Key lines with a walk behind tractor

Hello people,

I love P.A. Yeoman's key line design and the idea of storing vast amounts of water in any landscape. I have been working on the landform with an old backhoe but my next idea is longer term maintenance. Our property is in a canyon and it doesn't make sense to run a big tractor over it long term. If I was really cool I would use a mule but my best next thought is to use a walk behind tractor with one shank like on the key line plow.

Any thoughts?