Winnipeg flood
© Joe Bryksa, Winnipeg Free Press
A man walks down the flooded Marchand Road in Winnipeg to his home in an April 2009 file photo.

The City of Winnipeg plans to raise 15 kilometres of dikes, fill three million sandbags and protect about 700 properties this spring to protect against river levels that could rise slightly higher than those experienced during the 1997 Red River flood, called Manitoba's 'Flood of the Century.'

And properties located alongside the Assiniboine River make up a larger proportion of the list this year, as the Assiniboine is expected to play a larger role in the coming flood, city flood-protection engineer Grant Mohr told reporters Tuesday.

Based on initial provincial flood predictions, the City of Winnipeg is preparing for a worst-case scenario that will see the Red River rise as high as 7.5 metres above normal winter ice levels. That's just over 15 centimetres above the peak river level during the 1997 flood and also 72 centimetres above the peak level during the 2009 spring flood.

On Monday night, the city plugged river-flow estimates into the city's flood manual, an interactive software package developed in the wake of the 1997 flood. It determined 700 properties will need to be protected this year, down from about 800 in 1997.

The reason for the difference is the different flood dynamic expected this year, as the Assiniboine is expected to account for about 25 per cent of the flow of the Red River during the peak flood period. That means higher water on the Red River north of the confluence of the Assiniboine but less severe river flooding in the southern portion of the Red River within the city. It also means more of a flooding risk on western portions of the Assiniboine within the city.

The city will notify all affected property owners within the coming months.

The city also plans to perform about 325 land-drainage operations to prevent city rivers from overwhelming the sewer system. These operations include closing drainage gates and operating pumps. About 420 manholes will also be sealed.

Both the city and province hope up to 3,000 Winnipeg homeowners install sump pumps and backwater valves under an incentive program unveiled Tuesday.

The subsidy program pays up to 60 per cent of the cost of installing a sewer backup system to a maximum of $3,000 per house.

The package covers up to $1,000 towards the installation of an approved in-line backwater valve and up to $2,000 towards the installation of a sump pump.