Sound Transit's new line blamed for electrocuting fish in Lake Washington

Dead fish have been discovered near the I-90 floating bridge carrying Sound Transit’s Link light rail between Seattle and the Eastside. Officials have not determined how many fish have died, how long the deaths have been occurring, or whether mitigation efforts have stopped the problem.

According to KOMO News, Sound Transit CEO Dow Constantine said the Washington State Department of Transportation alerted the agency on Aug. 3 after a diver discovered dead fish near the bridge.

Sound Transit deployed dive teams, fish biologists and engineers to investigate and found a possible link between the deaths and the electrical system used to protect the bridge from corrosion.

"That work identified a potential connection or correlation between fish mortality and localized portions of the bridge's cathodic protection system," Constantine said, "particularly towards the ends of bridges where the strings of anodes were clustered and actually resting on the lake bed."

Cathodic protection uses electrical current to prevent corrosion of metal structures. Sound Transit said the electrical management technology has been tested and used on other bridges without known adverse effects on fish.

However, strings of anodes used by the system on the I-90 crossing had been resting on the bottom of Lake Washington. Officials decided to lift the strings off the lake bed and suspend them in the water. That work wasn't completed until Aug. 23, 20 days after Sound Transit was first notified about the dead fish.
Whether that fixed the problem remains unknown.

"We are still in the discovery mode," Constantine said.

Initial findings indicate most of the dead fish are non-native or invasive perch and bass, according to Constantine, but salmon have also been identified among the dead. Fish biologists and engineers continue to analyze images collected by dive teams.

Washington Transportation Secretary Julie Meredith insisted the issue does not threaten people using the bridge. "The bridge remains safe, safe for the traveling public," Meredith said. "WSDOT and Sound Transit are going to continue to share the responsibility for guaranteeing that."

The Crosslake Connection opened March 28, linking Seattle with Mercer Island and the Eastside. Engineers had to develop specialized track bridges that could accommodate movement of the floating bridge while also addressing the electrical current generated by the rail system. Now, the system designed in part to protect that infrastructure is under investigation as a potential cause of fish deaths.

The latest problem comes as the embattled Sound Transit is also investigating another high-profile malfunction elsewhere on its Link system. Following Sunday's Apple Cup at Husky Stadium, a packed Link train became disabled between the University of Washington and Roosevelt stations, stranding passengers for nearly two hours. KOMO News reported that passengers reported losing power and air conditioning before rescue trains were brought in.

It was not the first time Sound Transit stranded passengers following the Apple Cup at Husky Stadium. After the 2021 Apple Cup, another heavily loaded Link train became disabled shortly after leaving the UW station. A protruding rod between the tracks snagged and nearly severed a cable bundle controlling critical systems on the train.

Sound Transit's subsequent investigation found that contractors had failed to shorten the rods to their specified height and the agency's commissioning process failed to catch the problem. Sound Transit also concluded that testing of its newer Series 2 trains should have simulated the heavy passenger loads experienced following the football game. With hundreds of passengers aboard, the trains rode lower.

The agency acknowledged that evidence of trains striking the rods had been discovered before the Apple Cup failure and corrective work had begun but had not been completed.

Sound Transit CEO Peter Rogoff later said of the 2021 incident, "It is our fault passengers were put in that position." Five years later, passengers leaving the same event at the same stadium were stranded by another Link malfunction.

But the problem beneath Lake Washington potentially carries broader consequences. Sound Transit still does not know how many fish have died, when the deaths began, or whether its Aug. 23 modifications have stopped them. The agency says monitoring and analysis are continuing.

"We are committed to ensuring that the long-term solution is effective and monitored on an ongoing basis," Constantine said.