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Vantage to Pomona Heights Chapter 4 230 kV Transmission Line Project FEIS Environmental Consequences PAGE 4-33 Common to All Route Segments (Section 4.2.3) and for Route Segment 1a/NNR-1. Refer to Section 2.3 - Required Design Features Common to Action Alternatives for a complete list and description of RDFs. With the implementation of RDFs, long-term impact levels for Route Segment NNR-4o would include 2.1 miles of low and 2.5 miles of moderate impacts. Underground Design Option Construction of NNR-4u would result in approximately 42.3 acres of long-term disturbance to vegetation. Long-term disturbance would occur primarily in sagebrush annual grassland (19.0 acres) and sagebrush/perennial grassland (22.7 acres). The remaining disturbance would occur in 0.2 acre of annual grassland and noxious weeds, 0.3 acre of bitterbrush perennial grassland, and 0.1 acre of perennial grassland. Approximately 4.4 acres of vegetation would be disturbed on a short-term basis. In addition to impacts described above in Section 4.2.3, additional underground construction disturbance would occur through open cut trenching and excavation for the installation of underground duct bank, splice vaults, and construction of access roads and temporary work sites. RDFs described above for Section 4.2.3 and for Route Segment 1a/NNR-1 would also be implemented for the Underground Design Option. Following the implementation of RDFs, long-term impact levels to vegetation for NNR-4u would include 2.1 mile of low and 2.5 miles of moderate impacts. Special Status Species and Priority Ecosystem No federally listed special status plant species or priority ecosystems are known to occur along Route Segment NNR-4o/NNR-4u. Special status plant surveys conducted for the proposed Project documented snowball cactus within Route Segment NNR-4o/NNR-4u (Table 4.2-5). However, following the special status plant surveys, the NNR-4o/NNR-4u route was realigned and the snowball cactus occurrence is now located outside of the Project ROW and, therefore, won’t be impacted by the proposed Project. Approximately 43 percent (26.3 acres) of federal lands within this route segment were surveyed for special status plants (Table 3.2-3). As not all land within the route segment corridors was surveyed, impacts could occur to special status plant species. With NNR-4o, long-term disturbance to special status species potential habitat would occur to 2.3 acres of suitable and 3.0 acres of marginal habitat. With the Underground Design Option (NNR-4u), long-term disturbance to potential habitat for special status species would occur to 6.3 acres of suitable and 7.0 acres of marginal habitat. Route Segment NNR- 4o/NNR-4u corresponds to one priority ecosystem (big sagebrush-bluebunch wheatgrass [Pseudoroegneria spicata]). RDFs described above for Route Segment 1a/NNR-1 and Impacts Common for All Route Segments (Section 4.2.3) would be implemented during construction and maintenance of Route Segment NNR-4o/NNR-4u to minimize impacts to special status plants and include: adhering to measures and terms and conditions developed during the consultation period with the USFWS; avoiding or spanning areas supporting special status plants where practicable; marking populations of special status plants for avoidance during construction; and developing a Plant Protection Plan as part of the POD to identify specific measures for the protection of special status plants. With the implementation of RDFs, impacts to special status plant species and potential suitable habitat are anticipated to include 2.1 mile of low impacts and 2.5 miles of moderate impacts for both the NNR-4o and NNR-4u route segments. Snowball Cactus Refer to Route Segment 1b for information on snowball cactus. One occurrence of snowball cactus was documented during the special status plant survey along Route Segment NNR-4o/NNR-4u. This occurrence consisted of 1 – 50 individuals at a single point. As previously stated, following the special status plant surveys, a route realignment occurred for Route Segment NNR-4o/NNR-4u resulting in the snowball cactus occurrence being located outside the Project ROW. Since not all federal and state lands