In mid-November, for the second time this year, the City of Boulder opened a new trail for cyclists.
The Cobalt Trail, previously closed to riders, was rerouted and designed with smoother, non-technical features for improved flow. Trail crews also revamped a washed-out section of the Eagle Trail, using modern trail-building techniques to accommodate cyclists and recreationists with disabilities.
As part of its North Trail Study Area Plan, published in 2016, Open Space and Mountain Parks has been working on reroutes at Boulder Valley Ranch to open more trails to cyclists and improve accessibility for adaptive cyclists and other trail users.
The City of Boulder contracted with Timberline Trailcraft to help reroute the Eagle Trail, while the Cobalt Trail was built by Boulder Mountainbike Alliance trail program director Mike Rutter along with trail crews from OSMP and Volunteers for Outdoor Colorado. Both trails were designed specifically for cyclists, incorporating switchbacks and undulations that riders can pump to maintain speed. The trails are also wider than other city trails, such as the North Sky Trail, to accommodate adaptive bikes, which often have three wheels and a wider base.
All OSMP trails are open to people using adaptive mountain bikes and other mobility devices, also known as Other Power/Driven Mobility Devices (OPDMDs). But some are more accessible than others.
“Many trails are not constructed to accommodate OPDMDs well, including the old Eagle Trail alignment,” Phil Yates, a spokesperson for OSMP, said.
Some trails are too steep to physically accommodate adaptive mountain bikes, but others, like the Eagle Trail, can be made accessible by adjusting the grade, cross slope and width. “Through modest trail design and construction techniques that most visitors won’t notice, the new Eagle Trail reroute can help welcome a broader group of visitors,” Yates said.
OSMP is also developing signage for its trails to provide information about trail width, maximum slope and cross slope, so visitors with disabilities can make more informed decisions about whether to ride a trail. The city also offers trail accessibility guides for people using wheelchairs, which are more limited than adaptive bikes.
The expansion of cycling trails in Boulder has been aided by the Boulder Mountainbike Alliance, which advocated for more bike access during the development of the North Trail Study Area Plan.
The Cobalt Trail
The most notable change to the Boulder Valley Ranch area is the opening of the Cobalt Trail to cyclists. This approximately one-mile trail connects the upper mesa to the Boulder Valley Ranch trailhead. From the trailhead, riders can complete a 12-mile loop by continuing on the Left Hand Trail and crossing U.S. 36 to reach Joder Ranch, where they can access the northern end of the new North Sky Trail.
The Eagle Trail
The Eagle Trail reroute replaces a steep and often washed-out segment connecting the top of the mesa to the Sage Trail below. The trail now includes several switchbacks and grade dips to shed runoff, making it more sustainable. This section is now much less steep, making it easier to ride uphill. Further rerouting will take place next year, including a one-third-mile reroute on top of the mesa west of the existing reroute, according to OSMP.
Future plans
The city will continue to make changes based on the North Trail Study Area Plan in 2025 and 2026 to restore habitats and open two more trails to cyclists.
Next year, OSMP plans to reroute the Hidden Valley and a short section of Degge trails, both of which are not currently open to cyclists but will be after the reroute. The trails will also be designed specifically for adaptive cyclists.
However, the rest of Degge Trail will permanently close in 2025 to improve habitat around Mesa Reservoir, according to Yates. Mesa Reservoir Trail will also close for the same reason. Also in 2025, OSMP plans to replace two undesignated trails with a new Shale Trail that will connect the section of the Eagle Trail on top of the mesa to the Boulder Valley Ranch trailhead. This trail will be closed to cyclists. By removing the undesignated trails, OSMP aims to reduce impacts on Bell’s twinpod, a small yellow flower known to grow only in Boulder, Larimer and Jefferson counties, which is classified as vulnerable to imperiled by the state.
