Officials are predicting the Carp River could flow over its banks as early as Friday.
Both the Mississippi and Rideau Valley Conservation Authorities say the Ottawa River and other large waterways will likely peak late next week.
Smaller waterways like Ottawa's Sawmill Creek and Graham Creek are also expected to be high this weekend.
The City of Ottawa is preparing for the flood threat and is urging residents to do the same.
On Wednesday, city officials said free sandbags would be available for those residents living in low-lying areas.
As the spring thaw continues, warmer temperatures and increased rainfall are expected to increase the region's flood risk.
The snow pack currently sits near record levels and conservation officers are continuing to monitor the river flow on a daily basis.
