Most successful water catchments for dry climates?

Hello all. In Spain they love stripping the earth bare so that everything is leached out and rocky clay is exposed to the sun. The whole country is slowly becoming desert due to this and many other poor land/water management practices. My husband and I have a small parcel of land that is open with plans to turn this into the productive food forest I know it can be. I know the different phases and techniques I want to pursue for the property but for the water collection at the trees I'm unsure of which method is best. It is likely I will experiment with the existing almond trees and see what works best but I'm curious what other people have been successful with.

Here are the ideas I'm contemplating: Creating swales for water catchment and then on the ridge where the tree is located create hugelkulture beds -or- dig around the tree to create a basin so that runoff from the swale sinks into the tree roots as well -or- pile a bunch of rocks around the base of the tree -or- a combination of these. I will be sheet composting, mulching and have chickens. But first I need to plan water use and earthen works.

Thoughts?

Welcome to permies, Eleisia!

Sepp Holzer did some work in your region, so reading some of his stuff on ponds and hugels might be useful for you. Hopefully some of our dry-lands permies will have good info for you and some threads to read.

I'd certainly also do some research on companion planting so that you know what to start to provide support for the trees you want. Even if you feel you can only do so on a small scale, it can help. Last fall I planted a small "rescue" apple tree in a dry spot with no soil and gave it a Seabuckthorn friend (nitrogen fixer) and some Egyptian Walking Onion for an herb level. The poor tree is barely a foot tall, but it's put out lots of leaves so I'm hopeful it will grow. I also dug a big hole - bigger than intended, but that's another story - which I filled with compost. I will theoretically be able to add fresh compostable matter there to add some gentle moisture although at the very least I can pour a bucket of water over the pile and that water will soak down to root level, rather than evaporating off the top.

Seems to me, like hugelculture is a technique best suited to damp climates that have an occasional dry spell. They don't seem effective to me in areas that are consistently dry with an occasional damp episode.

What works best for me in the deep desert is small little bunds... Catchments less than a foot tall that can capture runoff and allow it to sink into the ground. Being small, it's easy to make lots of them. Searching for  "Net and Pan" will give lots of results for this type of water catchment. The technique is to make tiny little ridges (net) in the ground that channel runoff to pool (pan) near the roots of a tree.

I typically make the nets out of the native dirt. They only need to be perhaps 3 inches high. I might make the pans as deep as a foot, adding a spillway from each pan that is armored with stones to prevent erosion. I typically start small. As the system matures, fine dirt and sand fills in the bottoms of the nets and pans. This is easy digging dirt that can be easily scooped out to increase the height of the bunds over the years.

Eleisia,

Swales is the most common answer to your problem.  However, unless the property has a lot of slope, swales might not be the key feature to combat dry soil.  As you pointed out, stripping the land to bare earth is the issue.  My property was bulldozed to bare earth, then overgrazed about 4 years before it came to me.  I have been repairing it ever since.  If you have large rain events, swales might be appropriate.  If you have smaller events, keyline may be the best solution for you.  With either approach, keep in mind that getting life back into the soil after it has been abused is the single most important act you can take to combat abused earth.

(If I have done my conversions right)  Every 1 mm of rain over a hectare, will deliver 10,000 liters of water.  Approach the question from this perspective:  "Am I getting enough water annually; or am I not keeping enough of it in my soil?"  If you get adequate rain fall, then I would focus on de-compacting, hydrating with keyline, and raising the organic matter percentage of the soil with fine rooted cover crops. before investing in the expense of earthworks.  Raising the organic matter of your soil by 1% (in the top 30cm) will allow the soil to hold an additional 200,000 liters per hectare.  That is a lot of water to put back into the soil and be available for trees.  This can be achieved without terraces, swales or earthworks.  Putting life, fine roots, and plants back in the soil is your biggest tool to recover soil, if you have adequate rainfall to start.  

We have several water catchments of different types that we use.  For remote locations we use something like these:





When looking for picture, I saw this unique idea:



It looks like it is better than hauling buckets!

Anne Miller wrote:

It looks like it is better than hauling buckets!

On damaged, bare ground, having water pour from a height like that last picture may do more harm than good. I would want to dig a pothole that could get filled with mulch or compostables, or put a half-buried pipe or bucket with holes in them, add a flexible hose to the water tank and fill those. Then the water would be deeper, nearer the roots and less prone to surface evaporation.

