- August - October '08 Trail Work -
"Donkey Kong"

Yes, a flurry of trail building activity continued with the creation of this trail. I had spotted this portion of the park - quite underutilized and forgotten - as I always do; looking for interesting places. Places with a look or a feel or something interesting about their topography. Like the previous Toby build, this spot is a steep and fairly "useless" hillside. And yet, it is often these spots that are at the same time brimming with character. A small tributary creek - the North Branch - figures in the mix, tumbling along toward the main Jones creek, down at the bottom of this extremely steep slope. Another small forest glade, off the beaten path, feeling as if it is another secret place to spend quality time away from the cares of the world. Feel; check. Interesting topography; check. Hard work ahead.... CHECK!
Here we go with the bench cutting again, right off the bat. The type of forest you are working in dictates what you will be needing to do as well as the grade of the slope. Here, we have a very diverse canopy, but one dominated by Hemlock trees; one of my favorites. They create a beautiful feeling of being in a room with very high ceilings, and very clean floors! Very little undergrowth is present under the Hemlocks, which makes them ideal for all kinds of enjoyment. The other side of that coin is that it sees them invariably covered in a thick "carpet."
This is my own term for the tangle of tiny roots and decaying organic matter that frequent the Hemlock forest. This carpet can range from a general 3-4" thick everywhere all the way past a foot or more depending on how deep the nooks & crannies are.  Since this hillside was chosen partially due to its multitudinous crannies, we'll be benching a bit!
You may note as you walk through Jones that there are many portions of it that seem unusually humpy or hummocky. This stems from a couple of factors. On many occasions, this is as the result of glacial activity, and these hummocky areas are called Ground
Moraines. These are created as the material inside the ice sheet  variously melts and drops in random blobs and chunks, leaving the strange looking uneven surface. These too can be added to by hundreds of years of tree fall, where a root wad from a large tree  raises a large chunk of earth vertically in the air, where it then decays and falls into a pile, creating a hump. This hillside is littered with both sorts of features, just brimming with humps and bumps and shelves and drop offs. Perfect terrain for biking!
As you can see from these pictures, the trail is purposely taking advantage of many of these humps in a connect-the-dots fashion, also at the same time weaving left and right around trees and ditches, all to create a very engaging and energetic ride.
Quite by design, there are large sections of this trail that require no peddling at all if one applies the technique of "pumping" the ground to create speed. It is quite possible to employ this technique from a very slow speed and in the end be traveling amazingly fast, IF the terrain is right. Given enough velocity at some point, a rider can float up the face and over the crest of a hump with little to no loss of speed, landing on the downhill side, and creating further forward velocity by pushing the bike downward - or pumping it - into the downhill slope. There are man made tracks built for this specific type of riding, where the better riders actually remove their
drive chains as a show of their skills, and can generate speeds in excess of 30mph. Mother Nature has very graciously provided just such topography here as original equipment, requiring only the recognition of its existence, and a little smart layout and digging to take advantage of it.
This hillside has finite limits, both created by the property line on one end, and a sheer drop off into the creek on the other. Like on the Toby trail, it is on a steep hillside, although not quite so extreme in very carefully chosen spots. This offers a much better situation, as the bench cutting required is necessarily less in depth. The layout here sees the trail creating 4 separate tiers as it flows back and forth across the hillside, each tier punctuated at its end by a switchback turn. In the case of this overall more moderate slope, the turns can be made wider in arc, and the dirt taken to create the upper portion of the turn is sufficient to build up the lower part without resorting to stone bench building as on the Toby turn.
At right you can see we are bobbing and weaving toward the first switchback turn at the property line. This turn is banked enough that the rider can carry quite a bit of speed around it and maintain it going into one of the most brilliant sections of trail to be found anywhere. The humps, bumps, and jogs laid out to create a perfect rhythm for the rider who can take advantage of them.
At left is the first switchback turn looking back toward the beginning of the trail. A proper switchback downhill turn like this takes on the shape of a light bulb, and that is very much done intentionally. You can see that as you head both toward and away from the turn, you are traveling slightly uphill. Another aspect of building on hillsides that one has to take into account is ground water flow management.
