Water Safety Statement - North Bay-Mattawa Watershed

Water Safety Statement - North Bay-Mattawa Watershed

Message Number:    2025-05

Issued:                   March 28, 2025, at 2:30 PM EDT

From:                     NBMCA Duty Officer, Githan Kattera

Watershed Conditions Statement – Water Safety: indicates that high flows, unsafe banks, melting ice or other factors could be dangerous for users such as anglers, boaters, swimmers, children, or pets. Flooding is not expected.

If you have a flood emergency, please contact your municipality. If you live in an unincorporated township, please contact the Ministry of Natural Resources (MNR) – North Bay District.

A Watershed Conditions Statement – Water Safety remains in effect for the North Bay-Mattawa watershed.

This is an update to the previous Message Number 2025-04 dated March 21, 2025.

Current Conditions:

Water levels on area lakes and rivers are normal for this time of year. As of March 25, the moisture content in the snowpack is an average of 83.3 mm, which is normal for late March. After recent mild temperatures and rainfall, the snowpack has limited capacity to absorb additional moisture, and the ground is frozen or saturated.

Water level for Lake Nipissing and the Ottawa River at Mattawa are normal for this time of year and are well below flood thresholds.

Current water levels can be viewed by searching Station Names “Ottawa River”, “Mattawa River”, “Chippewa Creek”, “La Vase River”, “Wasi River”, and “Lake Nipissing” at https://wateroffice.ec.gc.ca/search/real_time_e.html

Forecasted Conditions:

Environment Canada has issued a Snowfall Warning for the North Bay – Powassan – Mattawa area, with significant snowfall, ice pellets, and potentially freezing rain today and tonight. A second storm is expected Sunday, bringing more snow, ice pellets, and freezing rain. Approximately 30 mm of freezing rain and rain is forecast for Sunday (Mar 30) into Monday. Temperatures are forecast to remain below freezing through Sunday and warming to 4°C for Monday as the precipitation transitions to rain. Water levels and flows are expected to increase. Temperatures are forecast to return to well below freezing for Monday night.

Water levels on the Ottawa River are managed by upstream dams and reservoirs operated by provincial and federal governments. Forecasts are available at https://ottawariver.ca/

The water level on Lake Nipissing is regulated by dams operated by the federal government. Forecasts are available at https://www.canada.ca/en/public-services-procurement/services/infrastructure-buildings/bridges-docks-dams/frenchriver-dam.html

Historic Flood Conditions:

For comparison, in response to 34.5 mm of steady rain over 12 hours with frozen or saturated soil conditions and minimal remaining snowpack in March 2024, the water level on Chippewa Creek increased by 83 cm over 15 hours, peaking about 3 hours after rain ended.

Risk:

Fluctuating water levels on local lakes, rivers and streams are deteriorating ice conditions on local lakes.  Rainfall on frozen and saturated soils may cause rapid changes in water levels in urban creeks within the City of North Bay, especially during and after periods of intense precipitation. With temperatures returning to well below freezing on Monday night (Mar 31), any increases in water levels are likely to be of short duration.

All residents, especially those in low lying areas, are encouraged to monitor the conditions that are developing. Banks adjacent to rivers and creeks are very slippery at this time and when combined with faster flows and cold open water, pose a serious hazard. The public is encouraged to keep children and pets away from watercourses and off waterbodies. 

Municipalities are encouraged to monitor water crossings for debris that may affect the movement of water through culverts and bridges. A close watch on local conditions and updated forecasts and warnings from Environment Canada is also recommended.

Staff at the North Bay-Mattawa Conservation Authority will continue to monitor weather and watershed conditions and update this message based on the changing weather and streamflow conditions.

This message will be in effect until (or updated before) Friday, April 4, 2025, at 4:00 PM EDT.

The general public is advised of these messages through the www.nbmca.ca website with the flood status icon and a link to information about current conditions. NBMCA also circulates these messages to local media and social media, posting on Twitter (@theNBMCA), Instagram (nbmcainfo), and Facebook (NBMCA).

The public is invited to share photos of watershed conditions on social media using #NBMCAFlood.

Media Release issued March 28, 2025

https://www.nbmca.ca/watershed-management/flood-forecasting/flood-watch-status-terminology/