Environmental Assis for Orono Substation Expansion

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The USFWS indicated in correspondence with Xcel Energy that there are no federally -listed or proposed species and/or designated or proposed critical habitat within the action area of the Project (Xcel Energy, 2011a). As of March 31, 2011, no rare flora features have been identified along either route. The natural heritage database search did identify two native plant communities outside of the routes but within the search area (Appendix B-5). Because both routes alternatives avoid known native plant communities and rare plant species, no impacts to sensitive plant communities or species are anticipated. Trumpeter Swans were identified as being within the Project area. The greatest concern with trumpeter swans is the potential for collision with transmission lines, as discussed in Section 5.15. Mitigation Measures The primary technique to minimize the potential for impacts to native plant communities is avoidance through routing. Both Routes avoid impacts to identified plant communities. As discussed in Section 5.15, installation of Bird Flight Diverters can minimize potential for avian collisions with transmission lines. 5.17 Archaeological & Historic Resources Impacts to archaeological resources could result from construction activities along the route and could include: • Damage to surface soils throughout the Project area from heavy rubber -tread or metal - tracked vehicle operation. • Subsurface excavations necessary to remove old wood power poles or install new poles. • Damage to surface soils from dragging heavy objects (e.g., power poles). • Damage to surface soils through grubbing, stump removal and grading. In response to a request from the Minnesota State Historic Preservation Office (SHPO), Xcel Energy commissioned a Phase Ia background research and literature review to better understand the existing archaeological and historic resources that may be affected by the Project (Xcel Energy, 2011a). The Phase Ia report did not identify any archaeological site or inventoried standing structure within either route. No known archaeological sites were identified within the route, and the Phase Ia report anticipated that the potential for the Project to impact undiscovered archaeological sites as low because of the Project's location within the existing Orono Substation site and along existing transportation corridors or in areas already disturbed by residential development. The Phase Ia report did recommend, and the SHPO concurred, that archaeological surveys be performed in two areas within the Project area. As no historic structures have been identified within or near either route, no physical impacts to historic standing structures in the Project area are anticipated. Environmental Assessment PUC Docket E002/TL-11-223 Page 51