Native peanut tree planted 2 years ago
I started to dig a long, shallow trench by hand yesterday, with a mattock and rake. While it's incredibly slow and hard work, there is little chance for mistakes to be made. I gently chisel away at the earth until a shelf is formed to catch the rainwater when it does arrive. It's the basic cut and fill principal, but the shape of the swale has to run exactly on contour, or it will drain water down hill again, rather than capture and hold it - which is what we're aiming for.
This is just the first swale I've dug for this area...I plan at least two more.
North facing slope receives full sun - picture taken in AM
Above, is what the slope looks like without swales. It gives perfect drainage, which means a lot of "constant" water is required to keep this area moist - not present at the moment. The poor plants I've been attempting to grow, always struggle during this period. With the implementation of regular swales down the slope however, it will prolong the natural irrigation it does receive with each rain event.
The swale plan is this..
Earthworks are carbon friendly, as they're dug by hand
It may take a while to dig by hand, but the best part is free labour with no associated fuel costs. Unless food counts - but I was planning on eating anyway. I've noticed the cut and fill on contour, makes for navigating the slopes a lot easier too. This will be very handy the older we get! David has already killed two domestic mowers in six years, cutting the grass on these unforgiving inclines. Hopefully we'll be able to put in more trees (this is our bush-tucker area) so the canopy shade will gradually out-compete the grass.
One of the complimentary ideas with swales is planting trees below them, so they'll be fed nutrients and watered from the swale above. It's kind of like an irrigation pipe made out of sculpted earth. No plastic hoses or extra water tanks required. That makes my bank account, much happier!
It just goes to show that even when you do have slopes, they can be tamed. Not only is it good for the owners, but it's also sensible land management - giving nature a helping hand along the way. All you need is some hand tools, a basic plan and a little (okay, a lot!) of sweat.
How did you figure out the contour? I think it's the lack of familiarity with the terminology but I have not understood this aspect of Permaculture as of yet.
ReplyDeleteApparently you can make something out of wood (like a triangle) to get the exact contour, but I like to do things by eye. That's why the hand method works for me. Laser levels are generally used if machinery is involved.
ReplyDeleteWhat contour really means are points plotted on a graph to determine the "flat". Have you ever seen those contour maps which look like squiggly circles? A hill or mountain is often represented by rings to show the highest point. When I cut to contour by eye, I'm looking to make a flat area from a sloped one.
I wouldn't recommend doing large areas if you weren't confident, but there's no harm in experimenting with small areas. If you have a tree which struggles in dry conditions, do a very small swale about 1-2 meters above the tree - it can be a trench as small as a metre long. Then when it rains, see how it fills with water.
Because we don't cut very deep, it's easy to cut to contour by eye. We observe how the water is held in the area after a good rain period, and make small adjustments if needed. My rationale on the matter is, nothing was growing well (all natives) so I'm hardly going to hurt anything by experimenting. Because it's small amounts of dirt I'm moving, any miscalculations are small too.
I guess that's the benefit of having little money, because I'll end up with a cut to contour slope with enough time and observation. I'm generally pretty good with my eye gauge, but then we've had a lot of practice digging swales by hand, lol.