The city of Aspen will spend $40,000 designing the final piece of a pipeline tied to a controversial hydroelectric plant, Aspen City Council decided on Monday night.
The “Thomas Reservoir Outfall Drainline,” as it is referred to in city materials, was originally designed to deliver water down a hill to a hydroelectric plant that would be built underneath the Castle Creek Bridge.
As the project was being designed, however, engineers told the city that the reservoir at the upstream end of the pipeline lacked a safety valve to drain its 10 acre feet of water in an emergency. Since then, officials have emphasized the pipeline’s public-safety purposes.
An opposition group led a referendum campaign last year that resulted in Aspen voters rejecting the $10.5 million project by a narrow margin.
The 4,000-foot-long pipeline, however, already has been built, at a cost of around $3 million.
All it now lacks is a “tailrace,” to deliver water from the reservoir back to Castle Creek at the would-be site of the plant, before it could be functional for draining purposes.
Council approved the spending to get a detailed design for the tailrace, but some members expressed concern that doing so would inflame the suggestion that the city is still forging ahead with the hydro plant, despite the rebuke from voters in November 2012.
“Rightly or wrongly, this is always going to be tied to the hydro plant,” Councilman Adam Frisch said.
Councilman Dwayne Romero said it is important to state clearly that the pipeline is for public safety purposes, and “make sure the facts are on the table.”
The drainline would be important if other pipelines feeding the water-storage reservoir from farther upstream on Castle and Maroon creeks malfunctioned. If water department officials could not shut those pipelines off, particularly during high runoff times, then water could spill over the top of the Thomas Reservoir earthen dam, threatening the neighborhoods below with flooding.
Frisch noted that the $40,000 study will come back with a “substantial” price tag for the actual work, and the city must then decide if that money would best be spent on the pipeline, or on other public safety measures.
A few years ago, a preliminary estimate put the tailrace’s price tag at $750,000.
The November 2012 vote was “advisory” in nature, meaning it had no legally binding effect, and the current or a future council could revive the project if they dared to do so, politically.
Also on Monday, council approved an $800,000 supplemental request from the city’s electric department for higher-than-anticipated costs for purchased power in 2013. Costs went up because the city’s electric wholesalers raised their rates, while less power was available.
The Castle Creek hydro plant was originally designed to generate around 5 million kilowatt hours per year of electricity, or about 8 percent of the utility’s power load.
A lawsuit opponents filed in 2011 over the hydro plant’s water rights entered a new phase this month, with an agreement by the city and the plaintiffs for new studies on the project’s environmental effects. The study could lead to a settlement in the case.