Monster, another good thing to remember is that if the river is wider then normal, its shallower, what you are looking for is a narrow spot which acts like a funnel bringing food and current ( which go hand in hand) I might add that a sharp turn is just that, a really narrow spot. Look on the web for aerials and that alone will show you the turns and where most of the holes are.
To find depth, use a sinker and count while its falling to get an idea of howdeep it is. or the slip bobber method, going in 1 foot intervals until you figur eit out, a lot of this will happen with experience where you will be able to look at aspot and determine where the deep holes are.
Most river based on size, watershed, elevation drop and sediment load will have a consistant depth for the mjority of the deep spots. On the GMR from south Dayton to Middletown is about 18-20 feet. If you fish the GMR above Dayton you are looking at about 10-12 feet deep as the deepest spots in the stretch. its all reletive to the water you are fishing.
I suggest a lot of time on the water to figure out where the channel runs and follow it from bank to bank seeking the deepest spots within the channel. This is one of those things that only years of experience can teach you vs just having someone explain it to you
Salmonid