Projects underway to bridge #Colorado’s water supply gap

From Water Deeply (Matt Weiser):

At least seven major new reservoirs and water diversion projects are being planned in Colorado, which had a population of 5.6 million in 2017. Many would continue the controversial practice of diverting water across the Rocky Mountains from the state’s Western Slope, where the majority of Colorado’s precipitation falls, to its more arid Front Range, where people are flocking to Denver, Boulder, Fort Collins, Longmont and increasingly sprawling suburbs.

The water projects have been inspired partly by the Colorado Water Plan, an effort by Governor John Hickenlooper to solve a projected water deficit of 560,000 acre-feet by 2050, or enough to serve more than 1 million households. The plan calls for 400,000 acre-feet of new water storage and an equal amount of water conservation.

The plan is only two years old. But critics say it has prioritized gray infrastructure – new dams, pipelines and pumps – over green projects like water conservation and sustainable land use…

The state water plan does not recommend any specific water development projects. But Hickenlooper has personally endorsed several of them. He also appointed all the voting members of the Colorado Water Conservation Board, the entity that oversees the Water Plan and awards grants for water projects.

Greg Johnson, chief of water supply planning at the Water Conservation Board, said the state’s plan emphasizes conservation just as much as new water supply projects. But he said the latter may be more more pressing in some cases.

“Some of the bigger projects that are in permitting right now are helping meet really critical supply needs that a lot of those faster-growing northern Front Range suburbs have, where they’ve got new developments going up all over the place,” Johnson said. “They have maybe a 10- or 15-year horizon to get some of those things done.”

One of the water developments endorsed by the governor won a $90 million loan in 2017 from the Water Conservation Board – the largest loan in the board’s history. Known as the Windy Gap Firming Project, it proposes a new reservoir called the Chimney Hollow Reservoir near Longmont to store Colorado River water diverted through an existing tunnel under the Continental Divide.

The loan covers nearly one-fourth of total costs for the project, which is proposed by the Northern Colorado Water Conservancy District.

As its name implies, the project is intended to “firm up” existing Colorado River water rights held by a dozen Front Range cities. The cities already draw on these water rights, but can’t fully tap them in some years because of storage limitations. The new 90,000 acre-foot reservoir will solve this problem and allow them to divert the river almost every year.

The project would result in diverting 30,000 acre-feet more water out of the Colorado River every year than is currently diverted…

Other major projects in the works include the Moffat Collection System, a plan by Denver Water to expand Gross Reservoir to hold 77,000 acre-feet of additional diversions from Colorado River headwaters streams; and the White River Storage Project, a proposal for a new reservoir of up to 90,000 acre-feet in the northwest corner of the state, near the town of Rangely…

Greg Silkensen, a spokesman for the Northern Colorado Water Conservancy District, said the Windy Gap project is vital to many fast-growing Front Range communities that have lower-priority water rights.

“The Colorado economy is just crazy. Everybody and their brother is moving here,” Silkensen said. “There is a great deal of environmental mitigation that will go forward if the project is built. There’s going to be a lot of benefit to the Upper Colorado River if it does go through.”

Those projects include stream habitat restoration in the Colorado River and water quality improvements in Grand Lake, part of the existing Western Slope diversion system.