By Mary Burger
The long answer.
Ostensibly, the purpose of any path or trail is to get from point A to point B. But, we all know the reality is somewhat different. The experience of hiking, running, biking, or whatever, is the goal in itself. For a trail to provide a good trail experience, it needs to offer the user a path free of unnecessary obstacles, and risks, and allow the user some fresh experience or reason to use it.
Every trail, indeed every use of the outdoors, has a cost to the environment. A good sustainable trail has the least impact on the environment, and offers the user a low risk adventure. A poor trail damages the environment, and increases the risk of injury to the user.
A sustainable trail drains the water off the edge in a sheet fashion such that it does not erode the trail. A poor trail does not allow the water to sheet off. Water which remains on the trail removes surface material causing ruts, and undercuts, which in turn are difficult to navigate. Left unattended, the water which is caught in the rut, accelerates, and increases the damage with every rainstorm. The sediment which is carried away by the water deposits in low lying areas, and buries the local vegetation. Roots rocks and other items are uncovered when the surface material is washed away causing the surface of the trail to become unstable, and difficult to use. The user then steps outside the original trail area, to prevent themselves from falling or injuring an ankle, and creates a secondary trail or braid. Since the secondary trail follows the line of the original trail, it does not correct the problem and falls prey to the forces of water as well. Now, we have a larger impact zone in the environment.
The difference between a sustainable trail and a poor trail is mathematical in nature. A good trail will climb the hill on the side, (or cross slope) and will keep the rate at which it climbs the hill, (or grade), to less than 1/3 the cross slope. When a trail grade exceeds 1/3 the cross slope, the water will be caught on the trail; guaranteed.
When the grade is too severe, there are three options. We can install steps, such as we did on the Mt. Esther trail. We can install drainage structures, such as we did on the lower portion of the Crags to Devil’s Playground trail, (C2DP). Or we can reroute the trail to put is back on the cross slope, such as we are proposing to do with the upper portion of the C2DP.
Steps are difficult to install and can only be used if the grade is less than 30%. That is, for every 4 inches of height gain, you want at least 12 inches to rest you foot on. Long stretches of steps are are difficult for the user. Also, steps are difficult to install and require continuous maintenance. Rock steps are generally more in keeping with the local environ, but their installation is an art. Wood steps are more uniform, but they are heavy to carry into remote areas, and do not look natural.
Drains are generally used whenever the grade is greater than 12% or, greater than 1/3 the cross slope. But drains are limited in their effectiveness when the grade exceeds 25%. Because they cause a rise and fall of the trail surface, they are uncomfortable to the user. The users then go around the drains or actually remove the rocks which support the drains which causes them to fail.
Raised trail and trench is another method of drainage which we used quite effectively on C2DP. This allows the trail to sheet drain into a trench, and then we drain the trench periodically. This method reduces the potential for the user to cause the drain to fail. However, raised trail and trench is only appropriate for trail that is less than 15% grade. Otherwise, the water does not sheet into the trench.
Best case, one designs the trail correctly the first time, then the repairs consist of removing downed trees and cleaning out drains. When all else fails, the trail route must be changed, or the trail will need to be closed because it threatens the user and the environment.
When a trail is being used because of its destination and the trail is non-repairable such as the stretch of the C2DP above the logging camp. The USFS must act carefully to determine if a re-route is appropriate. This process is called a NEPA, after the National Environmental Protection Act which details how the process occurs. We have requested a NEPA for a reroute on the C2DP. It may take years before the process is complete. Meanwhile, we will do such repairs as we can. You can help by staying on the trail, such as it is, and not creating braids.
