Gross Reservoir Expansion Proposal Presents Water Demand, Environmental Concerns

Gross Reservoir

“In the West, when you touch water, you touch everything.” Legend has it that Wayne Aspinall, the congressman who represented Colorado’s Western Slope during the mid-20th century’s years of dam building, proclaimed this sentiment as one of his guiding principles. He could not have anticipated that debates over water in the Mother of Rivers would lead to a contentious argument over whether to accommodate the expansion of one of Denver’s water supply pillars.

With a population expected to rise nearly 20% between 2020 and 2050, Denver faces the possibility that Boulder County might reject plans to expand Gross Reservoir. The governing board of commissioners in the nearby county is preparing to decide whether to use a powerful state land use law to deny Denver permission to double the size of the reservoir. Boulder County has not yet announced when it will take up Denver’s application for a 1041 permit needed to move forward with the $464 million expansion, but Denver Water has mounted an insistent campaign that it is necessary to provide adequate drinking water for its customers. 

Aftermath of Two Forks

Wrangling over the Gross Reservoir expansion is not the first occasion of intense conflict over Denver’s water demand. During the 1980s the city pushed for construction of the Two Forks Dam, which would have flooded Cheesman Canyon and created both a structure taller than Hoover Dam and the largest lake in Colorado. Denver Water said at the time that more storage was essential to provide water for the city. Nevertheless, the U.S. Environmental Protection Agency vetoed it in 1990, declaring that the dam would cause “unacceptable environmental damage.”

Slightly more than a decade later, in 2002, a severe drought led to the first water use restrictions in Denver, while the massive Hayman Fire in the Pike National Forest led to an intrusion of sediment in the utility’s reservoirs. 

To ease the water demand, the city moved from the idea of constructing a new reservoir — and flooding a canyon beloved to recreationists and environmentalists — to  expanding an existing one. Gross Dam and Reservoir, completed in 1954 on South Boulder Creek, is capable of holding about 40,000 acre feet of water carried from the Fraser River through the Moffat Tunnel.   

“Not only did the opponents to Two Forks highlight that expansion of existing facilities would be less damaging, they provided the complete roadmap to Denver Water,” Jeff Martin, project manager for the Gross Reservoir expansion, said. “We listened, we learned from our history.” Martin explained that Denver Water first contemplated the undertaking formally called the Moffat Collection System Project in 2003. By 2009, the city had asked the U.S. Army Corps of Engineers and the Federal Energy Regulatory Commission for permits needed to increase storage in Gross Reservoir by 77,000 acre feet and raise the dam by 40 meters.  

Building Alliances on the Western Slope

To buttress support for the project, Denver Water took an unprecedented step in 2013 by entering into an agreement to preserve the very river on the Western Slope that supplies Gross Reservoir. The Colorado River Cooperative Agreement commits the utility to a slew of promises, including limiting its service area to its current scope, paying $11 million of expected costs to restore sections of the Colorado, Fraser and Williams Fork Rivers and mitigate damage done by its diversions, and releasing 2,000 acre feet of water to the Colorado and the Fraser during low-flow, high-temperature events. 

These duties are conditioned upon the completion of both the Gross Reservoir expansion and the Windy Gap Firming Project, now being constructed by the Northern Colorado Water Conservancy District. “The agreement ushered in a new era of cooperation that for the first time in Colorado history brought together the West Slope and the Front Range on a shared vision for a secure and sustainable water future,” Denver Water chief executive officer/manager Jim Lochhead said. 

Bart Miller, an attorney at Western Resource Advocates in Boulder and the group’s Healthy Rivers Program director, emphasized that the agreement obligates Denver Water to reduce diversions during drought years. “The project itself was shaped and designed to avoid damaging or affecting flows in the driest of years,” he said. “The project will only take water in the average or above-average years.”

Gretel Follingstad, a former water planner for the New Mexico Office of the State Engineer, said that other Colorado River basin restoration benefits,  including planting  trees on river banks and narrowing conduits to benefit trout populations, should not be taken for granted because they likely could not have been assured in a courtroom fight over Fraser diversions. “I think the benefit to the river itself is better when you have a cooperative agreement than when you just have litigation,” she explained. “With litigation you run the risk of still dewatering the Fraser but not having any restoration to begin with. Instead of a win-win on both sides you end up with a win-lose.”

Follingstad, a Ph.D student at CU-Boulder whose research focuses on adapting water systems to deal with climate change impacts, believes the CRCA and the projects that it has spawned are also demonstrating to Colorado that Denver Water is interested in being a good corporate citizen. “They are basically showing an example of what we haven’t really seen a whole lot of, pre-2010, when collaborative agreements started becoming a much more used tool in water management,” she said. “It is a move in the right direction.”

Does Denver Really Need the Water?

