Watershed Illustration

Hillslope flow processes

Hillslope flow processes describe the movement of water within a catchment before it arrives at the stream channel. Understanding these processes are important for predicting how streams respond to rain events, as well as some of the water-quality characterisitcs of the water reaching the channel.

Rain that falls onto the ground during a storm can take one of three basic paths:

  1. it can be intercepted by plants or by hollows on the ground surface, and ultimately returned to the atmosphere by evaporation;
  2. it can infiltrate, or soak downward into the ground; or
  3. it can run off the surface toward the nearest surface water body.