The Bureau of Reclamation says it will empty Steinaker Reservoir near Vernal to repair a crack in the dam face that bureau officials acknowledge they may have caused.
The 300-foot crack in the earthen dam appeared last April while the bureau was emptying the reservoir to reinforce the dam for earthquake safety, said spokesman Barry Wirth."It's possible that we may have caused the slump," he said.
Four exploratory holes drilled in the dam face since April have revealed no additional movement. But Wirth said it is better to err on the side of caution when dealing with a potential dam break that could send a wall of water cascading into Vernal.
The drawdown is under way and should be complete by the end of July, said Dave Rasmussen, director of the Uintah Water Conservancy District.
It will leave about 1,000 irrigators and some 18,000 acres of farmland without water from Steinaker, but Rasmussen said the district has arranged for other water sources that should make up most of the difference.
"We shouldn't be left in too bad shape," he said.
"Some irrigators are frustrated by the inability to get a full complement of water," said Wirth. "I sympathize, but in the long run making sure the dam is properly repaired and back in service is the right way to do things."
The bureau estimates the cost of the repairs at between $1.5 million to $2 million.