An ice fisher was the first to notice water escaping at Panguitch Lake Dam earlier this month. He contacted the owners, who went out the next day to see the problem for themselves, according to Allen Henrie, president of the West Panguitch Irrigation Company.
The prognosis on the damaged dam — which is tasked with holding in enough Sevier River water to supply area ranchers, farmers and Panguitch City — wasn’t good.
Water had been unobtrusively seeping through the dam for decades, according to inspection reports. But this year, a wind storm pushed thick and heavy sheets of ice up against the top portion of the dam, atop a 2-foot concrete addition made in 1942 to increase the dam’s capacity.
The pressure pried open the concrete, allowing water to flow through until the top of the dam threatened to buckle, putting thousands at risk. While the problem persists, thanks to quick intervention by construction crews, the dam now doesn’t seem poised to fail.
The dam was constructed in 1872, less than a decade after Latter-day Saint pioneers settled Panguitch, and the consequences of a dam failure have grown alongside the town’s population. This year, an estimated 2,000 people were on notice to evacuate.
The Salt Lake Tribune analyzed years of inspection reports and other communications concerning the Panguitch Lake Dam and spoke with the Utah Division of Water Rights, the dam’s owner and an outside dam expert to better understand this near-disaster.
That investigation found an out-of-date emergency action plan and a history of seepage and other upkeep concerns, which engineers, in inspection reports and in recent interviews, explained weren’t life-threatening. But the exploration also shed light on how the state monitors so-called “high hazard” dams, and how a lack of funding poses a risk for Utah’s growing population, which is increasingly settling downstream of these structures.
In a January hearing with state legislators, Division of Water Resources Director Candice Hasenyager outlined the problem in dollars and cents.
The average cost to upgrade a dam is $4.6 million. The state’s annual dam safety funding is $3.8 million.
“We have roughly about 100 high hazard dams that still need to be upgraded, and at the current funding level,” she said, “it’s going to take about 100 years.”
The Division of Water Rights reported that about 277 of the 700 dams that the agency inspects are “high hazard,” a designation meaning that if the dam were to fail, people would likely die.
This is not just a Utah problem, according to Utah State University civil and environmental engineering professor John Rice. Dams across the country are in need of costly repairs.
The resource problem reveals itself in other ways, he said. For instance, state engineers last year couldn’t evaluate many inspection points at Panguitch Lake Dam because they were underwater.
“So, in a perfect world with enough resources, they should have said, ‘Well, this needs to come back and be seen again’, or ‘next year, we need to come out and make sure that we’re here when the water level is lower,’” Rice said.
But they didn’t. And this year, before the dam’s next scheduled inspection date in July, a crack formed.
Everett Taylor, an assistant state engineer for dam safety with the Division of Water Rights, said the situation was unexpected. “Most dams don’t have a problem with ice pushing up against them. This is certainly something unanticipated,” he said, “and nothing we identified … says there was deterioration that led to this.”
So how big of a problem is all this? Should more Utahns be concerned?
“It depends, I guess,” Rice joked, “whether they live downstream or not.”
The ‘perfect storm’ and near-disaster at Panguitch Lake Dam
(Rick Egan | The Salt Lake Tribune) Workers move earth to secure the rim of the Panguitch Lake Dam, on Thursday, April 11, 2024.
Panguitch Lake Dam is owned and operated by West Panguitch Irrigation Company, which supplies water to local ranchers and farmers. The company also provides untreated secondary water for Panguitch City residents’ landscaping and gardening.
In 1942, the West Panguitch Irrigation Company added two feet of concrete to the top of the dam to contain that year’s snowmelt, which threatened to overwhelm the Sevier River’s reservoirs.
Henrie, the company’s current president, said that the 1942 modification to the dam may have contributed to the breach last week — along with adverse weather conditions that he said made for a “perfect storm.”
Engineers in 1942 bypassed the rules and formal approval process to make the addition, a Tribune analysis of dam inspection reports found.
At the time, West Panguitch Irrigation Company said they “fully intended” for a civil engineer to submit construction plans before starting work, “but the melting snow and the quick run-off of the water above the said reservoir filled the Panguitch Lake much quicker than we anticipated.” The company added that a representative of the Water Commission of the Sevier River “advised that this work be done immediately, as the reservoirs along the Sevier River were almost full.”
It’s not clear yet to what extent this addition’s hasty implementation 82 years ago impacted seepage or contributed to this year’s cracking. Taylor said that it won’t be possible to determine the true cause of the damage to Panguitch Lake Dam until the lake’s water level sinks below the cracking.
