Thanx for the responses. This is a ground water pond so the only inflow is from the watershed. I have never calculated the watershed, I'll do that. There is no dam per se, just a big clay lined bowl; The 4" overflow was added as an afterthought. My initial thought was to use a trencher that cuts 5 1/2" wide trench and finesse the 6" pipe into place. For a little more money I can rent a mini excavator with a 25" wide bucket and lay a larger pipe or 2 or 3 6" pipes side by side. the distance on the existing pipe is about 225' and the proposed route is 250'.