Lay out your trails poorly, and you create nothing but rivers where ground water will collect, pick up velocity, and begin to erode the trail you worked hard to create. The aspect of creating these slight uphill slopes is called Grade Reversal. It's fun to go down hill, of course. Water "thinks so" too. In order to not create rivers, and since water will not flow uphill, you need to reverse the grade of the trail. This light bulb shape is the classic means of doing so in a corner, which is more vulnerable to water flow erosion because of the brief portion of the turn the heads strait down the slope, or "Fall Line" in technical terms. The ground water will accelerate dramatically here. A grade reversal prior to the turn keeps water from up the trail from entering the turn. A grade reversal shortly after the turn is even more crucial. So too is the concept of "Out-sloping" of the trail tread; making the trail surface slightly off camber to the direction of travel so that ground water will sheet gently off the
downhill side of the trail instead of running straight down it to reach the grade reversal ahead before running uphill and off the trail.
All of those twists and turns in the trail are indeed designed to be fun, but are also providing the much needed feature of the Grade Reversal to help manage ground water. As we now exit the previous switchback corner at right, we head into another series of these fun grade reversals. You can see that any ground water here would be flowing down the side slope, onto the trail tread, and then downhill on that tread from both directions toward the lowest point. In this area is where we need to create that out-slope to allow the water to then exit the trail tread without collecting in a puddle. Both flowing and stationary water create erosion of the soil, so a properly built and sustainable low maintenance trail will carefully take that all into account at all times. If the ground does not naturally offer these slight out-sloped shapes, they can be created by subtly creating what are known as "nicks"; artificial shallow low and out-sloped spots for water to gently flow off the trail surface.
If you are getting the idea that proper trail building is an art as well as a science, you win a gold star!
Here at left, the trail takes a sudden and dramatic turn steeply down the hillside for a moment in order to take advantage of one of the largest glacial ground moraine terraces on the hillside. This was a key feature I sought to visit when laying this trail out. You also see the presence of one of our little supervisors that came to visit this new and exciting trail.
This trail friend mysteriously appeared one day to help us warn folks who stumbled on this work in progress that this was an active work zone, and to take appropriate caution.
At this point, we are barely half way across the second tier of this trail, and there are still two more tiers to go before reaching the creek bottom below. About a half mile of energetc and engaging trail packed into less than a quarter acre!
At right we have reached the lowest tier at the bottom of the hill, and are running up against the sheer drop off into the creek ahead. Time to climb back out of the secret creek glade and closer to the light of the main park again.This represents one of the steeper grades on this trail, and yet is immanently rideable because of the third downhill switchback turn and a subsequent swift banked downhill turn section that precedes it. You can see to some extent by the depth of the cut that the hillside is steep. This entire section is rather long, and so to maintain proper ground water flow, it is also slightly out-sloped along its entire length to keep water from running down the tread and gathering erosive momentum.
The picture below much better illustrates just how steep the hillside is, and yet with proper techniques employed, a fun and sustainable section of trail is very feasible.
Above we have exited the creek glade and begun to head out toward the Mud Flats trail and into park civilization again. In case you were wondering, yes, the trail is named for that classic early video game of the same name. I am not a video gamer, and while I know very little of that stuff, I am just aware enough to understand the similarities between the layout of this trail and that game to see that the name is entirely appropriate.

And in case you were not suitably impressed already with the dedication it must take to build such trails, here is even further evidence. Well into the season where daylight wanes early in the evening, the Trail Tribe works mid-week by lantern light in an effort to finish the job at hand. Thereby was completed a very nice section of entertaining single track trail, full of exciting twists, turns, climbs and dives. Just how we like it!
You just knew we'd be getting to the payoff. At left, swooping around the upper switchback corner.
Many of the features utilized here, these many glacial moraine ledges, appear to be pretty hairy stuff. Indeed, you don't want to make a mistake, but if you keep up your nerve and your momentum, and look up the trail where you want to go, they are not really that bad. We call this "pucker factor," and it's what makes a trail really fun. This trail is obviously memorable!
The shot at right more than any other shows the extreme grade of the hillside here. To the untrained eye, such terrain seems useless. And yet as you can see, given the necessary insight, building skills, and the requisite amount of persperation, a visit to a quiet out-of-the-way place, and another memorable experience, can be created!

"Donkey Kong"
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