Vantage to Pomona FEIS Index 34 - Laserfiche WebLink

Home Browse Search

Vantage to Pomona Heights Chapter 4 230 kV Transmission Line Project FEIS Environmental Consequences PAGE 4-92 approximately 8.5 miles. Anticipated ground disturbance includes 24.8 acres of suitable Sage-Grouse habitat, 31.5 acres of marginal habitat, and 32.4 acres of unsuitable habitat (Table 4.3-8). RDFs are anticipated to be effective at reducing impacts to Sage-Grouse habitat (refer to Sections 4.3.3.1 and 4.3.3.2). With the implementation of RDFs, the scale of disturbance and degradation to Sage-Grouse habitat is anticipated to be low for 13.5 miles and moderate for 4.6 miles. Construction of Route Segment 2c would require an estimated 124 structures in a landscape dominated by low growing grasses and shrubs. An estimated 60 (48 percent) of the new structures would be located greater than 0.25 mile from an existing transmission line (Table 4.3-5). Fifty-nine percent of the Route Segment 2c ROW is within the estimated Sage-Grouse population range, and 29 percent of the ROW corridor is within the core population range (Figure 3.3-4). Approximately 5.5 miles of Route Segment 2c are within four miles of an active lek. The lek is described in Section 4.3.3.3 Sage-Grouse. Potential impacts to lekking Sage-Grouse would be minimized by the implementation of RDFs (refer to Sections 4.3.3.1 and 4.3.3.2). Lek impact levels are anticipated to be low for 12.6 miles and moderate for 5.5 miles. 4.3.4.7 Route Segment 2d Approximately 36.6 acres of long-term and 5.2 acres of short-term disturbance would occur through the construction of Route Segment 2d. Most of the long-term disturbance would be sagebrush/perennial grassland (34.1 acres). Perennial grassland and annual grassland compose the remainder of long-term and all short-term disturbance (Table 4.3-4). RDFs would be implemented to minimize habitat loss and degradation, as described in Section 4.3.3.1. Impact levels to habitat are expected to be low for 1.3 miles and moderate for 5.7 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 2d would require an estimated 50 structures, all of which would be located greater than 0.25 mile from an existing transmission line (Table 4.3-5). Within 1.0 mile of Route Segment 2d, potentially suitable habitat is present for 62 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 2d include critical habitat for bull trout, Chinook salmon, and steelhead, occurrences of loggerhead shrike, white-tailed jackrabbit; and regular concentrations of chukar, mule deer, and elk. Cliffs along the Columbia River provide nesting habitat for raptors; several prairie falcon nests have been documented on the cliffs. Ferruginous hawk nests have also been documented near 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 2d approaches to within 150 feet of the Columbia River where it connects with Route Segments 3b or 3c. No structure or road construction work would occur directly within the Columbia River. Impacts to Chinook salmon from the construction of Route Segment 2d 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