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54 °F 5 Day Forecast Friday, November 28, 2003 Today's News | Classifieds | Autos | Homes | Jobs | Tempo | eSouthernOregon | Home Delivery SECTIONS Home Page Local News Sports Business Obituaries Life Opinion - Politics AP News Weather Classified Archives Site Map EXTRA Newspaper in Education Personals Movie Times TV Times E The People CLASSIFIEDS Find a Car Find a Home Find a Job Find a Rental Place an ad eSouthernOregon Automotive Communities Entertainment Publications Recreation Calendar CUSTOMER SERVICE Frequent Questions Advertising Information Home Delivery Employment Contact Us Media Kit Network Affiliate Email Story to a Friend October 12, 2003 Dam engineers prepare for catastrophic waters Iron Gate in Siskiyou County upgraded to handle 1,000-year flood By MARK FREEMAN Mail Tribune Northern California’s Iron Gate Dam is getting beefed up to handle the mother of all Klamath River floods — if one ever comes. The 41-year-old earthen dam is getting raised 5 feet and its bedrock spillway will get a slicker surface in preparation for a Noah-like flood, the kind likely to occur once in more than 1,000 years. State and federal regulations require Pacific Power, which owns the dam and small power-generation plant in Siskiyou County, to retrofit Iron Gate Dam to ensure that water would not spill over its top during what would be the biggest flood the Klamath Basin could generate. "It’s really preparing for a worst-case scenario, a flood of biblical proportions," said Jon Coney, a Pacific Power spokesman in Portland. "It’s a 1,000-year flood and then some." Advertisement The dam, built of earth and rock, is not anticipated to fail under those conditions, Coney added. Iron Gate Dam is the fifth dam on the Klamath. It’s the lowest dam on the system and creates the 944-acre Iron Gate Lake in eastern Siskiyou County. The dam — standing 173 feet tall — is the only earthen dam on the Klamath River and was the last one built. It is meant primarily to control river flows downstream. Construction crews are now installing tongue-and-groove metal sheets to raise the dam top 5 feet — effectively giving Iron Gate a long iron gate across its top. The work will raise the lake’s maximum surface and control the pace of water flowing down its north-side spillway during the worst flood imaginable, Coney said. The top portion of the spillway is carved directly out of bedrock while the lower section is concrete. As part of the project, construction crews will line the bedrock with gunite (a concrete mixture sprayed under pressure) so water will spill more quickly during a massive flood. "It’s basically the same stuff you spray on a pool," Coney said. "It gives it a slicker, smoother surface so it spills water faster and more efficiently." The work is strictly for flood control and Iron Gate Lake will remain the same size and depth, Coney said. The work is being done by W.G. Moe and Sons, based in Portland. Work began two weeks ago and is scheduled for completion in mid-December. The entire project, including studies and engineering reports, will cost Pacific Power about $1.4 million, Coney said. Hydrologists often label floods by their likelihood of occurrence, usually expressed in the type of event expected once in so-many years. The 1997 New Year’s Day flood that sent Ashland Creek water cascading through downtown Ashland was considered smaller than a 70-year flood, or one likely just once every 70 years. The Rogue River flood of 1964 was a 100-year flood. Reach reporter Mark Freeman at 776-4470, or e-mail [email protected] Mail Tribune Home Local News | Sports | Business | Obituaries | Life Opinion - Politics | AP News | Archives | Site Map E Southern Oregon | Classified Copyright © 1997-2003 Mail Tribune. All rights reserved. Privacy Policy | Terms & Conditions Website Feedback 3 WEEKS FREE! ADVERTISERS SPECIAL SECTIONS Auto Finder Job Finder Home Finder Joy Magazine Homelife Magazine Tempo Real Estate Showcase Food for Thought Hike of the Week Wellness Connection Outdoor Journal Moving to Southern Oregon? Volunteer Openings Prime Times