Doug,

I'll take a guess...the problem is the crappie. Your pond is way too small for crappie(black, white or purple),unless you can intensively fish/remove and keep their numbers in check...and very few can do that.

I don't see any correlation between stunted bass and your "trickle tube" and that's a term I'm not familar with but assume it is some kind of pipe stand overflow.

It has been reported here that by overstocking predators such as LMB and even HSB you can get the crappie under control...you might want to do a search on crappie and read those previous posts.
Sorry, but you will not find many fans of crappie in small ponds herein simply because of the problems you have described.

As far as your dam situation, hopefully what you are describing as rivers going around each end of the dam are actually natural spillways for overflow. That water should be directed away from the base of the dam in order to prevent serious erosion problems and eventual loss of the dam. That's very important.