Though we are more worried about droughts than flooding at this moment, it is good to remember, and there is an excellent article, "The Coming Deluge", in the February issue of Sacramento Magazine (pp. 138-149) which spends some very well-spent ink on the Auburn Dam. Unfortunately there is no link to the article, but here is the section on the dam and 500-year level flood protection :
“Flood control has been a passionate issue for U.S. Rep. John Doolittle from California’s fourth congressional district; his obstinate push for a flood control dam at Auburn pitted him against his colleague, Rep. Robert Matsui, for much of his political career. Critics said the dam would destroy the land and disrupt recreational sue of the area.
“Doolittle believes area residents and politicians alike are in a state of denial when it comes to our flood risk. “City councils have been swept out of office because of floods,” Doolittle says, adding that “the evasiveness [you’re seeing] about evacuation plans and the flood protection we have versus the flood protection we need is…a result of posturing politicians. People want to talk about it enough to say they tried to get funding, but we don’t want to talk about it [to the extent that] it may scare [away] business [investment].” What we need, says Doolittle, is to “control the rivers.” What we need, he says, is 500-year flood protection.
“Sacramento faces up to a 5---year flood event,” he notes. “Why are we putting all our eggs in a basket of 200-year flood protection? You hear all this talk of improvement of the levees to provide 200-year flood protection. Why?”
“Doolittle likens 200-year flood protection to equipping automobiles with seat belts that protect passengers at speeds up to 30 miles per hour “when most cars travel at speeds of 40, 50, 60 miles per hour,” he says. It’s why talk of an Auburn Dam, which could provide 500-year flood protection, has resurfaced.
“It’s stunning to me that the state of California and the city of Sacramento…aren’t riveted on achieving that level of flood protection, “ Doolittle says. “The idea that we can’t afford 500-year flood protection is gross incompetence. We can’t afford not to have it.” He argues, adding that damage estimates in the event of a flood totaled $40 billion—and that figure was tabulated 10 years ago. Given the growth in property values and population that have taken place since 1996, “imagine what that number would be today,” says Doolittle.
“Indeed, according to estimates by the U.S. Army Corps of Engineers and California’s Department of Water Resources, Sacramento could not handle 500-year flood levels at the I Street Bridge in Old Sacramento. Water would rise to above 38 feet—and over the bridge. Maximum flows from a 500-year flood event along Fair Oaks Boulevard, which runs somewhat parallel to the American River though several Sacramento suburbs and into town, could reach 530,000 cubic feet per second (compared to the 134,000 cubic feet per second of 1986) and top54 feet at the Watt Avenue bridge (which reached 47 feet in 1986 and 45 feet in 1997). According to maps available from the Department of Water Resources and SAFCA, several evacuation routes would be underwater in a matter of hours. If two or three levees failed at once—one in Natomas, one in Goethe Park and one downtown—it’s conceivable that, for whole communities, there would be no way in and no way out.” (pp. 142-146)
