2011-05-12_PERMIT FILE - M2011028 (2)

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(MAPCO) Natural Gas Liquids (NGL) pipeline; and (3) a 10-inch-diameter MAPCO NGL pipeline. The two MAPCO pipelines parallel the Northwest pipeline route through Ridges Basin. Both Northwest and MAPCO are subsidiaries of Williams. The portion of Northwest's 26-inch-diameter natural gas pipeline to be relocated is part of Northwest's existing Ignacio-to-Sumas natural gas transportation system. The portion of MAPCO'S 10-inch and 16- inch-diameter pipelines to be relocated are a part of MAPCO's existing Rocky Mountain NGL transportation system, which transports NGLs from natural gas production areas in the Rockies to markets in the mid-continent and Gulf coast regions. Northwest and MAPCO propose to abandon a total of 14.91 miles (4.97 miles for each of three pipelines) of existing pipelines within Ridges Basin, of which a total of 13.11 miles (4.37 miles for each of the three pipelines) could be abandoned in place and a total of 1.8 miles (0.6 mile for each of the three pipelines) removed. Portions of the pipelines to be removed lie under the proposed Ridges Basin Dam and outlet works. The sections of pipelines to be relocated are situated approximately 2 miles southwest of Durango, Colorado. 2.1 New Pipeline Construction Proposed Northwest and MAPCO propose to construct a total of approximately 12.9 to 20.7 miles of new pipeline (4.3 to 6.9 miles for each of three new pipelines) to replace their existing pipeline facilities through Ridges Basin depending on the route selected (the difference in length reflects two pipeline alternate routes considered). In order to maintain service to its customers, the new pipelines must be installed and connected to the respective systems before the existing pipelines can be taken out of service. The replacement pipelines would not increase the capacity of any of the three pipeline systems. The Northwest pipeline would be installed in a permanent right-of-way 75 feet wide. Additional space, up to 40 feet, may be required in places where greater access is needed during construction. The two new MAPCO pipelines would be constructed parallel to the Northwest pipeline in an adjacent 75-foot permanent right-of-way. Additional space, up to 40 feet, may be required in places where greater access is needed during construction. The MAPCO pipelines would be separated 20 feet from each other and 20 feet from the Northwest line for the entire route, except for approximately 3,507 feet of Horizontal Directional Drill (HDD) boring plus transition areas (northern route only). 2.2 Disposition of Existing Pipelines When the new Northwest and MAPCO pipelines are completed and tied-in, the corresponding 14.91 miles of existing pipelines would be abandoned. Approximately 13.11 miles of pipeline (4.37 miles for each of three pipelines) could be abandoned in place. About 1.8 miles of pipeline (consisting of 0.6 miles each of three pipelines) would be excavated and removed. After tie-in to the relocated pipelines is accomplished, the sections of existing pipelines to be abandoned would be cleaned to remove any residual liquids. The residual liquids would be captured and disposed of in accordance with appropriate environmental regulations. Prior to filling of the reservoir, the portions of the pipelines that are abandoned in place would be capped and filled with water to prevent buoyancy. When Reclamation begins construction of the dam, additional sections of pipe would be removed as necessary for excavation of the dam foundation and borrow areas and construction of the coffer dam and diversion channel. Several sections of Northwest's existing pipeline in the Ridges Basin area are coated with asbestos felt wrap. Appropriate abatement and disposal techniques would be used along any section of pipe coated with asbestos felt wrap that is removed from the trench. None of the existing pipeline that could be B-3 Weeminuche Construction Authority P.O. Box AA - Towraoc, CO 81334 A I MA5 <4LAGM ag"El.- tc?iT 14 - PAGE H-SS