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Vantage to Pomona Heights Chapter 4 230 kV Transmission Line Project FEIS Environmental Consequences PAGE 4-97 degradation, as described in Section 4.3.3.1. Impact levels to habitat are expected to be low for 16.5 miles and moderate for 5.2 miles (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 3b would require an estimated 181 structures, of which 160 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 3b, potentially suitable habitat is present for 66 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 3b include critical habitat for bull trout, Chinook salmon, and steelhead; occurrences of striped whipsnake, night snake, sagebrush lizard, loggerhead shrike, American white pelican, black-tailed jackrabbit, pallid bat, and regular concentrations of chukar, mule deer, waterfowl, and common loons; and a breeding colony of black- crowned night herons and great blue herons. Basalt cliffs and bluffs provide nesting substrates for raptors and several nests of golden eagles, peregrine falcons, and prairie falcons. Bald eagles nest and winter within one mile of the route segment. The Hanford Reach supports the larger of the only two remaining healthy naturally spawning fall Chinook salmon populations in the Columbia River System (Nugent et al. 2002). Route Segment 3b parallels the Hanford Reach for 2.7 miles to the Priest Rapids Dam. No structure or road construction work would occur directly within the Columbia River. For the Columbia River crossing the structures would be approximately 200 foot tall lattice steel structures for the up to 2,800 foot crossing. Impacts to Chinook salmon from the construction of Route Segment 3b could include increased erosion, sedimentation and elevated turbidity. The potential for impacts would be minimized by implementing RDFs that apply and maintain standard erosion and sediment control methods. Specific erosion and sediment control measures and locations would be specified in the SWPPP. These may include straw wattles, straw bale barriers, and silt fencing which would be placed at construction boundaries. The implementation of RDFs is anticipated to be effective at minimizing impacts. Impact levels are expected to be low for the entire route segment. 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 3b 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). Aside from the Columbia River, 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 structure 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, and sagebrush lizard have been documented within one mile of Route Segment 3b. Potential impacts to these three species include direct habitat loss, indirect habitat loss or