Introduction: How to Design and Build a Trail
This how-to is specifically for volunteers and students working on the interior trails of the Balcones Canyonland Preserve at Concordia University. The purpose of these trails is to allow access for scientists, students and stewards of this private nature preserve to areas that require attention for preservation, maintenance, and environmental studies. We expect the work on the secured preserve to take place over time, so this document will be helpful in passing on tips, tricks and methods to future trail tamers.
Dr. Sam Whitehead, pictured above, is the Director of Environmental Sciences at Concordia University and advisor to the Balcones Canyonlands Texas Master Naturalist at Concordia University Texas. Please email him with any access or queries otherwise Sam.Whitehead@concordia.edu.
Step 1: Assess Your Site
First, you must assess your site. An overhead drone photo will provide a visual preview of trail points you might not have access to yet. Topographic surveys provided by GIS maps will give you and idea of the best paths to avoid the least grading.
We were lucky that our friend and professional photographer Patrick Wong put together a beautiful map for us to begin sketching our trail proposal for the University's board to approve before beginning work. In the drone photo, we notice that what lines were already cleared from tree surveys in previous years.
Step 2: Locate Nodes of Interest
When designing a path, it is important to take time to locate the nodes of interest.
Step 3: Assess the Path Between Nodes
People usually spend more time at these points, so additionally I like to draw cones that delineate the view. With an overlay of the topography plan, you can start to see how the terrain may shape this aperture for the trail visitor. Think of walking through Central Park as the curves in path and manipulations of height hide the road from the inside and reveal points of interest creating moments of awe.
Of course, you should walk your node and cone diagram before making any cuts.
If you have access to a GPS receiver, you can very clearly map the path of least resistance
Step 4: Begin a Physical Trail Layout
Begin laying out the trail. Pink flagging tape is a great way to make your design visible. A good bundle of tools would be: a bow saw, pruning shears, sledge hammer, flagging tape, come along and the all star macleod. Long pants, long sleeves, hiking or construction boots and a large container for water would be important for even an hour of work.
A 30" clear path is a good rule of thumb and tends to be about the length of the wooden part of a shovel handle for an easy check. You will want to remove all large rocks, limbs and leaves from the path. A useful method is to toss what you have removed several feet below the bottom edge of the path to avoid debris collection on the trail after rainfall. A good rule of thumb is to not exceed a 20% slope. If the terrain is sloping greater than 20%, you may consider a different path, steps, or terracing. If you must maintain a slope for vehicles, switchbacks are the best way to approach a steep slope, but are more work and use the most space.
Always be sure to clear the trail of all tools, trash and water bottles after every work session. The goal is to provide access to nature, not leave your mark.
Step 5: Clear the Curb Above
Besides clear the path itself, you will want to remove large rocks and rubble above the path that might fall on to visitors after heavy rains or tree fall.
It is important to provide a bit of cross slope to your trail, maintaining a high and low slide with a 2-5% slope. Side slope allows rain to drain immediately as it enters the trail path, as opposed to turning your entire trail bed into a river that may erode the path and endanger plant root systems at the trail edges.
Step 6: Clear the Curb Below
You will also want to clear the edge of the curb below the path to avoid puddling or debris collection, cluttering your new trail. 6' at a minimum is a safe distance between trail tamers. You will both be clearing brush, throwing limbds down the trail side, and swinging tools. This distance is really important to avoiding injury and maintaining a chummy day.
Step 7: Path Material Selection
Not all trails require a covering. For the private areas of the preserve, we left the ground bare and packed down the dirt with tools and our feet. As you consider your trail bed covering, look at what materials are near or naturally occurring to avoid incurring costs.
- Crushed Limestone: On the preserve access trails, we plan to use crushed limestone roadbed as the land as a high percentage of limestone anyway and its is quite cost efficient. Finely crushed limestone works well for trail running and biking, which was an important consideration as we plan for fitness stations along the preserve access trails. Crushed fine aggregates of any material are not recommended for slopes steeper than 5% as they would wash away with heavy rainfall.
- Decomposed Granite: Decomposed granite fines tend to have drainage problems as the crushed fines are known to lock together mechanically over longer periods of moisture and can become a moss habitat. The City of Austin counts decomposed granite as impervious cover in the building department, but not crushed limestone. It is a beautiful material but I tend to stay away from it.
- Cedar Chips: We considered using downed ashe junipers around the preserve area in the form of wood chips to mitigate wildfire fuel and reduce building costs, however after light internet research we discovered that leachates from cedar chips have been known to disrupt ecosystems of natural waterways. As there are several natural springs on our preserve, we decided not to use this material. Hemlock, spruce, pine or fir chips have been used in other parts of the country without this problem, however it trail riding is strong discouraged as a tire cannot grip on wood chips. Wood chips would be a great surface for a running trail.
Step 8: Voila! You Made a Trail!
Invite your friends, make interpretation maps, and enjoy your new access to nature!
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Please be positive and constructive.