Opponents of the Gross Reservoir expansion are adamant that, regardless of Denver’s efforts to lessen its impacts on Colorado River basin waters, Denver must address its water needs by using less instead of continuing a habit of extracting and moving water from the Western Slope and building another reservoir. They argue the city has not done enough to conserve and that, in an era of human-caused climate change, there is not going to be water to divert. “It’s an unsustainable system,” Jen Pelz, an attorney and Wild Rivers Program Director at WildEarth Guardians, said. “If we keep putting Band-Aids on the systems, we’re missing the forest through the trees.” 

Martin vigorously disputes this claim, pointing out that Denver’s water conservation efforts have reduced water use in the city by 20% even as its population has grown by 15% since those programs were launched. Miller backed him up: “They’ve kept their water use flat for the last four decades,” he said. “They’ve managed to keep their average annual use the same as it was 35 years ago.”

To Tom Cech, co-director of the One World One Water Center for Urban Water Education and Stewardship at Metropolitan State University, it is not realistic to expect Denver Water to meet the needs of a city population expected to increase by 88% since the demise of Two Forks Dam by conservation alone. “Some would say there’s more that could be done, but it’s a pretty robust water conservation program,” he said. “To meet the water needs of people moving here you’ve got to find other sources of water.” 

Data provided by Denver Water suggests that average annual demand is likely to increase by 94,000 acre feet per year between 2002 and 2032 and that the agency may face an annual shortage, without additional storage, of more than 34,000 acre feet. Those figures are based on a 2002 projection on which Denver Water continues to rely as justification for the project. 

Pointing the finger at landscaping is easy to do, Follingstad said, but the reality is that Denver might be running up against a limit of what changes in household use habits can accomplish. “When you use water conservation to meet supply needs, you get to a point where you can’t reduce use any further,” she said. “That means conservation is not the silver bullet.”

Follingstad believes that, contrary to the critics’ take that Denver has not done enough to assure conservation, the city’s efforts so far should enhance its credibility when it claims more water is needed. “Denver Water is a lynchpin of water conservation,” she said. “That should speak to their benefit in this situation. They’re not arbitrarily going after a reservoir expansion project without really calculating the need, without calculating in the amazing conservation practices they’ve achieved.” 

Denver Water does agree that additional conservation is possible. According to the 2002 estimate of the expected 34,000 acre feet shortfall within its service area by 2030, it can make up 16,000 acre feet via additional conservation measures. 

The city has also seen, contrary to the 2002 supply prediction that is the basis of its claimed need for the Gross Reservoir expansion, no shortfall by 2016 and an actual decline in water use since 2002. A Denver Water fact sheet relating to the project and posted online in 2018 says its conservation efforts have already reduced actual water use from pre-2002 drought levels by 22%. 

The city also has additional storage under construction in the South Platte River basin. According to a March 2018 report in its TAP newsletter, Denver Water is in the process of converting sand and gravel mine sites into nine small reservoirs as part of its Downstream Reservoir Water Storage Program that will store about 32,000 acre feet or about 10.5 billion gallons. The water, like that Denver stores at Gross Reservoir, comes from Western Slope rivers and streams in the Colorado River watershed and, since it is diverted out of its home watershed, can be reused.

A more unpredictable challenge for the Mile High City is the ongoing impact of climate change. “At some point, if you have a two- or three-year drought, the water levels in reservoirs that Denver currently has are going to go down and down to the point where that reservoir is dry,” Cech explained. “The concern is a multi-year drought. We can get through a one-year drought, a two-year drought, but what about a four-year drought or a 10-year drought?”

According to a 2015 report by CU-Boulder and Colorado State University, the statewide average annual temperature has increased by two degrees since 1985 and will increase by an additional 2.5 to 5.5 degrees above a 1971-2000 baseline by 2050. By then, snowpack is expected to decline, spring runoff will likely shift to a period that is one to three weeks earlier than it occurs at present, and longer and more intense droughts will occur.

Denver Water maintains that, considering only the projected temperature change, water held in storage could decline by 7-20% as a result of evaporation while household use increases by 6-7%. “If you wanted to find, over the last 10-15 years, public officials who are least likely to deny climate change, the best place to find those public officials would be in water utilities,” Patricia Limerick, a professor or history at the University of Colorado at Boulder and director of the school’s Center of the American West, said. 

Clean Water Act Permit, FERC License, and Federal Court Litigation

Before expanding Gross Reservoir, Denver needs a permit from the U.S. Army Corps of Engineers that allows Denver Water to inundate 281.1 acres of land, including 280 acres of the Arapaho-Roosevelt National Forest, surrounding the existing lake. Before flooding that land, Denver Water would remove as many as 650,000 trees from a total of 456 acres, including at least one acre of old-growth ponderosa pine forest. Opponents decry this and other environmental consequences from the project, such as destruction of more than five acres of wetlands and more than four acres of riparian habitat, sinking of Forsythe Falls, and damage to the fish population in South Boulder Creek. The project will also increase diversions from the Fraser and the Upper Williams Fork River on the Western Slope.

