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9.2.2 Create Additional Wetlands <br /> Based on the site-assessment work completed by CDPHE and ABC, the existing <br /> wetlands area appears to be at least partially effective in reducing the concentrations of <br /> some metals in the adit discharge. Additional wetlands areas will be constructed in a <br /> ponded depression immediately adjacent to the toe of the existing cover over the fine- <br /> grained tailings below the former mill area. Wetlands will also be constructed along the <br /> existing, normally dry ditch along the south side of the Swan River valley down to the <br /> existing wetlands area. <br /> The created wetlands will be supplied by water from existing surface-drainage patterns <br /> as well as likely inflow from groundwater within the dredge tailings along the south side <br /> of the valley. The existing depression and ditch will be filled with clayey soils obtained <br /> either from on-site borrow areas or from off-site sources. The area will be raised above <br /> the existing grade but graded to match the existing slope on the north side and the toe of <br /> the covered fine-grained tailings on the south side. The toe of the covered tailings may <br /> need to be re-graded to match the wetlands area and minimize erosion. Topsoil will be <br /> placed throughout the area and graded rough to create microtopography conducive to <br /> water retention and species survival. <br /> Plant communities will be established to match the existing wetlands and to be <br /> compatible with the climate and topography of the area. The created wetlands will be <br /> planted with plugs of water sedge and large-leaf bur avens (Geum macrophyllum)on 2- <br /> foot centers. Plugs from the existing wetlands area may also be transplanted to better <br /> match the existing vegetation. <br /> Construction of additional wetlands will provide additional treatment area for residual <br /> seepage out of the covered fine-grained tailings and discharges from the main existing <br /> wetlands area. This will further reduce the dissolved-metals mass entering the aquatic <br /> environment along the south side of the Swan River valley. <br /> 9.2.3 Divert Swan River <br /> The main channel of the Swan River currently flows along the south side of the valley <br /> upstream of the IXURoyal Tiger site. A series of beaver ponds partially block the <br /> channel at a location about 300 feet upstream of the IXURoyal Tiger site. A small <br /> culvert beneath the current access road allows a portion of the flow to move into the <br /> dredge tailings on the south side of the valley adjacent to the site. The main channel <br /> trends north out of the beaver ponds, across the valley, and crosses the access road <br /> near its intersection with Tiger Road. <br /> The portion of the Swan River flow that currently moves through the culvert along the <br /> south side of the valley adjacent to the IXURoyal Tiger site will be diverted to the main <br /> channel along the north side of the valley. This will be accomplished by installing a <br /> check dam at the point where the existing culvert allows flow beneath the access road. <br /> An outflow channel approximately 225 feet long will be excavated from the beaver ponds <br /> to the point where the main channel of the Swan River flows along the north side of the <br /> valley across from the site. <br /> Based on GPS measurements collected by Summit County personnel,it appears that <br /> the check dam can be constructed less than 10 feet high, and likely no higher than the <br /> existing access-road grade. The channel will be sized to carry maximum flows <br /> determined through an engineering analysis of the drainage upstream of the point of <br /> diversion. <br /> IXURoyal Tiger VCUP Application Page 24 of 33 <br />