in Trailbuilding and Advocacy

Thought I'd compile several helpful trailbuilding links. I've referenced the IMBA site in the past but they keep the themes pretty high-level in hopes of selling the trailbuilding textbook. Anyway, here are the best things I've been able to find:

• IMBA - 10 Trailbuilding Mistakes http://www.imba.com/resources/trail-building/10-most-common-trailbuilding-mistakes
• IMBA - An Easy Way to Toughen Trails http://www.imba.com/resources/trail-building/easy-way-toughen-trails
• American Trails.org - design elements of sustainable contour trails http://www.americantrails.org/resources/trailbuilding/MAsustain.html
• American Trails Trailbuilding Handbook - all around trailbuilding handbook

Does anyone else have any good trailbuilding resources to link to? Either design techniques (how to lay out the trail) or construction techniques (ex. how to bench cut)?

Great post Brendan! I especially like the Easy Ways to Toughen Trails link. I have referenced it many times myself. All of these are great ideas to keep in mind anytime someone is out doing trail work or design.

The basic rule once a trail is built: Do everything you can do to get the water off the trail as soon as possible! Wish there was a quick line on Nicks, Rolling Grade rises, etc.

Does anyone else have any good trailbuilding resources to link to? Either design techniques (how to lay out the trail) or construction techniques (ex. how to bench cut)?

You hit the root level of resources I use, and I have some books.

I'll try to describe an important way to deal with fall line and slope. It's often a problem where one does not consider all of the total climb you're making, where the fall line is, and the slope you're using. It's why I have my homemade surveyor's sticks.

When you have clinometer keep stakes or a person above you so you can know that slope and do not just make a reading of slope at the angle where somebody is climbing.

Also consider the way grade reversals and varying pitch can be part of your total slope. You can fix water and riding problems if your total run might be 5% but have sections twice that and negative slope within.

I will add that people often underestimate cutting bench not cutting high and deep enough for the final result. Very often a partial bench cut needs cribbing to be sustainable. I'll take a spade or one of our flat square shovels and start a deep cut well above where most would think is needed and leave the flag at edge of solid part of the tread. This can be done with a rogue hoe or pulaski but many do not realize how much dirt has to be moved or how unstable the dirt they move might be.

Add to that - corridor prep. For much of Pokerville we had a 10 foot wide corridor prepared before we ever cut tread. This has really paid in two ways. That wide corridor makes it much easier to adjust where you cut for best flow vs compromise, and it adds up to a few years of less maintenance work. The time and effort for using the WeedWrench is very much worth it.

One of the weakest points in the IMBA approach to trail building in my opinion is their way of building switchbacks, their rolling crown design.

While their design apparently works well, the amount of labor and materials needed to build the massive turning platform makes it likely that once you try it you will work hard to avoid building one again. My question to you trail builders out there: can anyone show me a location in the lower Midwest where someone has actually built a rolling crown switchback? Maybe DeWayne has done one with his Ditch-Witch?

This resource:

http://www.scn.org/sbtp/swbk-defex.html

took me about a week of casual reading and several email exchanges with the author to make sure I understood what he is trying to say. It's not an easy read, but it lead me to realize that the option that IMBA casually dismisses as a "climbing turn", with subtle modification, is actually the way that professional road builders make switchbacks.

I tried to build a rolling crown switchback on the east side of Over Lode. After putting in about 80 hours (mine + others) of work, and still having nowhere near enough retaining wall or dirt, I ran out of time and just left it partially finished. Then I read (and reread) the link above.

I put a curb log across the middle of the turn to prevent people from shortcutting it. Since the rest of the turn was already a correctly designed (non-rolling crown) switchback, the job was done. The new approach saved me at least another 20 hours of labor, and I'm very happy with the result.

It's difficult to describe a 3-dimensional structure with words, but the difference between what IMBA refers to as a climbing turn, and a properly designed switchback is while a climbing turn simply makes a loop over the surface of the slope, a switchback is cut into the hillside across the trail's top leg, and the spoil is used with a small retaining wall to build up the lower leg of the turn.  As a result, in a switchback, the section of the turn that is aligned with the fall line will have a shallower slope than the fall line. If the trail leading into the upper leg of the turn is correctly designed with a grade reversal, the combination of reduced slope and grade reversal make the turn resistant to erosion from water damage and wheel slippage.

Another difficulty with the rolling crown design is the presence of the raised crown in the turn forces the designer to concentrate the elevation change into the trail legs leading in and out of the turn. Because the turn is typically being built on a steep slope, it becomes necessary to carefully plan the trail leading into and out of the turn to accommodate the crown in the middle of the turn. It's easy to get well into building the turn and suddenly discover that the slope of the trail leading out of the turn is unacceptably steep. Time to build a ramp, requiring more fill dirt. To be fair, an experienced builder, unlike myself, would be less likely to have difficulty with this point.

It's fairly easy to imagine that this sort of construction might use more dirt than was mined from cutting the upper leg of the turn. It's also possible that the options for getting the dirt to the work site might entail either running a line of wheel barrows up and down the hillside on the singletrack you just built, or making a borrow pit nearby (I've seen this discussed on MTBR) . Ask William how the property owners at Black Hawk feel about the borrow pits made during the construction of some of the dirt jumps out there.

This isn't to say IMBA is wrong and I have a magic pipeline to the truth. It's just that their labor estimates seem to me to be on the optimistic side, and there is an easier, more effective way to do the job.

Walt

Agreed Walt. From discussions with Dewayne on the Beer Run Trail he has made the true rolling crown switchbacks on projects before. The labor and material estimates made my eyes pop. Something like 130+ hours of labor for each one, with a machine! You will notice that Beer Run has four Inslope Turns with retaining walls on it The difference on a 45 degree slope being 8-10' retaining walls vs. 4' retaining walls.

Although it's short and sweet, there's a neat one-page article in this month's Popular Mechanics about building pump tracks, it has a couple nice tips.

The basic rule once a trail is built: Do everything you can do to get the water off the trail as soon as possible!

Besides being good for sustainability, this also means you can get out on the trails sooner after it rains! More riding time!

I and 19 other volunteers built a rolling crown switchback in central Texas on The Goodwater Trail with no motorized machine, and it took 140 man hours.  All our rock was sourced within wheel barrow distance, as was the back fill and soil.

The rolling crown switchback isn't the only solution to turns on slopes; a descending/ascending turn can work, and, as Tom stated, insloped turns can be built sustainably, too, with proper qualities above, at, and below each turn.

Dewayne

I think many will agree that if it can be avoided a properly constructed switchback is avoided due to the high cost of doing it right. What we know of as switchback in most cases are poorly designed climbing turns that break all the rules of trail building. With that said I'd love to build a couple of rolling crown switchbacks sometime just to have the experience of doing it.