Can't say I've dove it. You might be able to get away with it form now until about early April. Once it starts warming up in earnest, the boaters will be out in full force. The bottom, I imagine is mud & decaying plant matter (easily stirred up). The temps depend on the time of year you go. The surface can range form about 80 degrees in mid- late summer down to about 39 degrees this time of year. Below 50ft or so it is about 45 degrees year round. Like I said, I've never dove any lakes, just the quarries & a few strip mine pits, so I'm going off the pit dives. In the pits the average vis was 10ft or less. It's basically almost black water diving. As for the size of the fish, it depends on the species. Bluegill & crappie can get a couple of pounds, Bass can get 3-10lbs, catfish 5- 100lbs. If you decide to go & let me know & if I'm free, I would be glad to join you to explore. Just to let you know a couple of things to be aware of, 1. there's probably lots of fishing wire down there so have a cutting tool with you & 2. you will need to have a float with a dive flag displayed on it to warn any boats to stay away (state law & for your safety, since you will be in a public water way) & 3. there can be a current in areas,as it is a dammed up river. Let me know if you decide anything.