After mowing a clear strip to the side of my 18' by 400' long runway (with 61' of vert drop, at 5600' ASL) with the L3301 and the flail mower, I rented a trencher (because using the U25, even with the smallest bucket, would have tore more things more then I needed just for 1" poly line) and got to work. No rocks, but this time year the dirt is rock hard, one good thing about the trencher is it pulverized the ground, so easy to backfill, the mini would have scooped up big clumps.
Then after laying the main lines (two circuits, due to my pressure pump limitations and the fall) I went to tie in the first sprinkler (180 degree coverage, 18' of throw, spaced 18' on center) and then realized I'd need to hand dig the required hole for the sprinkler head, as their location is offset from the main line 16". No big deal I figured, a 12" by 12" hole about 10" deep, I just grabbed a shovel.
2 minutes later, and sweating heavily with only a small divot in the ground, I remembered I had recently bought a mini excavator......and it was 94 degrees out, so I got the U25 out and walked it down the line and made short work of it, 21 holes, and I didn't even break a sweat! After the first hole, where the dirt came out in one big solid clump (hard to backfill with) I used the bucket to slice the hole rather then one big scoop, so much easier to backfill.
The runway is not watered by my domestic well, but from a spring about 700' and 80' lower away. The L3301 and the mini were instrumental in first discovering this spring (while I was putting in a mountain bike trail on a steep wooded section of my 40 acres), then digging it out and setting it up. A small solar powered pump pushes the water up into a 750 gallon storage tank in one corner of my hangar, which is good for a good soaking of one circuit. Then a day later I do it again. I can also choose to augment the slow output of the spring in refilling the storage tank with my well, if I want to speed things up. Now, the native grasses won't dry out and get dusty mid summer, especially where I touchdown each time, it will be interesting to see the change after repeated watering versus NO watering.....the sprinklers are pop up type so no hazard running into one. A fun project, and after just a couple days the change is already visible, and audible, instead of the grass crinkling when walked on (dried out) now it's silent and the surface is not rock hard but slightly cushy.