The Dirt on Sustainable Trails
Moving dirt is a big part of creating sustainable trails. No one knows this better than Steve Thomas from Terra Firma Trails (pictured above in a mini-excavator). He has been working with FOW for nine years on various projects related to the Sustainable Trails Initiative (STI).
We sat down with him just before National Trails Day on June 4 (see a gallery of volunteer photos below) to learn more about the process of closing down an unsustainable trail and cutting a new, sustainable one. He has been working on a 100-foot section of the White Trail between Kitchen’s Lane and Mt. Airy Avenue. This was the site of FOW’s volunteer work on National Trails Day. We will be doing more work on this section of trail on Saturday, June 11. Click here to volunteer for this workday.
Want to learn more about what FOW does and why? Read excerpts from our conversation below!
Q: FOW has done a lot of work at Kitchen’s Lane over the years. It was one of our Merck sites [Wissahickon Stormwater Mitigation and Sediment Reduction Project, 2010-2011], and we closed trails that had turned into gullies and rerouted other trails. What are we doing now at this site?
A: This is the other side of Kitchen’s Lane, between Kitchen’s Lane and Mt. Airy Ave. What we’re working on is the White Trail, and we closed the existing trail because it was so eroded and getting wider and more and more roots were exposed.
Q: Is this the trail that runs along the creek?
A: It is the main trail above the creek. So not the small trail right along the creek, but the one up from that, which is the White Trail.
Q: Why is FOW closing this trail?
A: It is unfortunately in bad shape all the way to Livezey Lane. It needs far more work that what we’re doing now, but this is a piece of that. As part of the STI plan, the south side of Kitchen’s Lane was taken care of, so now we’re working north and trying to piece everything together.
We’re closing the old trail; it is actually closed now. It’s done, and been restored, and the new trail has been built. On National Trails Day, volunteers will be working on the finishing touches–so trimming the roots and just raking out the trail. Next week it should officially be open.
Q: How have you done this work so fast?
A: I’ve done this for a long time—and using the equipment, of course, in the professional industry, and FOW also uses its machines. Everything had been flagged out a month ago or more, so we knew what corridor we were working with.
Q: This trail runs farther up from the creek, out of the flood plain, correct?
A: Not far above the original trail, but definitely above that, about 50 feet.
Q: What was so bad about where it was?
A: It was too steep. It was not sustainable with the grade. And unfortunately, once a root or a rock is exposed, people have a tendency to walk around that, and then another rock or root is exposed and they walk around that. So in some spots the trail was probably 15 feet wide.
Q: And that is encroaching on habitat?
A: Yes. Of course there is more barren ground that easily erodes; the vegetation was completely gone.
Q: This wasn’t a fall-line trail, right?
A: It was on a steady grade, but for a sustainable trail you try to keep it less than an average of 8% grade, and this was pushing 20% in some places. There was a structure [similar to a boardwalk] that was built a number of years ago that was supposed to be part of the trail itself, and it was made out of 4x4s and it was completely falling apart. The surfacing material within that structure was long gone and washed away some time ago. So people were not even using the original trail tread; they were 10 feet below it.
Q: How did you close the old trail? What are the steps involved?
A: With the old trail, it’s using the excavator and scarifying the tread and breaking up the compaction so it actually has a chance to revegetate. And then pulling in organic material, so all the old organic material cut from the new corridor, went to the old corridor.
Q: So you carry along seeds to the old trail corridor?
A: Exactly. So it’s all native, we hope, and then any trees or big logs or anything like that, I use the machine or drag it over by hand over the top of the organic material to keep people out.
Q: What kind of machines did you use to cut the new trail?
A: A mini excavator. We cut with that. And then I used the FOW ditch witch with a blade and just fine tuned the tread.
Q: On National Trails Day, volunteers will be doing detail work. What does that entail?
A: It’s basically trimming the roots. When you build a new trail, there are unfortunately roots everywhere within the hillside. So you need to go through with loppers and trim the roots back and make sure that both your back slope, which is the uphill side of the trail, is laid back at a grade so that when water comes down the slope, it gently comes down your back slope across the tread, and then down the outslope of the trail.
If you keep that vertical edge [created when the trail is first cut], even though we don’t see water in a hard rain event actually coming down the slope because of the organics [plants], once you’ve opened up a bench for the new trail, you will actually see water pouring out of the organics and it will drop directly onto the trail if you kept the vertical edge and erode the trail away. So we make it a smooth transition.
Q: From vegetation to trail?
A: Yes. So it’s mostly trimming roots, and a lot of it is aesthetics, but it does make a difference in the longevity of the trail.
Q: In the past, FOW has had to do some challenging work in order to make the trail sustainable. Are you having to do anything like that on this section of trail?
A: This trail is an easier fix. There is definitely some corridors within the park that for one reason or another we have to stick with the original alignment, and for that reason we have to use structures such as roman pitching [stacking stones side-by-side] or retaining walls or steps, and it becomes much more involved. This trail is pretty straightforward.
Q: What about the trail you closed? Are there plans to do planting there?
A: I think so. The hope is to give it a chance to settle in, then on another volunteer day we may plant saplings.
By Denise Larrabee, FOW Editor/Writer