Vantage to Pomona FEIS Index 34 - Laserfiche WebLink

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Vantage to Pomona Heights Executive Summary 230 kV Transmission Line Project FEIS October 2016 PAGE ES-iv compared with the Agency Preferred Alternative. However, the Underground Design Option would disturb more wildlife habitat (254 acres vs. 204 acres) and more Sage-Grouse habitat (243 acres vs. 192 acres), because it would require more vegetation removal. As the NNR Alternative (Overhead Design Option and Underground Design Option) closely parallels Pacific Power’s existing Pomona-Wanapum 230 kV transmission line for the majority of its total length, utilizing nearby existing roads will greatly reduce the need for new access roads, decreasing the amount of direct habitat impacts associated with the Project. The much lengthier Alternatives A-H would each result in at least 316 acres of direct impacts to wildlife habitat, require at least 477 structures, and result in anywhere from 203 acres (Alternative C) to 296 acres (Alternative F) of direct impacts to Sage-Grouse habitat. For all Project Action Alternatives, disturbed areas would be restored following construction. However, because of the long recovery times for restoring sagebrush communities (30 to 120 years), any direct disturbance to sagebrush steppe would be considered a long-term impact. The least amount of ground disturbance resulting in indirect habitat impacts (through the spread of noxious weeds and invasive species and potential increased fire frequency) would occur with the Agency Preferred Alternative. The NNR Alternative - Underground Design Option would result in greater habitat impacts (254 acres) in underground construction locations through trenching and new, permanent access road construction. The NNR Alternative - MR Subroute would require construction in areas that are not located adjacent to an existing line and in areas with few or no access roads, resulting in 260 acres of impacts to habitat. Alternatives A-H would result in much more ground disturbance (316 to 350 acres) due to their longer length. Due to the Agency Preferred Alternative and the NNR Alternative - Underground Design Option’s location adjacent to the existing Pomona-Wanapum 230 kV Transmission Line, it is unlikely that the addition of structures 200 feet from a similar existing structure would have much, if any, effect on the density of corvids or raptors. Construction of the Agency Preferred Alternative and the NNR Alternative - Underground Design Option would require the fewest structures greater than 0.25 mile from an existing transmission line (50 structures). All other Action Alternatives are longer and follow existing transmission lines for lesser proportions of their lengths, necessitating more structures greater than 0.25 mile from an existing transmission line. The close proximity of the underground sections to existing overhead lines would negate most of the benefit to wildlife that undergrounding might otherwise have provided. The Action Alternatives traverse through sensitive wildlife habitats (sagebrush-steppe, riparian areas, intermittent streams/dry gullies, wetlands, and trees) ranging from as low as 21.8 miles for Alternative G to as high as 35.1 miles for Alternative A. The Agency Preferred Alternative would cross 31.1 miles of sensitive wildlife habitat, primarily sagebrush-steppe and is on the moderate to high end of impacts to sensitive wildlife habitats compared to all the Action Alternatives. The NNR Alternative – MR Subroute would have the least amount of its centerline within one mile of documented special status species raptor nests (9.1 miles), followed by Alternative A (10.0 miles), and then the Agency Preferred Alternative (10.5 miles). Alternative C would have the greatest length of its centerline within one mile of special status raptor nests (19.6 miles). The Agency Preferred Alternative, NNR Alternative - Underground Design Option, and NNR Alternative – MR Subroute had the shortest length of centerline within 0.5 mile of special status wildlife species occurrences (8.6 miles), and the greatest amount associated with Alternative B (19.4 miles). Additionally, the Agency Preferred Alternative and NNR Alternative - Underground Design Option would cross 5.0 miles of Priority Species Regional Areas, the least amount among the Project Action Alternatives. A portion of each of the Action Alternatives would be located within the Sage-Grouse YTC Priority Area of Conservation (PAC). The Agency Preferred Alternative and the NNR Alternative - Underground