Update to this string - I'm just shy of 24 months with the new oversized culvert and all is well. Even with all the big rains we've had this year the new 24" culvert is doing the job. Haven't seen it run more than 1/2 full yet. So my advice to anyone in the planning and construction phase of a pond is, use NRCS to calculate your max size needed, then go bigger than that.

Dale

[Linked Image from i90.photobucket.com]

"When tempted to fight fire with fire, remember that the Fire Department usually uses water." - anonymous