They are moderately steep streams with gradients from 2 to 4 percent. They usually occupy narrow 

 valleys with gently sloping sides. Riffles are their dominate characteristics, with frequently spaced 

 pools. They are usually very stable unless the stream is flowing through finer soil particles, in which 

 case the stream can be moderately sensitive to channel erosion from increased peak flows. Cirque 

 lakes and the associated wetlands are a minor component of this map unit. 



The riparian vegetation is dominantly Abies lasiocarpa/Streptopus amplexifolius is the riparian habitat 

 type occurring on somewhat poorly drained sites. Abies lasiocarpa/Oplopanax horridum is the 

 dominant habitat type occurring in small pockets of poorly drained soils. 



The nitrogen yield is moderate and the phosphorus yield is high. Exceptions to these ratings are in 

 cirque basins that have a high nitrogen yield and cirque headwall, which are mostly rock and have low 

 nitrogen and phosphorus ratings. All cirque basins have sensitive soils and the glacial troughwalls 

 have sensitive soils where precipitation exceeds 50 inches per year. 



Gently to Moderately Sloping Glaciated Lands - (3467 acres, 5.9% of Big Creek) 



Glaciated lands occur in both valley bottom and upland landscape settings and are primarily composed 

 of glacial moraine landforms. Parent materials are continental or alpine glacial debris with or without 

 volcanic ash surface layers. The soils are underlain by bedrock composed of argillites, siltites, 

 limestones, dolomites, and quartzites. The dominant slopes range from 5 to 50 percent. On the valley 

 bottoms the glacial moraines occur on rolling hummocky topography with slopes that range from 5 to 30 

 percent slope. On the uplands the glacial moraines occur on straight to slightly concave slopes that 

 range from 20 to 55 percent in gradient. These glacial moraines typically occur at the base of glacial 

 troughwalls. The primary soils are moderately deep to very deep with very gravelly moderately coarse 

 and medium textures. The major vegetative cover Is a dense coniferous forest with occasional 

 meadow openings. 



This landform is moderately to highly dissected by 2nd to 4th order perennial streams, with a dendritic 

 stream pattern. The streams usually occupy narrow valleys with gently sloping sides. The streams are 

 characterized by low to moderate entrenchment, low to moderate confinement, and have low to 

 moderate sinuosity. These streams are typically classified as either A or B stream types. The A stream 

 types have gradients from 4 to 10 percent. These are typically straight (non sinuous) cascading 

 reaches, with frequently spaced pools. When they are flowing through boulders (A2) they are very 

 stable with low sensitivity to increases in water yields, peak flows or sediment. The lower elevation 

 flatter streams are B stream types. These steep streams have gradients from 2 to 4 percent. Riffles are 

 their dominant characteristics, with frequently spaced pools. The streambed materials typically range 

 from fine sand to small boulder in size, with gravel to cobble size materials being predominant. Large 

 woody debris is the primary gradient control in these stream reaches. These streams are usually stable 

 unless the stream is flowing through finer soil particles. In which case the stream can be sensitive to 

 channel erosion from increased peak flows. Wetlands are a minor component of this map unit. 



The riparian vegetation is dominantly Abies lasiocarpa/Streptopus amplexifolius, Abies 

 lasiocarpa/Oplopanax horridium, Abies lasiocarpa/Calamagrostis canadensis, and PIcea/Cornus 

 stolonifera riparian habitat types. 



The nitrogen yield is low and the phosphorus yield is moderate from this landform group. Sensitive 

 soils occur where this landform receives more than 50 inches of precipitation per year. 



Mountain Slopes and Ridges - (5360 acres, 9.2% of Big Creek) 



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