Signage to the Treadwell Ditch Trail. (Michael Penn | Juneau Empire)

Duncan Campbell, of Trail Mix, works on a log bridge for a new Treadwell Gorge reroute trail on the Treadwell Ditch Trail on Thursday, Aug. 8, 2019. (Michael Penn | Juneau Empire)

Devil’s Club growing along the historic Treadwell Ditch Trail on Thursday, Aug. 8, 2019. (Michael Penn | Juneau Empire)

A new Treadwell Gorge reroute trail on the Treadwell Ditch Trail built by Trail Mix crew and volunteers on Thursday, Aug. 8, 2019. (Michael Penn | Juneau Empire)

A new Treadwell Gorge reroute trail on the Treadwell Ditch Trail built by Trail Mix crew and volunteers on Thursday, Aug. 8, 2019. (Michael Penn | Juneau Empire)

Crew leader Duncan Campbell, right, and Trail Mix Project Manager Ryan O’Shaughnessy work on a log bridge for a new Treadwell Gorge reroute trail on the Treadwell Ditch Trail on Thursday, Aug. 8, 2019. (Michael Penn | Juneau Empire)

Volunteer Dave Haas shovels gravel for a new Treadwell Gorge reroute trail on the Treadwell Ditch Trail on Thursday, Aug. 8, 2019. (Michael Penn | Juneau Empire)

Crew leader Duncan Campbell, right, and Trail Mix Project Manager Ryan O’Shaughnessy work on a log bridge for a new Treadwell Gorge reroute trail on the Treadwell Ditch Trail on Thursday, Aug. 8, 2019. (Michael Penn | Juneau Empire)

Diego Noboa, of Trail Mix, left, and volunteer Craig Good clear an area of debris for a drainage pipe on a new Treadwell Gorge reroute trail on the Treadwell Ditch Trail on Thursday, Aug. 8, 2019. (Michael Penn | Juneau Empire)

Trail Mix board member Jack Kreinheder videos with drone as Trail Mix crew and volunteers work to build a new Treadwell Gorge reroute on the Treadwell Ditch Trail on Thursday, Aug. 8, 2019. (Michael Penn | Juneau Empire)

A sign marks the exit to the Bonnie Brae Subdivision just south of the new Treadwell Gorge reroute on the Treadwell Ditch Trail on Thursday, Aug. 8, 2019. (Michael Penn | Juneau Empire)