A controversial 53-year-old plan to build a major dam above Lyons is attracting renewed attention as a northern Colorado water district seeks to maintain its right to use the water associated with the long-dormant project.

The St. Vrain and Left Hand Water Conservancy District, based in Longmont, serves thousands of people and dozens of farms in Boulder, Larimer and Weld counties. Earlier this year, it filed a petition in a special water court to retain its right to use the water at a later date. The water right dates back to 1971, according to Sean Cronin, the district’s executive director, and is classified as conditional because the water has not yet been captured and used.

The district has not said whether it plans to pursue the dam project, but some critics have raised alarm about the possibility.

Environmental group Save the World’s Rivers says the dam project is expensive and harmful to the river’s environment, and it’s time for the district to look at other options.

“They’ve done their due diligence for (more than) 40 years, and the world and the state and the county and the community have changed a lot since then,” said Gary Wockner, director of the river advocacy group. “And they’re still proposing to build this huge dam.”

The group and its subsidiaries have filed suit to stop several major dam and reservoir projects in Colorado, in some cases resulting in construction delays and strengthening environmental protections.

While the construction of dams and reservoirs was common in Colorado decades ago, such projects are rare today due to their cost and water scarcity, among other reasons.

The water right associated with the Coffintop Dam project could generate 84,000 acre-feet of water, and the dam was designed to be more than 350 feet tall. By comparison, the Horsetooth Dam west of Fort Collins is only 155 feet tall. One acre-foot of water is equal to 326,000 gallons, enough to supply at least two urban households for a year.

Whether the Coffintop Dam will ever be built is unclear, and many would say it’s unlikely. St. Vrain Valley water officials have talked for years about using small gravel pits further downstream along the river to store the water and abandoned the dam proposal. But Cronin declined to comment on whether the district actually plans to build the dam at some point in the future or if it would use the water elsewhere, citing the confidentiality of the water court proceedings.

“In 1971, the St. Vrain and Left Hand Water Conservancy was entrusted with the management of the water right for the benefit of the entire valley,” Cronin said via email. “And to that end, it has worked, particularly over the last decade, to ensure that the ultimate use of the right reflects the values ​​of the entire valley community.”

The district is fulfilling its legal obligation to maintain water rights, he said.

“The St. Vrain and Left Hand Water Conservancy District believes it has acted very conscientiously, in part because it has had substantive discussions with community leaders for years about how this water right will bring numerous benefits to the valley, including, but not limited to, environmental benefits,” Cronin said.

The case comes after Lyons officials passed a resolution last November declaring their intention to fully protect the river, a key feature of the city, in the context of a growing “rights of nature” movement in Colorado that urges communities to protect their waterways from the threat of development.

Nederland passed a similar resolution in 2021 but withdrew it in May after Wockner’s group filed suit to fight a dam the city is considering on Middle Boulder Creek.

Although the solution for Lyons is similar, Cronin said it was negotiated with the involvement of the St. Vrain district, which has a good working relationship with the city.

City Administrator Victoria Simsonsen declined to comment on the case Wednesday, but said talks over water rights were ongoing.

Bob Brakenridge, a Lyons resident, said it would likely cause great concern if a new dam proposal were to surface. Brakenridge is vice chair of the Lyons Ecology Advisory Board.

“I personally, and I think many other people here would be strongly opposed to any actual dam construction. … And it’s disturbing that they’re holding on to this water right, for whatever reason,” he said, clarifying that he was not speaking on behalf of the environmental committee or the city.

However, Cronin said the county has an obligation to ensure that water rights are preserved and ultimately used in a way that benefits county residents.

“The district welcomes anyone to join in the discussion of ways to maximize this water right, as long as participants support the district’s mission to protect water quality, secure and preserve drinking water, grow local food, keep rivers and streams healthy, and store water for dry years,” he said.

Story Type: News

Based on facts either directly observed and verified by the reporter or reported and verified by knowledgeable sources.