Appendix D Jakabe Restoration EA

Rosgen Types

Rosgen "B" channel types are moderately steep (between two and four percent), and and are common with scour pools irregularily spaced. These types are moderately entrenched (1.4-2.2) - the channel being slightly incised, with moderate width-to-depth ratios (>12) and sinuosity (>1.2). They are found within "V" type valleys with steep or moderately steep to gentle side slopes, usually in forested systems, with substrates ranging from gravel (B4) to cobble (B3). These channel types are characterized by low to moderate sensitivity to disturbance, low streambank potential, and vegetation having a moderate influence in determining channel stability. These areas are important for fish habitat with spawning areas provided by woody material.

Rosgen "E" channel types are lower gradient (slopes less than two percent, but can range to 4%) which are slightly entrenched (>2.2) with low (<12) width-to-depth ratios, meandering (sinuosity is >1.5), gravel dominated channels (E4) with /pools and well developed . Valleys are usually wide and gently sloped with the stream having a relatively wide and active . These channel types are characterized by very high sensitivity to disturbance, high streambank erosion potential, and vegetation having a very high influence in determining channel stability. This stream type provides excellent fishery habitat and is most sensitive to both direct and indirect disturbances. Like Rosgen "E" channels, Rosgen "C" types are also lower gradient streams wich are slightly entrenched (>2.2) with moderate to high (>12) width-to-depth ratios, have high sinuosity values (>1.2), and characterized by riffle/pools. These streams can be found within a variety of types that have low gradient alluvial valleys. Substrates of these stream types within the watershed are dominated by gravel (C4). These streams are highly sensitive to changes caused by and stream flow. These channel types are characterized by very high sensitivity to disturbance, very high streambank erosion potential, and vegetation having a very high influence in determining channel stability.

Rosgen "F" channel types are low gradient channels which are highly entrenched (<1.4) - having a highly incised stream channel. Width to depth ratios are moderate to high (>12) and sinuosity values are moderate (>1.2). Substrates of these stream types within the watershed is dominated by cobble (F3). These channel types are characterized by moderate sensitivity to disturbance, very high streambank erosion potential, and vegetation having a moderate influence in determining channel stability. These areas ofter provide poor fish habitat and are typically areas identified for enhancement work.