Off the point of that larger rocky outcropping is 8 feet in the summer drought and 10 feet during the spring rains. There is definitely a spring that seeps out of the rocky outcropping into the deeper park of the pool. I've put a mask and snorkel on and dove in... There is almost a cavern and cuts about 10' feet under that rocky ledge. I think most of my hold over trout hold up right where the chilly spring seep meets the warmer water. Temps in the heat of summer stay in the 66 degree range, however I don't know what the DO levels are. The largest brown trout I stocked this spring was 15" in late March and my dad caught a 21" brown trout in late May. I doubt a non supplementally fed brown trout is gonna pack on 6" in 2 months. So I am thinking at least a few are surviving each year.