Thursday, June 29, 2017

Breckenridge dam repairs expected to cost at least $16 million

#Breckenridge #Colorado
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Breckenridge Town Council left Tuesday's work session reeling from sticker shock, as permanent repairs to the Goose Pasture Tarn Dam were pegged at $16 to $18 million.
Even worse, those estimates were put together last year and are already outdated. In reality, the price tag to fix erosion problems plaguing the spillway at the Tarn Dam, built by the Theobald family in 1965, is expected to come in much higher.
One reason town officials are forecasting the fix at a higher rate is the town can't start work on the dam until a new $50 million water treatment plant is finished, which is tentatively slated for 2020.
Judging by market changes over the last three to four years, it will likely cost more than $20 million to fix the dam by the time the town can begin to address the underlying spillway issues.
"I think we start building that (dam), and five years from now, it's not going to be $16 million," said Councilman Mike Dudick, who has a background as a developer. "But I think one of our primary responsibilities is the health and safety of the citizens, and we can't have a failure of that dam, so we have to do it and figure out a way to pay for it."
Mayor Eric Mamula echoed Dudick's comments, with the mayor emphasizing the need for the council to find the necessary funding to fix the dam and protect the "people who live below this thing."
The mayor admitted this "is not the kind of news you like to hear," but he said it's something council must tackle and they must "do this right."
"Yeah, it's terrible," Mamula said of the situation and potential cost. "Because you figure by the time we seriously get to it in four years … guaranteed it will be $30 million to fix this dam."
The good news is neither town officials nor council members seem to think a dam failure is imminent in the coming years. Still, as council looked to assess the risk of a devastating event, its members asked questions like, "What's our true risk for catastrophic failure?" and "Where is that perfect storm?"
In response, town manager Rick Holman told them "it's safe to say the state would force us to close it now" if the dam were in any real danger of failing.
But as a representative of the design firm working on the dam also told council, "It's a real risk," and included in his presentation were images of the Oroville Dam in California, which collapsed in February 2017 after a spillway there failed.
"I think it's important citizens understand we're going to do everything we can to make sure the dam doesn't fail," Mamula said after the meeting. "That's No. 1. This is about the safety of the community, and the council is obviously committed 100 percent to make sure this thing is fixed correctly, not just some Band-Aid that's going to have to be fixed again down the road."
According to a memo addressed to council from Public Works director James Phelps, the town noticed a problem in spring 2015, when devices measuring groundwater pressure at the dam recorded abnormally high readings, specifically in an area beneath the lower spillway slab.
Upon seeing the readings, town staff immediately initiated meetings with a dam engineering firm and state officials.
The discussions raised more alarms, according to the memo, and several concerns were identified, the biggest of which was that the groundwater pressure could be stronger than the downward force on the eroding spillway, leaving the spillway "close to failure" and the dam in danger of breach.
The memo states that town staff continued to monitor the dam and spillway throughout the 2015 runoff season, and their assessment was an immediate repair was necessary.
Last spring, the town hired a contractor to perform a temporary fix on the dam and address concerns of increased water pressure pushing on the spillway slab. To mitigate risks, they also reduced water levels in the reservoir and lowered the emergency spillway crest level to keep water off the spillway, while also placing sandbags across the service spillway crest, according to Tuesday's presentation.
At the same time the temporary repair work was being completed, the town hired another engineering firm, Kumar and Associates Inc., to assess the dam issues and make design recommendations for a permanent repair.
At Tuesday's town council work session, a representative of Kumar and Associates walked council through the PowerPoint presentation with two options for repairing the dam. One was framed as a temporary, piecemeal spillway fix at $9-10 million, while the other, described as a more permanent dam solution, was tagged at $16-18 million.
During the work session, no council member expressed support for anything but the permanent fix.
"We don't really have any options other than doing what we're doing," Dudick said, as the council members begrudgingly resigned themselves to the more expensive of the two options. Dudick added that until the town can start work on the dam, Breckenridge "will have to have a four-year plan to mitigate risks."
Councilman Mark Burke did not attend Tuesday's work session or the regular meeting that followed it.