Craig,
I'm probably a minority of one on this question on this Forum...but you asked to hear other opinions.
Whatever you decide, do have emergency spillway(s). They don't cost much of anything and can provide great insurance.
We usually get 100 year floods about twice a year in my area.
Last year only had one, however. I have 4 ponds of varying sizes with more on the way. None have anything through or in the dam except for good clay. None have ever had a single problem with natural spillways. One pond is an estimated 75 years old. The spillways are as functional today as when it was built....and with virtually no maintenance. Now, I can't say the same about folks I know who have drain pipes.
Perhaps today's materials and installation methods have been perfected to where drains don't fail...I just don't trust them and don't see spending $8000 or more for one.
The argument about removing bottom water seems valid, but a siphon system could do that also. In addition, I would much rather spend my money on the best aeration system I could get, rather than on a bottom drain.
I'm pleasantly surprised to see a NRCS person with similar thoughts....they seem to always push drain systems. Look around at your neighbors, talk to them...both with and without bottom drains. I'd put a lot of weight on their experience. Some areas are not suitable to natural spillways either as emergency or main line. That certainly is a consideration.
I'm just offering another opinion, which you requested. Certainly not interested in another emotional discussion of same. Gather the facts and make an informed decision.
