Here is an excerpt.
“Around the country, 15,000 miles of dirt levees serve as the final line of flood defense for major cities, rural communities and undeveloped farmlands. Federal projects built roughly half, but most are now maintained — often haphazardly — by local governments and flood-control districts. Corps inspectors drive by once a year to check for signs that tree roots, animal burrows or other obvious changes are undermining the structure’s integrity. “It’s not a detailed examination. They can send a ’buck up’ letter if a city is not doing a good job,” says Galloway, now an engineering professor at the University of Maryland.“If faulty levees fail, Galloway worries that heavily populated parts of St. Louis, Dallas, Denver, Houston, Tacoma, Los Angeles, St. Paul and Louisville could be flooded. At greatest risk, many experts believe, is California’s state capital. “If I were living in Sacramento,” Galloway says, “I’d be very concerned.”
CLOSE CALLS
“Sacramento, in fact, is just as vulnerable as New Orleans. “Katrina was a wake-up call for anybody who lives behind a levee,” says Sacramento Mayor Heather Fargo.
“The city grew up where the American River rushes down from a steep Sierra Nevada watershed to feed into the Sacramento River. It relies on 125 miles of earthen levees, many dating to the early 1900s. Quite possibly, those defenses could give way if heavy rains roll in from the Pacific Ocean and melt Sierra Nevada snows above the city. The resulting flood could inundate virtually the whole city, surrounding the California state capitol with water and driving 400,000 residents from their homes.
“In 1862, Governor Leland Stanford was rowed through Sacramento’s streets to take his oath of office in the Capitol. Following that episode, Sacramento tried to protect itself by raising the downtown district by 15 feet and later by building hodgepodge levee defenses. To hold floodwaters upstream, the federal government finished building Folsom Dam on the American River 23 miles above Sacramento; in the mid-1960s, a bypass channel was built to divert 80 percent of the Sacramento River away from the city’s core. But some levees, built when land was still being farmed, were too low and too flimsily maintained to handle even a 50-year flood, leaving Sacramento and the surrounding regions exposed.
“Indeed, Sacramento has eluded close calls in each of the past two decades. In January 1986, jet-stream winds sped warm Pacific rainstorms straight from Hawaii (a phenomenon that’s been dubbed “the Pineapple Express”) and thawed heavy Sierra Nevada snowpacks. For 10 days, “we had a whole series of storm systems charging right at us, and we would have lost our levees if there’d been just a few more hours of rain,” recalls Stein Buer, the Sacramento region’s flood-control chief. Sacramento barely escaped again in the winter of 1997, when the heaviest Pacific storms swerved north of the American River watershed.
“After the near-miss in ’86, local governments began reinforcing levees and raising them by three feet. Two years from now, two-thirds of the city will be protected against a 100-year flood, freeing homeowners from the federal government requirement that they buy flood insurance. “We do think that a 100-year level of protection is pretty minimal,” Fargo says, so California politicians are pressing Congress and the Corps to expand floodwater storage capacity behind Folsom Dam. This summer, however, the Corps tripled its original $215 million cost estimate for Folsom improvements.
“Meanwhile, the metropolitan area’s population of 1.5 million continues to grow, and development is extending onto delta farmlands behind questionable rural levees. This summer, the state agreed to pay $428 million to 3,000 residents whose homes were flooded when the 1986 storms broke one Yuba County levee 40 miles north of the capital. In June 2004, a levee 10 miles from Stockton, California, collapsed suddenly in good weather, and 19 square miles of cropland was flooded under an average of 12 feet of water, causing $100 million in damage. It took seven months to pump the water out and repair the breach.
“With the delta sinking and sea levels rising due to global warming, geologists at the University of California at Davis calculate there’s a two-out-of-three chance in the next 45 years that an earthquake or winter storm will breach enough levees to disrupt water deliveries to Los Angeles and other Southern California cities for months or even years.
”A system designed almost 100 years ago can’t support the amount of change that’s going on here, but so far we’ve shown no willingness to invest enough to fix the problem,” says Jeffrey Mount, one of the UC-Davis scientists. In November, Congress appropriated $38 million over the next year to start beefing up Folsom Dam and keep shoring up Sacramento’s levees. It also approved $12 million to continue Napa’s project and dedicated $750,000 to emergency levee assessments in the vast delta where the Sacramento and San Joaquin rivers flow into San Francisco Bay.”
