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IRIS <br />MITIGATION AND DESIGN, INC. <br />SCHWARTZWALDER MINE PHASE 1 - UPSTREAM CUTOFF WALL AND LOW FLOW BYPASS <br />PIPELINE - BIOLOGICAL ASSESSMENT <br />Permanent impacts to previously disturbed PMJM riparian habitat total 0.14 acres of riparian area on <br />either side of the road crossing (see Figures 7 and 8 and Table 8). There will be approximately 0.02 <br />acre of permanent impact on the west side of the cutoff wall due to riprap installation and <br />approximately 0.12 acre of permanent impact to previously disturbed riparian area on the east side due <br />to the aforementioned boulder drop structure and riprap, which will transition down into Ralston Creek. <br />5.4 Bypass Diversion Pipeline, Staging and Access Area Impacts <br />The remainder of the proposed temporary bypass pipeline work for Phase 1 includes placement of <br />approximately 3,500 linear feet of 18 -inch low flow pipeline aboveground along the north side of the <br />existing access road through the Site. Additional items that will cause temporary impacts to previously <br />disturbed and undisturbed PMJM riparian and upland habitat include installation of the proposed 18- <br />inch low flow bypass pipeline, establishment of the dewatering discharge location, gravelling of staging <br />and stockpile areas, and equipment access to and around the work area (see Figures 7 and 9 and <br />Table 9). These activities will have only temporary impacts to previously disturbed and undisturbed <br />PMJM upland and riparian habitat. <br />Of the 4.27 acres of proposed temporary impacts to uplands, the majority of impact (3.55 acres) will <br />occur on previously heavily impacted upland area that is not considered PMJM habitat. This area <br />includes the access road itself and areas north and south of Ralston Creek around the Site center <br />where previous mining activity has heavily impacted the upland areas (see Figures 2 and 3.) These <br />heavily impacted areas are not considered PMJM habitat due to lack of appropriate upland vegetation. <br />Of the remaining 0.66 acre of proposed temporary impacts to PMJM upland habitat, the majority will <br />occur on previously disturbed upland areas (see Table 9). The majority of the temporary impact to <br />uplands occurs around staging areas where the uplands have been previously impacted but grass and <br />vegetation growth has rebounded to some extent. In addition, the proposed low flow bypass pipeline <br />will cross some previously disturbed upland area on the north side of the existing access road where <br />the road is too narrow to install the pipeline. Of the 3,500 linear feet of pipeline placement along the <br />road, approximately 640 feet will be placed across the previously impacted upland area located on the <br />north side of the road. However, the pipe will be installed aboveground and have minimal impacts to <br />the PMJM habitat. The pipe will be removed and the area restored to preexisting conditions once this <br />bypass pipeline is no longer needed (at completion of Phase 3 when the 100 cfs Temporary Diversion <br />Pipeline is also decommissioned). The low flow bypass pipeline will cross into previously undisturbed <br />upland area in a few locations, totaling 0.06 acre of impact. These areas will be restored to preexisting <br />conditions once the pipeline is removed (see Figures 7 and 9 and Table 9). <br />Page 30 August2011 <br />