As a flood warning continues for the Mattawa River subwatershed including the Town of Mattawa, the North Bay-Mattawa Conservation Authority (NBMCA) says a flood watch is now in effect for the Lake Nipissing shoreline in the NBMCA watershed.
“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,” says 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.”
She adds the Mattawa Island Conservation Area is covered by the floodwaters and the access road has been closed.
NBMCA says based on information from the Ottawa River Regulation Planning Board, the Ottawa River water levels at Mattawa may exceed the major flooding threshold and there may be further increases to the outflow from reservoirs upstream of Mattawa.
By comparison, NBMCA says 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 while from the Otto Holden dam were around 25% greater at their maximum than at this time.
“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,” says 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.”
Officials add conditions are changing rapidly, and water levels may increase beyond what is forecast.
The Flood Watch for all other areas in the NBMCA watershed continues.
Residents, especially those in low–lying areas, are encouraged to monitor the conditions as they develop, and prepare accordingly.
