Fundamentals of Rosgen Stream Classification System

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Summary of the Level II Types and Delineative Criteria

This figure illustrates the representative channel cross-section configurations, dominant particle size class of the stream bed materials, and channel form measurements for the full set of 41 Level II stream types. The nine Level I, or major stream types are refined by the addition of six categories of channel materials (bedrock through silt and clay); and by field measurement of entrenchment, sinuosity, width/depth ratio, and water surface slope. The naming of Level II stream types combines the Level I letter (A through G) with the number representing the dominant bed material (1 through 6), resulting in type names such as B3, C4, A2, and so on.

Note that the blank areas in this chart are due to the fact that certain (usually large particle) bed material sizes are not naturally found in combination with certain (usually low-gradient) channel types. Study this summary chart, then click the 'next' arrow below to advance to the next screen and read more about each of the main Level II delineative criteria.

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