Manitoba government report denies Portage Diversion flooded Lake Manitoba in 2011

Diverting billions of litres of water from the Assiniboine River didn’t cause flooding in Lake Manitoba in 2011, says a Manitoba government report released today.

Steve Ashton, Manitoba transportation and infrastructure minister, said the province’s decision to divert water from the Assiniboine River to Lake Manitoba in the spring and summer of 2011 contributed little to the flooding of farmland and residential property around the lake.

“What the report also shows is the degree to which the operation of the Portage Diversion had very minimal impact on the lake,” he said during a news conference to release the report, a technical review of the Lake Manitoba, Assiniboine River and Lake St. Martin flood.

In the spring of 2011, the province expanded the channel that carries water from the Portage Diversion to the south end of Lake Manitoba so it could transport more water to the lake.

At the time, farmers and landowners around the lake said the government was artificially flooding their land to spare Manitobans downstream of Portage, including Winnipeggers.

The flooding around the lake’s perimeter inundated thousands of acres of hay and pastureland. As well, dozens of ranchers were forced to move their livestock to higher ground. In response, the province paid out flooding claims to farmers for their losses. To this day, a number of cattle producers in the region maintain they should receive compensation for lost production in 2012 and 2013.

In the news conference, Ashton said moving 25,000 to 34,000 cubic feet per seconds of water from the Assiniboine River to Lake Manitoba for weeks in 2011 wasn’t a significant factor in the flooding.

“I think it had an impact, according to the report, of 0.09 feet,” he said.

In July of 2011, Lake Manitoba water levels peaked at 817 feet above sea level, approximately five feet higher than the maximum regulated level for the lake.

The province did acknowledge that artificial flooding did flood 23,700 acres of pasture around the lake for a brief period late in the summer of 2011, when water from the Portage Diversion entered Lake Manitoba.

In addition to releasing the technical report on the 2011 flood, the province announced it would review operating rules for the Portage Diversion, the Fairford outlet at the north end of Lake Manitoba and the Red River Floodway.

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