thanks, I liked this project, and started another new project with same idea, however riskier because near house... also found out afterwards much less clay in this area.
Just in case the the raised level isn't high enough I went with concrete 'no bottom' cylinders, at about $5/pc it is worth it. Also helps to keep water and fertilizer where it needs to go, and also from the pig uprooting the saplings. I think they are kind of ugly, but when used uniformly like this, not too bad.
In 5 years I can always break the cylinder and turn the area into a mound once the citrus taproot has gotten in deep.
Mostly all lime, with some special citrus like kaffir, dekopon, texas grapefruit, pink lime, var. meyer, tangerines etc. about 35 cylinders put in. All premium soil mix which is a mixture of mountainous 'sandy' mineral clay and composted manure and betel husk. I may have to cull the dekopon, tangerines, and texas grapefruit, not sure if our wet season will count as a 'chill'
Also all gray water is now rerouted to this water, including overflow from cesspits, dishwater, washing machine, etc. I have planted Thai Hyacinths (reportedly my species is edible), liles, and lotus, and released some koi. The water in the pictures seems very dirty, but pictures taken when just 2 weeks in. The small pond and ditch is now full of tadpoles and koi have survived, I did release about 1 gallon of homemade 'vinegar' aka 'jurinsee' which is full of beneficial bacteria to activate the pond, and now surprisingly with all that gray water I have a very clean pond and currently in the dry season. The basin of the pond broke the water table and is self filling, will never dry out completely. The ditch leading into the pond may dry out completely, but not a big deal. I am not using this water for irrigation or raising any fish to eat.