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<br />"~"~!8 <br />I, ~ lJ C. .:.. ;r. '" <br /> <br />Adverse aquatic effects in the East and West Forks of the San <br />Juan, such as sediment related fish spawning problems or <br />destruction of aquatic insects or algae are not anticipated. <br /> <br />The water quality analysis asstmles that mass wasting would be <br />limited to small slumps and debris flows which would only <br />introduce minor am:lUnts of sediment to stream channels and <br />would be mitigated with revegetation. If a large debris flow <br />or landslide occurs, in spite of the stability monitoring, <br />avoidance of high hazard areas, and phased construction, <br />sediment increases above the am:lUnts displayed in Tables <br />rJ-7, IV-8 and IV-9 could occur. This could consist of <br />debris flow deposits into streams or secondary erosion of <br />mass wasting debris into a stream. Stream channel <br />aggradation (deposition) and widening (Beschta, 19B4) could <br />be expected with temporary sediment yield increases until the <br />channel re-establishes the original geOO1orphic equilibrium. <br />The West Fork watershed has several natural active mass <br />wasting areas which ~riodically input landslide and debris <br />flow deposits to the river or tributaries. The West Fork has <br />been able to "handle" such events, although several river <br />segments are braided with large accumulations of alluvial and <br />colluvial deposits. <br /> <br />d. Floodp1ains and WetJanCls <br /> <br />(1) Alternative One <br /> <br />Develorment in the South Meadow area of Wolf Creek Valley is <br />projected to impact 10.16 acres of wetlands as detailed in <br />Westfork Investment 1 s Section 404 Dredge and Fill Permit <br />application filed with the Corps of Engineers and released <br />for public comment on March 28, 1985 as Corps of Engineers <br />Public Notice No. 8831. Based on the information contained <br />in Public Notice No. 8B31, a discharge of approximately <br />37,645 cubic yards of dredged and fill material would be made <br />into the West Fork of the San Juan River and adjacent <br />wetlands for two bridge crossings, a roadway, r.ortions of <br />four golf course holes, residential develoIlHent and <br />channelization work (see Map 24) . <br /> <br />Potential inpacts to the Palustrine wetlands which will occur <br />as a result of the highway relocation have been assessed for <br />a two-lane highway with a 150 foot right-of-way. Highway <br />designs indicate that the realigned highway will directly <br />impact 3.5 acres of wetland within the limits of fill (40,500 <br />cubic yards of fill will be required). During construction <br />wetland wildlife habitat in proximity to the site will be <br />adversely affected. In addition, heavy equipnent and fill <br />material on the site may result in a short-term increase in <br />erosion. Those areas immediately adjacent to and downslo);:e <br />of the project will also be affected. H<:wever, the wetlands <br /> <br />179 <br />