Trail design and construction
Hosted by AmericanTrails.org
American Trails is proud to present "Building Your Trail Right the First Time" as a part of the American Trails "Advancing Trails Webinar Series"
Presented by John Favro: Owner, Trails Guy; and Chair, American Trails
This webinar, held July 18, 2013, teaches how to place a trail on the landscape so that it is consistent with the natural environment so that it will be aesthetically pleasing, meet user needs, and require minimal maintenance in the future.
Main topics include:
You can purchase this archived webinar on the American Trails Online Store
QUESTIONS and ANSWERS
Q. Where/how do you build a trail in a meadow?
Building in a meadow is never recommended. Sometimes, however, you must do this for environmental or management reasons. If this is the case (depending on availability of materials and labor), graveling the trail or a causeway would be my first choices and a turnpike my second any of which will be more expensive in most places than a sustainable curvilinear re-route. You will also incur additional future maintenance costs for the life of that trail.
Q. What if you have a great viewpoint, but it is very steep and virtually impossible to design a curvilinear alignment to get to it and one switchback won’t get you there? My users want to get there, and we want to accommodate their interests. How would you approach this challenge?
If people wish to get to a location, they will go there! If your trail is limited to hikers or equestrian users, steps would be an option. If you have other types of users, a staging area could be developed where motorized or bicycle users could leave their equipment while they take the stairs to the vista point. Recognize that stairs will be expensive and will increase maintenance costs.
Q. For a backcountry trail, what type of material might you use to make it more accessible – if you don’t want to pave it?
A good sand/gravel mix will bind up to make a good accessible surface. If you do not have sand and gravel available, you would have to transport it in which could be expensive. There are also chemical binders available to make a hardened tread, I have not used these but you could do a search on the internet and check with manufacturers.
Q. If I don't have a clinometer, can I just guess the grades?
You could but you would be wrong much of the time. I have been doing trail work using clinometers for 40 years and I cannot consistently and accurately guess grades.
Q. What is the recommended width for a backcountry trail?
The U.S. Forest Service seems to have the best standards for back country trails. For a class 3, single lane, Wilderness hiking trail; they recommend 12”-24”. For all of their design standards go to: www.fs.fed.us/recreation/programs/trail-management/trail-fundamentals/
Q. What do you like for mechanical trail building?
It all depends on the terrain, soil, and use type but for most applications, a Sweco trail dozer in combination with a mini excavator seems to work best.
Q. What do you prefer for the most sustainable types of wood when building wood structures? What are your thoughts on pressure treated wood, especially in situations with contact with water? And pressure treated lumber for wood structures?
I prefer pressure treated wood unless management or environmental concerns prohibit it. Actually, the pressure treating done these days will not leach much into water. If you would rather not use pressure treated wood, redwood or cedar would be my next choice.
Q. What's the difference between a causeway and a drainage lens?
Usually a causeway will have a border of large rocks to contain the fill, a lens does not have rock boarders. Both may use filter cloth to contain the material and distribute the load.
Q. What is the difference between a switchback and a climbing turn?
A climbing turn has a continuous grade throughout the turn and is usually used on flatter side slopes (>15%). A switchback is used on steeper side slopes and has a platform of much lower grade than the approaches at the apex of the turn.
Q. What are some good resources for costing trail projects?
The California State Parks has a robust costing process, contact their State Parks Trail Administrator. Other than them, contact your local park service or forest service folks and see if you can get recent trail contract bid award costs. Professional Trail Builders may be able to help too, contact them through their web site: http://trailbuilders.org/
Q. I see the importance of avoiding aligning a trail on top of a ridge. However, what are your thoughts on developing a trail that dances across and works the sideslope on either side of the ridge top?
I have done this and do not see a problem with this approach as long as the ridge crossing is minimal. You might need to place waterbars or grade reversals near the ridge crossing to prevent water from turning and going down the trail.
Q. Are there particular design strategies (in addition to what you discussed today) that you would use in areas with infrequent, but very heavy rain events?
Not really, follow the curvilinear design principles and the sustainable grade process I outlined and you should be fine.
Q. Do you have any recommendations for maximum trail grade based on soil type?
The process I outlined in the webinar takes in consideration all soil types. Having said that, generally, a sand/loam or a sand/clay mix will sustain greater grades (depending on usage, terrain, and precipitation).
Q. We want to build a trail through a marsh, which is dry most of the year, along a minor levee. We would be clearing and laying down gravel along the level high point of this levee. Is this advisable? It gets covered by slow, overflow water once a year or so.
