EIS Arapahoe & Roosevelt National Forest, Pawnee National Grassland

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CFiapter 3- Affected Environment and Consequences , f t 1 Table 3-7. Rosgen Stream T ype Classification 1 Channel Ctassification 'Generai Description. :. :°: : : . .. ... . -Generaily steeper headwater streams -Usually located in confined valley "A" type channels -Very low sinuosities and width/depth ratios -Often characterized by large substrate size -Most resistant to change from disturbance -Lower gradient mid-elevation streams -UsuaNy located in more open valleys °B" type channels -Moderate sinuosities and width/depth ratios -Variable substrate size -Moderately resistant to change from disturbance -Generally flat low-elevation streams -Usually located in broad valleys "C' type channels -High sinuosities and width/depth ratios -Smaller substrate sizes -Very susceptible to change from disturbance Source: Catena 22(3): 169• 199, 1994 Each of these stream type channels is further delineated with a numerical scheme, (1- 6), with the size of the substrate varying by number. The largest substrate (bedrock) is "1" and smallest substrate (silt, clay) is "6". By using this standardized classification system, it is possible to type streams based on charac- 'pristics and to compare those streams with reference streams. Reference streams are those in which the watershed has had no disturbance or a known amount of disturbance, or the stream channel is representative of a stream without disturbance or of a known disturbance. When comparing streams in disturbed watersheds to reference streams in similar undisturbed watersheds, it is possib{e to detect eifects of the disturbance on the stream channel. In addition to using reference stream comparison, the Forest also limits disturbance in individual water- sheds to tolerance levels which will safeguard watershed potential from effects of land manage- ment. - Watershed Improvement Needs Watershed improvement planning is the process of watershed problem identification, cause and effect determination, and resource coordination necessary for developing a plan to improve the watershed condition. The most effective applications for this type of planning include entire watersheds or subdrainages within watersheds. The entire watershed is preferred because it fits within the concept of ecosystem management. Supplementaf Table S-2 shows the projected projects that are planned to be completed over the next decade by altematives. The Forest is presently averaging about 180 acres a year of watershed improvement projects. Affected Environment Watershec9s The Forest has been delineated into 143 prescription watersheds using a standardized numbering system code developed and coordinated with other federal agencies. These water- eds range in size from approximately 1,000 acres to 20,000 acres. Watersheds are mostly ?n-level watersheds but may be 5th- or 7th-level to meet the acceptable size requirements 3-36 Routt National Forest - E/S (WateNRiparfan/Wetlands)