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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 />2.2.5 PMJM Habitat Mitigation Plan <br />The following mitigation measures will be integrated into the Project to minimize impacts to potential <br />PMJM habitat (see Figures 7 through 10). <br />• Phase 1 major construction activities will occur during the PMJM hibernation period between <br />mid- to late- October through early May. <br />• Phase 1 construction activities will be completed within one winter season to minimize potential <br />impacts to PMJM and associated habitat. <br />• The Phase 1 cutoff wall will be located within an existing unpaved road crossing of Ralston <br />Creek to minimize potential PMJM riparian habitat impacts to trees, shrubs, and lush herbaceous <br />understory vegetation. <br />• Approximately 3,500 linear feet of temporary 18 -inch low flow bypass pipeline will be placed on <br />the surface of the existing unpaved access road to the Site thereby minimizing impact to PMJM <br />riparian and upland habitat. Of the approximately 3,500 linear feet of proposed pipeline, <br />approximately 200 feet will be buried below ground just east of the proposed cutoff wall and <br />2,550 feet will be placed entirely within the existing access road. The remaining 650 feet of <br />pipeline will slightly overlap into previously disturbed upland with approximately 100 feet of <br />impact into existing riparian area (see Figure 3). <br />• The cutoff wall has been designed in a location with minimal impact to trees, shrubs, and lush <br />herbaceous understory vegetation. The location, which is approximately 400 feet downstream <br />from the initial planned location, shifts impacts associated with the cutoff wall to lower quality <br />PMJM riparian habitat downstream of the northern waste pile, minimizing impacts to higher <br />quality PMJM riparian habitat near the location where the cutoff wall was originally planned. <br />• All equipment will use the existing unpaved road to access the Site. The cutoff wall location is <br />along this unpaved road and can be accessed from the east. Equipment and materials will be <br />staged on the already disturbed upland area around the Site. This construction strategy will <br />minimize the footprint of impact to the Site (see Figure 3). <br />• All temporarily disturbed upland and riparian areas will be graded to pre- construction conditions <br />including the re- establishment of 6 inches of topsoil to reach final grade. These areas will then <br />be ripped before being seeded with either a native upland or combination transitional <br />Page 13 August 2011 <br />