Here's an oddball question. We have an old concrete manure pit on our farm. It has a shed roof, 2 open side walls above pit, front and back have walls, close to 20'x20' and ~ 8' deep. It hasn't had real manure in it for years. It stays full of water (from rain gutters) and am sure there's some sludge on the bottom. It actually is a little hazardous for critters as we've found possums (who knows what else) dead in there.
What kind of project could I make from this? I've had a few ideas, like raising fatheads/baitfish, or maybe crawfish to eat. I could drain it, and even section it off for some sort of small nursery. I've also thought of making a bomb shelter out of it... It's has some uses, but, as it sits, it is useless. Throw me some thoughts.