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Arrowhead-Weston

Project Map: American Transmission Company

Project Description

The American Transmission Company's 345 kV Arrowhead-Weston transmission line stretches 220 miles from Duluth, Minnesota to Wausau, Wisconsin. The line was first proposed in 1999 to improve reliability of electric service in the region. Construction began in 2005, and the line was energized in February, 2008.

Important characteristics:

• Siting: 75% of the project was sited on existing rights-of-way, in the same corridor as other infrastructure such as transmission, pipelines, roads or railroads. This minimized the need for impacts in previously undeveloped areas.
• Wetlands: The project crosses 80 miles of wetlands, so the American Transmission Company (ATC) took extensive efforts to limit impacts on this fragile habitat.
  • Using minor changes in routing, ATC adjusted the line so that 45 structures that would have been placed in wetlands were relocated to less sensitive areas. The final aggregate footprint of all structures in wetlands is less than one half-acre.
  • As much as possible, constructions in wetlands occured in winter months, so ATC could make use of ice roads.
  • In wetland areas, ATC installed 36,000 protective wooden mats made of oak planks between 8 and 16 feet in width. The mats covered up to 29 linear miles, providing a surface for equipment to drive on, protecting sensitive ground underneath.
  • ATC used hundreds of clear-span bridges for crossing waterways during construction, so that no impacts were made to streambeds.
  • In inaccessible areas, ATC installed ladder hooks, so that ongoing maintenance could be done via helicopter, reducing the potential for future ground disturbance.
• Bird Habitat:
  • ATC removed existing transmission line from a bird sanctuary along the route and re-routed double circuit line around the preserve.
  • When osprey nests were found along the route, ATC installed nesting platforms nearby.
• River Crossings: The line crosses the Namekagon River in the St. Croix National Scenic Waterway, which is managed by the National Park Service. To minimize visual impacts from the river, ATC used high-tension conductor, and consolidated the number of wires at the river crossing from 12 to 6. This allowed ATC to double the space between poles from 800 feet to 1600 feet, so poles could be set back from river banks, where they are less visible to river users.

Resources

ATC Arrowhead-Weston map
ATC Arrowhead-Weston project website
ATC Arrowhead-Weston Facts and Figures
ATC Arrowhead-Weston Benefits Report

Organization: American Transmission Company (ATC)
Location: Minnesota, Wisconsin
Project Phase: Construction (wetland mitigation)
Written by: Alison Berry This e-mail address is being protected from spambots. You need JavaScript enabled to view it  

Last Updated: November 5, 2012