The city of Montreal is urging the few dozen residents of Ile Mercier to leave their homes but is not yet prepared to make that order mandatory.

That may change as floodwaters continue to rise.

The few dozen residents of Ile Mercier, a small island in the middle of the Riviere des Prairies connected to Ile Bizard by a low-lying road, have been on alert for several weeks after their only roadway off-island was partially submerged in mid-April.

With a new surge of water this week, the borough's mayor Normand Marinacci called for a voluntary evacuation.

"Generally people don't want to leave. They just want to stay in their house so they can supervise their sump pumps. They want to protect their house," said Normand Marinacci.

The last time the island flooded this badly was in 1998, when Marinacci was a councillor.

"When I came back this year there was a woman who still had a picture of me in 1998 when I was helping her out," he said.

His main concern is that power to the island will be knocked out by the flooding.

"That is where the fire department may have to force people to get out. But for the moment everything's under control," said Marinacci.

One resident said she was worried about the water, but intended to do what she could to protect her home.

"We came home and we had three-and-a-half feet of water in the basement," she said.

Another resident said he intended to stay, and so did his neighbours.

"Nobody wants to leave because if you leave you lose your house. You lose your belongings," he said.

When people are ready to leave -- or forced to -- the borough has emergency shelter ready.

Meanwhile emergency crews are keeping a close eye on the western and northern sections of Ile Bizard as the water rises in the Lake of Two Mountains.

Flooding has been reported all around the lake, from Ste. Anne de Bellevue to Pointe Calumet.

Water levels throughout southern and central Quebec are expected to continue rising for the next week, with substantial amounts of rain forecast for Friday and the weekend.