Flurry of Big and Tall Engineering Hits the South End

City Light workers had a busy week of big and tall engineering near Seattle’s south end, all in an effort to make our transmission system safer.

Between July 21 and July 24, City Light workers and engineers straightened out a leaning 150-foot transmission tower, installed a massive metal pole in the middle of a rail yard, and replaced an aging wooden transmission structure in a wetland.

The work was performed during a planned outage of a major transmission corridor, near Interstate 5 south of Boeing Field, and over a busy train corridor. It required a delicate dance of permits, agreements with regional agencies and community outreach in a diverse neighborhood with territorial views.

All of it is part of a larger project to upgrade the aging structures and cables connecting the Creston-Nelson substation in the Rainier View neighborhood with the Duwamish substation to the west.

The first and probably trickiest part involved a transmission lattice tower on the west side of I-5, near the Martin Luther King. Jr. Way exit. During planning for replacement of adjacent poles, engineers discovered that the tower’s foundations gradually sank over the past 30 years, causing it to lean three feet to the side.

Crew chiefs Todd Warren and Bruce Lee, their crews, and Ironworkers Curt Blazich, Shaina Cornelius and Justin Forrest took on the job, with planning and design by Civil Engineers Norm Hodges and Irv Ogi. They first built an enclosing cage and reinforced the bottom of the structure. Using 100-ton hydraulic jacks and wires, they moved the tower’s legs up 11 inches on the northeast corner, seven inches on the southeast corner and four inches on the northwest corner. When they were done, the tower was within one inch of true plumb, an amazing feat.

“This was a first for the lineworkers, including the crew chiefs, manager and myself,“ Line Supervisor Tom Caddy said.

At the same time, workers led by Crew Chiefs Anthony Borgioli, James Alexander and Kath Johnsen got going on the installation of a 150-foot tall metal monopole in the middle of the Burlington Northern Santa Fé (BNSF) train yard. The pole raises the lines to allow BNSF to safely use a new crane to move cargo on and off trains under the power corridor.

The massive monopole was custom built for the job and installed in sections ranging from 30- to 40-feet long. Workers installed the pole and lifted and reconnected the transmission cables.

Concurrently, workers lead by Crew Chiefs Gary Legere and Ken Busby completed the replacement of an older wooden “H” frame structure (named for its shape) carrying transmission lines between the Creston-Nelson and Duwamish substations. The job was scheduled for last year, but issues related to the wetla nd terrain delayed it until now.

“All of this work happened in only four days, during the time-limited clearance on two of 230kV transmission lines,” said Mary Junttilla, project manager.

Between now and October, City Light workers and contractors will remove 10 H frames in the area and replace them with eight metal monopoles 120 to 153 tall, install new cables, and restore the landscape of the area, including enhancing existing wetlands. The upgrades will improve transmission system safety, increase reliability and flexibility and add capacity in the Duwamish industrial area.

April Volunteers Live Up to Public Service

Public service means just that, serving the public. This April, dozens of City Light employees put the walk in the talk, volunteering their own time to restore sensitive river waterfront and to rehabilitate the home of an elderly Korean War veteran.

On April 19, City Light employees returned to the Duwamish River to help with cleanup and restoration of the river’s shoreline, teaming up with the group Forterra. Volunteers removed weeds, mulched, worked on irrigation and erosion controls, and made other important improvements to the Duwamish Hill Preserve  in Tukwila.

The preserve is part of a larger regional effort to restore habitat and to clean up the Duwamish River and waterway. This marked the third consecutive year that City Light contributed to the Earth Day Duwamish clean up.

Then on April 26, City Light and McKinstry volunteers added a little sweat equity to the home of an elderly man in Ballard as part of this year’s Rebuilding Together Seattle project. Volunteers tore off and replaced back and front porches at the home, fixed plumbing and wiring, landscaped the yard, installed a new washer and kitchen stove, painted, and removed debris and trash. The owner of the home, an Air Force Korean War veteran and English literature teacher, also received a new bed and a framed and signed historical picture of his house. All the work was completed in less than a day.

The home in Ballard was one of 25 different rehabilitation projects sponsored by Rebuilding  Together Seattle this year.

Keeping the power on and the ospreys safe

In the ongoing saga between ospreys and City Light infrastructure near the Duwamish River, the birds have been getting the upper talon.

That could change this spring. When the ospreys return to take advantage of the easy fishing and tall power line towers for nesting, they will find a new set of barriers designed to protect the power lines and keep the birds safe. They will also find new nesting platforms nearby, where they can raise their chicks in peace.

This March, City Light crews installed adjustable, triangular covers on top of the crossbeams of the electrical towers spanning the Duwamish River, near our substation. In between the covers, workers installed rods with loose plastic pipes that roll when birds try to perch on them. The barriers will hopefully prevent osprey from perching on the crossbeams and being able to wedge sticks and other nest building materials into the tower.

The lines and jumpers below have also been wrapped with insulating sleeves to prevent power outages when nest materials fall and make contact.

“We will be checking the Duwamish towers periodically this spring, to evaluate the effectiveness of the exclusion devices and will check the nesting platforms to see if the ospreys are being accommodated, which should reduce the risk of them nesting on City Light structures where they can cause outages or be injured or killed,” said City Light Wildlife Biologist Ron Tressler, who oversees the project.

“Hopefully the exclusion devices and platforms will result in osprey leaving our towers alone but if they don’t work, we’ll be back there again for another try,” he said.

City Light and NB Power in New Brunswick, Canada, are the only two utilities in the world using these experimental nesting deterrents. The devices were designed and fabricated by Jim Kaiser of Osprey Solutions, a specialist hired by City Light to help with some of the osprey issues.

The birds arrive here in spring to take advantage of the salmon released by the Icy Creek Pond hatchery upstream. In their natural habitat, ospreys prefer to build their nests on the top of large snags or deformed trees near water.

But the Duwamish waterway is an industrial corridor where the tallest bare structures are light poles, communications towers and other artificial structures. So those sites are being used by the increasing population of ospreys. Even thin light poles are suitable – ospreys can build a nest on as little as one square foot of space, according to Kaiser. There are approximately 12 nesting pairs in the lower Duwamish.

The City Light towers on the Duwamish, besides serving as a tempting nesting surface, also carry several major electrical feeders that supply critical Boeing infrastructure. Over the years, ospreys have caused periodic outages, affecting Boeing’s operations.

In the past six years, osprey pairs have also nested on light poles at the Insurance Auto Auction lot on East Marginal Way, near the Duwamish River towers, and on a communications tower in the Sound Transit operations and maintenance facility near East Airport Way. Since the last nesting season, the company who owns the tower has installed exclusion devices to prevent osprey from nesting there in the future. Because these birds will return and likely try to find an alternate nest site on one of our nearby poles, City Light crews installed two new, safer platforms for the ospreys to nest and raise their young.

All of these efforts are part of City Light’s Avian Protection Program, which monitors incidents with birds and implements measures to keep the animals safe and the electrical equipment operating.