 cm above the current elevation* over the next week. Water levels are expected to exceed peak levels observed
    April 22, 2023, by about 50 cm.

* Current elevation as of 8:00 a.m., May 2, 2023.

Peak river conditions remain dependent on the amount of rainfall received. Forecast levels over a four-day period are provided at the Ottawa River Regulation Planning Board website (Forecasts - Ottawa River Regulation Planning Board) and updated daily as conditions could change quickly. Wind and wave effects are not included in this forecast. Water levels may fluctuate due to high wind gusts forecasted for Wednesday and Thursday.

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 12th, 2023 at 5:00 PM. Updates will be provided as conditions change.

South Nation Conservation

MEDIA CONTACT:
Erin Thorne, Communications Specialist,
ethorne@nation.on.ca, 1-877-984-2948.

FLOOD DUTY OFFICER:
Katherine Watson, Water Resources Specialist – Monitoring
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/occurring within specific watercourses and municipalities.

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