Channel pattern and river-floodplain dynamics in forested mountain river systems

摘要: Channel pattern effectively stratifies the dynamics of rivers and floodplains in forested mountain river systems Pacific Northwest, USA. Straight channels are least dynamic, with relatively slow floodplain turnover dominated by old surfaces. Braided most as low 25 years predominantly young Island-braided meandering have intermediate dynamics, moderately frequent disturbances (erosion patches) maintaining a mix Return intervals for erosion increase order braided, island-braided, meandering, straight (8, 33, 60, 89 years, respectively). A threshold lateral migration channel occurs at bankfull width 15–20 m. The likely mechanism underlying this is that larger deep enough to erode below rooting zone bank vegetation. Above threshold, not confined between valley walls exhibit patterns distinguishable slope discharge, slope–discharge domains can be used predict patterns. Meandering braided consistently identified model, prediction errors largely associated indistinct transitions among adjacent plots against discharge. Locations difficult identify accurately current model. predicted spatial distribution reflects downstream decline slope, which correlated declining ratio bed load suspended load. Ecological theory suggests biological diversity should highest where disturbance regime island-braided sustains high habitat successional states through time.