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Medford wants an earthquake-proof sewer plant By MELISSA MARTIN Mail Tribune The city of Medford wants a guarantee that its sewer plant would keep working if an earthquake shook Southern Oregon. The city hired a Washington company to add steel cables and reinforcing beams to protect treatment processes in the event of a major groundshaking. Some 108,000 people depend on the Regional Water Reclamation Facility that treats sewage from homes and businesses in Medford, Central Point, Jacksonville, Talent, Phoenix and Eagle Point. Water board prepares for quake strengthening The Medford Water Commission is gearing up for earthquake upgrades. Engineers will design seismic upgrades for the Robert Duff Treatment Plant beginning in 2005, said Larry Rains, the Medford Water Commission's principal engineer. The Medford Water Commission provides drinking water for about 100,000 people in Medford, Eagle Point, Jacksonville, Central Point, Phoenix, Talent and White City. About five years ago, the commission had an earthquake analysis done for all of its facilities except the treatment plant on the Rogue River near TouVelle State Park The commission has checked off several items from the recommended list of seismic upgrades, including removing a water tank on Pierce Heights in Medford that easily could have tumbled down the hill during a quake. Crews also stabilized generators at Big Butte Springs, the commission's year-round supply near Butte Falls. "The Regional Wastewater Treatment Plant provides for public health by treating sewage," said Cory Crebbin, Medford's public works director. "If we have an earthquake and the plant can't treat sewage as a result, there will be a whole lot of raw sewage around creating a serious public health threat." The Medford City Council last week awarded a $247,000 contract to Diamaco Inc. of Bellevue, Wash. This is the second time Medford has upgraded the Kirtland Road plant. But this time, the city is preparing for an even bigger quake. "Often times, we don't know where all the faults are, and that's certainly the case in the Medford area," said Yumei Wang, director of the geohazard program for the Oregon Department of Mineral Industries. "They take us by surprise." The upgrades will prepare the sewer plant for an earthquake that has a 2 percent probability of occurring in 50 years. That can't be translated into a magnitude, Wang said, because geologists have changed the way they predict earthquakes as they learn more about Pacific Northwest fault lines. While Medford felt a magnitude 5.8 quake in 1993 that originated near Klamath Falls, such tremors would pale in comparison to a quake originating off the Oregon coast. Geologists predict a big event - a magnitude 8 or 9 earthquake - originating from the Cascadia Subduction Zone, which extends from Northern California to British Columbia. Cascadia earthquakes occur about every 300 to 600 years, and the last major event took place in 1700, according to the U.S. Geological Survey. By comparison, the earthquake originating near Olympia, Wash., in March 2001 had a magnitude of 6.8. At the regional treatment plant, crews will work through the summer on the upgrades, which include: Adding steel cables to the top of the trickling filter, the plant's first biological process, where growing organisms begin breaking down raw sewage; At the aeration basins, building 6-foot, steel-reinforced concrete walls between the two tanks, where oxygen is injected into the waste to further break it down; Bracing the walls of the digester control building; Adding more bracing to the 85-foot-wide dome cover that catches digestive gases in the anaerobic digesters. The dome needs more bracing, explained Harley James, Medford's water reclamation division superintendent. Devices allow the cover to move without twisting. "If we do get a quake that could create a wave in the tank, it would prevent the dome from coming off the tank," James said. The upgrade will be paid for from user fees, James said. It will not cause an increase in Medford sewer bills, which are $4.66 per month. Neither will the project add to the $1,212 in system development charges, one of the fees added to the cost of building a single-family home. The upgrades will further protect the solidly built plant, said Paul Albertine of Miller Engineering. The city paid his firm $76,320 in September to design the seismic upgrades and oversee the construction work. "The facility would do pretty well during the earthquake," Albertine said. "The damage we would expect would be minor in terms of the integrity of the plant, but it could stop plant operations." Mail Tribune Home | Ottaway Newspapers, Inc. | Dow Jones & Co., Inc. | Privacy | Contact Us Copyright � 2001 Mail Tribune, Inc.