Manitoba's Flood Management

The Red River Floodway.

As the rain fell heavily in Toronto this morning and I hoped my basement wouldn’t flood, it was hard not to think of Manitoba, where next week, flood waters are expected to peak somewhere between the levels the province (and nearby state of North Dakota) saw in 1979 and 2006.

While the flood isn’t supposed to reach the levels of 1826—Manitoba’s worst flood on record and estimated to result in more than $5 billion in damages if it happened today—it could come very close to 1979 levels. According to yesterday’s flood bulletin, this would occur if a 25-millimetre rainstorm were to occur in Manitoba next week on top of snowmelt.

Luckily, the flood probably won’t come close to 1997′s “Flood of the Century.” After that flood, which enveloped and devastated Grand Forks, ND with floodwaters over five kilometres inland, total damages for the Red River region were US$3.5 billion. In Manitoba, 28,000 people were evacuated and the flood caused $500 million in damage to property and infrastructure.

The 48-kilometre Red River Floodway protected Winnipeg in 1997—but just barely, nearly reaching capacity and threatening the city’s protection.

In the past, the floodway has saved Manitoba more than $10 billion in flood losses. Constructed in the 1960s at a cost of $63 million, the floodway has operated over 20 times between 1969 and 2004—but due to ice in the Red River that could damage the structure and flood the town of Selkirk, the floodway has not yet been opened.

On this day in 2003, Prime Minister Chrétien and Manitoba Premier Gary Doer announced a $160-million investment for the Red River Floodway expansion. Once complete, the expansion will increase the capacity of the current channel from 1,700 cubic metres (60,000 cubic feet) of water per second to 4,000 cubic metres (140,000 cubic feet) per second. The project is still underway, with channel widening expected to be complete this spring and bridge work carrying over until 2010.

Over the course of the project, approximately 21 million cubic metres of earth will be excavated from the floodway channel.

Once completed, the project will protect more than 450,000 Manitobans, over 140,000 homes, over 8,000 businesses, and prevent more than $12 billion in damages to the provincial economy in the event of a 1-in-700-year flood. (Click here to watch a flood simulation video that demonstrates the expansion’s effectiveness.)

Luckily, reports say the ice is expected to move by early next week, just in time to open the floodway. In the meantime, Manitoba jurisdictions south of Winnipeg, such as Emerson, Montcalm and St. Jean Baptiste, have been working to fortify ring dikes, drop sandbags and prepare disaster plans, prepping for the worst.