Black Nubble Wind Farm Project Basis of Design for Primary Access
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Black Nubble Wind Farm Project Basis of Design for Primary Access Roads and Summit Roads Prepared by: DeLuca-Hoffman Associates, Inc. 778 Main Street, Suite 8 South Portland, ME 04106 Black Nubble Wind Farm Project Page i Basis of Design for Primary Access Roads and Summit Roads Table of Contents 1.0 Introduction......................................................................................................... 1 2.0 Seasonal Restrictions.......................................................................................... 4 3.0 Basis of Roadway Design ................................................................................... 4 3.1 Longitudinal Grades....................................................................................6 3.1.1 Upper Black Nubble Access Road.................................................. 7 3.1.2 Upper Black Nubble Summit Roadway.......................................... 7 3.1.3 Lower Black Nubble Access Road ................................................. 7 3.1.4 Lower Black Nubble Summit Roadway ......................................... 7 3.2 Horizontal Alignment ................................................................................. 8 3.3 Roadway Width.......................................................................................... 9 3.4 Transverse Grades..................................................................................... 10 3.5 Cuts and Fills ............................................................................................ 12 3.6 Roadway Surface Treatment..................................................................... 12 3.7 Temporary Construction Roads ................................................................ 12 3.8 Natural Resource Areas ............................................................................ 13 4.0 Anticipated Improvements to Existing Roads .................................................. 13 4.1 Areas with Insufficient Turn Radii ........................................................... 14 4.2 Vertical Realignment ................................................................................ 15 5.0 Materials of Construction ................................................................................. 17 6.0 Other Tools for Construction of the Roadway.................................................. 17 7.0 Implementation ................................................................................................. 18 8.0 Closure .............................................................................................................. 18 Black Nubble Wind Farm Project Page ii Basis of Design for Primary Access Roads and Summit Roads List of Appendices Appendix 2.1 – Mountain Road Maps (C-1 to C-BN7 and C-BN18) Appendix 2.2 – Toolbox of road section designs (C-46 to C-55) Appendix 2.4 – Cut/Fill Road Analysis Detail (C-BN24 to C-BN30) Appendix 2.5 – Slope Maps Appendix 2.6 – RMW Narrow Road Specification Appendix 2.7 – DeLuca-Hoffman Site Visit Notes Appendix 2.8 – Inset Area Detail (C-40 to C-43) Appendix 2.9 – Substation Interconnect Layout, Grading and Erosion Control (C-44) Appendix 2.10 – Additional Civil Design Criteria Appendix 2.11 – Civil Engineering Design Specifications Appendix 8.3 – Vestas V90 Transport Guidelines List of Tables Table 1 – Access to Wind Turbines Table 2 – Transverse Slope Black Nubble Wind Farm Project Page 1 Basis of Design for Primary Access Roads and Summit Roads 1.0 Introduction DeLuca-Hoffman Associates, Inc. was retained to prepare designs and portions of the permit applications for a series of wind turbines proposed to be sited on Black Nubble. DeLuca- Hoffman Associates, Inc. designed the primary access roads and summit roads, which will be used to access the wind turbines from existing roadway systems; and also prepared the Stormwater Management Report, Erosion and Sedimentation Control Plans, Road Maintenance Plan, Solid Waste Narrative, and Blasting Narrative associated with the primary access roads and summit roads. Note that the term “summit road” is synonymous with “ridgeline road” within this application. The work of DeLuca-Hoffman Associates, Inc. is summarized in a series of reports as follows: Basis of Design for Primary Access Roads and Summit Roads; Erosion and Sedimentation Control Plan for Roadway Construction; Stormwater Management for Primary Access Roads and Summit Roads; Road Maintenance; Blasting Narrative; Erosion and Sedimentation Control Plan for Transmission Line Corridor Construction; and Solid Waste Narrative. The narratives prepared by DeLuca-Hoffman Associates, Inc. are supported by the project Civil Engineering Design Drawings