Replacing aging transmission line while protecting wetlands.

From day one, we knew Dairyland Power Cooperative’s 23-mile transmission line replacement project would take an unconventional approach. Much of a four-mile stretch of the existing and new 161 kV line route crosses U.S. Fish and Wildlife Service and Wisconsin Department of Natural Resources land, which includes a wildlife area, floodplain and sensitive wetlands protected by the USFWS and the DNR.

Together with Dairyland, we developed a design and construction plan with four segments. Two structure types were identified for the segment crossing the wetlands: single pole steel with delta configuration, and Y-frame steel. After evaluating both options, the USFWS and the DNR selected Y-frame structures to keep structure heights at or below tree level.

We carefully planned every activity to minimize disruption to the wetlands during construction. Using heavy lift helicopters, we removed existing structures, transported the foundations, new structures and equipment to the site, and placed them on/in the ground from the air. A smaller helicopter was used to transport other equipment, bring in linemen and string the line.

Meeting USFWS and DNR requirements, the Dairyland project was completed with no mechanized access, preserving Wisconsin’s wetlands.