The Grand River Conservation Authority (GRCA) has issued a flood watch for the river’s entire watershed.
The agency says the heavy rain the area experienced earlier this week combined with the warmer temperatures has resulted in snowmelt and increased runoff into local waterways.
Despite the fact that cooler temperatures have returned, the GRCA says water levels will remain elevated, and it is warning of the potential for ice jams, which will cause flooding in low-lying areas.
Several roads in Waterloo Region have already been closed as a result of the higher water levels, including Tannery Street in Ayr, Holland Mills Road in Wilmot and Three Bridges Road in St. Jacobs.
The GRCA says the water levels for the Nith River peaked overnight and could reach Flood Warning Zone 2 in Ayr on Wednesday afternoon.