Bill Eubanks, the owner and managing partner of national public interest environmental law firm Eubanks & Associates in Washington, D.C., represents opponents of the Gross Reservoir Expansion who have asked a federal court to block the project. To his clients, the central problem is that the U.S. Army Corps of Engineers failed to determine whether Denver’s claims about its water needs are accurate. “Rather than pushing back and asking questions, as they are required to do under federal law, they just accepted Denver Water’s view,” Eubanks said. 

“The Corps of Engineers certainly put out a lot of paper, but nowhere in that paper did they ever scrutinize what Denver Water was saying about demand, whether this project is truly needed to meet demand, and whether there are any alternatives,” Eubanks continued. Indeed, in a legal document filed in the case brought by Eubanks’ clients, Denver Water admitted that the extra storage room provided by a larger Gross Reservoir “will be filled only in average and above-average runoff years and will be reserved for use during droughts or system emergencies.”

Denver Water and the federal agencies sued by Eubanks’ clients have asked a U.S. district judge in Denver to dismiss the lawsuit on grounds that project opponents did not raise their arguments before the Federal Energy Regulatory Commission, which granted the utility a required license under the Federal Power Act in July. Eubanks said he considers this move to be an indication that Denver Water cannot defend the project on the merits. “Rather than confronting our claims candidly, they’re trying to find a way out,” he said. “They’re looking for a mulligan to get out of this suit.”

Whether the Army Corps of Engineers succeeds in obtaining a dismissal of the complaint depends on whether the agency’s unprecedented legal argument is accepted. “There’s not a single case, ever, in the federal court system where a court has done what they are asking this court to do,” Eubanks said. “It would be a very novel and peculiar precedent, given that no one here is complaining about anything FERC has done.”

Boulder County’s 1041 Powers Pose Possible Barrier to Expansion

Regardless of what the federal court does, Denver Water’s plan for Gross Reservoir faces another legal test in Boulder County, one that has killed and forced significant changes to other water projects in Colorado’s recent history. 

In February 2019, the county commissioners decided that Denver Water must obtain a permit under a 1974 state law that gives local governments the authority to regulate construction of water projects. Under that law, called the Areas and Activities of State Interest Act, counties are allowed to impose conditions on a project, or deny permission to build it, even if the state would authorize it or demand fewer or less onerous terms. The AASIA was used by Eagle County to block the Homestake II Project sought by Aurora and Colorado Springs during the 1980s and, more recently, by Pueblo County to force Colorado Springs to substantially alter its $825 million Southern Delivery System.

Denver sued to prevent the county from exercising its so-called 1041 powers in an effort likely aimed at preventing just such outcomes. Boulder County district judge Andrew Macdonald rejected its arguments in December 2019. On Sept. 21, after filing and then withdrawing an appeal of Macdonald’s decision, Denver filed an application for the 1041 permit. A public comment period set by Boulder County ended on Nov. 7.

According to a March 2018 letter from Boulder County attorney Ben Pearlman, Denver may face some significant obstacles to obtaining the county commissioners’ assent to the Moffat Collection System Project. Pearlman argued that Denver’s effort to build small storage sites in the South Platte basin indicates the projections it supplied to FERC and that provide support for its 1041 permit application may not be accurate.

The question is whether this discrepancy matters. Miller argues it does not and should not be held against Denver Water because the utility now urges the project on grounds that it is needed to provide resilience to its systems. “Denver has pretty robust sources, but they feel that in some climate and catastrophe scenarios, there can [be] major impacts on the ability of their system to deliver,” he said. 

The county also fears that climate change will further reduce the amount of water from the Colorado River and its tributaries that is available for diversion. “Because Denver Water has defined the purpose and need for the project to be the development of 18,000 acre-feet of firm yield, which is exactly the amount of firm yield that an enlarged Gross Reservoir could hold based upon historical averages, if there is any diminution in stream flows due to lower average annual flows, the preferred alternative of the expansion must be rejected,” the letter said.

Denver Water’s 1041 permit application does not address concerns about need or climate change impacts on Western Slope water availability. It does admit that the Gross Reservoir expansion project will inundate portions of Winiger Gulch Potential Conservation Area and more than 240 acres of Winiger Ridge Environmental Conservation Area, destroy 3.9 acres of plant communities considered to be of “local concern,” and cause a variety of short term air quality, water quality, and noise impacts and possible invasion of non-native aquatic species. To Miller, those local concerns probably loom large for Denver Water at this stage of its quest to raise Gross Dam. “The folks in Boulder County are going to bear the burdens of this project if it’s built,” he said. 

“Denver Water will come with a lot of ideas and they’ll have to listen. You can imagine some or many of those concerns being addressed.”

Boulder County has not announced when it will consider the 1041 application. Dale Case, the county’s director of community planning and permitting, said in an email that he does not expect the hearing to occur until at least February or March 2021. Miller pointed out that, whenever the hearing occurs, the commissioners will face a complex problem. “These are long-term decisions, they’re going to have lasting impacts, and we’re living in a world where there’s less and less water,” he said.

— Hank Lacey

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