The various types of environmental variations which occur in sufficient quantity to provide habitat diversity to support a wide range of species in the stream.
Stability refers to the permanance and erosion potential of the stream banks.
Natural channels which are geologically very stable (e.g. bedrock or very cohesive clay), or artificial channels made of very stable materials (e.g. concrete).
Streams that appear to maintain stable riffle/pool and channel characteristics, but which exhibit some symptoms of instability (e.g. high bedload, eroding or false banks), or show the effects of wide fluctuations in water levels.
Characterized by fine substrates in riffles that often change location, have unstable and severely eroding banks, and high bedload that slowly creeps downstream.
