(North Bay May 3, 2023). A FLOOD WARNING continues for the Mattawa River subwatershed including the Town of Mattawa, according to the North Bay-Mattawa Conservation Authority (NBMCA). A FLOOD WATCH is now in effect for the Lake Nipissing shoreline in the NBMCA watershed. A FLOOD WATCH continues for all other areas in the NBMCA watershed.

“The Town of Mattawa has declared a State of Local Emergency. The Ottawa River water level at Mattawa has now exceeded the threshold for minor flooding. Low-lying areas in and around the Town of Mattawa are being affected by both the Ottawa River and Mattawa River,” said Chitra Gowda, NBMCA CAO. “The Ottawa River water level at Mattawa has increased by around 92 cm since Sunday morning (April 30). There is a potential for further water level increases in both rivers in the next few days,” continued Gowda. “The Mattawa Island Conservation Area is covered by the floodwaters and the NBMCA has closed the access road.”

A Flood Warning continues for the Mattawa River subwatershed including the Town of Mattawa. Based on information from the Ottawa River Regulation Planning Board, the Ottawa River water levels at Mattawa may exceed the major flooding threshold. There may be further increases to the outflow from reservoirs in the Abitibi-Timiskaming region, upstream of Mattawa. The Ottawa River water levels are managed by dams and reservoirs operated by provincial and federal governments. The Ottawa River Regulation Planning Board posts current data and forecasts on their website https://ottawariver.ca/

For comparison, when river-based flooding occurred at Mattawa in May 2019, the water level on the Ottawa River at Mattawa reached a maximum level that is 80 cm higher than the present level. Flows from the Otto Holden dam in May 2019 were around 25% greater at their maximum than present.

“A Flood Watch is now in effect for the Lake Nipissing shoreline area. The Lake Nipissing water level has increased by 18 cm since April 30,” said Angela Mills, NBMCA Flood Duty Officer. “The lake level is expected to increase further this week, due to the significant rain event that started April 29.” Conditions are changing rapidly, and water levels may increase beyond what is forecast. The water level on Lake Nipissing is regulated by dams operated by the federal government. Current water levels can be viewed by searching for the Station Name “Lake Nipissing” at the website https://wateroffice.ec.gc.ca/search/real_time_e.html

The Flood Watch for all other areas in the NBMCA watershed continues. With the significant rainfall received since April 29, water levels on local creeks and rivers rose sharply. Some local creeks and lakes are expected to remain high for the next few days. A period of warmer, drier weather that is forecast to start May 5 might help to lower the water levels in the local creeks and rivers.

Residents, especially those in low-lying areas, are encouraged to monitor the conditions as they develop, and prepare accordingly. Shorelines of creeks and rivers will be 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 shorelines. 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 – North Bay District.

As part of the NBMCA Flood Forecasting and Warning Program, staff will continue to monitor weather and watershed conditions and update this message based on the changing weather/streamflow conditions. Staff remain in contact with municipalities and other partners as required.

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), Facebook (@theNBMCA) and Instagram (nbmcainfo).

This message will be in effect until (or updated before) Monday May 8, 2023 at 4:00 pm.



Angela Mills, Duty Officer, cell: 705-497-4668
Chitra Gowda, CAO, cell: 705-477-0372

Terminology: Notification Levels

Spring Freshet 2023 & Flood Bulletins