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  • Transmission Line Access Roads


Project Highlights:

  • Over 1,100 miles of access road improvements constructed or designed
  • Over 60 fish passage culvert designs
  • Various project lengths, from one structure to 40+ miles long
  • Employ a field-heavy design approach
BPA Access Roads - transmission lines
Access Roads - bridge

Project Summary

Client: Bonneville Power Administration
Location: Oregon and Washington
Services Provided:
  • Civil Engineering
  • Land Surveying
  • Construction Inspection
The Bonneville Power Administration (BPA) has over 15,000 miles of transmission lines strung across some of the most rugged terrain in the Pacific Northwest. Maintenance of this critical infrastructure is made possible by maintaining a less glamorous but equally vital infrastructure – an estimated 22,000 miles of access roads.
MacKay Sposito assists BPA’s Access Roads section to execute their ongoing program of work. Our engineers travel to remote parts of the region to assess road condition, document needed improvements, estimate construction costs, and prepare construction documents.
We have adopted a field-heavy design process that utilizes a resource grade GPS and design-related collection schema to produce contract plans. In areas that require preparation of a site specific design plan, we perform the surveying work and general civil design work, which often includes fish passage culverts, bridges, retaining walls, and other slide repairs.
MacKay Sposito has also provided construction inspection for multiple fish passage improvement projects on BPA’s transmission line access roads. These projects include providing Quality Assurance/Quality Control inspection for upsizing existing corrugated metal pipes (CMPs) with large-diameter arch structures as well as actually removing existing CMPs and replacing them with prefabricated bridges. A significant amount of work includes monitoring re-establishment of the stream beds in addition to ensuring proper construction of the bolder weirs for fish resting pools.