Vantage to Pomona FEIS Index 34 - Laserfiche WebLink

Home Browse Search

Vantage to Pomona Heights Chapter 2 230 kV Transmission Line Project FEIS Proposed Action and Alternatives PAGE 2-23 Alternatives. These areas, as well as those areas where no access road construction would occur because of the presence of water, were assigned an Access Level 0 and no ground disturbance was assumed related to access road construction (other permanent and temporary disturbance, such as structure base disturbance, was estimated, but not considered in Access Level determination). To determine the potential impact of access roads in other areas, existing roads, slope, and vegetation were considered. Existing roads were assigned a Level 1 or Level 2 designation, considering the extent to which they may require improvement. The route segment centerlines for the Action Alternatives were assigned Access Levels based on proximity to existing roads. Typically, paved, gravel, and wide dirt roads within 750 feet of the assumed centerlines were given an Access Level 2 (as defined in Table 2-4). Within approximately 750 feet of the Access Level 2 (or 3) existing road, the assumed route segment centerlines was assigned the corresponding Access Level with the lower level given if both Level 2 and 3 were present within 750 feet of the assumed centerlines. The distance from existing roads criterion was used in areas with generally unrestricted access; I-82, for example, was not considered a road that would be used for access of the proposed Project. Some roads were not considered accessible even if they were within 750 feet of the assumed centerlines. Areas beyond 750 feet of an existing road were then assessed to determine the extent of potential road construction that might be needed. During this access road assessment phase, areas where annual grassland vegetation or previously disturbed areas were identified based on Gap Analysis Program vegetation cover. In these areas, where slopes were less than eight percent, it was assumed that centerline access would be possible without grading new roads (overland access). Some isolated areas may require the laying of gravel or other ground disturbing activities. A 14-foot travel way would be groomed and graded where necessary. To determine the extent of new road construction, ground slope was determined based on digital terrain modeling. Intersection of the assumed route segment centerlines with the digital terrain model slope class (0 to 8%, 8 to 15%, etc.) determined access levels for each 0.1 mile increment where no existing roads occur and where overland access is not likely to occur. 2.2.3.3 Work Areas and Set-up Sites Work areas are required at each structure site to facilitate the safe operation of equipment and construction operations. The size of the work area is driven by the need to lay down the poles, install the necessary hardware and frame them to full length. A temporary disturbance area of approximately 150 feet by 125 feet (18,750 sq. ft./0.43 acres) would be required at each H-frame structure location and an area of approximately 150 feet by 80 feet (12,000 sq. ft./0.28 acres) for single pole structure location. Side hill construction would occur in certain areas requiring the establishment of leveled trails to access structures. Additionally, pads or leveled areas would be necessary for equipment set-up for installation of the poles. Typically, the blading for the trail would not exceed 12 feet, depending on the hill slope. The blading for the building pad would be done along the same area as the access road to reduce the overall amount of blading required for crane set-up and would not typically exceed 30 by 40 feet at the structure. Pulling and tensioning sites for stringing the conductor would result in a temporary disturbance of 125 by 400 feet (50,000 sq. ft./1.15 acres). Sites for pulling and tensioning would be located approximately every 11,000 feet (two miles) or less. This is the length of the longest reel of conductor wire that would be utilized by the proposed Project. For mid-span setups, work areas are located within the 125-foot ROW corridors and up to 250 feet in length. Setup sites for corners and heavy angles are the width of the ROW corridor and up to 250 feet in length on both sides to allow for equipment to be set up in line with the pulling of the conductor. Additional set up sites could be selected by the construction contractor if approved by the landowner and/or land manager. Where feasible, all areas would be selected to allow