The Bee began a series yesterday about the danger of flooding in Sacramento, (they also did a series on flooding in 2004), and promises to look at all of the issues and all of the options.
The first articles in the series is excellent.
Tempting fate: Are we next?
Sacramento’s flood peril is highest in U.S.
By Deb Kollars — Bee Staff Writer Published 2:15 am PST Sunday, October 30, 2005
First in an ongoing examination of the region’s flood risks
In cities across the nation, rivers, streams, lakes, creeks and seas have made their sinister mark, inflicting damage and heartache when they flood.
There is, however, no major city in America more at risk of a catastrophic New Orleans-style flood than Sacramento.
That is the firm and unnerving conclusion drawn from a Bee survey of the 30 largest metropolitan areas in the nation, conducted over the past month. Compared with other big cities, Sacramento is marked by a potentially deadly combination of geographic, hydrological and demographic factors unmatched anywhere in the United States.
Take a look at the collection of strikes against us:
* We sit at the confluence of two major rivers, the Sacramento and the American.
* They drain vast watersheds that begin high in the mountains, meaning a major flood would come with staggering volumes and ferocious velocities.
* Huge sections of Sacramento – including miles of neighborhoods, the downtown commercial center and the state Capitol – rely on levees to keep from going under in times of high water.
* Unlike other cities that sit on high ground or bluffs above rivers, much of flood-prone Sacramento sits lower than the levees and the rivers at flood stage. That means places such as Natomas, downtown, east Sacramento, Rosemont, North Sacramento, Oak Park, Curtis Park, Land Park, River Park, Greenhaven, the Pocket, south Sacramento and assorted neighborhoods along the north and south sides of the American River would fill up like giant soup bowls during a disaster-level flood.
* Sacramento’s levees offer less protection than those in many other cities. Officials worry they could fail or overtop if a large late winter or early spring storm system brought more water than they were designed to handle. Warm “Pineapple Express” systems are especially feared, because they can sidle up against the mountains, rain for days, and cause too much snow to melt at once and barrel down river corridors.
* Recently, a new and insidious worry has emerged: Engineers discovered after the floods of 1997 that seepage is occurring deep beneath Sacramento area levees that could cause internal erosion and unforeseen failures.
* Beyond the levees is another concern: Folsom Dam, which holds back the American River to the east of the downtown core, is ranked No. 1 on the federal Bureau of Reclamation’s safety priority list. With nearly a million people living downstream, no other dam in America has greater need of additional protection against a monster storm, according to the bureau.
* Finally, unlike other cities, where flooding may be severe but tends to occur on a localized scale, a major flood in Sacramento would spread for miles and run as deep as rooflines in some places. According to the Sacramento Area Flood Control Agency, more than 300,000 people and 140,000 structures are in the direct path of a serious flood in Sacramento.
In the eyes of the nation’s top flood experts, only one other big city could rival Sacramento for the top catastrophe-prone title.
And it has been largely destroyed.
For the rest of the story: http://www.sacbee.com/content/news/projects/flooding/story/13790554p-14632249c.html