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Ofl2~-:::! disturbed over the 30 year build out period. This means that an average of about 20 acres would be disturbed each year. Initial work for this EIS showed relatively high amounts of soils (52%) in the West Fork drainage that had a high or severe erosion hazard rating. Only nine percent occur in the East Fork drainage. Soils with high or severe erosion hazard will be avoided where possible. On-site erosion can be minimized if appropriate reclamation practices are employed. It is predicted that, as a result of applying mitigation measures (discussed in Appendix A, and more detailed ones to be designed during the Master plan study), the on-site soil loss will be reduced by 90% (Refer to discussion of Table IV-6). It is anticipated that by holding erosion to this level, and by avoiding soils with low revegetation potential whenever possible, soil productivity will not be reduced beyond the "tolerance" level. The reduction that would occur will not significantly impact the ability of the soil to establish a satisfactory vegetative cover for visual or aesthetic concerns, for further erosion control, or for production of herbage and forage for livestock or wildlife. In Stmnary, the irrpacts of development will be substantially reduced, especially for the back bowl area which only has 9 percent soils with a high or severe erosion hazard rating and where no roads will be developed. A small portion of eroded soil, however, will be delivered to stream channels and carried downstream as sediment. Table IV-2 stmnarizes the combined impacts of soil disturbance and subsequent sedimentation for each alternative. There are introduced quantities of sediment fran soil disturbance in close proximity to streams. For the total soil disturbance from the project it is estimated that there will be an increase of 244 tons of sediment per year. Although this amount may seem great it is extremely small compared to natural geologic erosion and sedimentation. (See Water Quality section for more discussion on sedimentation.) Again, for the same reason that erosion was predicted to be low in the back bowl area (no roads, lower erosion hazard, etc.), and sedimentation will be similarly insignificant in the back bowls (16 tons from developnent east of Windy Pass and 228 tons from development on the west side of Windy Pass). Most ski trails, roads and lift lines will be placed on soils with only slight windthrow hazard so little windthrCM is expected. c. Alternative Three The environmental consequences which may be associated with the implementation of this alternative would be the same as those described in the discussion of Alternative T\oIO above, except no development would occur in the back bCMls. :1 157