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Report Eyes Reducing River Flows

Aplan to reduce the flow on the Red River during flood stage is feasible but would come at a huge cost, a yet-to-be-released study says.

Reducing peak flows by 20 per cent is doable but the price tag would be at last $1 billion, according to a model developed for the Red River Basin Commission.

The project would also require massive upstream storage areas to temporarily hold back water and mitigate the flood risk.

The cost of retaining flood water would come on top of another $1 billion or more for a proposed diversion around Fargo-Moorhead similar to the Winnipeg Floodway.

But the Red River Basin Commission hopes U.S. politicians will see the money as a wise investment instead of a cost.

“We want to show legislators it’s worth spending $2 billion on flood protection because the benefits are more than that,” said Lance Yohe, the RRBC’s executive director.

WORTH IT

The proposed plan to lower peak flows on the Red was a topic of discussion at the commission’s annual conference Jan. 18-20.

Following the 2009 flood, the North Dakota and Minnesota legislatures each contributed $500,000 for the RRBC to develop a report on long-term solutions for the flood-prone Red River basin.

The commission held public meetings in North Dakota, Minnesota and Manitoba to gain public input on flood control. Yohe said the study is 75 per cent complete. Legislators in the two states are scheduled to receive the final report by June 30, 2011.

Yohe said the report will focus on three areas: infrastructure to solve flooding problems, flood plain management and technical details.

The RRBC’s goal of reducing peak flows on the Red River is central to the overall plan, he said.

The plan would involve using water retention systems to reduce flows on tributaries feeding into the Red. The cumulative effect would be a reduced flow on the Red itself, said Charles Anderson, a senior engineer with the Minnesota engineering firm of Widseth Smith Nolting which developed the model for the study.

MANITOBA NOT INCLUDED

The model covers the Red River basin northward to the Canada- U.S. border, but does not include Manitoba.

The storage capacity required to hold back enough water to reduce flows by 20 per cent would be 885,000 acre-feet. That’s equivalent to 13 per cent of the total flow during the record 1997 flood, Anderson said.

Although a 20 per cent reduction doesn’t sound like much for such a massive flood, it would have prevented the 1997 dike breach at Grand Forks, North Dakota which flooded the city, according to engineers.

Anderson said his firm visited watershed management districts in North Dakota and Minnesota to identify potential sites for water storage. It’s felt enough sites can be found, although it will be a challenge for watersheds to reduce tributary flows and some will not be able to accomplish it, he acknowledged.

Some water retention projects in North Dakota and Minnesota are already underway, said Yohe. One is a 60,000 acre-foot project; another is for 20,000 acre-feet. Together, they make up nearly 10 per cent of the total storage required, he said.

Yohe said the RRBC is trying to raise $1 billion for water retention. It hopes to get half of that from the U.S. government through federal agencies dealing with land-based projects.

The commission also expects state legislatures to budget for water retention and flood control over the next 10 to 20 years.

TARGET

Yohe said the RRBC will not build projects itself. But it will forward the report to watershed districts in Minnesota and water resource districts in North Dakota which do have that mandate.

“We’re going to push it over to them and say, here’s the target, here’s the information, here’s where the sites are. Go build them.”

Yohe said Manitoba will be asked to contribute financially if analysis shows the flow reduction levels at the border can be achieved.

The Manitoba government is contributing $70,000 to study whether water retention in tributaries on the north side of the border can also achieve a 20 per cent flow reduction.

Most of the work will be done in the U.S., home to 90 per cent of the Red River watershed, said Steve Topping, an executive director with Manitoba Water Stewardship.

“Nonetheless, we need to do our part also,” Topping said. [email protected]

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