I have an area between some trees that pools with water due to our clay soil. A local arborist mentioned using this technique of these deep, narrow holes in a grid pattern. It will avoid bothering the roots of the trees and should hopefully hold a similar amount of water to just digging a regular French drain.
However, not sure what tool to use for this. He mentioned using some sort of 3 feet pry bar I think? Would that work?
I don't think an auger will work… the holes will be too wide.
Also, what type of gravel do you guys think will be best for this?