Born high in the Carolina mountains and dropping an average of 49.3 feet per mile in its race past the stately woods of Sumter National Forest, for 40 miles this tumultuous (and sometimes disarmingly placid) mountain river separates South Carolina and Georgia. The Chattooga became a sort of national quest after its starring role in the movie “Deliverance.” (For guided raft tours, contact Wildwater Ltd., Box 309, Long Creek, SC 29658.