Saying a big new dam “no longer fits today’s needs or values,” the St. Vrain and Left Hand water district in Longmont agreed to give up a 55-year-old right to build an on-channel reservoir on the relatively undisturbed South St. Vrain Creek, pleasing environmental groups and local elected officials.
The St. Vrain and Left Hand Water Conservancy District said it had reached a deal with nonprofit Save the World’s Rivers to store a large water right by other methods, such as old gravel pits, rather than the 350-foot-high Coffintop Dam holding 84,000 acre-feet it has studied since 1971.
“This is something we and our communities have contemplated for decades,” said water district board president Christopher Smith, in a statement announcing the agreement. “The Coffintop project, as envisioned more than 50 years ago, no longer fits today’s needs or values.”
The bottom line is “Coffintop Dam is dead,” said Save the World’s Rivers founder Gary Wockner, who has led opposition to multiple Colorado dams through his nonprofit organizations. But he also praised the “good work” of the St. Vrain district in trying to preserve the revered creek in its current state.
“It became clear through discussions that the district shared values around avoiding a new on-river dam while still meeting its mission,” Wockner said. “That made an agreement possible.”
A stipulation giving up a new on-channel dam just southwest of Lyons has already been accepted by the water court. St. Vrain will later file to move the water storage right to a different location when it has settled on a plan. The stipulation does not restrict the nonprofit’s rights to comment on and raise concerns about any alternative storage proposals pursued by St. Vrain, Wockner noted.
“St. Vrain Creek is the lifeblood of our town, and a large dam upstream was never embraced by our community,” Lyons Mayor Hollie Rogan said. Parts of South St. Vrain Creek are considered expert Class V kayak runs. “We’re pleased the district will not pursue Coffintop Reservoir and look forward to continued collaboration.”
The potential size of the dam was one affront to many in the community. By comparison, the massive Gross Reservoir dam was 340 feet high before the current dam-raising project there.
Longmont also said it welcomed the no-dam deal, and looked forward to continue working with the district on future water supplies from the valuable St. Vrain storage rights.
St. Vrain valley water officials have talked for years about using small gravel ponds along the river farther downstream to store the water. They had talked of leaving the dam proposal behind, but also renewed the town’s dam rights in a 2024 water court filing required every six years to retain its options.
When Save the World’s Rivers submitted formal opposition to the renewal in water court, the two sides began discussions.
“I met with Gary several times, and I gained respect for his organization’s objectives,” water district director Sean Cronin said in a release by the district. “And I appreciated his willingness to come to the table and talk through complicated issues abandoning the dam proposal.”