Colorado River Connectivity Channel

Reconnecting the Colorado River

As part of the Windy Gap Firming Project’s permitting phase to build Chimney Hollow Reservoir, the historical impacts of the original Windy Gap Project were also evaluated, including the loss of river connectivity following construction of the Windy Gap Reservoir dam on the Colorado River. To minimize the dam’s impact on aquatic habitat and species, the Municipal Subdistrict, which owns and operates the Windy Gap Project, agreed to decrease the reservoir’s footprint and construct a connecting channel around the reservoir capable of passing water, fish and sediment, thereby reconnecting two segments of the Colorado River. Construction activities began summer of 2022 and were completed in fall 2024. 

Connectivity Channel Features

The Colorado River Connectivity Channel project will allow public access for fishing along most of the new channel and includes:  

  • Windy Gap Dam Embankment Modification – A new southern embankment will create a smaller reservoir and provide space to construct the new channel and floodplain.
  • Diversion Structure – A new diversion structure will direct and allocate river flows between the reservoir and the new connectivity channel. The structure will allow sufficient flow into the reconfigured reservoir to meet pumping requirements when the Windy Gap Project’s water rights are in priority, while also maintaining flow in the connectivity channel for sediment and fish passage. 
  • Connectivity Channel – A new channel and floodplain will connect the Colorado River above and below the reconfigured reservoir. To the extent possible, the new channel and floodplain will allow natural geomorphic and ecological river processes to take place while maintaining dam safety.   
  • Fraser Stream Gauge Retrofit – Improvements to the Fraser River stream gauge immediately upstream of Windy Gap Reservoir will facilitate fish passage. 

Project Partnerships

Multiple invested stakeholders are assisting to ensure a successful connectivity channel project. Stakeholder contributions include design, project management, fund raising and time. 

The Municipal Subdistrict and Trout Unlimited contracted with AECOM to conduct the final design. Other project partners include Colorado Parks and Wildlife, Colorado Water Conservation Board, Grand County, the Colorado River District and the Upper Colorado River Alliance.

A New Channel for Fish and Sediment Passage

Aerial image showing the Colorado River Connectivity Channel and Windy Gap Reservoir.

A collaborative project that reconnects the Colorado River, restoring a vital habitat link between river segments upstream and downstream of Windy Gap Reservoir, and improving stream health and ecosystem function.

 
People in a river installing fish monitoring equipment.

Prior to construction, Colorado Parks and Wildlife (CPW) installed fish-monitoring equipment above and below Windy Gap Reservoir in order to later document the effectiveness of the Connectivity Channel. CPW also placed additional antennas within the channel during construction and will conduct on-channel surveys by boat. Project partners will additionally monitor for water quality, macroinvertebrates, various riparian conditions and geomorphologic processes, all of which will inform an adaptive management plan to ensure the project’s goals are achieved long-term.

People in high visible vests monitoring the first flows through the Colorado River Connectivity Channel.

Connectivity Channel construction got underway in the summer of 2022, and by Oct. 25, 2023, the project was far enough along to send the first flows into the new channel. That same day, Colorado Parks and Wildlife fish-monitoring equipment signaled that fish were already starting to use the channel.

A small amount of water in Chimney Hollow Reservoir behind the dam.

The Colorado River Connectivity Channel is part of a $90 million package of environmental measures associated with Chimney Hollow Reservoir near Loveland, which is where Windy Gap water will be stored.