SUSTAINABLE TRAIL BUILDING 101
We design, build, and maintain to limit erosion from trail users themselves, and from the forces of nature. For trails, woods roads, and gravel driveways, it begins with deliberate planning, construction techniques, and regular maintenance.
Water, Water, Water
We ask where and how surface runoff is collected. In what manner will it be shed away? Trail building borrows on roadbuilding techniques, and also uses its own unique set of guidelines, described below.
Attraction and Control Points
A great trail experience begins with intentional design. Look at these huge moss covered marble boulders. We inventory the project landscape and design layouts to showcase the natural environment.
Grade & Layout
As much as the layout of the site and building conditions allow, we find grades climbing at an average of less than 8-10% to be more durable. Many builders also follow the half-rule as a general guide, where the grade of the trail must be less than half the grade of the hillside or slope it traverses. The more a trail can be stretched across a side slope, the gentler the climbing grade that may be achieved (resulting in a more durable installation).
To minimize our installation footprint, single-track type trails are typically built without ditches or crowns like on a typical automobile roadway. Alternatively, to minimize erosion from water that might accumulate on the tread, the entire surface is tipped downhill for water to escape in a sheetlike manner.
We install grade reversals as a natural gentle barrier to stop water from traveling down a trail. When descending a trail, a grade reversal is a section of trail that briefly trends back up hill. With proper outslope in the transition section between down and uphill grades, water will escape out of the bottom of the dip. Riding or running down a trail with repeated grade reversals can provide a fun, roller coaster-type feel!
This construction technique climbs or descends across hillsides using a step-like fashion rather than following along at a continuous grade. The changes in grade allow trail users a chance to rest. The low spot of these undulations provides a place for runoff to escape the trail.
Banked and insloped tread is popular in modern construction because they prevent trail runners and bikers from slipping off the turn. A small dip or longer grade reversal before the turn stops runoff from entering the turn, and a drain at the bottom of the turn facilitates dumping any water that accumulated within the turn itself.