Project Overview

Current Status of Windy Gap Firming Project
Northern Water’s Municipal Subdistrict and the 13 Windy Gap Firming Project participants continue making progress as the project moves closer to design and construction.

After the Subdistrict submitted the WGFP's 401 water quality certification application to the Colorado Department of Public Health and Environment, the CDPHE conducted a public comment period, evaluated the application, and then issued the WGFP's 401 water quality certification in March 2016.
Section 401 of the federal Clean Water Act requires that the state provide the U.S. Army Corps of Engineers with a certification that the project will comply with applicable water quality standards. Staff forwarded the CDPHE's 401 water quality certification to the Corps, which is now considering issuing a Section 404 wetlands permit for the WGFP. Final design and construction of Chimney Hollow Reservoir can begin once the Corps has issued the 404 wetlands permit.

Design work is anticipated to take two years, and project construction another three to four years.

Windy Gap Firming Project Reaches Milestone
Video: Dec. 19 Record of Decision Signing Ceremony  

On December 19, 2014, following years of effort, the U.S. Bureau of Reclamation, Northern Water and its Municipal Subdistrict signed a new Windy Gap carriage contract. Simultaneously, Reclamation issued a Record of Decision for the Windy Gap Firming Project, enabling continued progress to design and construct Chimney Hollow Reservoir.

To view the Record of Decision, Final Environmental Impact Statement and other associated documents, please visit Reclamation's Windy Gap Firming Project EIS page.

News Releases:
 Northern Water: Reservoir Project Moves Forward
 USBR: Reclamation Signs Record of Decision
The WGFP is a collaborative proposal between 12 Northeastern Colorado water providers and the Platte River Power Authority. The WGFP would improve the Windy Gap Project’s reliability by constructing a new storage reservoir for Windy Gap water at Chimney Hollow near Carter Lake.

Windy Gap Project Overview
The Windy Gap Project was first proposed in 1967 by the cities of Boulder, Estes Park, Fort Collins, Greeley, Longmont and Loveland. Built between 1981 and 1985 and located on the West Slope near Granby, Windy Gap consists of a diversion dam on the Colorado River, a pump plant and a 6-mile pipeline to Lake Granby, the largest storage reservoir in the Colorado-Big Thompson Project system.
During wet periods when Lake Granby is full, the Windy Gap Pump Plant cannot operate due to the absence of reservoir storage for Windy Gap Project water. If constructed as proposed, Chimney Hollow Reservoir would fill this new storage space need.
New Windy Gap Carriage Contract
Northern Water’s Municipal Subdistrict is coordinating the Windy Gap Firming Project on behalf of the project’s 13 participants. As part of the WGFP’s ongoing permit phase, the Subdistrict and Reclamation negotiated a new carriage contract to transport Windy Gap Project water through the C-BT Project facilities to Chimney Hollow Reservoir. The new contract was signed in December at Northern Water’s Berthoud headquarters. 

Grand County 1041 PermitThe firming project reached a major milestone when the Grand County Board of County Commissioners approved a 1041 permit and several related agreements in late 2012. 

The permit and agreements create a package that greatly exceeds the project's required mitigation by providing significant voluntary benefits, including improvements to the Colorado River, additional water supply for West Slope water providers, and long-term commitments to Grand Lake and the Colorado River.

How Water Is Reshaping the West – Nova Next/Rocky Mountain PBS, November 11, 2015

The site of the proposed Chimney Hollow Reservoir with
Carter Lake on the right. View the Chimney Hollow Reservoir map.

Project Answers 13 Participants' Need for Water Supplies
 The Windy Gap Firming Project would benefit 10 cities, two water districts and a power provider. Northern Water's Municipal Subdistrict is coordinating the permitting process for these residential providers, who face a serious lack of water supply as the region continues to grow.
  Project Participants
Map shows the locations of the 13 participants in the Windy Gap Firming Project. 
Click map to view it. 
Dedicated Storage The firming project would meet a need recognized about 25 years ago by Windy Gap participants: a dedicated reservoir to store Windy Gap water.

Because of the project’s junior water rights, Windy Gap water cannot be diverted in years of low runoff. Conversely, during some wet periods storage space in Lake Granby is not available for Windy Gap water, which has a lower priority than C-BT Project water.
Chimney Hollow Reservoir would change the project’s reliable annual yield from zero acre feet of water to about 30,000 acre-feet, improving the reliability of water deliveries to participating water providers and, ultimately, the water users they serve. 

Chimney Hollow Reservoir
The 90,000 acre-foot Chimney Hollow Reservoir would be located southwest of Loveland and just west of Carter Lake, which holds about 112,000 acre-feet of water. 
The reservoir would be filled using Windy Gap’s original 1980 water rights decrees with appropriation dates of 1967, 1976 and 1980, and diversions would adhere to previously-agreed-upon limits.