I have four days left at Bean Tree Farm. I have been working and reading quite a bit. I also went to the Tucson Gem Show all weekend, which was an extremely visually and energetically overwhelming experience. This past week we mostly worked on water harvesting swales. Swales are essentially dug out basins that collect rainwater and also prevent erosion. In the drylands it is vital to have swales on your land in order to replenish the water table and they also help to water the vegetation. There was a pomegranate tree in the back of the lodge that was elevated above the level of the surrounding ground. We spent two days reshaping the earth to create a water basin for the tree and an adjacent pathway to the compost pile.
Generally the roots of a tree grow as wide as its crown. The lowest part of the ground before we altered it was beyond this point. So the water that puddled in this area was not easily accessed by the pomegranates roots. Additionally the ground sloped away from the tree, which caused further water loss. This area was originally a chicken yard and garden, which is why the ground was not already altered to suit the existing structures and trees.
We used the water level (bunyip) to figure out how the water would flow to that area, which then helped us determine exactly where and how much we should dig. We first removed the the layer of top soil and set it aside to use later. Most ground contains 6 inches to 1 foot of topsoil above a layer of subsoil. For the most part topsoil has organic matter, microorganisms and nutrients (good for growing plants), subsoil is made up of inorganic mineral particles (good for natural building).
Once we dug a large portion of the swale we used the bunyip to fine tune our depth and dimensions. The upslope ground had to gradually decrease in level in order to direct water flow to the swale, any high points could direct the flow away from the basin.
Once we completed the swale and adjusted the slope of the pathway we dug out a spillway on the left end of the swale to prevent any water from coming in contact with the cob structure behind the swale. If the basin got filled, the excess water would flow through the spillway and around the cob wall.
The rocks slow down the water flow and reduce its erosive force.
I am leaving for Mexico in a 8 days! There is a wonderful man living at the earthbag house my family built several years ago. Together we are going to create a permaculture design for the site, which will be a wonderful opportunity for praxis. The first thing we will need to do is make a bunyip and map out the site. The next will most likely be waterharvesting earthworks!
The Tucson Gem Show was quite the experience. It was incredible to see so many beautiful mineral specimens in one place, but I could not help but think about the environmental cost of mining and transporting millions of pounds of rocks to one place to sell for thousands of dollars. I was also curious about who mined them because it did not seem like the people selling them were the ones who dug them out of the ground. There were people from all over the world, and so many different stones. After all it is the largest gem show in the world. Here are some photos…
more photos later…