BOATING ON THE YAMPA RIVER, Dinosaur National Monument. Shooting the rapids is becoming increasingly popular in Dinosaur National Monument. During the summer of 1955 more than 1,000 people made boat trips through the Yampa and Green River Canyons. The most popular type of boat is the rubber landing raft shown. Canoes and other types of craft are used by the more experienced "white water" enthusiasts. The first boat trip through the Green River Canyons was made by the one-armed Civil War major, John Wesley Powell, in 1869.