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Gross Reservoir Dam outside Boulder, Colo., on Monday, July 1, 2019. Denver Water is planning a major expansion of the reservoir that will increase height of the Gross Reservoir Dam by 131 feet and water storage by 77,000 acre-feet. Local residents and environmental groups are fighting against the expansion due to concerns about environmental impacts and the lack of conservation efforts. (Chris Schneider/Colorado Sun)

Boulder County is poised to accept $10 million in mitigation from Denver Water in exchange for stepping out of the way of the controversial Gross Reservoir expansion, though environmental opponents say county leaders took a cheap deal and they will continue their fight. 

Boulder County’s commissioners will vote Tuesday on the settlement, which has Denver Water putting up the fund to mitigate noise, light and dust impacts on reservoir neighbors, trading land to expand Walker Ranch Open Space, and paying for South St. Vrain Creek wildlife improvements. 

In exchange, Boulder County would accept Denver Water arguments filed in federal court over the summer that the expansion is exempt from county review. Denver Water’s suit accusing Boulder County of slowing down the project said Denver already has the federal permits it needs through a federally-regulated hydroelectric generator at the base of Gross Dam. 

“The settlement proposal avoids the legal risk that a federal court will order the project to proceed without any county-approved mitigation measures,” Boulder County Deputy Attorney David Hughes said in a news release announcing the proposed deal with Denver Water.

Oral arguments in Denver Water’s lawsuit were to start Thursday, but the suit would be withdrawn or dismissed if the governing boards agree. Boulder County’s commissioners will discuss it Tuesday, though environmental groups say there should be a full public hearing on the merits of the proposed deal before a vote. Denver Water’s board would take up the agreement Wednesday.  

Save the Colorado, which has led coalitions fighting further diversions of Western Slope and Colorado River water into Front Range city water systems, said opponents of the Gross Reservoir expansion were betrayed by county officials who had promised to include them on settlement talks. Save the Colorado director Gary Wockner said the opponents had proposed $70 million in mitigation for Gross Reservoir. Conservation groups had agreed previously to a $15 million mitigation fund for Grand County improvements to the Colorado River as part of the Windy Gap and Chimney Hollow project now underway by Northern Water. 

“Because the county staff cut a minimal deal behind closed doors that cut out the public, we won’t know what’s realistic” for a Gross Reservoir settlement, Wockner said. “The Boulder County commissioners need to vote ‘no’ on Tuesday and send this back to the negotiating table where the public actually gets a voice.”

PLAN-Boulder County, a citizens’ group working on sustainable development, also attacked the settlement as damaging to the county and to the Colorado River headwaters to the west. 

Susan Stanley, of Boulder, and her dog Wile E. Stanley paddle board on Gross Reservoir outside Boulder, Colo., on Monday, July 1, 2019. According to Stanley, she comes to the reservoir often and opposes the dam expansion. Denver Water is planning a major expansion of the reservoir that will increase height of the Gross Reservoir Dam by 131 feet and water storage by 77,000 acre-feet. Local residents and environmental groups are fighting against the expansion due to concerns about environmental impacts and the lack of conservation efforts. (Chris Schneider/Colorado Sun)

“It is appalling that such a massive and impactful project could proceed in our county without local review,” PLAN co-chair Peter Mayer said. “We urge the Boulder County commissioners to reject this inadequate settlement agreement which doesn’t begin to address the damage this project will cause the environment and region.”

The proposed $464 million Gross expansion project would raise the dam by 131 feet and water storage by 77,000 acre-feet. Construction would impact surrounding forests, trails, roads and neighbors, and also temporarily cut off access to popular open spaces in parts of the area.

Denver collects Western Slope water in the reservoir and sends supply down Boulder Creek to be treated for use by Front Range communities. The dam was built by Denver in the 1950s. Gross fills with South Boulder Creek water, but the pool also holds Fraser River water that Denver Water owns the rights to and pumps through the Moffat Tunnel under the Continental Divide. 

Though Boulder County gets no water from Gross or Denver Water, the Denver agency has called the reservoir expansion key to solidifying and balancing the northern part of its metro-area supply and delivery system. 

Many dam and pipeline projects need local approvals as part of the state-sanctioned “1041” process, which gives counties and cities right of approval for significant land use decisions. Conservation groups and some local officials are using the 1041 process to slow down Northern Water’s complex Northern Integrated Supply Project on and around the Cache la Poudre River. 

Boulder County had scheduled hearings to put the Gross expansion through a local 1041 process through the fall, until Denver Water sued and said the county no longer had a role in approvals. 

“The actions of a single local jurisdiction, Boulder County, threaten to derail and undermine a federally permitted and state supported project vital to a safe and secure water supply for one-quarter of Colorado’s population,” Denver Water said, when filing the federal suit

It’s unclear what changed the minds of Boulder County’s leadership. Previous filings in the federal case, and in an earlier state court case over the same issues, showed the county was for years well aware of Denver Water’s claims that federal permits were all they needed to expand Gross. 

“Denver could have brought its federal field preemption claim when it filed its state court lawsuit in 2019,” Boulder County’s attorneys argued in August, when asking the federal judge to dismiss Denver Water’s latest lawsuit

  • The $10 million settlement Boulder County commissioners will vote on includes: 
  • $2.5 million for the construction impacts on immediate neighbors of the reservoir.
  • $5.1 million to Boulder County open space funding to acquire new land or repair and maintain trails and facilities under extra strain from visitors who can’t use Gross Reservoir spaces.
  • $1.5 million to mitigate greenhouse gas emissions from construction.
  • $1 million for South St. Vrain Creek restoration. 
  • A transfer of 70 acres of Denver Water land near Gross Reservoir to Boulder County to expand Walker Ranch Open Space.

The environmental groups’ proposal for $70 million in mitigation included $15 million for Grand County Colorado River corridor mitigation, the same kind of projects that are part of the Windy Gap settlement with Northern Water. Save the Colorado also wanted a multi-level outflow structure from the new dam so that South Boulder Creek water below the dam would be a natural local temperature for fish and wildlife. 

As part of that settlement proposal, the environmental groups said they also would have agreed to stop their own lawsuits against Gross expansion. Instead, they say, Boulder County left them out of last week’s negotiations with Denver Water. Wockner said Saturday they have not yet decided what to do about their legal actions. 

Michael Booth is The Sun’s environment writer, and co-author of The Sun’s weekly climate and health newsletter The Temperature. He and John Ingold host the weekly Sun-Up podcast on The Temperature topics every Thursday. He is co-author with...