State awards contract to replace bridge to volcano; contractor hired to raise Toutle dam
Two long-sought Mount St. Helens-related projects will restore access to volcano blast zone in 2027, block sediment from clogging Cowlitz River
Two significant and long-awaited construction projects near Mount St. Helens are set to go.
Nearly three years after a debris slide destroyed a key bridge to the heart of the Mount St. Helens blast zone, the state has awarded a contract to replace it.
Farline Bridge Inc. of Stayton, Oregon, was the lowest of 10 bidders at $2.68 million and was awarded the contract on March 3, according to the Washington State Department of Transportation.
Farline will replace the span at the far east end of South Coldwater Creek near the outflow of the Spirit Lake drainage tunnel. A slide on May 14, 2023, slammed the old, 85-foot-long bridge with more than 300,000 cubic yards of debris, damaging it beyond repair.
The damage has shut down Spirit Lake Memorial Highway — State Route 504 — at Coldwater Lake since then, preventing access to the Johnston Ridge Observatory. The facility is the marquee volcano visitor center operated by the U.S. Forest Service. Perched at about 4,700 feet above sea level, it offers views directly into the volcano’s crater and lava dome.
The new bridge is scheduled to be completed by late summer, but it won’t reopen until spring 2027 because the Forest Service will need time to restore power and do other maintenance at Johnston Ridge, according to WSDOT.
This timetable means Johnston Ridge will remain inaccessible to the public during the six World Cup soccer matches scheduled in Seattle from mid June to early July. They are expected to attract tens of thousands of fans from all over the world.
Explaining the time it took to launch construction, WSDOT said it needed to study the stability of the steep terrain upstream and design the new span.
Farline’s bid was well below the state’s $3.9 million estimate for bridge replacement, and it was significantly below that of the second lowest bid — $3.1 million, submitted by Stellar J. Corp. of Woodland. The highest bid was $5.14 million from Johansen Construction Co. LLC of Sumner, Washington.
The new, two-lane span will be slightly curved and be about 100 feet in length — about 15 feet longer than the old one.
Mount St. Helens’ eruption on May 18, 1980, blasted away the top of the volcano, flattened 150-square miles of forest, sent mudflows raging down rivers, killed 57 people, destroyed 200 homes and sent clouds of ash around the globe.
Contractor hired to raise sediment-retaining dam for $29 million
For the first time in more than a decade, the U.S. Army Corps of Engineers will raise the height of the sediment-retaining dam on the north fork of the Toutle River to restore its ability to protect Cowlitz River communities from flooding.
The Corps’ Portland District recently awarded a contract to Odin Environmental Solutions, LLC, which was the low bidder at $28.97 million. That’s well below the Corps’ $38.2 million cost estimate.
Odin is a nationwide firm with a western office in Rosewood, California.
The high bidder was Flatiron Dragados Constructors, Inc. with a bid of $42.4 million.
Raising the spillway 10 feet will restore the silt-trapping efficiency of the 125-foot tall rock and earthen dam. The Corps built the structure 40 years ago to check the flow of Mount St. Helens debris into the Cowlitz River, where it can increase flood risks by clogging and raising the riverbed.
The dam works by slowing the river’s flow, forcing it to deposit sediment that it carries off the giant debris avalanche deposit that the volcano dumped into the upper Toutle during the 1980 eruption.
The Corps last raised the dam’s spillway crest 7 feet in 2012, and this modification effectively trapped sediment for about 10 years, according to the Corps. However, the storage area behind the dam has been full for several years, allowing sediment downstream.
Raising the spillway creates more storage space upstream. The corps estimates that the 10-foot spillway lift will enable the dam to trap an additional 90 million cubic yards of material. Stacked straight up, that much debris would bury 67-acre Lake Sacajawea Park about 850 feet deep.
Odin is expected to mobilize to the site in mid-April and start work in May. Work occurring within the river will follow environmental in-water work windows and is scheduled to begin July 1 and conclude by Sept. 30, according to the Corps.
All work is expected to be completed by Nov. 26.
Local officials have expressed concern about the amount of volcanic debris that has accumulated in the Cowlitz and are seeking federal funds to dredge the river. However, the Corps says diked communities along the lower Cowlitz still have authorized levels of flood protection.
The corps “remains committed to maintaining the authorized level of flood-risk protection for communities along the Cowlitz River. The sediment retaining dam and associated sediment-management measures are part of a long-term system designed to slow sediment movement and help protect downstream communities such as Castle Rock, Kelso, and Longview,” according to a Corps statement.
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Excellent news! I look forward to going across the new bridge next year!
This is great news! Both for the scope of the projects and the bids came in under estimates! That doesn’t happen often!