KLAMATH FALLS, Ore. — The Oregon Department of Transportation is preparing to embark on a long-term project aimed at retrofitting seven bridges in the Klamath Falls area deemed of particular risk in the event of a strong earthquake.
The $32 million project begins this year and will continue over the next four years, ODOT said. Six of the bridges will be retrofitted, though one — on U.S. 97 over Lakeport Boulevard and UP Railroad — will be completely replaced.
"The bridges are located on U.S. 97, which is a primary north-south highway and 'lifeline route' in the event of a major earthquake," the agency said. "Due to its inland location, U.S. 97 is expected to fare much better than the other primary north-south routes I-5 and U.S. 101 – which will be badly damaged or completely destroyed in the wake of a Cascadia subduction event."
Oregon officials have identified these seven bridges as the most vulnerable to a quake of magnitude 8.0 or greater, which is eventually expected in a Cascadia subduction event off the Oregon coast.
Geologists think that the tectonic plates off Oregon's coast shift once roughly every 300 years, resulting in a major earthquake and subsequent tsunami. The last event happened 321 years ago, and scientists believe that another one is overdue.
Klamath Falls also sees occasional localized earthquakes, with ODOT referencing the Scotts Mill and Klamath Falls quakes of 1993.
"U.S. 97 will be the first primary route to achieve its resiliency goal with the completion of the south U.S. 97 bridge bundle," ODOT said. "A similar group was completed last year on the north end of U.S. 97 just south of Biggs Junction."
A contractor for the project will be selected by competitive bid over the summer, with bridge work expected to begin after that.