jsec: Thanks for the photos and advice. The form and poured transition makes alot more sense than trying to use what I had planned (a manhole transition peice). Actually, if I can get access I may try a form and pour-in-place transition. eitherway a 4-6" deep socket is great advice. Hard to see in the last picture but is that the makings of a rebar debris cage on top or did you pour an inlet later? Short of seizmic activity that thing should be there long after we are all gone.

I hadn't thought about ever having to drain mine down. I figured if it silted up I could dredge it from the banks...do people still do it that way or is that risking the seal? I'll have to look into siphon drains to understand how they work.

Thanks,