I had a forage pond built above the main pond, but during this recent flood (10.45 inches in 47 hours) the two ponds merged for two days with about a four foot wide , three to four inch deep canal between them. Fortunately, I didn't have any fish in the forage pond, and no bass yet in the big pond. I doubt BG or CC would swim that small gap in a flood, but I can see possible problems in the future. Eventually, I think I will set up a 1/4 inch hardware cloth barrier.