After last year’s record-breaking snow totals, Panguitch Lake filled, and as spring runoff began to spill into the reservoir this year, the lake was at a higher level than usual, Henrie said. Three days of heavy wind pushed an ice sheet on top of the lake into the top of the dam, he said, causing the 1942 addition to lift and tilt, letting water through.
Taylor confirmed that the ice pressure on the dam caused the top of the structure to crack and tilt like a toppling domino. He added that water also spilled through cracks in the dam below the addition.
Inspections and enforcement
(Google Maps) The Panguitch Lake Dam, seen in the upper right corner of Panguitch Lake.
State Division of Water Rights engineers inspect “high hazard” dams like the one in the mountains above Panguitch City once a year.
Last year’s inspection report noted that the owner had not submitted a current emergency action plan and did not send all of its representatives to the inspection. That prompted a reminder from the Division of Water Rights: “Although the reservoir was spilling over the dam, and inspection of the dam was limited,” officials wrote, “other important information needed to be discussed.”
Henrie told The Tribune that the information in the outdated plan from 2019 that the division had on file was correct, except for some contact information, and therefore did not hinder the emergency response last week.
Over the last decade, inspectors asked West Panguitch Irrigation Company to remove the willows and other vegetation growing near the dam, monitor seepage at various points, fill holes and low spots on top of the dam and replace equipment, reports show.
While the inspection reports often noted seepage, Rice explained that all dams likely have some seepage. It’s typically not a concern unless that water is eroding away part of the structure.
Taylor said, “on this dam, while we did monitor the seepage and noted that in our inspection reports, it was less of a concern to us.” Inspectors, he said, are on the lookout for when seepage amounts change.
Panguitch Lake Dam’s most recent pressing issue was in 2019, when water was flowing out of the dam through a broken gate at a rate of 10 gallons per minute. The irrigation company soon addressed the problem.
When an issue is found on a privately owned dam, it’s the dam owner’s responsibility to fix the issue. If they don’t, the Division of Water Rights can issue an order of corrective action and fine if they don’t act.
Rice said that sometimes when a state agency finds an issue, an owner will say, “‘OK, gotcha. We don’t have any money now. We’ll see what we can do about it.’” He added, “some dam owners, of course, are more responsible than others.”
This is typically tolerable because dam problems can be slow-moving. Issues can be monitored or maintained with a quick fix for some time, or they may not present themselves until water levels are abnormally high.
If an issue is deemed “critical,” however, Rice said a dam owner would need to move quickly, which was the case at Panguitch Lake Dam this month.
Taylor said the division’s best enforcement mechanism when privately owned dams aren’t up to snuff is to restrict the amount of water a reservoir can hold.
“That means that we tell them, ‘You can’t fill your reservoir full. You need to keep it at a level that we set,” Taylor said. “Typically that conversation [prompts] the owner to address any necessary maintenance we’re requiring.”
Utah’s dams ‘need attention’
(Utah Department of Public Safety) A crack in the Panguitch Lake Dam is shown on Tuesday, April 9, 2024.
In 2020, the Utah section of the American Society of Civil Engineers gave the state a C+ grade in dam safety — better than the D grade it gave the nation. The group echoed concerns about population and development growth, stating that “many dams that were initially constructed using less stringent design criteria are now upstream from population centers.”
The civil engineers further raised concerns about how an earthquake could damage these structures, and acknowledged that, in the future, “dams will become even more critical to preserving Utah’s quality of life and public health.”
“The western region of the U.S. continues to receive pressure to provide stable water resources amidst challenges associated with dramatic growth, drought and climate change,” the report card read. It added that many neighboring states are looking to more dams — “a renaissance in dam construction” — to meet future needs.
Rice said despite Utah’s better-than-average grade, its “dams do need attention.”
“We do need more money for that,” he said, “as we do for all of our infrastructure.”
This year, Utah engineers are finishing upgrades on the Millsite, DMAD and Sevier Bridge dams, Hasenyager said, but about 100 more high hazard dams still require upgrades.
At Panguitch Lake Dam, officials continue releasing water to relieve pressure on the crack site, but the situation appears to be under control.
In the early days after the crack was discovered, Henrie said an inspector stayed there day and night to watch for imminent failure. Now they just use a live video feed.
Panguitch Lake levels were predicted to dip below the crack in the dam last week. Since spring runoff could increase water levels again, engineers will need to continue releasing water to repair the dam, while balancing the water needs of the ranchers and farmers and Panguitch residents.
“I’m very pleased with where we’re at,” Taylor said, “and I’m looking forward to operating this reservoir safely through runoff and getting it repaired through the remainder of this year.”
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