Rivers are complex natural systems. A classification system is often used to stratify river reaches into groups that share common physical characteristics. A stream classification system provides better communication among those studying river systems and promotes a better understanding of river processes. The river classification system presented in this course is based on measurable physical parameters. The stream classification presented in this technical supplement is condensed from the more detailed version by Rosgen (1994). It is intended for planning purposes, but is not sufficient for design. Appropriate data for use in river classification systems can be obtained from simple measurements and estimates. Topics: Stream Reaches Plan view (planform) type and level I classification Valley types Channel slope—level I, II Morphological description (level II classification) Bankfull discharge validations Entrenchment Channel material Width-to-depth ratio Sinuosity Interpretations and uses of the Rosgen stream classification system Stream management Channel evolution Planning stream restoration measures Communication Prediction Trends and dominant processes