included with this submission. Please refer to Cover Sheet C-1 for a complete list of the project drawings. The designs and reports prepared by DeLuca-Hoffman Associates, Inc. rely upon baseline information provided for this project by other consultants of Maine Mountain Power. Civil Engineering Design Specifications for the project are provided in Appendix 2.11. Black Nubble Wind Farm Project Page 2 Basis of Design for Primary Access Roads and Summit Roads The baseline data prepared by other consultants include the following: The identification and location of wetlands and other natural resources by Woodlot Alternatives. Surficial Soils Surveys, identification of water courses and seep areas, and narratives prepared by Albert Frick. Base topographic mapping prepared by Aerial Survey with ground truthing survey integrated by Westwood Professional Services. Geotechnical evaluations and recommendations for Roadway Construction prepared by S. W. Cole. Information for the basis of Roadway Design “Narrow Road” specification established by Endless Energy Corporation, revision E, dated December 13, 2005, included with this report in Appendix 2.6. Note: The only change made to the “Narrow Road” specification provided in the attachment from what was submitted in the preliminary LURC submission last year, is that a platform trailer will be used to transport blades with a 62-foot rear overhang and 20-foot front overhang, and wide-outs will be provided every ¼ mile instead of every ½ mile for vehicle passing. Dimensions of the blade transport trailer are provided following the “Narrow Road” specification in Appendix 2.6. Transportation guidelines for Vestas V90 are included in Appendix 8.3. These V90 transportation guidelines have been reviewed and partially considered for the road design, however, the “Narrow Road” specification sets the parameters for road travel width and curve criteria. Additional Civil Design Criteria are provided in Appendix 2.10. Black Nubble Wind Farm Project Page 3 Basis of Design for Primary Access Roads and Summit Roads LURC Chapter 10, Rules and Standards, defines three roadway classifications with minimum roadway widths ranging from 8 to 18 feet. In an effort to design the roadway to meet the specific requirements of this project, a minimum gravel travelway width of 12 feet is proposed for access roads and 32 feet for mountaintop summit roads. A wider travel width up to 20 feet is required at the tightest curves of the proposed access roadways and at wide-outs for passing of equipment. The roadways have been designed to minimize the use of ditching and to fit the natural topography of the land such that cuts and fills are minimized while preserving the scenic qualities of the surrounding land to the extent possible. A potential connector access road through steep terrain between Lower and Upper Black Nubble is shown on the project Base Map. The potential connector will be reviewed further in the final design and could potentially eliminate the need for the proposed Upper Black Nubble access road. There are other physical elements of the project such as the electrical power transmission lines, staging area, and small buildings with attendant construction areas, which are being designed by other consultants and discussed in separate portions of the application. Site grading and erosion control for turbine sites will be included with the final roadway design drawings. A portion of the access to the proposed wind turbines and substation will use existing roads. These roads are shown as red lines on the Base Map C-3, and have the following lengths: Table 1 - Access to Wind Turbines Existing Road Segment Distance Distance (ft) (miles) I.P. Road from Route 16 to tee intersection just beyond the Batch Plant Site. 26,928 5.1 Road segment from tee intersection to Lower Black Nubble (includes portion of RE2). 16,896 3.2 Road segment from tee intersection to proposed road to access the Substation 8,000 1.5 TOTALS 51,824 9.8 Black Nubble Wind Farm Project Page 4 Basis of Design for Primary Access Roads and Summit Roads 2.0 Seasonal Restrictions Once the project is complete, seasonal restrictions will be applied to roadways associated with the project. In general during snow months the access roads to the turbine sites will not be plowed. Access to the turbine sites will be via tracked snow vehicles or ATVs, as site conditions allow. Only small ATVs will be allowed to use these roads during the spring thaw to prevent damage to the roadway. 3.0 Basis of Roadway Design The basis for the design of new roads, as well as upgrades to existing roads, is discussed in this narrative. This report and the accompanying plans provide horizontal alignment and vertical alignment for the proposed roads. The baseline data available for design is limited to 2-foot contours developed