Euro-American (EA) beaver trapping was a regional and watershed-scale disturbance that occurred across the North American continent. This concentrated removal of beavers altered drainages by creating thousands of localized base-level drops as beaver dams failed and were not repaired. These base-level drops led to the development of channels as ponds drained and water eroded the fine sediment trapped behind the dams (Dobyns 1981; Fouty 1996, 2003; Parker et al. 1985). The speed at which drainages transformed from beaver-dominated to channel-dominated varied as a function of climate, upland and riparian vegetation, and the subsequent land uses. As the drainage network pattern changed, flood magnitudes and frequencies increased and base flows decreased, creating stream systems much more sensitive to climatic variability.