Heya Inge
I'm somewhat in the same situ as you are, as some friends want to start some kind of eco-friendly project on Curacao, with Aqua-ponics, for what they contacted me.
Read a few of your posts, and saw you already know about the diabase, the rock and mostly thin layer of dirt on top of it. So if you want deep soils, you will have to ship it in, or create it yourself, but, as it is the tropics, I guess the soils will not get very deep ? Anyway, with this given, swales and other ways to store water in the soil, seems like a not so productive way of water harvesting, I'd see if there could be ways of having a cistern or something like that, big ponds shaded by trees, fish in it to eat the mosquito-larvae. Another thing that comes with the shallow soil is the pipes for cooling ....
ALso, another way of agriculture that needs less water, like aquaponics or bioponics might be something to look into. Especially the use of grey water is something you'd want to look at.
About the coral used in building houses : I don 't know if that is still condoned, but if so, the coral tends to form "salt-roses" (zoutrozen) on the walls, because the salt in it attracts moisture from the air and the stucco swells and flakes off.
I've seen this in old houses built by the dujtch.
There are ways to make bricks from compressed earth. There are machines you can buy, they are made in south-africa, and use the soil, some cement (think about 8%) and electricity for the press, as well as a band of about 7 people to operate them. The compressed bricks have a pretty good strength (think even better then poured concrete) and an added plus is the blend pretty nice with the soil around them.
Then there is bamboo ofcourse ..... I'd try the woven bamboo sheets and cover them with cob, do some experiments with waterglass, kwark, that kind of stuff.
I haven't been on Korsou for about 20 years. When I last was there, it was very dry, only thorny bushes. What I've seen lately on some pictures is very different. It looks pretty lush and way better.
My plan is to "dig" ditches where I want to try and have fish, so the water temperature needs to be as low as possible (because of DO) and have flood&drain beds on top of them. The pumps should be solar operated (pumps are a few euro's each, which will flood & drain about 20 plants (for instance tomatoes) and consume about 5 watts each. Will be setting up a prototype this year, have it run for at least a year and see if I need to change something.
Will probably start with using urine, but when the system is working correctly, will bring in fish or yabbi's.
Anyway, when you go there, we might run into each-other. Will probably be goin this year. Good luck on your project ;o)
Cheers !
