Site of Chimney Hollow Reservoir via Northern Water.
Map from Northern Water via the Fort Collins Coloradan.
Chimney Hollow Reservoir site via the Bureau of Reclamation
Site of proposed Chimney Hollow Reservoir — Windy Gap Firming Project via the Longmont Times-Call
Windy Gap participants (2012)
Windy Gap Reservoir
Windy Gap Reservoir
Here’s the release from the US Army Corps of Engineers Omaha District (Kiel Downing/Cheryl Moore):
The Corps of Engineers, Omaha District, finalized its Record of Decision (ROD) approving the Windy Gap Firming Project on May 17, 2017. The project is proposed by the Municipal Subdistrict, Northern Colorado Water Conservancy District (Subdistrict) and involves the construction of Windy Gap Firming Project Water Supply facilities for its customers and 13 other Front Range water providers. The Subdistrict requested a Section 404 Clean Water Act (CWA) Permit from the Corps’ Omaha District Denver Regulatory Branch. “Due to the potential for significant environmental impacts to the East and West Slopes of Colorado, this project resulted in the preparation of an Environmental Impact Statement (EIS)” said Kiel Downing, Denver Regulatory Office Chief. The U.S. Bureau of Reclamation (Reclamation) was the lead federal agency preparing the EIS, and the Corps participated as a Cooperating Agency.
The original Windy Gap Project, constructed in the early 1980’s, was intended to provide more than 40,000 acre-feet of firm yield to the east slope, but due to operational constraints that didn’t happen. The project currently captures water from the Colorado River, pumps it to existing reservoirs on the west slope and moves the water through a tunnel system (the Colorado-Big Thompson Project operated by Reclamation) to the Front Range of Colorado. Because of the historic deficiency in water deliveries and lack of storage, the Windy Gap Project participants have not been able to fully rely on existing Windy Gap Project water for meeting a portion of their annual water demand. As a result, the participants, initiated the proposed construction of the Chimney Hollow Reservoir, which would firm all or a portion of their individual Windy Gap Project water allotment units to meet a portion of existing and future municipal and industrial water requirements. The Chimney Hollow Reservoir, as proposed, is a 90,000 AF capacity reservoir that will be dammed at the northern and southern limits.
Reclamation published the Windy Gap Firming Project, Environmental Impact Statement in November of 2011, and ROD on December 12, 2014. The State CWA Section 401 Water Quality Certification began shortly thereafter with the Subdistrict submitting its application to the State in March of 2015. The State issued the Section 401 WQC for the WGFP on March 25, 2016. This determination was necessary for the Corps determination under Section 404 of the CWA. The Subdistrict provided the Corps its Mitigation Plan for permanent and temporary impacts to Waters of the U.S. associated with the WGFP on March 17, 2017 and the Corps with continued agency collaboration, updated study information, and new Federal and State requirements, finalized their ROD shortly thereafter marking the end of the federal approval process.
From The Loveland Reporter-Herald (Jeff Stahla):
Kiel Downing, Denver regulatory office chief for the Corps of Engineers, announced Wednesday afternoon the Record of Decision for the Clean Water Act permit for the Windy Gap Firming Project, which includes the reservoir.
With the final federal permit in hand, Northern Water officials can start planning for construction of the $400 million project, which is set to start in late 2018 or early 2019, according to Northern Water Public Information Officer Brian Werner.
“We’re smiling,” Werner said. “These things come along once in a generation.”
Berthoud-based Northern Water will manage the construction of a pair of dams in a valley west of Carter Lake that will hold approximately 90,000 acre-feet of water, or about 29 billion gallons — enough water for more than 90,000 households.
Water to fill Chimney Hollow will come from the Colorado River basin in years when its flows are above average. The water will be carried through a diversion at Windy Gap Reservoir in Grand County to Lake Granby and the Colorado-Big Thompson Project.
Municipalities including Loveland, Fort Collins and Greeley conceived of Windy Gap in 1970. The need for storage space for the communities involved to “firm” their ownership of the Windy Gap water rights expanded in later years to include Chimney Hollow Reservoir because in above-average precipitation years, Lake Granby often does not have enough space to store the additional water.
Rep. Hugh McKean, R-Loveland, said he was ecstatic when he heard about the Corps of Engineers’ approval, comparing it to Christmas.
In his time serving on the Loveland City Council and then the Colorado House of Representatives, he has seen how much the storage project was needed…
For cities such as Loveland, Windy Gap water fills an important role for its municipal users because it is a 365-day-a-year, deliverable water source, unlike in-basin seasonal water offered through local ditch companies. It will join the Colorado-Big Thompson Project shares in the city’s water portfolio…
McKean acknowledges that because the water has not been diverted before, questions and concerns will emerge from Western Slope water users and communities. However, because the Windy Gap Firming Project water is available only in years of above-average flows on the Colorado River, municipalities on the Front Range won’t be served until water rights holders on the Western Slope get their allocations.
He said he will be in Montrose this summer at a meeting of the Uncompahgre Water Users Association to talk about the project’s effect on the basins and in the context of the state water plan.
From the Associated Press (Dan Elliott) via The Colorado Springs Gazette:
The federal government gave final approval Wednesday for a $400 million dam and reservoir in northern Colorado where 13 cities and water districts will store water from the other side of the Continental Divide.
The Army Corps of Engineers issued a permit for construction of the Chimney Hollow Reservoir in the foothills about 50 miles (80 kilometers) north of Denver.
The corps regulates some of the environmental impacts of big water projects.
It is the last approval the reservoir needs, said Brian Werner, a spokesman for the Northern Colorado Water Conservancy District, which oversees the project.
Construction could start in early 2019, after the district refines the plans, hires a project manager and awards contracts.
Water for the reservoir would be pumped from the Windy Gap Reservoir on the Colorado River near the town of Granby, west of the Continental Divide, through an existing tunnel under the Rocky Mountains to the east side of the divide.
The 13 water providers own the rights to the water but have nowhere to store it. The project is formally called the Windy Gap Firming Project because it would firm up the water supply.
The Chimney Hollow Reservoir will store up to 90,000 acre-feet (1.1 million cubic meters). One acre-foot (1,200 cubic meters) can supply two typical households for a year.
New reservoirs are always contentious in Colorado. Water managers and urban planners argue the state needs more because it does not have the capacity to store all the water it is entitled to under agreements with other states. They also say Colorado needs more water for its growing population.
Some conservationists oppose new reservoirs because of their environmental damage and because the state’s rivers are already overtaxed.
“The Colorado River is on life support right now,” said Gary Wockner, director of Save the Colorado. “If the patient is bleeding out, you don’t cut open a new artery to try and heal it. Instead, you should work to protect and restore the river, not further drain it.”
Wockner said his group will likely challenge the Corps of Engineers permit in court.
Trout Unlimited negotiated some environmental improvements in the Colorado River near the Windy Gap Reservoir as part of the project. Mely Whiting, an attorney for the group, said she had not yet seen the final Corps of Engineers permit.
Water providers that will pay for and benefit from the Chimney Hollow Reservoir are the cities of Broomfield, Erie, Greeley, Longmont, Louisville, Loveland, Superior, Evans, Lafayette and Fort Lupton, as well as the Central Weld County and Little Thompson water districts.