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COALVILLE — The Echo Dam near Coalville is only the latest of a dozen dams in Utah and Wyoming that have been upgraded in recent years because of what we've learned about earthquakes.
The goal is to avoid the nightmare situation a moderate earthquake could create: a wall of water racing down Weber Canyon, taking out town after town on it's way to Ogden and the Great Salt Lake.
Marvin Mair has lived at the foot of Echo Dam as caretaker for more than 40 years. Last week crews tore out the two houses he's lived in.
"It was home to me, home to my family. I raised two kids here," Mair said.
He never worried much about the big dam looming over his home. But now he and his pet peacocks are moving out to make way for the big fix.
That's worrisome because you have 12 or 13 towns along the Weber River between here and Salt Lake ... (It's) a significant amount of people, and you'd have damages estimated to be in the billions.
–Mike Talbot, U.S. Bureau of Reclamation.
"It needed to be done," Mair said. "Yep, it's just progress."
The problem is the dam was built 80 years ago, when scientists knew a lot less about earthquakes. If the earthen dam shakes, rock, dirt and sand under it could liquify, causing the dam to slump and possibly fail catastrophically.
"That's worrisome because you have 12 or 13 towns along the Weber River between here and Salt Lake," said Mike Talbot, project engineer with the U.S. Bureau of Reclamation.
"(It's) a significant amount of people," Talbot continued, "and you'd have damages estimated to be in the billions."
A surprisingly small quake could trigger that catastrophe; above magnitude 5.6, the risk is there. The fix will raise the safe level to magnitude 7.2.
Crews plan to excavate to bedrock at the foot of the dam and widen the dam with compacted dirt and rock. They'll also lower the reservoir and beef up the dam on the upstream side.
The timing of reservoir levels will be crucial over the next two winters to avoid what farmers and irrigators dread: water shortages at the wrong time of year.
"We hope not, and we won't want that to happen. But there could be (water shortages)," said Ivan J. Ray, general manager of the Weber River Water Users Association.
Meanwhile, Mair is going to be OK. The veteran caretaker is moving to a new home a few miles away and says the government is making it good on the financial side.
The project is scheduled for completion in 2015 at a cost of at least $40 million.
Email: hollenhorst@ksl.com
