Special water-sport sandals or just plain canvas sneakers are fine. Thin mountain air and water reflection can add up to a nasty sunburn. Apply sunscreen liberally. Also a hat is a good addition. If you want to take a cooler, make sure it's a small one.
Larger ones can damage a raft.
Leave your Rolex watch and diamond bracelet at home. Less is more on the river. Don't litter and respect private property along the river. Materials contained within this site may not be used without permission.