I had to drain and lime my forage pond last fall because baby BG and LMB had swam up the one inch deep water from the main pond during an overflow, and had grown and decimated ALL the FHM. It's probably going to be a yearly thing if it floods in spring; pump it down to a 8 foot wide six inch deep puddle, net everything out I want to keep, and throw about 10-15 pounds of hydrated lime into it.