If only it were as easy as painting.(Photo from 12/30/12)
This thread is two years old, and records the last time we did "official" maintenance was done on the Jackson Trail. Since then a majority of attention has been diverted into the construction of the Jim Donnelly Trail. This incurred some sacrifice on other trails, like the Jackson and Grizzly Gulch. Of course one has to acknowledge persistent trail fairies always exist.
Without the work of trail fairies and past efforts Jackson Trail would be in even worse shape now.
We built scores of small drains and dips, and debermed the trail tread in practical places (meaning the labor investment was small). The first things we do to the old trails is make sure that all drainage crossings are sunk in so that flood water doesn't hop out of the gulch and start flowing down the trail. Now, after a series wet winters and maintenance efforts on the Jackson Trail, we are able to see what works and what doesn't. The grade reversals at gulches have worked well. Some need reinforcement now. Small multiple drains don't last, clog, and are overwhelmed. Even the big reversals clog up.
In the photo above, shot into the sun, the trail tread reflects the sheen of standing water. There is a big drain dip by the exclamation point. It has been working to reduce the flow of water below, and the trail below it (where the bike is) is better off for it. The drain is almost completely silted up though, and may cease to function in the future, as water is clearly going over it even in the post strom trickle.
The next photo is of a reversal which Drew Perkins (of Emma McCrary Trail fame) helped us install.
This one is situated just below the approach to the first steep ramp of the Jackson Wall section. There's a drain right at the bottom of the wall. This one is the second water-trap. I wanted to make this a very big reversal. I remember saying something like, "Drew, what we need here is something at least as big as a coffee table hump across the trail at an angle like this (scratches line with mcleod) to stop water for a good while."
Looking down at this drain dip the extent to which the tread below the dip has been spared erosion is evident. Clearly the drain is doing what it was intended to do. It was well sited and robustly constructed.
The bad thing is that the trail above the dip is now deeply cupped, and the berm is formidable.
(Above, the way it looked on 1/30/2010)
I've shied away from massive berm removals because the labor is so hard. The option of cutting gaps, dips, lenses, and reversals into these berms to give water a place to escape is much more attractive when you perceive the magnitude of the excavations in reality.
Diesel and I have had so many discussions about this stuff over the years. Now with Pliebenberg in the mix we have another voice. It would be great to bear motorized equipment upon these problems. It would be great to have more time labor too. In the end, finish hand work is required.
My conclusions after the 2010 trail work season, to be realistic with the amount of labor we have, were that we should be building bigger reversals and rolling grade dips; focus more upon quality rather than quantity of drainage; and take trail maintenance section by section.
Cupping, concave entrenchment of the trail tread, is a general result observed above the dozens of drain dips that have been constructed on the Jackson Trail. In some areas this has become severe. Switchbacks suffer from this as well. Sometimes it looks as though that when the drains clog up, there is an acceleration of erosion, as the the venturi effect speeds up the water and loose materials bearing small rocks scour the trail into a v-shaped profile.
When a drain clogs under an intense rain-storm it forces the water back onto the trail.
Happy New Year!
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