Feds ink $300 million Windy Gap water diversion out of #ColoradoRiver — The Denver Post

Site of proposed Chimney Hollow Reservoir -- Windy Gap Firming Project via the Longmont Times-Call
Site of proposed Chimney Hollow Reservoir — Windy Gap Firming Project via the Longmont Times-Call

From The Denver Post (Bruce Finley):

Federal water authorities signed off Friday on the $300 million Windy Gap Firming Project to siphon more water out of the Colorado River Basin into a huge new reservoir for the high-growth Front Range.

The west-flowing river water — up to 8.4 billion gallons a year pumped back eastward and under the Continental Divide — is expected to meet the needs of 400,000 residents around Broomfield, Longmont, Loveland and Greeley.

A U.S. Bureau of Reclamation decision clears Northern Water to build the 29 billion-gallon Chimney Hollow Reservoir, assuming it obtains state water quality and federal wetlands permits.

The reservoir would sit southwest of Loveland, west of Carter Lake. Work would begin by 2018, Northern Water spokesman Brian Werner said.

“It’s going to make water supplies more reliable,” Werner said. “You want to make sure you have a firm supply year in, year out so you have water for the basic needs of your communities.

“With all the growth we’ve seen in northern Colorado, we keep pushing that envelope of how close we are when that really dry year hits. We’ve got a lot more people moving in — one of the fastest-growing populations in the country — and part of this is about preparing for the future.”

For more than a decade, western Colorado communities have fought the project, contending it will degrade the ailing Colorado River Basin.

The project would divert river water near Granby and pump it through an existing 9-foot-diameter tunnel under the Continental Divide, to be stored in Chimney Hollow.

Numerous studies have found this will increase environmental harm that began in the 1930s, when federal agencies began pumping west-flowing water back eastward, through the Adams, Moffat and other tunnels, to Colorado’s semi-arid Front Range. Water temperatures spiked. Algae spread. Sediment clogged channels and choked aquatic life.

Negotiations during the past six years led to plans to try to minimize environmental harm and offset damage.

Northern Water has agreed to:

• Install temperature-monitoring devices and not divert water when the river gets too warm.

• Release trapped water for 50 hours at least once every three years, ensuring flows of 600 cubic feet per second, to simulate natural floods essential for ecosystem health.

• Give 977 million gallons a year to Grand County.

The project would increase the amount Northern Water diverts annually to more than 250,000 acre-feet, bringing total water diverted from the Colorado River Basin to 67 percent of the natural flows. Northern Water supplies 33 cities and irrigation water for 650,000 acres of crops.

From KUNC (Nathan Heffel):

The record of decision states that the proposed Chimney Hollow Reservoir site is the preferred location for holding water transported from the Western Slope via the Colorado Big Thompson Water Project. The proposed reservoir would feed 10 municipalities across Northern Colorado including Greeley, Loveland and Fort Lupton.

Northern Water’s Brian Werner said this is an important step in a long process bringing, what he calls, water stability to Northern Colorado users.

“We have two steps remaining next year [2015], we need a state water quality certification and then a wetlands permit from the Army Corps of Engineers,” Werner said. “Once those steps happen we move forward with design, that’s probably a year, year and a half. And then we can start going out to bid and onto construction.”

Werner said a 2017 or 2018 ground breaking on the project is likely.

Project managers said the Windy Gap Firming Project could provide 26,000 acre-feet of additional yearly water to Northern Colorado cities if constructed. Currently that additional water is lost in years of high run-off since there’s no place to hold it. During low run-off years, water is unavailable because the Windy Gap Project holds junior water rights.

“This makes reliable a water supply to a number of Northern Colorado communities that haven’t had the reliability factor with their Windy Gap water supplies. So it gives them another comfort level in terms of future water supplies,” Werner said.

“With the drought throughout the Colorado River basin and always on people’s minds, this is a huge step in terms of finding and putting together a future water supply for these communities.”

The federal permitting process for the project began in 2003, and the Bureau of Reclamation issued a final Environmental Impact Statement in 2011. A fish and wildlife mitigation plan was also approved at that time by the Colorado Parks and Wildlife Commission.

More Windy Gap coverage here and here.

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