I am currently in Southern Ecuador introducing permaculture to families here. They live in the mountains and many work on lands over 50% slope.
Currently many of the families are only planting corn here so I want to introduce them to the three sisters...
However on the steep slopes there is a large problem with water retention and run off.
At first I wanted to introduce swales but have read that on steep slopes they are not a viable option.... We are a team of two working by hand so large scale works are not an option. (impossible for machinery to reach some of the land we are working with. )
Any help or suggestions would be appreciated....THANK YOU!
Swales are viable options on steep slopes. Just don’t make them bigger than maybe about a foot deep, but have many of them. The advantage you have here is that if stuff is arranged properly, you can let gravity do your work for you. For example, the Polynesians planted candleberry trees right next to the streams that flowed down the volcanic slopes into their villages, so they would drop the berries, which were used as fuel, into the stream.
I suggest food forest (and just forest) to stabilize the slopes.
Using three sisters is a good start, sunflowers and amaranth are reportedly good companion plants for all of the sisters, as well as being awesome chop-and-drop chickenfeed and bird attractors. You can stabilize the corners and right, left and downhill sides of the garden beds with perennials.
Earthworks are the skeleton; the plants and animals flesh out the design.
Myron Platte wrote: I suggest food forest (and just forest) to stabilize the slopes.
The issue of slope stability is a true issue in these slopes! You indicate 50% slope, which translates to around 45° hillslopes. This is way above the stability angle of unconsolidated material, which is usually around 35°. Such areas are usually very prone to landslides, which can be deadly for people living there. I would think well abouth Swales, since what they do is get water into the ground, further weakening their cohesion and thus might increase the probability of a landslide ...
Water retention on such steep slopes is a big NO-NO. Mostly these slopes found a balance between runoff and infiltration which makes them sort of stable as long as the weather stays within "normal" fluctuations for that area. If you would get an exceptionally wet rainy season the risk of landslides goes up A LOT. Please ask the people living there about these stories, I'm pretty sure they saw a slope or two come down somewhere in the past decades.
General rule of thumb for swales is: only on slopes less steep that 1:3 / 18° / 33% (I hope I got those figures right, I always use the 1:X method when measuring, because that's fast and easy and fool proof :-) ) with as main reason stability. On steeper slopes you can use terracing with retaining walls. Those are a lot of work, more so when the slopes get steeper. On slopes 1:1 you cannot really do much (for every meter horizontal you need to build a meter high retaining wall), except for hoping that you don't get killed in a massive landslide. The pictures below show one on a 1:1 slope. And I have seen WAY worse :-( ...
Since you're dealing with a reality of "this is where poor people live", there might be an option you could try: slopes are seldom totally the same everywhere. Look for areas that are less steep than average, with nobody living right below them (so that if there would be a landslide it won't kill anyone). Generally landslides occur when excess water cannot drain away quickly enough. That builds pressure by weight while weakening the stability of the soil at the same time until the whole or part of the slope gives way, relieving this pressure. To avoid things getting to that point make sure you have an exit channel for excess water. This channel needs to go to an even more uninhabited area! Normally you could use the natural occuring gullies (super eroded in these landscapes) for this. I think people tend to stay clear of those. Like this you can try to build some terraces.
Good luck! People in your area don't have a lot of options so hopefully you can help them improve, even if just a little!
I'll be watching this thread carefully. I've got 4 acres and more than half of it is hill at similar grades. I've finally started in on working on plantings on a specific hill behind the house after staring at it for a year or so. I started here because of all of the California Bays looming over the house both blocking light and threatening to fall on it, as they do often enough. I understand there's a lot of dangers in altering the landscape too much, either in grade or capturing too much water in the soil. I'm taking a light approach and am following established animal trails, establishing them further with timber from trees I've cleared and rock from the area. Then creating small uphill retaining walls for planting dwarf fruit trees, and filling in here and there with interesting native bushes and other plantings like yerba buena, salal, alpine strawberry, huckleberry, creeping manzanita.
The idea is that not only will the hill stability not be compromised, but there'll be a lot of low maintenance fruits berries and herbs growing--the other big issue with hills is just getting up there to tend to things. We'll see if it pays off.
Indeed you have an interesting situation ahead of you.
Can I ask what the # sisters are please?
As I think about your situtation I realise many communities have experience and I can see some ideas are coming along already.
What is the rainfall there ? Because that seems to be one of the causes of land slides.
But when you look at those terraces built in Japan in the photos it will be interesting to see how they are stabalised.
John Daley Bendigo, Australia
The Enemy of progress is the hope of a perfect plan