City talks Big Creek Dams failure

Tim Gross, center, talks to a crowd of local citizens interested in reconstruction of the Big Creek Dams. The city engineer gave the crowd a tour of the dams on Wednesday, talking about how important it is to secure money for rebuilding the dams, as well as how the current dams will fail during an earthquake. (Photo by Madeline Shannon)

NEWPORT — The pending Cascadia earthquake local officials expect to decimate the Big Creek Dams will leave Newport without access to other sources of water, city officials said this week, one of the many concerns that the city engineer believes warrant a reconstruction of Big Creek Dams.

“We’d have no water supply,” Gross said during a tour of the Big Creek Dams site Wednesday designed to put the problem squarely in the public eye as the city gears up to pursue funds for the new dams.

“There is no alternative water supply to Newport,” Gross said. “Nobody else can produce the amount of water we need and no one can pump us the water we need. We’re all on our own.”

The lack of water in the event of dam failure wouldn’t be the only problem, the longtime engineer said. Because of the amount of water held in the Big Creek Dams, those in the Lakewood Hills area would be trapped there if the dams burst, Gross said.

“We know exactly what homes would be in that area and what water would come through,” Gross added. “At 19,000 gallons per second would be traveling through the pace of the upper dam at the initial failure. A lot of water comes really fast, and that’s the initial scary part. People’s lives would be lost.”

Those aren’t the only issues at stake in the event of a dam failure. Chances of rebuilding the dams and restoring the water supply after a major earthquake is almost zero, Gross said, compelling the community to take action before an event that destroys the dam.

“That’s the urgency of what we’re trying to accomplish here,” Gross said. “It has to be done now because we can’t wait for an earthquake to cause it to fail.”

The new dams, once construction gets underway, will take about four years to build. If all the money for the project were available now, getting the project “shovel-ready” would take two years, according to Gross. With that money not yet in the city’s pocket, even two years of prep work before construction begins is a wishful timeline.

“Being realistic, we’re going to be lucky to see a dam here in 10 years,” Gross said. “I don’t see how we’re going to be able to raise the money faster than that. I don’t see the state just handing over $70 million.”

Despite the challenges in securing enough funding for reconstruction of the dams, local officials are working with state officials to show them what those on the coast are working with when it comes to the importance of the dams.

“We’ve had people from Senator Merkley, Senator Wyden and Kurt Schrader’s office come out here,” said Newport Mayor Dean Sawyer. “They’ve been standing here, so they understand what our problem is.”

The price tag for rebuilding earthquake-resistant dams before the currently-used ones fail is $60 million to $75 million, by Gross’s estimates, far more than the city can pay for on its own. That’s why city officials are in communication with state legislators about getting the money Newport needs to rebuild the dams.

So far, the city acquired two $250,000 grants, according to Gross, and another $250,000 grant is pending. The money might only be a drop in the bucket, coming out to one percent of the overall cost of the project by Gross’s estimates. The city made an additional $44 million from the state legislature, but city officials expect about $10 million to actually come the city’s way from that request.

Part of the problem is the soils under the dams, which will give way and fail to support the structures above ground. The severity of the 200-second earthquake would cause the material under the dams to move like Jell-O, Gross said, which is different from liquefaction.

“You hear that word all the time with earthquakes,” Gross said. “That’s where you have sandy soil and water gets in it and makes the particles spread apart. That’s not how this fails — this is a soupy Jell-O. It’s like taking something and shaking it over and over again until it starts to drop.”

The bottom of the dam will kick out and water will go over the top, he added, which would happen even in a moderate earthquake scaled at 3.5 or above on the Richter Scale.

In 2017, the city estimated the total financial loss of the dams would total $327 million in gross domestic product and would affect thousands of people with jobs in and around the community. HDR Engineering conducted a study that saw the Oregon Department of Water Resources to elevate the Big Creek Dams to be one of the two most critical dams in the state.

Citizens who were part of the tour earlier this week were aware of the structural deficiencies of the current dams, and want to see safety measures included in the reconstruction of the dams.

“These need to be replaced, so we got to do something,” said Mike Broili, a local man who worked in the water resources industry for 25 years.

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