STORY AND PHOTO BY KAREN BOSSICK

Comments on a bridge replacement project and trail reroute at the popular Greenhorn gulch hiking and mountain biking area south of Ketchum are being taken through Dec. 11.

The Sawtooth National Forest is soliciting public comments on the Greenhorn Improvement Projects and associated projects.

Snowmelt off the Greenhorn Gulch Trail and snow load caused significant damage to the Greenhorn Gulch Trail and caused a bridge to collapse this past spring. Not only did avalanche debris pile up, but snow melt and rain rutted the area and undercut check dams.

The Greenhorn Gulch Trail is the most utilized recreation facility on the Ketchum Ranger District, according to trail monitoring data provided by the Wood River Trails Coalition. It averages 134 counter detections every day and had 308 detections on July 3, 2022. The trailhead itself sees more than 26,000 visitors a year.

THE PLAN:

The Ketchum Ranger District wants to remove the two remaining bridges on the Greenhorn Gulch trail along the first 0.3 miles of the trail. The third was removed in spring 2023 due to safety concerns caused by a broken stringer, or a structural piece in the framework.

One of the two remaining bridges is at the end of its useful lifespan. The third is in better condition but nearing the end of its useful lifespan. All three bridges were poorly sited in an area with beaver habitat and a frequently moving streambed.

The plan is to add 0.2 miles of trail along the north side of Greenhorn Creek to link the trailhead to a place just above the current third bridge. This would bypass the first and second bridges, allowing them to be taken out and reduce the amount of trail braiding in the riparian zone adjacent to the trailhead. A fully engineered bridge like those installed at Adams Gulch would be installed at a sustainable location.

Imperial Gulch Trail would be re-routed, moving it out of the riparian area. This would reduce future maintenance costs and allow for riparian area restoration.

The Greenhorn Trail above its intersection with Mahoney requires repairs that are beyond the capability of a hand crew. Many parts of the trail are in the fall line and there’s no side slope to reduce erosion.

The plan is to hire a Professional Trail Builders Association contractor and move the trail to the adjacent side slope to build sustainable tread without changing the overall character of the trail.

Submit comments on the project website at https://www.fs.usda.gov/project/sawtooth/?project=65065. Or email comments to intermtn-sawtooth-ketchum@usda.gov.

Comments can also  be hand-delivered to the Ketchum Ranger District or Sawtooth National Forest Supervisors Office between 8 a.m. and 4:30 p.m. weekdays. Note “Greenhorn Improvements Project” in the subject line.

Questions? Contact Recreation Program Manager Tamara Rowell at tamara.rowell@usda.gov or 208-622-0087.