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Boulder County’s review of proposed Gross Reservoir expansion underway

Application comes a few months after Denver Water dismissed its appeal of district court ruling


The Boulder County Community Planning and Permitting Department’s review of a planned expansion of Gross Reservoir in western Boulder County is underway, officials announced Thursday.

This is the latest in a years-long dispute between Boulder County and Denver Water, who owns and operates the reservoir and dam. A Boulder District Court judge in December 2019 affirmed the county’s right to require that Denver Water go through its 1041 land use review process in order to expand the reservoir.

The Gross Reservoir Expansion Project would, among other things, increase the reservoir’s current capacity by 77,000 acre-feet of water and raise the dam’s height by approximately 131 feet and its length by approximately 790 feet.

“Denver Water put in a request to determine if the expansion project would be exempt from our land use code,” Boulder County spokesperson Richard Hackett said.

However, the water utility company in July dismissed that appeal soon after the Federal Energy Regulatory Commission granted approval for Denver Water to continue with design and construction after the county told the company it would not conduct the review while the litigation was ongoing. The regulatory commission’s approval stipulates that project construction begin within two years. The project in 2017 received the other permit it needed from the U.S. Army Corps of Engineers.

The Gross Reservoir project by the state’s largest water provider would be the biggest construction project in Boulder County history, and it has drawn opposition from nearby residents and environmentalists. In fact, environmental advocacy groups in 2018 filed a lawsuit in U.S. District Court in Denver challenging the U.S. Army Corps of Engineers’ decision to grant the permit.

“For those of us who live close to Gross Reservoir, we will lose everything we moved here for: wild pristine beautiful scenery, clean air, clean water, boating, fishing, peace and quiet,” Celena Collins, former board president of The Environmental Group, said in a news release from when the lawsuit was filed.

That litigation is still making its way through the court. Mostly recently, on Sept. 25, environmental attorney Bill Eubanks, who represents the environmental advocacy groups, filed a brief in opposition of a motion for dismissal that was filed in August.

Denver Water, on the other hand, maintains it’s committed to conservation and the efficient use and reuse of water.

“The Denver Water system supplies water to over 25% of Colorado’s population, as well as commercial entities vital to the state’s economy,” Jeff Martin, program manager with the expansion project, wrote in a letter to the county.

No public meetings or hearings have been scheduled yet, but the county will announce them to its Gross Reservoir Expansion Project news list. People who want to receive emailed or text messaged notifications can sign up at Hackett said the agencies reviewing the application have until Oct. 14 to return initial comments, although the county has the right to extend that deadline due to extenuating circumstances caused by the coronavirus.

In the meantime, community members can submit questions or written comments to There is no deadline for doing so. Comments will be accepted until the Boulder County Board of Commissioners makes a decision.

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