But Friday, the federal Bureau of Reclamation entered a "Record of Decision" based on a final Environmental Impact Statement (EIS) that gives the green light to the dam project on the Gooseberry Narrows.
The approval, however, comes with no federal loan money. But it does include a raft of environmental mitigation requirements.
"It's a monumental day for Sanpete County," said Sanpete County Commissioner Claudia Jarrett. "All we want is the use of the water rights that have been adjudicated [to us]."
Reclamation's decision allows the Sanpete Water Conservancy District to build a 120-foot-tall dam that is capable of impounding 17,000 acre-feet of water on about 600 acres.
The planned project envisions rehabilitating an existing water tunnel through a mountain ridge that would transport water to Cottonwood Creek and down to the Sanpete Valley. Although Gooseberry Creek is in Sanpete County, it flows east into Carbon County and eventually runs into Scofield Reservoir.
For decades, the Gooseberry Narrows dam proposal has been a point of contention between Carbon and Sanpete counties.
Late Friday Carbon County Commissioner Mike Milovich said his county would fight the decision.
"We intend to do whatever we can to stop the project," he said.
In 1984, the counties entered into a water-rights settlement agreement. Since then, the Sanpete Water Conservancy District has been trying to get approval for the water project from the Bureau of Reclamation, said Wayne Pullan, deputy manager of the bureau's Provo Area Office.
A 1995 EIS and accompanying Record of Decision approved the dam project. But those documents were rescinded when it became evident that the environmental study was flawed.
Friday's decision from the bureau awards the water district a 15-year development period, Pullan said. If the district does not design and contract to build the dam within that time frame, the favorable decision would be rescinded.
Sanpete County's Jarrett said she is "confident" the water district will get financing that ultimately will be repaid by water users. The project is estimated to cost $34 million.
Pullan said he's glad the long process has been concluded.
"It's been a difficult project. There has been a fair amount of opposition and misinformation," he said. "We're pleased we can put this EIS to bed. It's well done."