I have not done anything. I have only about 15 acres maybe (have never took the time to measure it) for 3+ acres of ponds.
I was not planning on doing anything but thinking of your situation and how to solve it, if got me to thinking of mine.
What you could do (and I could also) is put a culvert through your terrace at some strategic point (I could dump mine into another terrace that I built recently that goes south to the creek). Then in normal times just cap the culvert or have a welding shop make a metal slide valve and leave it shut. If the pond was at full pool and large rains were being predicted, a person could open the slide gate and let the water bypass the pond. If it were in an accessible location, a person could even regulate the flow during or in the middle of a rain event. Pond full, go open the gate.
Normally I want all the water I can get as I want some flow through during the spring after a dry summer or fall to get rid of some excess nutrients. But once in a while like now there has already been plenty of flow through, the ponds are full, and do not need any additional water. So the gated culvert through the terrace would divert flow.
A person could even put the culvert 6" or a foot off the bottom of the terrace so some of the water would still flow to the pond but excessively hard rains that had the terrace running fuller could bypass some of the water.
Just an idea. Doubt if I do it, but I think something like that would work for ponds with excessive watershed.
