Klendathu is another planet.

Some places can't really support trees.

Yep. Water likes to stick to water. If the ground has some moisture already the water is more than happy to go into the ground with all of its other water molecule buddies. If the ground is completely dry it takes more time so it will either pool up or just keep flowing.

That just isn't practical. One of the big problems with dry ground is water likes to stick to other water molecules. They will work their way into the dry soil but it takes more time. A good example is comparing how much more and how much more quickly a slightly damp sponge will absorb water versus a completely dry one. If you were to pour water on both you'll see that most of the water will just run off the dry sponge.

If were to drill out a few holes in the dry sponge it's not going to really change much. The hole itself might become a small reservoir but it won't change the rate of absorption.

This would scale really poorly in the real world. You'd need so many holes drilled all over the place. It would be incredibly expensive and logistically impossible not to mention insanely dangerous. Having tens of thousands of open wells isn't a great idea.