Water Safety North Bay- Mattawa Conservation Authority watershed jurisdiction

Message Number: 2023-22

Issued:  December 25, 2023, at 4:30 PM EST

From:    NBMCA Duty Officer, David Ellingwood

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 and Forestry (MNRF) – North Bay District.

A Watershed Conditions Statement – Water Safety is in place for all areas of the North Bay- Mattawa Conservation Authority watershed jurisdiction.

Current Conditions:

Water levels are normal for this time of year. Area lakes and soils have begun to freeze. Moderate amounts of rain will trigger runoff quickly.

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

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.tpsgc-pwgsc.gc.ca/ontario/eaux-water/renseignement-information-eng.html

Forecasted Conditions:

Forecasts indicate 10 to 20 mm of rain are possible Monday evening (Dec 25) to Wednesday evening (Dec27). With current frozen conditions, water levels and flows are expected to increase across the watershed. Conditions can change quickly in response to intense precipitation.

The water level of Lake Nipissing is expected to remain stable or decline, per Public Services and Procurement Canada. The changes to water levels on Lake Nipissing depend on the amount of water flowing in from rivers, precipitation, and the amount of water flowing out through the control dams to the downstream French River.

The water level of the Ottawa River at Mattawa is expected to remain stable, per the Ottawa River Regulating Committee.

Historic Flood Conditions:

In response to very intense rain on September 17, 2023, Chippewa Creek increased by 113 cm in just 55 minutes, rising with a rate of up to 20 cm every 5 minutes.


The forecasted rain between Monday (Dec 25) and Wednesday and snowmelt from above freezing temperatures will increase water levels across the watershed.

Rain on frozen conditions may result in rapid changes in water levels on urban creeks in the City of North Bay, especially during and after periods of intense precipitation. Water levels in the watershed will also increase; however, flooding is not expected at this time.

All residents and visitors are urged to stay off the ice. Ice conditions can deteriorate with warmer temperatures, rainfall and increased flows. Banks adjacent to rivers and creeks are very slippery at this time and when combined with 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) Thursday, December 28, 2023 at 10:00 AM EST.


Media Release -   https://nbmca.ca/news/water-safety-statement-december-25-2023/


North Bay-Mattawa Conservation Authority Subwatershed map
NBMCA Subwatershed Map


Lake Nipissing

Flows through the dams are based on daily analysis of the current status of the lake and river and as agreed to by the Sturgeon-Nipissing-French-Wanapitei Water Management Group. Weather forecast is considered, along with the inflows from the upper watersheds and outflows through the dam to the French River.

You can view the current level on Lake Nipissing at North Bay on the graph below and the French River at the Water Survey of Canada (WSC) website.  Fluctuations in the levels are a result of the strong winds affecting the movement of surface water. Water level and flow information for the South River and Sturgeon River systems is available from Ontario Power Generation (OPG)

Flood warnings for Ontario can be found on the Ontario Flood Forecasting and Warning website.

Why the fluctuation in water level readings on Lake Nipissing?  Lake Nipissing can sometimes act like a bathtub, with water shifting in the lake, depending upon wind direction, speed and atmospheric pressure - known as a wind surge or seiche.  At times the wind can have such an impact that it may result in the level being higher or lower at the French River gauge compared to the gauge located on the North Bay shoreline.

Mattawa River

The current Ottawa River water level may be viewed at the Water Survey of Canada (WSC) website (note that there is a delay of several hours, and 100m should be added to the gauge reading for metres above sea level).

The Ottawa River Regulation Committee and Ontario Power Generation which operates the Otto Holden Dam provide information online regarding the management of water levels on the Ottawa River.  To view water levels and current conditions on the Ottawa River visit the Ottawa River Regulation Planning Board and Ontario Power Generation.

Watercourses  and Monitoring throughout the Watershed

There are other watercourses within the NBMCA jurisdiction which are monitored by NBMCA and other agencies.  These gauges are maintained by Water Survey Canada - Environment Canada and can be viewed in real-time online.

In addition to the Water Survey of Canada gauges, there are other staff gauges which are monitored by NBMCA or the Ministry of Natural Resources and Forestry:

  • Chippewa Creek
  • Lake Nosbonsing Dam
  • Mattawa River at Hurdman Dam
  • Parks Creek
  • Trout Lake
  • Turtle Lake
  • Talon Lake

Is your property at risk of flooding?

If you think that your property may be at risk of flooding, please contact your municipality.  

If you live in an unorganized township, contact Ministry of Natural Resources and Forestry District office at 705-475-5501.