Todd Sando, an assistant engineer for the North Dakota Water Commission, said the state had hoped the lake would drop 7 feet over the summer. But Jon Kelsch, the state Water Commission's construction chief, said officials confirmed Monday that the valve on a 10-inch outflow pipe used to drain the lake wasn't completely open.
Officials at first thought someone may have been tampering with the valve in a bid to improve fishing, but they have since determined it was simply set that way, although it's not clear why, Kelsch said.
The valve is now fully open, he said, but it will take weeks to lower the level of the lake from about 30 feet to 23 feet.
"We're weighing the possibility of letting it run all winter," Kelsch said.
Sando said the state also is considering stockpiling rock, dirt and sandbags at the dam before spring, in anticipation of high water.
Officials have not yet determined a long-term solution for the damaged Clausen Springs Dam, which was built in 1967, before state dam safety standards were enacted.
Breaching the dam by cutting a channel through it for a controlled release of water may be the cheapest and best option to protect the city of Kathryn, which is downstream should the dam fail, Barnes County Commissioner Harlan Opdahl said Monday. Draining the lake that way would cost about $100,000, officials estimate, while a permanent fix for the dam is pegged at $3 million.
"We have no choice; we have to do something," Opdahl said. "I say we breach it and drain her down and get it ready for next spring."
The dam is about 50 feet high and about 700 feet long and holds back a lake about the size of 50 football fields.
The town's 55 residents were evacuated for a few days in April after heavy flooding began eroding the dam's spillway six miles west. National Guard soldiers in helicopters dropped more than 100 one-ton sandbags to shore up it up.
The state has pledged $2 million toward fixing the dam, but the county must chip in $1 million, said Todd Sando, an assistant engineer for the state Water Commission. Money for some of the work could come through federal disaster funds, but they would only repair the dam to its condition before last spring's floods, Sando said.
Opdahl said the bulk of the county's budget is being spent rebuilding roads damaged by spring flooding.
"We can't find a million dollars for the dam," Opdahl said. "Just a normal amount of snow this winter and an inch on top of it next spring and that lake doesn't have the capacity to handle it."
County officials hired an engineering company to provide an estimate of how much it would cost to repair the dam and to study how bad the damage would be if it failed.
Chad Engels, an engineer with West Fargo-based Moore Engineering Inc., has said it's unlikely Kathryn would be leveled by "a wall of water" if the dam broke, but it would likely be destroyed by floodwater and mold. His firm is still working on its worst-case scenario study, but he believes floodwaters could reach 5 feet in the town.
(This version CORRECTS SUBS 2nd graf to correct to 7 feet sted 7 inches in 2nd graf.)