Geography and Climate of Winnipeg - Flooding

Flooding

Because of its flat topography and substantial snowfall, Winnipeg is subject to severe flooding. The Red River reached its greatest flood height in 1826, and this event still remains the highest flood stage of the last two hundred years.

A major flood in 1950 caused a State of Emergency to be declared and the Canadian Army was brought in to protect residents and property. Because of the flood, 100,000 residents were evacuated from their homes and approximately 10,000 homes were destroyed, along with many hospitals, schools and businesses. The flood prompted the Government of Manitoba, under former Premier Dufferin Roblin, to build the Red River Floodway. The floodway is colloquially referred to as Duff's Ditch, and is a 47 km (29 mi) long diversion channel that protects Winnipeg from flooding.

Construction on the floodway project began 6 October 1962 and cost $63 million. The project resulted in excavation of approximately 76.5 million cubic metres of earth. Completed in March 1968, it has successfully prevented over $10 billion in flood damages. The flood control system prevented flooding in 1974 and 1979 when water levels neared record levels. However, in the 1997 Red River Flood, water threatened the city's relatively unprotected southwest corner. Flood control dikes were reinforced and raised using sandbags and the threat was averted. Winnipeg suffered limited damage compared to cities without flood control structures, such as Grand Forks, North Dakota.

Other related water diversion projects farther away from Winnipeg include the Portage Diversion (also known as the Assiniboine River Floodway) and the Shellmouth Reservoir.