Vantage to Pomona FEIS Index 34 - Laserfiche WebLink

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Vantage to Pomona Heights Chapter 4 230 kV Transmission Line Project FEIS Environmental Consequences PAGE 4-95 implemented to minimize habitat loss and degradation, as described in Section 4.3.3.1. Impact levels to habitat are expected to be moderate for the 0.1-mile route segment (sagebrush/perennial grassland). The presence of new transmission line structures, which could provide additional perch and/or nesting sites for avian predators, could negatively impact nearby prey species such as small mammals and avian species, particularly when the new structures are built in an area where perching opportunities currently do not exist (i.e., greater than 0.25 mile from existing structures or trees). Construction of Route Segment 3a would require an estimated three structures, but none of the structures would be located greater than 0.25 mile from an existing transmission line (Table 4.3-5). Within 1.0 mile of Route Segment 3a, potentially suitable habitat is present for 58 special status wildlife species that are possible, likely, or known to occur (Tables 3.3-2, 3.3-3, and 3.3-7). Potential impacts and RDFs to address them are discussed in Sections 4.3.3.1 and 4.3.3.2. Species or wildlife resources that have been documented at specific locations within 1.0 mile of Route Segment 3a include critical habitat for bull trout, Chinook salmon, steelhead, striped whipsnake, night snake, sagebrush lizard, side-blotched lizard, black-tailed jackrabbit, and regular concentrations of mule deer, waterfowl, and common loons. Critical habitats for bull trout, the Columbia River Chinook salmon ESU, and the Upper Columbia River steelhead DPS occur within 1.0 mile of Route Segment 3a in the Columbia River. Tributaries of the Columbia River in and near the Project area are not part of the Upper Columbia River Spring Run Chinook salmon ESU; they are part of the Mid-Columbia River Spring Run Chinook salmon ESU which is not listed under the ESA (NOAA 2013). It is unlikely that spawning occurs in streams within the Project area. Bull trout and Chinook salmon are not known to spawn within streams within the Project area because the streams are too small and not cold enough over a long enough time period to provide suitable spawning and rearing habitat; however, bull trout could use streams for short periods for foraging (AECOM Environmental 2010). No transmision line structures or road construction work would occur directly within the Columbia River. Erosion would be minimized by applying and maintaining standard erosion and sediment control methods. The implementation of RDFs is anticipated to be effective at minimizing impacts to all three species. No identifiable impacts to the three species or their habitats are anticipated to occur through construction, operation, and maintenance of the proposed Project. Striped whipsnake, night snake, side-blotched lizard, and sagebrush lizard have been documented within one mile of Route Segment 3a. An area north of Vantage Substation with rock outcrops and shallow soils is considered an overwintering area for striped whipsnakes and side-blotched lizards occur there as well. Striped whipsnake is rare and localized in Washington. According to WDFW, occupied habitat extends from Highway 26, located north of Vantage Substation, south to Lower Crab Creek. Potential impacts to these four species include direct habitat loss; indirect habitat loss or degradation through spread of invasive weeds or change in fire regime, injury, or mortality due to crushing by construction equipment or vehicles during construction and maintenance activities; and increased predation from avian predators. As striped whipsnake is currently known to occur in one location near the Vantage Substation; impacts to the species or habitat could occur. However, the implementation of RDFs are anticipated to be successful at minimizing impacts to striped whipsnake, night snake, and sagebrush lizard as described in Sections 4.3.3.1 and 4.3.3.2. For all three species, impact levels are expected to be moderate for the 0.1-mile route segment. The Wanapum Pool fall and winter waterfowl area and common loon use area is located within 1.0 mile of Route Segment 3a on Wanapum Lake, just northwest of the Vantage Substation. Eight special status aquatic bird species occur or are likely to utilize the area (as described in Section 4.3.3.2): black-crowned night heron; great blue heron; Clark’s, western, and eared grebes; tundra swan; American white pelican; and common loon. RDFs include installing bird flight diverters in locations with known avian mortality