This first major construction work for the Poudre Headwaters Restoration Project was largely completed just before the end of 2021. Contractor L4 Construction installed a fish barrier at the terminus of the Grand Ditch by La Poudre Pass. The barrier will isolate the planned Greenback cutthroat trout recovery area in upper La Poudre Pass Creek and Long Draw Reservoir from western slope waters intercepted by the Grand Ditch.

The Poudre Headwaters Restoration Project is an ambitious multi-year effort to create a stronghold for Greenback cutthroat trout in the headwaters of the Cache la Poudre River on the Arapaho-Roosevelt National Forests and Rocky Mountain National Park. The project includes establishing permanent barriers to safeguard the native trout recovery waters from invasion by non-native species, as well as temporary barriers to help break up the nearly 40-mile total project into smaller manageable pieces for reclamation and reintroduction of greenbacks. With completion of the Grand Ditch barrier, the first phases of fish reclamation to remove existing non-native fish can proceed in 2022-23 in collaboration with Colorado Parks and Wildlife, and then stocking of Greenback cutthroat trout can proceed in a first section of recovery habitat that will include Long Draw Reservoir and Neota Creek.

Installation of the Grand Ditch barrier created some real challenges as winter weather began to set in at the project site over 10,000 feet in elevation. L4 crews had excavated the area for the barrier installation to specifications from US Forest Service engineers who designed the barrier. Pouring the concrete for the barrier - in a series of three different pours for different portions of the structure - required both keeping the work area dry by blocking inflow above the site and pumping water, and maintaining temperatures for the concrete to cure properly by building a large tent over the site and using large heating units to blow warm air into the tent. Plowing snow to keep road access to the site safe for work crews and trucks delivering the concrete was another challenge.

Work on the concrete barrier was ultimately completed in the final week of December. Additional channel work is planned in 2022, and efforts will also begin on other aspects of the larger Poudre Headwaters Restoration Project. In addition to the Forest Service, Rocky Mountain National Park, and L4, key partners and funders for the barrier installation included Water Supply and Storage Company’s Long Draw Reservoir Mitigation Trust (providing mitigation funding for impacts of their reservoir), the Colorado Water Conservation Board, and the Bass Pro Shops and Cabela’s Outdoor Fund. Partners in the broader project also include Colorado Parks and Wildlife and the US Fish and Wildlife Service. Colorado TU is grateful to all of those who are making this ambitious native trout recovery program possible.

Images below show the tented area and construction process, culminating in backfill material placed behind one of the wing walls for the new fish barrier.