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Vantage to Pomona Heights Chapter 4 230 kV Transmission Line Project FEIS Environmental Consequences PAGE 4-22 sagebrush/perennial grassland. Annual and perennial grasslands (1.4 and 1.1 acres, respectively) would also be disturbed on a long-term basis. Short-term disturbance would occur to approximately 5.2 acres of vegetation. General vegetation impacts are similar to those described above for Route Segment 1a/NNR- 1. Disturbance would be minimized by RDFs described above that are designed to reduce impacts to vegetation resources. RDFs include using existing public roads to access structure sites, minimizing blading and disturbance to plant communities, revegetating following construction, and implementing a Noxious Weed and Invasive Plant Management Plan. Refer to Section 2.3 - Required Design Features Common to Action Alternatives for a complete list and description of RDFs. Impacts for Route Segment 2d are anticipated to be: 1.4 miles of low and 5.7 miles of moderate. Special Status Species and Priority Habitats No federally listed plant species are known to occur along Route Segment 2d (Table 4.2-4). Two special status plant species are known to occur along sections of this route segment: awned halfchaff sedge (Lipocarpha aristulata; 0.2 mile; WNHP occurrence) and Columbia milkvetch (2.0 miles; documented in special status plant surveys), as described below. Beaked spike-rush (Eleocharis rostellata), gray cryptantha (Cryptantha leucophaea), Hoover’s desert-parsley (Lomatium tuberosum), Nuttall’s sandwort, and Piper’s daisy (Erigeron piperianus) also occur within one mile of Route Segment 2d. No WNHP priority ecosystems are known to occur along Route Segment 2d. One hundred percent (19.7 acres) of federal lands within this route segment were surveyed for special status plants; however, the majority of Route Segment 2d is comprised of non-federal land (117.3 acres) and was not surveyed (Table 3.2-3). As not all land within the route segment corridors was surveyed, impacts could occur to special status plant species. Long-term disturbance would occur to potential habitat for special status plants and include 12.8 acres of suitable and 2.6 acres of marginal habitat. RDFs described above for Route Segment 1a/NNR-1 would also be implemented during construction and maintenance of Route Segment 2d to minimize impacts to special status plants. With the implementation of RDFs, impacts to special status plant species and potential suitable habitat anticipated to include 0.2 mile of low impacts and 6.9 miles of moderate impacts. Awned Halfchaff Sedge Awned halfchaff sedge is a BLM Sensitive and Washington Threatened species. This species is found from California north to Washington and west to Idaho, Wyoming, Utah, Arizona, Colorado, New Mexico, Kansas, Oklahoma, Texas, Minnesota, Iowa, Missouri, and Indiana. In Washington, awned halfchaff sedge is known from two recent occurrences occupying approximately 2,718 acres along the Columbia River in Benton, Grant, and Franklin counties and five historical occurrences from Klickitat, Whitman, Benton, and Asotin counties. WNHP data indicate that awned halfchaff sedge occurrences intersect Route Segment 2d for 0.2 mile. This location includes a large buffer, so it is difficult to accurately determine whether this occurrence truly intersects the ROW corridor. The known occurrences of awned halfchaff sedge are within wetlands along the Columbia River. With the proposed Project, wetlands and the area immediately adjacent to the Columbia River would be avoided. All potential habitat on federal and state lands was surveyed; therefore, it is unlikely awned halfchaff sedge occurs in Route Segment 2d. With the implementation of RDFs described above and the assumption that occurrences would be spanned and avoided, Project construction, operation, and maintenance activities could impact individuals or habitat (moderate impact), but would not contribute a trend toward federal listing. Columbia Milkvetch Refer to Route Segment 2b for more information on Columbia milkvetch. Columbia milkvetch was documented during special status plant surveys along a 0.6-mile section of Route Segment 2d. Approximately 1.2 acres of long-term disturbance and 2.2 acres of short-term disturbance in known and potentially occupied habitat are anticipated to occur along this route segment, less than 0.1 percent of the