That is what most of ours look like that I have swapped out or replaced.
I've been needing to have some buried control valves located for years . . . I found a couple, but there are still some that I never knew about and have grown over. Haven't been able to use our sprinkler system because of it. I haven't really wanted to pay the $300 or so I was quoted to find them.
I didn’t bury it, but I repaired a lot of irrigation pipe from 1/2” to 4” lines. It probably averaged 12”-18” deep for most of the small stuff.
If you have access to one open end of the line you can buy some 18 gauge stranded copper wire and poke it into the line then locate with a metal detector.
i would also bury the new lines with the same wire outside and on top of the line for the same reason.
I've thought about digging to try and find the lines but just haven't messed with it in a long time. I have a handmade drawing that shows approximate locations that I used to find a couple of valves, but the valve boxes were about 7" under the surface. Those I have found on the other side of the yard are right at the surface. I think there are at least 4 more valves that I need to find and replace gaskets on . . .
