PPT Slide
Notes:
A conceptual model of the regions of various types of channel beds and channel erosional regimes in natural channels as a function of channel gradient and drainage area (from Sklar and Dietrich, 1998, op. Cit). Fluvial bedrock channels occur for relatively high channel gradients for a given drainage area, but debris flows may dominate for very high channel gradient. The red line is my editing of this diagram, with the suggestion that few debris flows occur in large river channels, even with steep gradients.