Where Do Trails Come From? - Part 2: Trail Building and Maintenance
By: Sirena Rana Dufault
As I mentioned in Part 1 of this series, when I tell people I design and develop trails with my company, Trails Inspire, they often say, “I never really thought about how trails get there.” In Part 1, I went over the steps for development and design of a trails system. Now, we’ll cover how the trails are built and maintained in Part 2.
Trail construction can begin once the managers of the land give the green light. For public land, the land management agency issues a permit for construction after the trails system has had the necessary environmental and cultural assessments and public outreach to comply with the National Environmental Policy Act (NEPA). For private land, the landowners make the decision to go ahead with the project after the initial system has been surveyed and designed.
I learned most of what I know about trail construction through my volunteer work with the Arizona Trail Association, which is the nonprofit that built and maintains the Arizona National Scenic Trail (AZT). When I joined the trail crew in 2007, there were still many miles of trail to be built near my home in Tucson. Construction techniques may vary a bit depending on the environment, but the overall principles remain the same.
Meet the Key Parts of a Trail
There are several parts to a singletrack natural surface trail.
First, there is the trail tread, which is the area you actually walk, bike, run, or ride a horse on. It is generally between 18” to 36” wide.
Second, there is the trail corridor, which is the area that has been cleared of brush on either side of the trail (and above if the trail is used by equestrians). Generally, singletrack trail has a trail corridor of three feet on either side of the center of the trail tread.
If the trail needs to be cut into the side of a slope, that is called a benched trail. The guidelines for constructing benched, semi-benched, and flat trails are depicted in the cross-section figure below from the Forest Service Trail Construction and Maintenance Notebook.
Understanding the Steps to Building a Trail
How a trail is designed and built determines future trail maintenance needs. Do it correctly, and your trail will require minimal cutting back of brush and minor repairs to the trail tread. Do it wrong, and the trail will require a lot of ongoing work due to washouts and vegetation.
It’s said that if you put a trail in the wrong place, you’re just creating work and frustration for generations to come. As I mentioned in Part 1 of this article, the most important part of trail design and construction is managing the drainage of water in the area. Improper drainage will turn your trail into a muddy mess, create a deep gully, wash out the trail in places, and provide an unsafe user experience.
Below are the five main steps to follow to build a solid trail to last for the ages.
1. Clearing the Corridor
To begin, the corridor is marked with pin flags, stakes, or flagging tape. This is used as a guideline for clearing brush and rocks. The first step is to take out the vegetation. Here in southern Arizona, that means cutting back or digging out cacti, thorny trees, and bushes, including the roots. In Arizona, it’s usually not possible to get all the rocks off of the corridor, but loose ones are removed and larger rocks are dug out.
After the vegetation has been cut, the goal is to make the new trail look like it’s an integrated part of the landscape. Grubbing the trail removes the vegetation. Cut pieces are moved far off the trail with the ends of the vegetation facing away from the trail. Rocks are placed with the weathered side up when possible.
3. Tread Work
After the corridor has been cleared and grubbed, the work on the tread (the part under your feet) can begin. Some trails just require a little raking, while others require moving a lot of dirt to make a safe and sustainable path. Trails that hang on the side of a slope are called benched trails.
You may think that an ideal trail tread is flat, but remember about the need for the trail to shed water properly. A flat trail will hold water and cause erosion. Instead, we use an angled outslope. The degree of this varies depending on the terrain, but 5-8% is the guideline I use in the desert.
Another option for trail building, depending on the terrain, is using a mini excavator. This still requires finishing work on the tread, but you can see in the photo below from Flagline Trails that it does a good job of roughing it out.
4. Drainage Features
In addition to the outslope, other features can be added to help the trail shed water, such as rolling grade dips or nicks in the tread. These are constructed to divert the flow so that it doesn’t funnel down the trail and cause erosion. Trails where you’re walking in a gully are a result of not shedding the water correctly.
5. Rock Work
Rock work can be used to armor the trail, or build drainage features, retaining walls, and steps. Rock work can feel a lot like a game of Tetris, finding the perfect stones in the environment and fitting them together. There is a lot of construction done on the base of rock work that is ultimately covered in the final product, so what you see on the trail is just a fraction of the work that was done.
Assessment and Maintenance of the Trail
Work on a trail doesn’t end after it’s built. There are two key steps that come next: assessment and maintenance.
After the trail has been built, it requires regular monitoring and assessment to fix minor problems before they turn into big ones. This is done by walking the trail and taking GPS points and photos of any areas of concern, such as overgrown sections of the trail, erosion, or washouts in the trail tread. This can be used to make a plan for trail maintenance events.
Even if a trail is designed and built correctly, it will require some ongoing maintenance. Staff or volunteers will need to prune back and remove trees and bushes regularly to keep the corridor open. In addition, they may need to repair areas of erosion and add additional drainage features, as necessary.
Appreciating and Getting Involved with Your Next Trail!
Trail building and maintenance is tough work, but very rewarding. It gives you a connection with that piece of trail and makes you realize all the effort that goes into the tread under our feet. There are few finer feelings than hiking out of an event on a new trail you helped create!
If you’re looking to volunteer doing trail work, check out your local trail association or parks and recreation division for information. The long-distance trail associations also have volunteer programs in place, as does the American Hiking Society. In addition, there are opportunities for trail jobs through the Americorps program. You can learn more about that in this blog.
Now that you know all the steps and effort that goes into creating, building, assessing, and maintaining a trail, I hope that you’ll consider being a part of it sometime! I’ve met so many wonderful folks working side by side to create a sustainable path that will provide recreation for generations to come.
---Sirena Rana Dufault is an advocate for the outdoors who adores exploring Arizona's trails, canyons, peaks and rivers. She is the founder of Trails Inspire, a consulting company that promotes the outdoors via writing, public speaking, photography, and trail design and development. You can follow her on Instagram.