The cuts, in the rural municipality of Wallace, were made overnight in an attempt to prevent a larger collapse of the raised roadways, which also serve as dikes.
Reeve Don Neufeld said it's better to have the water released a little at a time, rather than have a rush of water if the roads were to let go.
A couple of other roads are still holding and being relied on to serve as dams, he added.
"We're trying not to breach them," Neufeld said.
"That would be disastrous if those couple of roads let go. Then we're in a whole world of hurt."
Some 40 homes have been evacuated and about people in about 40 other homes have been told they might have to leave.
The regional municipality includes the communities of Virden, Hargrave, Harmsworth, Kirkella, Kola, Maples and Two Creeks.
Neufeld said he will meet with officials from the province and City of Virden later Wednesday to decide if some people can return to their homes.
Dave Jordan noticed the water coming up fast at about noon Tuesday. He called in some help to build a dike to protect his house, but by supper time, he was ordered to get out.
“There's a lot of water that could come here. It's the old adage, 'Prepare for the worst, hope for the best,'” he said.
The regional municipality of Wallace has also issued a warning to people to stay out of the areas where emergency operations are happening. Many people have been standing and watching the crews, but it is not safe, the warning says.
Anyone found in those areas will face charges.
A total of 34 communities in Manitoba have declared states of local emergency due to flooding from a weekend of torrential rains, while 53 Saskatchewan communities have done the same.
The area within the gold-coloured zone is under mandatory evacuation