We're in the wet-dry tropics, which means we get a bit of every type of weather every once in a while. It goes from heavy tropical downpours, to drizzle and all in-between, from months without end of blue skies and scorching sun, to weeks when we're fogged in without getting much rain at all. Our terrain is mountainous, with some semi flat areas and with some steep slopes. So our approach is: a bit of everything...

We started with swales and dams, but they are only helpful with those heavy downpours (for us about 30 mm per hour or more qualifies as those). We had a lot of heavy rains our first year, and then suddenly only some in the years after. The dams have only been full for 2 out of the 6 years we've been here. Without heavy rain we don't get a lot of runoff, so we needed a more diverse approach.

We chose terraces as our main approach. They work absolutely great with both small rains and the big storms. Surprisingly that's mainly because digging these terraces loosened the soil and broke up impermeable layers so now it takes up the water better. We do need to keep them mulched, because bare soil will close up again and then we get runoff again instead of infiltration. Downside of terraces is the amount of work! Backbreaking when done by hand! But worth it in my view. Or you bring in an excavator, they can make terraces very quickly, but you have to stay on top of the operator so he doesn't compact your terraces driving all over them! Let him figure out how to do it with only driving over the slope once, before shaping the terrace!

The garden needs a more regular supply of water, especially during the dry season. We are now experimenting with digging in half-rotten tree trunks about 20 cm under the surface of the garden beds. These seem to increase the amount of moisture the soil holds. If you try this, please make sure that excess rainwater in case of big storms can flow away, so you don't create pools which might make the logs float to the surface. We also placed our chicken coop next to the garden to catch the water from the roof in a couple of big tanks. These tanks we will also give a roof soon to keep them out of the sun and increase the catchment area to fill them quickly with the mild rains we so often get. From these tanks we water the garden during the dry season.

We never tried keyline ploughing, because our terrain is quite difficult and we prefer the terraces because they make working (mowing weeds) easier than on slopes. It's a one time job to make them, so we slowly continue with that.

Jay:

Thanks for the welcome on my first post! Sepp does come up a lot so I will look into his work. I have known about companion planting for ages and already have a list and notations on my plantings. ;) I also plan to start by planting natives to build the land and set up for the success of my production plantings. Sea buckthorn is an excellent plant! I'm excited to put one in. Sounds like you are trying to give that little apple a fighting chance!

Joseph:

Spain does get a surprising amount of water, it's just that people do not have good catchment or harvesting practices of said rainwater. In fact there have been huge flooding problems in the Mediterranean coastal regions I'm sure due to that. We have family in Languedoc in southwestern France (very similar climate) that have an excellent permaculture garden that advocate hugel which is why I want to give it a go. I think it will take much longer to break down in a long dry summer then in a more moist climate but could still be very beneficial. Just not going to put a mound of branches, a row so that the top doesnt dry out. That's an interesting concept you employ, I will do some more reading on it. It's very similar to what I had in mind that I was adapting from swale concepts.

Jack:

That's some good advice there. I believe there is enough water, but it needs to be conserved to provide throughout the summer. I think with enough shade and building up the layers on top of the soil along with creating water catchments that are essentially glorified ditches. My focus is primarily repair the soil for sure. I want to do lots of thoughtful planting to help the soil recover and do so in stages.

Anne:

I was thinking of placing an area for relaxation under a metal roof to serve a duo purpose, but most importantly of rain catching. ;)

Rene:

Thank you for sharing, I enjoyed reading about the variety of methods you employ. I think that truly is the best approach, trying a bunch of techniques and seeing what works best for your exact conditions. I think burying logs is a great idea. Will you be green mulching? Also do you have a layered canopy?

Eleisia,

Welcome! Thanks for doing one thing so few do--listing your location so we can know where you are located and the climate you are dealing with.  I'm afraid I don't have the expertise you need so I'll sit back and learn from the ones who do.

Good Luck!

Bryan:

Yeah of course! Everyone's projects are going to be very micro climate specific so sharing that is a really important detail. To elaborate on the project we plan on developing a food forest that will supply food not only for us but for our future Cerveseria. Serve as an example to teach others about soil and water conservation/restoration. I surely post in other forums as we continue to work on/develop projects. See you there. ;)