Rosgen Class B3 Forest Reference Stream Monitoring Data

In his book Applied River Morphology, Dave Rosgen describes the B3 Stream Types as “moderately entrenched systems with channel gradients of 2-4%. B3 stream types are typically developed in very coarse alluvial fans, lag deposits from stabilized slide debris, rock-fall, talus, and very course colluvial deposits and structurally controlled drainage ways.” He goes on to say that:

“The channel bed morphology is dominated by cobble materials and characterized by a series of rapids with irregular spaced scour pools. The average pool-to-pool spacing for the B3 stream type is 3-4 bankfull channel widths.”

"The Pool to pool spacing adjusts inversely to stream gradient. The B3 stream type has a moderate width/depth ratio and sinuosity greater than 1.2. Many B3 streams are associated with residual materials derived from resistant rock types or from alluvial and/or colluvial deposition. The channel materials are composed primarily of cobble with a few boulders, lesser amounts of gravel and sand.”"

“The bed and bank materials of the B3 stream types are stable and contribute only small quantities of sediment during runoff events. Large woody debris is an important component for fisheries habitat when available."

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  Click to enlarge Class B3 Stream in Summer 2002
• View a video clip of a Class B3 Stream in Summer 2002

Resources Describing B3 Stream Geomorphology

• Graph showing stream bed particle size distribution - (PDF format; 44KB)

Resources Describing B3 Stream Hydraulic Geometry

• Chart showing dimensionless BKF stage discharge curve - (PDF format; 79KB)
• Chart showing dimensionless hydraulic geometry curves and equations - (PDF format; 127KB)

Last modified: Monday, 10-Mar-2008 15:31:50 EDT