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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 />mulched. The seeding and planting locations will be reviewed and approved by the <br />Project Biologist before work can commence. <br />• Approximately 132 riparian trees will be impacted during Phase 1 construction activities. These <br />132 trees will be mitigated for along the restored Ralston Creek once the overall Project is <br />completed (end of Phase 3). <br />• Riparian and upland shrubs will be hand watered once planted and then be irrigated through the <br />proposed irrigation system as described below and in Attachment B of the PCN. <br />• After Phase 1 construction is complete, all bare upland and /or riparian areas will have topsoil <br />added, soil ripped and seeded from the upland, combination transitional, and /or wetland seed <br />mixes (see Tables 2 to 5) depending on the habitat type, and then be mulched /crimped. The low <br />flow bypass pipeline will remain in place to assist with dewatering needs during Phase 2 and to <br />allow for maintenance of the 100 cfs Temporary Diversion Pipeline during Phase 3. <br />• Weed control and monitoring (see Section 2.3.6) will be conducted within the restored and <br />mitigation areas of the project. Weed control will focus on leafy spurge, knapweed, and thistle. <br />Weeds will be sprayed with backpack herbicide application to avoid damaging desirable <br />herbaceous species such as wildflowers. <br />• A temporary irrigation system will be installed to provide supplemental water to vegetation in <br />areas where the alluvial water level may be reduced by the Project and in the locations of the <br />proposed mitigation areas in spring /summer 2012 (see Attachment B of the PCN). In order to <br />have water supply for the irrigation system, a legal water supply for the Project has been agreed <br />on, in principle, among Cotter, Denver Water, the Colorado State Engineer's Office in Denver, <br />and the Division 1 Engineer's Office in Greeley. Cotter will divert water from Ralston Creek <br />under the approved exchange for beneficial uses, including irrigation of riparian vegetation. <br />• Financial assurances will be bonded through the DRMS to cover the costs of project impacts that <br />cannot be mitigated for onsite following Phase 1 construction. These impacts include: <br />approximately 0.07 acre of permanent riparian impact, approximately 0.28 acre of temporary <br />riparian impact, 0.6 acre of temporary impact to previously disturbed upland, and approximately <br />132 riparian trees (see Tables 8 to 10). <br />Page 16 August 2011 <br />