Rosgen Class A2 Forest Reference Stream Monitoring Data

In his book Applied River Morphology, Dave Rosgen describes the A2 Stream Type as a "steep, deeply entrenched and confined stream channel associated with faults, scarps, folds, joints, and other structurally controlled drainage ways." He goes on to say that:

"Land forms supporting A2 stream types include canyons, steep side slopes, talus fields, glacial moraines, lag deposits, and coarse colluvial deposition." The slope of class A2 streams "ranges from 4 to 10%, producing channels that exhibit step/pool bed features."

"The sinuosity is low < 1.2 as is the width/depth ration (< 12). Width/depth ratios greater than 12 can occur where larger boulders contribute to channel bed and bank stability."

"The A2 stream type is a high energy and low sediment supply stream type, with corresponding low bedload and transport rates. The channel bed and stream banks are normally stable and contribute little to sediment supply."

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  Click to enlarge Class A2 Stream in Fall 2001
  
  
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  Click to enlarge Class A2 Stream in Fall 2001
  
  
• View a video clip of a Class A2 Stream in Fall 2001

Resources Describing A2 Stream Geomorphology

• Graph showing stream bed particle size distribution - (PDF format; 92KB)

Resources Describing A2 Stream Hydraulic Geometry

• Chart showing dimensionless BKF stage discharge curve - (PDF format; 10KB)
• Chart showing dimensionless hydraulic geometry curves and equations - (PDF format; 39KB)

Resources Describing A2 Stream Turbidity

• Chart showing rising limb dimensionless NTU as a function of discharge - (PDF format; 25KB)
• Chart showing falling limb dimensionless NTU as a function of discharge - (PDF format; 68KB)

Last modified: Monday, 10-Mar-2008 15:31:40 EDT