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 4-103 are located near wetlands (Erickson et al. 2005; Faanes 1987; Anderson 1978). Large, heavy-bodied birds with longer wings (i.e., herons, cranes, swans, and pelicans) tend to be less maneuverable than smaller birds and can be more susceptible to collision with overhead wires (CEC 2002; APLIC 1994). Bird movement patterns in the area are not known, however, migrating waterfowl arriving and departing from Nunnally Lake could collide with this route segment’s transmission line and structures, including overhead grounding/shield wires. RDFs include installing bird flight diverters in locations with known avian mortality through collision with transmission line infrastructure. Route Segment 3a is expected to have no identifiable impacts to waterfowl or aquatic bird species. With the implementation of RDFs, impacts to waterfowl and other aquatic birds is anticipated to include 1.0 miles of moderate and 24.2 miles of low impacts. An area of basalt cliffs and bluffs along the south edge of the Columbia River and another area of cliffs and bluffs on the north side of the Saddle Mountains provide nesting substrates for raptors. Several nests of prairie falcons have been documented at both locations. Within one mile of the route segment, a peregrine falcon nest has been documented on the cliffs along the Columbia River (approximately 300 feet from Route Segment 3c) and a golden eagle nest has been documented on the Saddle Mountains cliffs, approximately 0.8 mile from the route segment. Potential impacts to raptors would occur from biological disturbance during construction activities or from injury or mortality from vehicle strikes or interactions with other equipment used during construction. Noise from construction equipment and general construction activities could disturb and displace individuals during the sensitive nesting period. RDFs to minimize impact on raptors are described in Sections 4.3.3.1 and 4.3.3.2. RDFs include the stipulation that within the breeding season, construction would be avoided within species-specific raptor nest buffers to avoid disturbing nesting birds (1.0 mile for peregrine falcon, 0.5 mile for golden eagle, and 0.25 mile for prairie falcon; see RDFs in Chapter 2). Following implementation of RDFs, impact levels on peregrine falcons are anticipated to be moderate for 2.1 miles, impact levels on golden eagles are anticipated to be moderate for 1.3 miles, and impact levels on prairie falcons are expected to be moderate for 5.5 miles. Habitat disturbance associated with Route Segment 3c would be located within the Occasionally Occupied Habitat MU for Sage-Grouse (58.9 acres), Expansion Habitat MU (17.9 acres), Regularly Occupied Habitat MU (10.5 acres), and land not designated as a Sage-Grouse management unit (34.5 acres). Construction activities would disturb less than one percent of Regularly Occupied Habitat (Table 4.3-7). Anticipated ground disturbance includes 52.7 acres of suitable Sage-Grouse habitat, 28.8 acres of marginal habitat, and 40.3 acres of unsuitable habitat (Table 4.3-8). With the implementation of RDFs (Sections 4.3.3.1 and 4.3.3.2), the scale of disturbance and degradation to Sage-Grouse habitat is anticipated to be low for 14.8 miles and moderate for 10.4 miles. Construction of Route Segment 3c would require an estimated 186 structures, of which 119 structures (64 percent) would be located greater than 0.25 mile of an existing transmission line (Table 4.3-5). Approximately two percent (3,231 acres) of the JBLM YTC 95 percent population range is within four miles of Route Segment 3c (Figure 3.3-4). No active or inactive leks are known to occur within four miles of this proposed route segment (Table 4.3-6). Impacts to lekking Sage-Grouse associated with the construction of Route Segment 3c are anticipated to be low for the entire 25.2-mile route segment. 4.3.4.11 Route Segment NNR-2 Approximately 12.1 acres of long-term and 12.6 acres of short-term disturbance would occur through the construction of Route Segment NNR-2. All short-term disturbance and most of the long-term disturbance for this route segment would occur in habitat that has been disturbed in the past and is currently dominated by rabbitbrush, exotic annual grasses, perennial grasses, and developed areas, such as agricultural and residential areas (Table 4.3-4). The remainder of long-term disturbance will include 4.4