The small channels that collect runoff from rills are sometimes called concentrated flow channels, because they collect and convey the runoff from a number of rills. They may be in the valley of a small watershed, and hence may have a lower gradient than the rill system feeding them. The question is sometimes asked as to how large must a rill be to be classified as a channel. Rills receive their flow from smaller rills as well as a great deal of flow from inter-rill areas. Channels largely receive inflow from point sources (rills), and while discharge and sediment concentration are affected by the hillslope characteristics, empirical and process-based channel models are based primarily on channel characteristics, separately from hillslope configurations. Detachment, transport, and deposition processes can all take place within a short reach of channel.
Was this article helpful?