South St. Vrain Trail Work With Redstone Cyclery

BMA and Redstone Cyclery joined forces with a SQUAD of RAD volunteers to build rock gnar to fix erosion on a section of the lower South St. Vrain Trail during a two day trail building event July 28-29, 2018!

A section of the South St. Vrain Trail is fall line for approximately 200 feet right before it dumps you out on to the dirt road (ie: the super steep section many call the staircase only the stairs aren't really there anymore). When rerouted off private property in 2005 the alignment of the trail was forced into this fall line location. It's bookended on both sides by private property so it can't be moved.

We partnered with Dave Chase and his RAD bike shop, Redstone Cyclery, to go out and armor it while maintaining the difficulty of the trail.

The original construction utilized treated timbers to create check dams that doubled as stairs. These stairs were originally around 12" in height but due to erosion they have become close to 24" in height (18" is maximum desired height by USFS). The native soil had migrated down the hill and has created a sediment pool which is choking out native plants. The original width of this trail was approximately 24" and has now grown to over 5' in some areas due to users short cutting erosion issues and now exposed boulders. Tread depth is over 18" in some areas.

Work was done to replace the old timber check dams with concrete bollards. The area between the bollards was armored with rocks to prevent erosion in the future while keeping the trail steep and challenging. Rocks were loaded onto a tracked hauler with a mini excavator and moved up the steep hillside to where they were placed by hand. Trees were felled and cut to create gates and reduce user erosion created from short cutting of trail. Rock armoring was filled with smaller rocks and mineral soils to lock armoring into place and reduce further erosion.

Eroded soil that has collected in the sediment pool area was hand raked to expose original native plants. Reclamation of wider sections of trail created by user short-cutting was also part of the project.

View the project photos!


2018/07/28 - 9:00am - 2018/07/29 - 3:00pm