"The fate of rivers would evidently not be disregarded by Leopold’s watchful eye. In the late 1950s, he and W.B. Langbein initiated what came to be called the Vigil Network, consisting of sections in small s where natural changes would be recorded regularly. Some of these have been operating continuously for half a century, and similar schemes are in operation in Israel and Sweden. Just as productive were some of Leopold’s rafting expeditions down rivers for which he needed depth and velocity data. In 1965, he surveyed 450 km of the in this manner (and again many years later with his distinguished collaborator, the physicist, soldier, and desert explorer ). Besides feeding into the morphometric work, these investigations paved the way for a concerted attack on the problems of and , presaged in a joint study of flood control with T. Maddock Jr. in 1954 and developed with T. Dunne in 1978 and D.L. Rosgen in the 1980s."