Manitoba should use more ice-cutters and another Amphibex machine to reduce ice jams on the Red River, a report says. (CBC)

The man-made floodway that protects Manitoba's capital city from rising waters on the Red River should be operated differently to reduce artificial flooding of properties south of the city, an analysis of last spring's flood concludes.

More water should be diverted into the floodway inlet to reduce backflow of the Red south of the city, says the provincial government report, released Friday.

"Design work and benefit-cost analysis will begin shortly on improvements to the floodway inlet to allow greater flows into the floodway channel. This is expected to reduce river levels in Winnipeg during floods of lesser magnitude than that of 1997 (such as those of 2009 and 2006), and reduce flooding south of the floodway inlet in major floods," the report says.

The report also says ice-cutting resources should be beefed up to further limit sudden ice jams north of Winnipeg during spring break-up of the river.

"The 2009 flooding in the Red River watershed was made significantly worse by unusual ice conditions, which caused blockages in the drainage system and raised river levels beyond what would have occurred under normal conditions," the report says.

As well, it recommends raising parts of Highway 75 — the main highway between Winnipeg and the U.S. border — so that the thoroughfare can remain open during flood season.

Water Stewardship Minister Christine Melnick said the most critical lesson from this year's flood is that the designated flood plain should be extended from south of the city to communities north of Winnipeg to regulate development in those areas because they are at risk of being flooded out.

The 2009 Red River flood was the fourth-worst inundation in the region since 1800. Only the floods of 1826, 1852 and 1997 were more significant.