Hi, we work on a community garden in Malaga, Spain. We had quite a few urban market gardens until the town hall decided that the
water they were supplying was risky (since it lacks chlore). Now we are watering 800 m2 with a mere 6m3 of water a year.
In our
city, average rain is 500 mm, with some very intense episodes, so I thought on improving the slot to catch more rainwater. The terrain is a rectangle of 55x15 metres, oriented northwest. The West side is very sloppy, and it already has several
trees (orchard), the flatter terrain is still sloppy, about 5% with a few trees, but mostly wild herbs. The soil is full of clay and compact, but people here don't want to till. Fig trees, olive trees and a carob tree are the best thriving plants around here. We are already making
compost, but at a very slow rate, with worms and a drum composter in another place.
We don't have any money, only hands, a few hand tools, thieves problems and not many people to work on the slot. I think I've found the K point, and feel confident to mark a K line, and my first reaction was to dig a small
swale there, although several problems arise. Since it's not the biggest
land, I wanted the swale to be walkable, even in rainy weather, and this means filling the swale with organic material, perhaps mixed with the clay, and herbs on top
My idea is to have 60cm of walkable swale, 50cm deep, 5m long, followed by 100 cm of terraced beds (I don't want them sunked, since the clay could kill the plants on rainy weather), and repeat the structure downwards. The runoff of the upper swales
should drip to the center of the following swale downwards.
Grave has been suggested for filling the swale, since it's free for us.
My questions.
1. Is it ok to fill it with grave? Otherwise, do we mix the digged silt with organic material, or should we removed all the clay in the swale?
2. How is it better, a single swale with several spill offs or several swales throwing the excess water to the following swale (first to the same in height, then to the lower swales)?
3. We have only mixed a little bit of
compost in the upper layer of the bed, should we mix it deeper?
I'll try to provide pics next time, but if you want to google map it, it is called "Huerta Dignidad" in Malaga, Spain.
Thanks for your help.