Devils Lake may overflow naturally

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GRAND FORKS — Devils Lake has 14 to 15 percent chance of overflowing naturally by 2015, even after a second manmade outlet is operating next year, according to a new study by the U.S. Geological Survey.

The study is based on a combined water release of 600 cubic feet per second through two outlets — 250 cfs from the existing west-end outlet and 350 cfs from an outlet that will be built from East Devils Lake to the Tolna Coulee over the next year.

It also considered downstream water quality standards, according to Skip Vecchia, a statistician with the USGS North Dakota Water Science Center in Bismarck.

Devils Lake has risen by more than 30 feet and quadrupled in size since 1993, reaching an unofficial record elevation Thursday of 1,454.37 feet above sea level, less than four feet from the estimated 1,458 level at which it will start flowing naturally from Stump Lake to the Tolna Coulee and to the Sheyenne River.

The 18-year-old flood has cost more than $1 billion in road raises, levee construction and other flood mitigation measures.

The west end outlet was built in the mid-2000s, at a cost of about $28 million. Normally running between June and freeze-up, it costs between $300,000 and $400,000 per month to operate, said State Engineer Todd Sando.

The planned east end outlet, which will cost between $85 million and $95 million, is expected to operate at a monthly cost of about one-third of the west end outlet.

The USGS study was conducted in cooperation with the North Dakota Department of Health Division of Water Quality.

It examined six outlet scenarios, based on a total of 600 cfs being released, and water quality standards of sulfate levels of either 650 or 750 milligrams per liter downstream at the Baldhill Dam, north of Valley City.

The study was completed before Gov. Jack Dalrymple and the State Water Commission approved a new look this week at the possibility of installing a new gravity-flow outlet, to allow water to begin flowing naturally as early as this year.

“That would change everything,” Vecchia said. “If they try to hold that 750-mg level downstream, they would have to just eke water out of Stump Lake. If they let more water out and exceed 750, that’s when we would see bigger effects.”

Bonham is a reporter at the Grand Forks Herald, which is owned by Forum Communications Co.

Tags: devils lake, flood, news, outlet