I have seen this idea work but you will likely have accretion of tread material over time from the water overflow. You might consider a raised boardwalk that is build to be higher than the water overflow instead.
Q. Do you know if the Forest Service is planning an update to the 2007 Trails C & M Notebook?
I have heard of any update in the works right now. You might contact Bob Beckley at Missoula Technology and Development Center.
Q. Any reference book for building trails in tropical areas?
I am not aware of any book specific to building trails in tropical areas but there is a good book out by Kevin Myers called: “Managing Degraded Off-Highway Vehicle Trails in Wet, Unstable, and Sensitive Environments” that should be helpful. You can find it at this web site: http://www.fs.fed.us/t-d/pubs/htmlpubs/htm03712802/page11.htm. Also, American Trails has an extensive list of trail books that may help. Look on the web at: www.americantrails.org/resources/trailbuilding/index.html
Q. When developing your maximum sustainable grade, how do you factor in the distance or length of that grade? For example, a trail that has a 20% grade for 150 feet.
Look to where the trail is beginning to erode and use that distance where the erosion is occurring to shoot your grade. Do this at several locations and take an average of all of them then back off two or more percent to get your sustainable grade.
Q. If trying to abide by ADA guidelines for trail design and layout, there are situations where you are allowed exceptions if they create a "substantial harmto cultural, historic, religious, or significant natural features.” How do you approach determining what "significant" or "substantial" is?
I recommend that you look for ways to make a trail accessible at some level instead of looking for exceptions. Having said that, under the new Forest Service Outdoor Recreation Accessibility Guidelines, departures as you have mentioned are allowed. I would consult with your state historical preservation officer to assure that what you think is a degradation of a natural, cultural, or historic resource really is. [Editor: See Forest Service Trail Accessibility Guidelines (pdf 682 kb) for the language of this topic.]
Q. Are there differences in the trail bed materials/prep that you would do to address bicycle or equestrian use?
These uses do impact trail tread more than pedestrian uses. I would go with a sand/gravel mix that will bind up and withstand the wear if your soils are not suitable. Many places will be fine without extra trail bed materials if you follow the sustained grade and curvilinear trail principles, it will depend on the soil type, terrain, vegetation, and precipitation.
Q. Tell us about challenges involved in building camel trails!
The desert is like a shifting ocean so we recommended the possibility of hardening the high use trails with binders or sand/gravel mix to keep them in one location. The problem was when trails got deep ruts from high use, users would just create a new trail. Having your trails be in locations that have afternoon shade was also an issue because of the high heat. We located trails next to rock formations and small hills for shade.
Presenter for the Webinar: “Building Your Trail Right the First Time:”
John Favro advised the country of Jordan on
building camel trails
The Webinar Instructor is John Favro, a professional trail contractor and former U.S. Forest Service program manager. John retired from the U.S. Forest Service in 2008 after a 35 year career. His last position was Regional Trails Coordinator for the Northern Region. In that position he was the program manager for 25,000 miles of trails in 13 National Forests and Grasslands in Idaho, Montana, North Dakota and South Dakota. He began his work with the Forest Service as a trail crew worker in California and has built and maintained trails in many western states and in Alaska.
In addition to managing ranger districts, John also worked in timber, wildlife, fire, range, and managed trail programs in numerous locations in the west and Alaska. He has B.A. degrees in psychology and philosophy and has completed all course work for a B.S. in Natural Resource Management. He has taught classes on trail issues, construction and maintenance throughout the country and, during the summer of 2006, he assisted the country of Jordan as an advisor on trail and outfitter guide camp management.
John owns a trail consulting company (TrailsGuy.com) and currently does trail survey/design, trail consulting, and teaches sustainable trail building and maintenance, wilderness ethics, and crosscut saw certification. John is also very involved with Backcountry Horsemen. John and his wife, Susan, live in Alberton near Missoula, MT
Read John's article: "Sustainable Trails: doing it right the first time"
CEUs: This webinar was worth 0.10 CEUs but only if you attended the LIVE webinar. We are pleased to offer Continuing Education Units (CEUs) for American Trails webinars (included in the fee) through the Texas Recreation and Park Society (TRAPS), an authorized independent CEU provider through IACET (International Association for Continuing Education and Training). Be sure to sign up in advance for future webinars to take advantage of the CEUs. Check out our upcoming webinars…
You can purchase this archived webinar on the American Trails Online Store