Could #Colorado cities save enough water to stop building dams? — The Colorado Sun

From The Colorado Sun (Michael Booth):

Conservation groups want more “cash for grass” and other plans to acquire new water by saving it. But Denver and Aurora, among others, say there’s only so much to cut before a new dam is needed.

Conservation groups applaud water savings efforts like Aurora’s. What they want is far, far more of the same.

They point to reports required by the state water conservation board showing many large agencies on the Front Range cutting back spending and personnel dedicated to water conservation since 2013, at the same time those water departments press to build massive dam complexes for new water they say they desperately need.

Large water agencies like Denver Water and Aurora Water say they do have ongoing conservation efforts they take seriously, but that fast population growth on the Front Range overwhelms potential savings and they need new water storage…

It would be much better for Colorado’s environment, the conservation groups respond — not to mention cheaper — to acquire water by using less of it, rather than spending billions of dollars on dams and diversions of Western Slope water.

And yet, several projects are on the drawing board:

Aurora wants to team up with Colorado Springs to build Whitney Reservoir and divert more of Homestake Creek over the Continental Divide to the Front Range

Denver Water wants to expand Gross Reservoir above Boulder to hold more Fraser River water diverted from the Colorado River Basin

Northern Water has a $1 billion proposal to dam more Cache la Poudre River water for more than a dozen northern suburbs and cities

All of those would be unnecessary, the conservationists say, if the agencies doubled down on water-saving efforts that cut deeply into household use in the years after the devastating 2002 Front Range drought…

“We know that water in the West is increasingly in short supply and will only become more so as climate change results in worsening drought conditions and water shortages. The answer can’t simply be to pull every last drop of water out of our rivers,” said Juli Slivka, policy director at Wilderness Workshop, which is among the groups fighting any new dams on Homestake Creek.

Some of the bigger water agencies on the Front Range respond that conservation remains a primary goal, despite the falloff in their spending evident in annual reports required by the Colorado Water Conservation Board.

Aurora’s population will grow by hundreds of thousands of people by 2050, said Aurora Water spokesman Greg Baker. The agency focuses intensely on conservation to expand its water supply, Baker said, through programs like the smart meters and rebates to property owners who remove thirsty lawns, and with Prairie Waters, the largest potable water recycling system in the state.

But that growth, highly visible on Aurora’s eastern edge at the Highlands or Painted Prairie, means stretching existing water use is not enough for future supply, he added. Acquisition of new water must continue. The agency just spent about $17,000 an acre-foot for 500 acre-feet of farm water in the South Platte River Basin, Baker said.

“That’s more than we could find through conservation right now, unless we took such draconian measures — you know, say we banned all outdoor water use,” he said.

Denver Water, serving 1.5 million customers as the largest water agency in Colorado, said it is proud of conservation efforts launched after the wakeup call of the 2002 drought, achieving its goal of a 22% cut in per capita water use in a campaign from 2007 to 2016. Since then, said Denver Water’s manager of demand planning Greg Fisher, some resources have shifted to the concept of “efficiency” — focusing less on absolute cuts to everyone’s use, and instead consulting with larger customers and homeowners to ensure they are using only the water they actually need…

Denver Water’s officially reported tally of its conservation work fell from 36 full- and part-time staff and a budget of $8 million in 2013 — the first year of required reporting — to five full-time staffers and $1.5 million in spending in 2019, the last full year before the pandemic shut down many field services. Denver’s peak of conservation staffing, at 40 in 2016, was the same year the agency said it achieved the long-set goal of 22% per capita reductions in use.

Denver Water says daily water use fell from 211 gallons per person in 2011, before another severe drought began in 2013, to 165 gallons a day in 2016. Since then, Fisher said daily use has declined to about 140 gallons. In the years since the 2002 drought, Denver Water’s annual overall use has gone down, even as the customer base has climbed by hundreds of thousands.

The Denver agency says the state conservation reports are partially misleading because they ask for too narrow a classification of spending that ends up cutting water use. For example, Fisher said, Denver Water is spending more money on staff time helping local agencies rewrite green building codes to require more efficient water use…

Aurora’s conservation staffing has changed less dramatically, from 15 full-time and 13 contract positions in 2013, to a total of about 24 positions now, officials said. The emphasis has shifted over the years, Baker said. Most home and building owners have long since swapped out older toilets for efficient models, and individual homeowner irrigation audits are not as productive as broader efficiency programs…

Environmental conservation groups opposed to diverting water from Western Slope rivers are especially focused this year on Boulder County’s Gross Reservoir, where Denver Water wants to raise the dam by 131 feet at a cost of $464 million. A higher dam would allow Denver to bring over more of the water it owns in the Fraser River, part of the Colorado River Basin west of the Continental Divide. Denver also says it needs more water storage on the northern end of the Front Range in case changing climate patterns and wildfire runoff threaten water collection in the southern South Platte River basin, where most of its available water is collected…

Multiple environmental groups have sued to stop Gross Reservoir and sought to scrap it during the local permitting process. Boulder County held the power over a key construction permit Denver Water needs this year. Now Denver Water has asked a federal court to take over jurisdiction for the permit because the agency believes Boulder County Commissioners have already demonstrated their intent to block it…

Aurora Water says it is one of the few Colorado utilities that is doing exactly that [paying cash for grass], with its “water-wise landscape” payments. Aurora will design a homeowner’s low-water garden for free, and pay material costs up to $3,000 for 500 square feet — even more for a zero-water landscape, Baker said…

Denver Water says it offers everything from low-water “garden-in-a-box” kits, to rebates for installing the kind of smart controllers Aurora promotes, to training for landscapers…

Building storage, though, must remain a part of the water acquisition mix, both Denver and Aurora argue. As the system has gotten more efficient through conservation, Denver Water said, possible future gains diminish. In the 2002 drought, Denver said, its short-term restrictions cut water use 30%. After years of conservation work, similar restrictions in the 2013 drought — for a significantly larger customer base — cut water use only 20%.

“We are reaching the edges of supply,” Hartman said.