SEATTLE — Sound Transit’s new light rail line across Lake Washington, Crosslake connection and the world’s first passenger rail service on a floating bridge, is under investigation after an estimated 2,000 fish died near electrical equipment hanging from the Interstate 90 span, Sound Transit CEO Dow Constantine said on Thursday, September 3, during the agency’s Executive Committee Meeting.
“On August 3rd, we were alerted by our partners at the Washington State Department of Transportation to some number of deceased fish in the vicinity of the I-90 floating bridge,” Constantine opened. “And we responded immediately by deploying teams of divers and engaging fish biologists and engineers and also coordinated with regulatory agencies and our tribal partners, and fisheries staff. That work identified a potential connection or correlation between fish mortality and localized portions of the bridge’s cathodic protection system, specifically toward the ends of the bridges where the strings of anodes were clustered actually resting on the lakebed in shallow water. And so, we’ve implemented an interim solution which was completed just 20 days later on August 23rd, lifting those strings off the lake bed and suspending them in the water.”
WSDOT Secretary Julie Meredith, who attended the meeting, said the crossing remains safe for the public.
“As you heard from CEO Constantine, we are taking this issue very seriously, taking steps to resolve the immediate issue, working to understand the root cause, and developing a long-term solution,” Secretary Meredith said. “These are the steps that are the priorities for both of our agencies. The bridge remains safe, safe for the traveling public, and Washtenaw and Sound Transit are going to continue to share the responsibility for guaranteeing that both now and over the long term.”
The Crosslake Connection opened for passenger service on March 28, completing the 2 Line running from Lynnwood to Redmond. The roughly 7-mile segment adds stations at Judkins Park in Seattle and on Mercer Island. It links the Eastside starter line, which began running between South Bellevue and Redmond in 2024 and reached downtown Redmond in 2025, with the 1 Line at International District/Chinatown Station.
The project fulfilled a vision dating back more than four decades. In the 1970s, communities on both sides of Lake Washington agreed to dedicate center lanes of the new Interstate 90 bridge for high-capacity transit. Voters approved the East Link Extension as part of the Sound Transit 2 ballot measure in 2008. Partial segments opened earlier, with the initial Eastside service launching in April 2024 and the extension to downtown Redmond in May 2025. The Crosslake Connection link was completed after the 1 Line reached Federal Way in December 2025 and Lynnwood in August 2024.
The East Link Extension project carried a baseline budget of $3.7 billion in 2015 that increased to $3.8 billion. Federal partnerships proved crucial, with the effort receiving $4 billion in grants over the last decade and serving as the largest single user of federal subsidized loan programs that saved local taxpayers money.
Lake Washington’s water level fluctuates seasonally. Wind, waves, traffic and temperature cause the pontoons to move. Sound Transit installed specialized track bridges and flexible bearings at the transitions between fixed and floating spans so rails stay aligned. High-tension cables and ballast adjustments strengthened the pontoons for the weight of 300-ton trains.
A second major challenge was stray electrical current. Light rail systems can leak current that accelerates corrosion of steel rebar inside concrete pontoons or weakens underwater anchor cables. WSDOT identified cathodic protection as essential as far back as 2008 to preserve the bridge’s remaining life. The system uses hanging anodes to manage current. Calibrating it was among the last tasks completed before opening.
Quality issues with concrete plinths — the raised blocks supporting the tracks on the I-90 approaches east and west of the floating span — also emerged in 2019. Problems included incorrect heights, voids, poor consolidation, failing mortar pads and faulty fasteners. In 2022 Sound Transit ordered demolition and reconstruction of approximately 5,400 to 6,000 plinths.
The Lynnwood Times reported that contractor Kiewit-Hoffman filed claims seeking roughly $184 million for extra work and delays. A Seattle Times review of claims documents indicated potential additional costs of $250 million or more across impacted contracts were included.
During the COVID-19 pandemic, an ready-mix concrete delivery strike lasting more than four months beginning in late 2021 further slowed progress. The original mid-2023 target to open the Crosslake connection slipped first to late 2024 and then to March 2026 — more than three years later.
Sound Transit later amended the East Link budget twice, adding $80 million in 2024 and $60 million in early 2026, bringing the authorized allocation to $3.817 billion.
Despite the setbacks to the opening of the Crosslake connection, the line now carries riders across the lake with views of Mount Rainier.
Sound Transit and WSDOT continue to monitor the cathodic protection system and the lake environment as they seek a permanent solution to the fish deaths.
Author: Mario Lotmore
One Response
If the cathodic protection system was identified as a possible cause of the fish deaths, how will Sound Transit determine whether lifting the anode strings off the lakebed has actually solved the problem?
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