Rivers are exposed to changing environmental conditions over multiple spatial and temporal scales, with the imposed environmental conditions and response potential of the river modulated to varying degrees by human activity and our exploitation of natural resources. Watershed features that control river morphology include topography (valley slope and channel confinement), discharge (magnitude, frequency, and duration of runoff events), sediment supply (volume, caliber and frequency of sediment delivery), and vegetation (riparian communities [bank strength, roughness] and in-channel wood debris). River stability and response to changing environmental conditions are highly dependent on local context (channel type and associated degrees of freedom; the nature of the imposed sediment, hydrologic, and vegetation regimes; imposed anthropogenic constraints; and the legacy of past natural and anthropogenic disturbances).
Buffington, John M. 2012. Changes in channel morphology over human time scales [Chapter 32]. In: Church, Michael; Biron, Pascale M.; Roy, Andre G., eds. Gravel-Bed Rivers: Processes, Tools, Environments. Chichester, UK: Wiley. p. 435-463.