Trail Design and Sustainability Best Practices
In addition to meeting user needs by providing a quality experience, well-designed and constructed trails minimize erosion and keep maintenance costs to a minimum. In the Southwest, soil types and volume/velocity of rainfall create unique challenges.
In our years of experience in designing, building, and maintaining trails for hiking, bicycling and horseback riding we have developed design and construction criteria that have proven to be sustainable. In addition to reduced maintenance costs, sustainable trails protect resources by minimizing erosion effects on plants, habitat, and cultural resources as well as discouraging the development of social trails to bypass eroded trails.
Sustainable trails, properly designed, provide users with a quality, enjoyable experience, and reduce the temptation to travel off-trail.
Insights: Trails designed and built to be sustainable lighten the land manager’s load by minimizing maintenance to the level that it can, for the most part, be done by volunteers. Circumventing erosion protects resources from sediment migration, head cutting, and user-created trails hikers or users will often be tempted to take to avoid eroded trail segments.
Sustainable trails enhance the user experience by providing a relatively smooth tread for feet and tires. This is achieved primarily by ensuring — both through design and construction — that water runs across and not down the trail.
Soil types – more specifically shear strength – determine the allowable grade. (Side slope grade is also a determinant because water will turn and run down a trail with a grade that is more than 50% of the side slope grade.) Decomposed granite is highly erosive, and maximum grade may be as little as 3%; solid bedrock, the other extreme, can be fall-line grade since erosion takes place on a geologic time scale.
All of the above objectives are incorporated as “positive control points,” places the trail needs to go if at all feasible. (Trailheads and intersections for connectivity are examples of positive control points.)
Negative control points, areas to be avoided, include sensitive habitat, cultural sites, and physical features that make construction impossible or excessively expensive.