One of the reservoirs I fish let the water out last year to work on the dam it dropped about 20 feet I was amazed at the things you find structure wise. I took a lot of pictures of the "lay of the land" unfortunately they have let more out and closed the boat dock this year but it was really cool to see that kind of stuff. When I smoked way back in the day I used to the old cigarette butt trick. I have had my Garmin a couple of years now and still have a hard time knowing what Im looking at but it is kind of cool.I am a dinosaur I guess. We watch the shore line and the drift of the lake while they let water out. We pretty much know the lay of the land underwater where we fish. Lake Eufaula in Oklahoma is a big lake. Have not fished in all areas yet. Figure now that I am retired and will have a boat next year the fun will begin. Have no interest in the electronics of fishing. Sometimes tossing a cig butt in the water will tell you a lot on where the fish are. I will leave it at that.