posted 10 years ago
For terraces, it will be more a matter of how wide you want the flat(ish) areas created.
While you are laying that out, you will see how tall your retaining walls will need to be to create the terraces.
In the Andes, the Inca built many terraces, most are from 5 to 10 feet wide.
These all have rock retaining walls and are quite magnificent to see in person, they are awe inspiring when you use the steps carved into the living rock of the mountain.
You described your land lay fairly well, using that information, I would be building terraces from the top all the way down to the point where you have a 1/5 rise over run.
At that point, swales would work pretty well.
My land has a rise/run (on the south face) that is around 1/2 (it varies from 1/2 to 1/4).
I have been putting in hugel swales simply to slow down the water, but these will also be used as the basis for where the retaining walls will be placed when I get to terracing this slope for part of my orchard and vineyard.
The other side of the driveway will also be terraced and those will be where I plant my corn, barley, oats, and other grains.
I have a nice slow slope that faces north and on it, the swales do a much better job than on the south face.
By the way I live on the top of the ridge, since that was the easiest area for building living quarters for us the chickens, goats, pigs and rabbits.