chapter 3 fundamentals of fluvial geomorphology and stream ...
chapter 3 fundamentals of fluvial geomorphology and stream ...
chapter 3 fundamentals of fluvial geomorphology and stream ...
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Other more ambitious <strong>stream</strong> classifications have beendeveloped by Neill <strong>and</strong> Galay (1967), Rundquist (1975), <strong>and</strong>Rosgen (1994). These classifications go well beyond a description<strong>of</strong> channel form to include description <strong>of</strong> l<strong>and</strong> use <strong>and</strong> vegetation inthe basin, geology <strong>of</strong> the watershed, hydrology, channel bed <strong>and</strong>bank materials, sediment concentration, channel pattern, <strong>and</strong>channel stability.Rosgen (1994) presented a <strong>stream</strong>-classification systemsimilar to the earlier Rundquist (1975) system. Rosgen (1996)included classification <strong>of</strong> valley type <strong>and</strong> introduced anentrenchment ratio, defined as the ratio <strong>of</strong> the width <strong>of</strong> the floodpronearea to the surface width <strong>of</strong> the bankfull channel. Table 3.5is a summary <strong>of</strong> delineative criteria for broad-level classificationfrom Rosgen (1994). Each <strong>of</strong> the <strong>stream</strong> types can be associatedwith dominant bed material types as follows: bedrock – 1, boulder– 2, cobble – 3, gravel – 4, s<strong>and</strong> – 5, <strong>and</strong> silt/clay – 6.Table 3.5 – Summary <strong>of</strong>Delineative Criteria for BroadlevelClassification (Rosgen1994)StreamtypeEntrench.ratiow/dRatio Sinuosity SlopeMe<strong>and</strong>er belt/bankfull widthDominant bedmaterial*Aa+ 2.2 >12 >1.4 < 0.02 4.0 - 20 1,2,3,4,5,6D na >40 na < 0.04 1.0 - 2.0 3,4,5,6DA >4.0 2.2 1.5 < 0.02 20 - 40 3,4,5,6F 12 >1.4 < 0.02 2.0 - 10 1,2,3,4,5,6G
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