The only reason why I don't recommend culverts is that they make great catfish spawning habitat and that doesn't align with most pond owners goals. The culverts in 10'-14' water probably won't be utilized in the summer unless you have bottom aeration due to low O2 levels that deep in un aerated ponds.
I gotta agree, I dumped several dump truck loads of PVC waterline into my pond, from 8 to 18" dia, cut into 4' long chunks, the CC are spawning in my pond, probably a number of them landed on end, stabbed into the dirt closing one end off for spawning habitat.
Its probably not the worst thing but am wishing they wouldn't reproduce. although I guess the otters need something to eat.
I love CC for eating but don't get around to fishing for them when there's crappie around. did catch some last yr on jugs with cut BG for bait.