Environmental Assis for Orono Substation Expansion

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Although tourism does not comprise a major portion of the economy in the immediate project area, Baker Park Reserve does offer camping and other recreational uses that might be considered tourism destinations. Impacts to recreational uses in the Baker Park Reserve are discussed in Section 5.9. According to United States Geological Survey topographic maps the nearest mining resource, an inactive gravel pit, is located approximately four miles east of the Project. Because no existing gravel, rock, and aggregate resources are being mined within or near the project route itself, no impacts are anticipated. Because of the number of transportation resources, presence of residential areas, and the Baker Park Reserve, it is unlikely that the discovery of currently unknown mineral would result in development of such resources for extraction. Mitigation Measures Because no impacts to agricultural, forestry or mining resources are anticipated, no mitigation is discussed. Potential impacts to tourism are related to recreational resources, mitigation measures are discussed in Section 5.9. 5.11 Geology & Soils Bedrock in the project area varies from 100 to 400 feet below the surface. The project area is underlain by Cambrian sandstone (MnDNR, 2011). Soils are formed in deposits of glacial till left by the Des Moines lobe. The soils in the project area are predominantly poorly drained hydric wetland soils of the Klossner, Houghton, and Muskego associations (Xcel Energy, 2011a). No geologic impacts are anticipated from the Project. As excavation for foundations for both the substation and transmission structures would be approximately 25 feet. Based on preliminary grading plans for the substation site, Xcel Energy estimates that grading would require approximately 15,700 cubic yards of cut and, depending upon the dimensions of a berm that may be constructed at the substation site, between 3,800 and 6,100 cubic yards of fill (Xcel Energy, personal communication, November 18, 2011). Temporary short-term disturbance of soils would result from site clearing and excavation activities at the substation site and structure locations, pulling and tensioning sites, setup areas and during transport of crews, machinery, materials and equipment over access routes (primarily along transmission right-of-way). Construction activities can increase erosion by removing vegetation, disturbing soil and exposing sediment to the elements. The eroded soil can quickly become a sedimentation problem when wind and rain carry the soil off the construction site and sediment is deposited in surface waters unless stabilized. In addition to erosion, the hydric soils in the project area are susceptible to compaction Mitigation Measures Typical conditions of a high-voltage transmission line route permit require the applicant to utilize erosion control techniques throughout the duration of the project to achieve vegetation establishment and, ultimately, final stabilization. HVTL permits also typically require that contours be graded so that all surfaces drain naturally, blend with the natural terrain, and are left in a condition that will facilitate re -vegetation, provide for proper drainage, and prevent erosion. All areas disturbed during construction of the facilities must be returned to their pre -construction condition. Environmental Assessment PUC Docket E002/TL-11-223 Page 44