Crews check if Stump Lake is right for outletTOLNA, N.D. — The North Dakota State Water Commission took the first physical steps Thursday toward building a gravity-flow outlet from Stump Lake to the Tolna Coulee in another effort to provide some flood relief to the chronically flooding Devils Lake Basin.
By: Kevin Bonham, Forum Communications Co., The Jamestown Sun
TOLNA, N.D. — The North Dakota State Water Commission took the first physical steps Thursday toward building a gravity-flow outlet from Stump Lake to the Tolna Coulee in another effort to provide some flood relief to the chronically flooding Devils Lake Basin.
Crews drilled four 6-inch-diameter holes some 80 feet into the frozen ground, bringing material to the surface, where hydrologist Jon Patch examined the material to see if the ground might be suitable to build an open-channel outlet that will be about 50 feet wide at its lowest point, about 60 feet below the surface.
“The main thing is we want to see if there’s an aquifer in the way,” said Erwin Curry, a water engineer with the water commission.
The Devils Lake Basin Joint Water Board, working with the water commission, had hoped to start construction on the $17 million outlet this winter. However, the project was delayed after four landowners tried to block access to their property to conduct soil tests.
Last month, Northeast Central District Judge Sonja Clapp last month issued an injunction to prevent the landowners from blocking access to their land.
More tests ahead
On Thursday, the test holes were drilled about 20 feet below the proposed bottom of the channel.
While crews come back to fill in the holes, according to the court order, Patch will recommend whether the proposed location is suitable to proceed to the next step — soil tests conducted by a private firm, according to Curry. If it’s unsuitable, the water commission will have to find a different route. So far, though, it looks good.
“There’s some sand and gravel. We think it’s an isolated pocket, not a full-fledged aquifer,” Curry said.
While Spiritwood Aquifer lies under portions of the Devils Lake Basin, it is far deeper than the proposed outlet, he said
When completed, the approximately one-mile-long outlet will be capable of moving about 500 to nearly 600 cubic feet of water per second from Stump Lake to the Sheyenne River.
That would just about double the capacity of two state-owned pumped outlets, the West End outlet, which recently was expanded from 100 cfs to 250 cfs, and a combined pumped, underground gravity flow 350 cfs outlet being built from East Devils Lake to the Tolna Coulee.
Devils Lake, which has risen by about 32 feet and quadrupled in size since 1993, hit a record elevation of 1,454.4 feet this summer, less than four feet from the natural spill elevation. However, it has dropped about a foot since then.
The Stump Lake outlet will be built at an elevation of 1,452 feet. State officials say the bottom of the outlet will be about 50 feet wide, with a 4-to-1 slope, which means it will be about 200 feet wide at the surface.
Kevin Bonham is a reporter
at the Grand Forks Herald, which is owned by Forum Communications Co.