Tuesday, January 30, 2007

On Road Construction-(1) Drainage

After purchasing our 55+ acres in the spring of 2006, I decided that my first task was to construct an access road. A crude road (path) was already there, most likely left from logging, but it was overgrown with weeds and briars and not at all negotiable by even a four-wheel drive truck. There were pockets that were clearly wet; water had no place to drain. My proposed roadbed also went between two slightly raised areas of forest; the roadbed sat at the bottom of a shallow "v". I didn't pay much attention to this discreet topography until I actually started trying to constuct a solid bed for an access road. The process has been very educational and reinforced several principals I had read about in a few books on Permaculture.

I will try to describe what I started with. After leaving a paved road, a crude car path ran through a 2 acre field. The state told us we had to move our driveway entrance due to safety issues (sight distances and travel speed). We had to move this access point to a much more inaccessible area which I will describe later. At the back side of the field the path entered woods and a clear stream crossing with steep banks was evident from a logging operation 10-12 years previous. Beyond that lies a second overgrown field transected by a stone wall. This field was in the early process of being taken over by trees and covered with briars and weeds. Deep skidder ruts criss-crossed this field and went up a shallow grade between two stands of white pine to the edge of a third field. Here the ruts ended when the path opened onto what was once another (fourth) field, now covered in 10 year old popple (quaking aspen) and balsam fir poles mostly. The second field and the shallow upward grade were very soggy. Initially I thought there was a small stream that crossed the path and went through the second field; this was not so. The path in its entirety was about a half mile long.

Shortly after purchasing the land, I bought a 30HP Kubota tractor with both a loader and backhoe. My goal for the first summer was to create a solid, dry access road. We decided to use the existing path as our access road This minimized the felling of trees and removal of roots plus this path was already compacted from previous logging access. At first, I thought that constructing a road would be easy and quick with my nice new tractor. A few days of work tempered my eagerness with reality. I realized that in order to build a good road, I needed to first focus on water movement, both above and below grade. If you read any good book on Permaculture (Permaculture: A Designers Manual by Bill Mollison is one of the biggies in this area of thought), it will talk about exploiting subsurface water movement to grow things. I wasn't yet thinking of growing things but I did need to think about moving water out from under my roadbed and away from it (see the next posting).

So, my first task was to manage the movement of water. Basic physics dictates that gravity rules. I needed to give water someplace to go downhill before I even started constructing a road. It was obvious to me that I needed to construct a drainage swale at the bottom of the shallow "v" grade and through part of the second (wet) field. A swale is basically a shallow ditch with graded sides. It provides just enough of a channel to both catch water and guide it away. A wet spring, followed by a wet summer (and then a wet fall) quickly turned my first task into a mud bath. Tractor tires, while nice and knobby for good traction can just as quickly make a puree out of a wet field. I found myself working the field until it rained again, waiting a week for the ground to dry out (if I was lucky), and then working it again. Yeah, I got stuck more than a few times.
Above is a shot of what the fields look like before their makeover. The weeds and briars were scraped from the field with the tractor blade and were buried. The larger brush was stacked to be burned later. I then used the back hoe to dig a one/two foot deep trench where I wanted the swale to be. The soil from the trench was used to fill in skidder ruts in the field. I then used the loader bucket to create gentle, sloping banks away from the trench. Most of the grading was done by back-blading with the front lip of the bucket. The soil was transported around the field in this manner, filling in the low spots and creating areas which sloped towards the swale. At this point, what had been an overgrown, briar filled field was now all soil. I’ll be the first to admit that I am somewhat of a perfectionist. Once the field was graded, I used an iron rake to hand rake the field. I collected and removed the rocks by hand and seeded with a conservation mix of grasses and clover (the deer love to graze here now). The field was covered with straw to keep the soil from drying out and the seed from disappearing. I now have a beautifully restored meadow. I even threw in some native wildflower seeds to see what would happen (http://www.americanmeadows.com).



Above are midway and after shots of one corner of the field to the left of the road. Note the swale running downhill in the second pic.

I should point out that I didn't resurface the field all at once. I'd get one part graded but another would be too wet to work. I'd rake an area and get fatigued so I'd seed and straw that and move on. So, I did it as I could, in about 6 pieces altogether. The finished section to the right of the road is shown below. Note the drainage swale that starts at the front of the pic and winds down through the field. I have only restored the upper half of this meadow. The rest will be restored next summer assuming things dry out enough. The meadow grew tall after I planted it. I left it this way till fall and then mowed it.


Now that the water had a place to go, I could begin the business of constructing a road.

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