Much of what we know about the functional ecology of aquatic and riparian ecosystems comes from work on regulated rivers (Johnson et al. 2012). What little we know about unregulated conditions on many of our larger rivers is often inferred from recollections of individuals, personal diaries, notes, maps, and collections from early scientific surveys (Webb et al. 2007) and from repeat photography (Turner and Karpiscak 1980; Webb 1996). Later surveys often included photographs typically taken at specific and relatively few locations. Because rivers and their related riparian ecosystems vary in both longitudinal and lateral dimensions, such records provide relatively general and incomplete information about historical resource conditions, especially at large spatial scales and over long spans of time.