Water Colorado's water plan: an end to mega projects? The latest draft of the plan sets strict guidelines for approving new diversions over the Rocky Mountains.

Underneath the surface of Colorado’s new water plan is an unspoken acknowledgment: the days of moving large amounts of water up and over the Rockies are probably done.

On July 7, the second draft of the statewide plan was released, the latest step in a decade-long process that will direct how Colorado’s water should be managed for years to come. The new draft sets a statewide water conservation target of 400,000 acre-feet and incorporates input from Colorado’s nine Basin Roundtables, groups of citizens and experts tasked with thinking about their region’s water needs. But the biggest addition is a revised set of guidelines for making decisions about new supply projects that could spell the end of any new big water transfers over the Continental Divide.

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The guidelines acknowledge what for years seemed unthinkable to many Coloradans: there may not be any water left to develop, without cutting into the water rights already in use.

That admission represents a huge shift in what the state publicly acknowledges about Colorado’s water supply, says Eric Kuhn, the general manager of the Colorado River District and one of the people who helped draft the guidelines. “Just a few years ago no one was questioning whether there was more Colorado River water to develop,” he says.

Already, a massive system of pipes and reservoirs — known as transmountain diversions – brings more than half a million acre-feet of water east from the Colorado River basin across the Continental Divide to cities and farms on the Front Range. Farmers on the west side of the Rockies, along with the majority of people living there, have long opposed any new diversions. But with groundwater reserves running out and a projected 5 million extra people living in Colorado by 2050, many water managers on the Front Range see a big new transmountain water project as an important tool for keeping pace with growth.

But there’s a problem with that solution, says Drew Beckwith, the water policy manager with conservation group Western Resource Advocates. Climate change will continue to exacerbate drought conditions, which means river flows will keep trending downwards while temperatures rise. That means taking more water out of the system will cut into existing projects — like more eaters making the size of the pie slices smaller for everyone. “It makes it very risky to take more water out of the river under those conditions,” says Beckwith.

That new mindset, encapsulated in the guidelines, challenges a long-held assumption that the state can and should develop its full allotment of water from the Colorado River under the 1922 Compact. The law requires that the Upper Basin states send 7.5 million acre-feet annually to the Lower Basin plus an additional 750,000 acre-feet for Mexico before splitting the remainder among themselves. According to the most recent study by the Colorado Water Conservation Board on the availability of supplies in the Colorado River Basin, Colorado has anywhere from one million to zero acre feet left to develop — depending on which climate model plays out.

On the West Slope, home to 84 percent of Colorado’s water supply, that possibility is driving calls for “not one more drop” of water diverted to the Front Range. Even Denver Water, the largest municipal water utility in the state with 1.3 million customers, acknowledges that protecting existing supplies is paramount. Their comments on the second draft state: “Denver Water receives about 50 percent of its total supply from the Colorado River. Therefore avoiding a ‘Colorado River Compact Call’ is critical to our ability to meet our obligations to our customers.”

But the lingering uncertainty over just how dry or wet Colorado’s future will be means Denver Water is covering both bases. Another section in its comment letter maintains that “the ability to develop new projects should be protected.”

The disconnect underscores just how touchy the issue of new water development in Colorado is — and why authors of the state water plan are tiptoeing around the issue. To critics, the presence of the new transmountain diversion guidelines may make it look like the plan simply endorses new projects. But in practice, says Beckwith, the necessary conditions make it seem unlikely that one will ever materialize: Any new project could only divert water during “wet years” to prevent exacerbating the risk of a curtailment on the state’s allotment of Colorado River water, which would happen if the state could not meet its Compact obligations to the Lower Basin.

To meet those requirements, Kuhn believes “Lake Powell would have to be essentially spilling." In the past 15 years, those conditions have occurred only once. For that reason, any new project will be a hard-sell. “Are you, as a city councilman, going to endorse a multi-billion dollar project that will only be able to take water in one out of every 15 years?” Kuhn says, though he notes that the guidelines do not impede expansions of existing projects that were already approved (such the Windy Gap Firming Project in northern Colorado).

With less than six months left until a final version of the plan is due to Governor Hickenlooper, debate over whether it merely greases the skids for new transmountain diversions will continue.

But for Beckwith, “this is as close as you can say to ‘there will never be a new [transmountain diversion] without actually saying it.”

Sarah Tory is an editorial fellow at HCN.