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Honourable , MLA Thompson
April 30, 2013

Incident at the Portage Diversion Channel

I rise in the house today to outline a very serious chain of events that unfolded yesterday at the Portage Diversion which put tens of thousands of people living along the lower Assiniboine River at risk.

As people know, the Portage Diversion is operated at spring break-up to manage ice flows on the lower Assiniboine River. When flows reach 5,000 cfs on the river the additional flow is diverted through the Portage Diversion to protect the communities of Cartier, St. Francis Xavier and Headingley and individual properties from damage caused by elevated water levels as a result of ice jams.

Flood Control Management knew as early as 11am yesterday that 2,000 cfs would have to be diverted into the Portage Diversion channel to prevent extensive ice damage and flooding.

An incident in the Portage Diversion Channel delayed the critical operation of the Portage Diversion by close to 12 hours.

Approximately 4 hours after the channel was operated a surge of water and ice came down the Assiniboine at the Portage River Control Structure. At one point during the night a 13,240 cfs peak Portage Reservoir inflow required 7,000 cfs to be diverted through the channel to protect communities and individuals downstream.

The 12 hour operational delay not only created a situation where Manitobans lives and property at risk due to ice jams but also forced Flood Control Management to operate the Portage Diversion at night where there was no way of monitoring the structure. This created the very real scenario that the control gates could have been damaged by ice.

If the control structure had been damaged the province would have lost control of the Portage Diversion creating a situation where the volume of water on the Assiniboine River at it crest would have overwhelmed the lower Assiniboine Dikes and caused a catastrophic breakout similar to what could have occurred in 2011 where communities east of Portage la Prairie would have been wiped out, low lying properties in Winnipeg would have been at risk, and highway #1 would have been closed indefinitely.