Every time we ride the bike friendly trails in Oakland’s Joaquin Miller Park we would comment on a particularly bad section of trail. It was essentially a mud bog that stayed wet all winter, even when every other part of the trail was dry. It was so bad that a go-around route had been formed by hikers and cyclists that had no desire to play in a swamp. It turns out that many other local mountain bikers felt the same way, so when we teamed up with the Bicycle Trails Council of the East Bay for a trail repair day, there was an excellent turn out.
The BTCEB did a great job rallying volunteers, as well as sourcing the materials we would use to harden the tread. The morning of the trail day, Daniel and I headed down to get a plan into place. Our first item of business: pull all the mucky organic material off the trail, as well as the sticks and logs that lined the mess. Most of the water that existed in the “before” image was gone, and while the surface was still mushy and damp, we were able to see the two well defined ruts running down the trail. The ruts ended up being somewhat useful, as we used one of the ruts as a shoulder to pack our rock into.
When our trail crews arrived on the scene, we went over our game plan for the morning and split up into several different groups. Group one would hike up to the road and transport the chunks of concrete down to the site. Group two worked to clear all the branches and organic matter away and prep the work site. Since the section was completely straight, we laid out a few branches to visualize the entrance line into the section in place of pin flags. (we didn’t have any) Instead of having a completely straight section, our plan was to break it up a bit by placing corral rocks and add some curves.
We also cut a bit more backslope into the uphill side of the tread to minimize erosion and guide water down and over our trail. (We cut our backslope at a standard 45º angle.)
Most of the trail has good flow, and my personal goal is to contribute to making a lot more of this good stuff happen throughout the entire system. (see the previous Flow Country article) To keep riders from straight lining the section, we added a stack of rocks to act as a corral and direct riders into the berm. More bermed turns= more sweetness.
Once we had materials stacked at various points at our site and had excavated a channel to place our stones, the group took a break for a quick rock armoring demo from yours truly. Since we had a lot of cool broken up pieces of concrete, we would be able to do a mix of flagstone paving and stone pitching. We broke up the section into a number of different cells, with keystones set up every 6 feet or so. Since we had a limited amount of concrete, we placed the rock to form a tread 12-18 inches wide, with the anchor stones a bit wider.
We weren’t sure what was actually causing the water to seep into the trail, so we laid down a bed of aggregate underneath our flagstones, and added drains at several points. After we placed our stones we packed them tightly with the small rocks to make the surface as solid as possible. Taking it a step further, we smashed some rock up to pack it all in.
We placed our broken up sections of former sidewalk smooth side down, so that the surface facing up was rough and looked more natural.
We didn’t have enough of the large pieces of concrete paving, we did some sections with a slightly different approach, pitching a number of the stones on their side. (much like a bookshelf-see the piece Inga is holding in the photo above) Since most of the stone is buried and packed as tightly as we could make it, the idea is that it will remain stable, even with the additional moisture from an underground spring.
To keep the entire section from being a complete straight shot and to keep trail users on the hardeneding tread, we placed rocks along the side of the trail at strategic points. The trick was to maintain the personality of the rest of the trail, which has some pretty solid flow.
We only had enough rock to focus on the wettest part of the trail, but we had enough small crushed rock that we were able to pound some into the tread, creating a transition point from straight dirt to the rocked section.
The best part of trail work is riding it afterwords. This section of trail which had turned into a hike a bike around a swamp, was now totally solid and ridable. We finished things off by decommissioning our trail builder line in from the car, as well as the go-around that had been formed on the uphill slope. Note the randomly placed rocks in the above photo and the vertical deadfall. We also disguised our trail work by spreading dry leaves around the side of the trail.
