Boulder’s Open Space and Mountain Parks Department is set to begin long-term trail improvement work in the western Boulder Valley Ranch area north of Boulder starting next week.

The changes to the area will include replacing certain trails, converting some trails for bicycle use and closing undesignated trails to protect habitat. Trails will also be made more accessible for disabled visitors.

Starting Wednesday, crews will begin work on re-routing a steep, erosive segment of Eagle Trail from the Sage Trail junction west to the shade shelter with a new, lower-grade 2/3-mile route. The Eagle-Sage trail junction will also be connected to a single-track trail next to the Sage Trail.

The Cobalt, Hidden Valley, and Degge trails will also eventually be re-routed and will open for bike use while still allowing hiking and horseback riding. Work on the Cobalt Trail could start as soon as Sept. 16, while the Hidden Valley and Degge trail re-routes are slated for 2025-2026.

Work is also planned in 2025 for the Shale Trail, and the Mesa Reservoir Trail and parts of the Degge Trail are expected to permanently close next year. A full list of the planned improvements can be found at bit.ly/3ATBOu8.

During the upcoming construction, trail closures should be minimal, according to the city, but short, intermittent closures may be needed. Information on current trail closures is available at OSMPTrails.org.