Updated

The provincial government on Saturday opened a dike holding back the swollen Assiniboine River to deliberately flood a swath of land in southern Manitoba in order to save a larger area downstream.

The controlled release southeast of Portage la Prairie, Manitoba, is expected to flood 225 square kilometers (90 square miles) and could affect at least 150 houses. People in the area have been frantically sandbagging around the clock as officials postponed the release a number of times this week in the hope it wouldn't be necessary.

Homes that will be hit first from rising water levels were evacuated days ago.

The provincial government said in a statement that redirecting the water will prevent 500 square kilometers (193 square miles) and 850 properties further downstream from being swamped. been an easy decision and homeowners will be compensated.

"We have worked to delay the timing of the release for as long as we safely could to allow more homes to be protected," Selinger said in a prepared statement aired during supper-hour newscasts.

"If we stood back and allowed nature to run its course, we would face an almost certain uncontrolled break of the dike. An uncontrolled break would be catastrophic and unpredictable, spilling water onto more than 500 square kilometers of land."

The release is taking place at a rate of 500 cubic feet (14 cubic meters) per second — about enough water to fill an Olympic-size swimming pool every three minutes.

Every day, the rate would be increased until it reached a maximum of 3,000 cubic feet (85 cubic meters) per second.

The result will not be a torrent of water, but a slow flow spreading-out over a wide, flat area, filling in low-lying sections between roadways — somewhat akin to maple syrup covering a waffle.

Meanwhile, soldiers and reservists have been hard at work, helping to sandbag and reinforce dikes along the river. The Assiniboine River is at record levels with officials calling this a "one-in-300-year" flood.

"The controlled release is designed to relieve pressure on the Assiniboine River dikes which are under heavy pressure form river flows," the government said in its statement. "They are being continuously monitored and repaired on an ongoing basis."

The province has been raising the specter of the intentional flooding for almost a week.

So far this year, 100 homes across the province have been flooded, although only 10 suffered anything more than basement flooding.