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<br />!Jrj?~(5 <br /> <br />the recelvmg stream <West Fork, San Juan River) is at the <br />highest yearly discharges due to snowmelt runoff. Much <br />smaller urban runoff storm loadings are anticipated during <br />July, August and September when the West Fork discharge is <br />lower. It is inportant to note that these urban runoff <br />estimates are potential loadings assuming no mitigation <br />measures. Proposed urban runoff mitigation/detention <br />measures, many of which are described in the 404 Permit and <br />Mitigation Plan Submission (Design Workshop, Inc. and J.T. <br />Windell, 1984) would reduce loading below the amounts shown <br />in Table IV-5. These proposed mitigation measures include <br />detention ponds, revegetation of disturbed areas, streambank <br />stabilization, construction drainage control, and a storm <br />drainage control plan. <br /> <br />Sewage treatment for the Wolf Creek Valley base area would <br />occur in a wastemter treatment plant that would initially <br />discharge (Phase Il 200,000 gallons/day in the West Fork of <br />the san Juan River. Ultimate discharge at full build out <br />would be about 1.5 million gallons/day. Taranto, Stanton, <br />and Tagge (In-Situ, 1986) used the QOAL2E Model to evaluate <br />the effects of this discharge on the West Fork of the San <br />Juan and cOrnp3re to water quality standards for the san Juan <br />River (Colorado Department of Health, Water Quality Control <br />Division, 1982). No waste quality control exceedances would <br />result from the private land developnent in Alternative One. <br /> <br />An impact not taken into consideration in Table IV-5 is the <br />dredge and fill operation presented in the 404 p;rmit <br />application. Approximately 37,600 tons of dredge and fill <br />will occur in some of the Riverine Wetlands associated with <br />the West Fork of the san Juan River and some Palustrine <br />Emergent wetlands on the bench above the river. This f ill is <br />primarily coarse rock riprap for streambank stabilization, <br />bridge abutments, roads and fill slope protection, soil fill <br />into wetlands to create dry areas for the golf course, and <br />some fill for residential construction (Design Workshop, Inc. <br />and J.T. Windell, 1984). Some additional sediment (Table <br />IV-5) will occur in the West Fork during construction phases <br />which include dredge and fill although this sediment would be <br />temporary. Stabilization of the strearnbank segments with <br />coarse rock riprap could reduce streambank source sediment <br />below existing levels in the segments. <br /> <br />1 <br />1 <br />.1 <br />I <br /> <br />1 <br />I <br />I <br /> <br />2. Alternatives Two and Three <br /> <br />The primary additional water quality effect of JI~tematives <br />Two and Three is sediment fraT! the ski area developllent on <br />Forest lands. Given the small amount of suspended sediment <br />and discharge data available to date, it was difficult to <br />establish baseline sediment rating curves for the Wolf Creek <br />Valley watersheds. Regional data for the Central Rocky <br /> <br />173 <br />