SWALES are water harvesting ditches on contour. They are extremely useful and an important design element for permaculture designers. During a storm, rain flows downhill, taking precious topsoil with it. Instead of having it run off the site, swales have the effect of slowing, spreading, and sinking the rain directly into the soil. Trees are always planted directly downhill of each swale, so that when it rains and the swales fill up, the rain sinks slowly into the soil directly into the roots of our trees. Here we are in January of 2009 at Explore Prep in East Oakland, diggin' swales at a Planting Justice community work party!
Hard work it is indeed, but the 20 of us were able to dig three 100 foot long swales in just 3 hours! Here are Yuro and James of West Oakland Youth Standing Empowered, with their ninja-focus! The low part of the trench is called a basin, and the pile of dirt directly below the basin is called the berm. The Berm is where we plant our fruit trees.
Here is James, checking to make sure our swales are level. He is using a simple tool called an A-Frame, which is constructed using three pieces of scrap wood and a level and used to mark out contours on a landscape. The level is placed on the horizontal middle part of the "A", and then moved across the landscape to mark out a line that has the same level elevation.
These swales here are one foot wide and one foot deep, and there is about 15 feet in between each swale. The size of the swales and the distance between them depends on the particular slope and average rainfall at a site.
With the swales in, we now can plant our fruit trees, directly downslope from each swale. Here we are a few months later, planting thirty fruit trees with about 80 middle school students at Explore Preparatory. In one afternoon, we planted apples, pears, plums, pluots, nectarines, peaches, persimmons, and apricots!
And finally, check out this video from one of the most impactful Permaculture teachers in the world, Geoff Lawton. He has demonstrated how permaculture water harvesting strategies can create edible oases in even the dryest and most degraded landscapes in as little as three years. Check out Geoff Lawton's work here: http://permaculture.org.au/