To plant above, within, or below the swale?

I live in central Washington state, a temperate climate with snowy winters and hot dry up to 100F summers. Sometimes no rain for 3 summer months and the rest of the precipitation is mostly all winter snow aside from occasional drizzles with rare rainstorms. About 25” per year of precipitation. I am building swales across the 2.5 acres with a mattock and shovel.

The greatest philosophical debate within my mind is whether to plant trees and seeds and things on the land uphill of the swale, within the swale, on the berm, or at the downhill base of the berm? So much variety of opinions out there, I’d just like to see what people think for this particular climate.

My goal is zero supplemental irrigation, minimal inputs, play the slow game, and grow high calorie foods.

Looking forward to responses. Thank you in advance.

In my dry desert climate during a thunderstorm, the whole soil surface lifts up, and moves downhill during runoff. Therefore, I don't plant in the bottom of the swale, because I'm constantly moving soil from the bottom of the swale to the berm.

Would it ease your mind to just do all 3? You'd have the bases covered as well as you can for whatever conditions come, with that approach.

Consider the most favorable setting for the type of plant chosen and stick to that for the majority of them tho to try and prevent large losses.

For example, the willows and sycamores I put in the swales have all survived, but I've lost some of those same species in other non-sunken areas because two consecutive rather dry summers.

Shade is a big factor too. Plant some fast growing (or just let the weeds surround) things to protect the baby trees no matter where they are. I also think this keeps mice and rabbits from finding them so easily. For the baby trees planted closer to my dwelling, every so often I pull weeds right around them and use that as mulch, checking for cracked in the ground around them (exposes roots to air, they don't seem to like that) and try to scratch up some soil to fill that in. It really does help to hit with a little water here and there that first and second year if conditions are real dry. I forget where I've planted many, and yes they die but I'm also surprised sometimes when I find one has made it!

Hope this helps, I'm learning too and just trying my best.

Observation might be the key factor.  What happens to your swales when it rains?

We make mini swales after planting out fruit trees, not before.

I hope you will find the answer that you are looking for.

I tried both, before and after, both worked with peach trees. But i'm on a slope and no clay to stagnate water. Otherwise i might have put them on top. Maybe sending a little phone picture could help people get a better understanding