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CHAPTERTWO Alternatives <br />The transmission structures for this project would be primarily wood poles. In some cases, <br />where there are physical limitations on guying/anchoring, galvanized steel poles may be used. A <br />specific design would be completed for the selected route to determine structure locations and <br />where wood and steel poles would be used. Some of the steel poles could be directly embedded <br />(similarly to wood pole construction), and some would be set on a foundation. Generally, the <br />structures on tangent (along a straight line) would be self-supporting. Angle structures, where <br />the line turns, are generally supported with guy wires. <br />The average pole would be approximately 61 feet above ground to the top of the pole (a 70-foot <br />pole embedded 9 feet into the ground) for a structure with an underbuild circuit and 56.5 feet <br />above ground to the top of the pole (a 65-foot pole embedded 8.5 feet into the ground) for <br />structures without the underbuild circuit. Minimum line-to-ground clearance for the 69-kV line <br />is 20.1 feet, with minimum clearance of 28.1 feet for railroad crossings. Minimum line-to- <br />ground clearance for the 12-kV underbuild circuit is 18.5 feet, with minimum clearance of <br />26.5 feet for railroad crossings. The underbuild circuit would be constructed no less than 9 feet <br />(at the pole) below the lowest 69-kV insulator. Approximately 15 structures per mile would be <br />required on the BLM portion of the route, with approximately 17 structures per mile on the <br />portion of the route with the underbuild circuit. <br />Transmission Line Construction <br />The general sequence to construct and energize an overhead transmission line is described in this <br />section. These activities will not take place until an alternative has been selected and BLM has <br />issued a ROW grant for construction operation on federal lands. <br />Line Survey <br />• Specifications for the transmission line design are derived from a survey of the area. <br />The survey is required to develop models for the design of the overhead transmission line, <br />facilities, analysis, and proposed line routes. In this case, a survey would not be completed <br />until an alignment alternative is selected. <br />Right-of--Way <br />Once an alternative has been selected and approved, ROW easements are procured. In some <br />cases, it maybe necessary to negotiate with individual property owners if county or federal <br />easements are not available along the selected route. Typical ROW width fora 69-kV line is <br />100 feet. <br />Access roads, overland travel paths, stringing turn around points, and staging areas are <br />designated. <br />Vegetation is cleared to accommodate necessary travel for construction, inspection, line <br />maintenance, and line clearance problems. <br />Preparation <br />• Permanent and temporary access roads are built. <br />2-45 <br />