SPENCER MICHELS: This is not New Orleans, 2005. Rather, it's Linda, California, north of Sacramento, 1986, when the Sacramento River broke through the levees that are supposed to contain it.
In 1997, more than 30 levees ruptured, killing nine people and flooding large areas of the state. But that flood, like others, was essentially forgotten within a few months, says University of California geologist Jeffrey Mount.
JEFFREY MOUNT: It got everyone's attention. Everybody ran around in circles and said, "We've got to do something about these levees, and do something about flood control here and nothing happened.
SPENCER MICHELS: Now Hurricane Katrina and the devastation in Louisiana have renewed California's fears a similar event could happen here, even as thousands of new homes are being built in vulnerable areas.
JEFFREY MOUNT: Katrina showed us what could happen. In that time, the population has skyrocketed, particularly on the flood plains.
SPENCER MICHELS: Mount points out that a court recently ruled that the state is liable for damage from most levee breaks, even if it didn't build the levees.
JEFFREY MOUNT: You could bankrupt this state if you had a major levee failure in one of the large metropolitan areas.
SPENCER MICHELS: What Californians worry about is a so-called "Pineapple Express," a series of warm storms coming in from the Pacific Ocean that can melt the snow in California's mountains and dump more water on the state than its rivers can handle. That fast-moving water can undermine and overtop a levee and create havoc.
The area most at risk is California's central valley, along the Sacramento and San Joaquin Rivers, which carry huge quantities of water from the Sierra Nevada Mountains to San Francisco Bay.
Cities built behind the valley's thousands of miles of levees are especially vulnerable, and so is the delta. The delta is a large, mostly below-sea-level region where water from the two rivers courses through hundreds of channels toward the bay past primitively constructed dirt levees built a century ago.
Freshwater from the delta supplies 23 million people in urban southern California and the bay area, and irrigates some of the most productive farmland in the world. If levees were to break, saltwater would be sucked into the delta from San Francisco Bay, ruining the water quality and halting the flow of water south.
JEFFREY MOUNT: This is the fifth-largest economy in the world, and what happens to this economy affects the world. So that's why you worry about it at the highest levels, the disruption of water supply.
SPENCER MICHELS: Storms aren't the only hazard. Mount estimates there is a two in five chance that an earthquake like the one that hit northern California in 1989 will strike the delta by 2050. And that could trigger devastating levee breaks, says Les Harder, chief flood manager for California.
LES HARDER: If we get a large number of islands flooding at the same time, ten, 15 or so, that might be beyond our ability to recover from. And that would be extended outages of water export for the state and its economy, maybe for a very long time. You'd be looking at maybe $30 to $40 billion.
SPENCER MICHELS: Mike and Jerry Robinson live and farm behind levees on an island in the delta, and they have put up with flood danger all their lives. The Robinsons' grandfather and father, like other delta property owners, hired Chinese laborers to build the levees with whatever material was at hand, so the land could be farmed.
Today, even though the state, the Army Corps of Engineers, some cities and local property owners all have some responsibility for maintaining or repairing levees, they still fail with some regularity.
JERRY ROBINSON: What happens periodically are rodents bore through the levees on the below-sea-level islands, and they start leaking at night or when nobody's around, and then all of a sudden a small problem becomes a huge problem.
SPENCER MICHELS: It was a huge problem last year, when a levee on an island known as Jones Tract gave way, ruining crops, shutting down a railroad and destroying roads. The local property owners tried to fix the problem through their reclamation district, but it was too big for them to handle.
JERRY ROBINSON: The local entities ran through their resources in a period of a day. We had rocks on barges and dredgers waiting, but we just had no money. And the state came along, the governor came down, said, "We will help," but it was three days later.
SPENCER MICHELS: Jones Tract repairs and damage totaled $100 million. But that's small compared to the several billion it could cost to upgrade all central California levees, and upgrading is considered vital; whether from earthquake or storms, major damage is envisioned for heavily populated areas along rivers, especially Sacramento, where up to 400,000 people live in danger zones.
SPENCER MICHELS: Like many American cities, Sacramento lies at the confluence of two major rivers. Old Sacramento, where the town began, used to flood regularly. Now it's a tourist area in the shadow of the Sacramento River levee. And in outlying areas not far from the levees, the population has grown tremendously.
Sacramento's levees are designed to protect the city from floodwaters that experts predict could occur once in a century.
LES HARDER: Sacramento has probably got the lowest level of protection for an urban area anywhere in the United States. It only has about 100-year level of protection.
SPENCER MICHELS: Even lower than New Orleans?
LES HARDER: Much lower than New Orleans. Most river cities of comparable size seek protection on the order of 300- to 500-year level of protection.
SPENCER MICHELS: Some of Sacramento's most expensive homes sit just on the other side of this levee, and should the water come over or under or through, the neighborhood could be underwater.
RUSS ECKMAN: You can see the roots of the trees here just how much material we've actually lost out of this site in just the last couple of years.
SPENCER MICHELS: Russ Eckman works on Sacramento area levee maintenance for the state.
RUSS ECKMAN: The water just rips right through here, and erodes it out, and you can see by these soils they're not really all that strong. It doesn't take a whole lot to break these soils down and wash them away. It's not if they are going to fail; it's when they are going to fail.
SPENCER MICHELS: That's a scenario city emergency planners Dave Brent and Jerry Colivas have been anticipating.
DAVE BRENT: The red area is the area that would fill up with a foot of water within two hours.
JERRY COLIVAS: We want to get those people out as quickly as possible. Ultimately, the water gets a lot deeper, and in fact, the water gets to be about 17 feet deep in this area.
SPENCER MICHELS: Seventeen feet deep?
JERRY COLIVAS: Yes.
SPENCER MICHELS: Sacramento officials watched in horror what happened in New Orleans, especially the lack of buses to evacuate residents.
JERRY COLIVAS: I said, you know, "Oh, my God, that's a real problem." And, you know, it rekindled me to say we really have to nail down our transportation.
SPENCER MICHELS: Sacramento would be easier to evacuate than New Orleans since there are many highways nearby, and high ground is fairly close.
But planning for disaster and strengthening levees address only part of the problem. Environmentalists and others fault California builders, who continue to construct homes near levees.
This development at Lathrop, south of Sacramento, was underwater in 1997. It sits just across the San Joaquin River from the island the Robinson brothers farm. In fact, they sold some of their land for development.
MIKE ROBINSON: This was a choice of the community, the city, to build here, to develop it. And it was a choice of the homeowners to buy here and to live here. It was their choice.
SPENCER MICHELS: But what's your gut feeling? Would you build or buy here?
MIKE ROBINSON: I probably would not buy a home here.
SPENCER MICHELS: Because?
MIKE ROBINSON: I know that there will be high water again. I know there may be seepage. I know that water may accumulate in areas and they may be at risk.
SPENCER MICHELS: In the delta town of Oakley, developer Shea Homes is building a large subdivision near a river, protected, they say, by a new $4 million, three-mile-long levee around the entire project. Vice president Don Hofer says the state needs such development.
DON HOFER: We live in a state today that is in dire need of new housing. And a lot of those opportunities exist in areas that are protected by levees. We disclose the entire situation to prospective homebuyers.
SPENCER MICHELS: Despite critics who contend that there are no completely flood-proof levees, the plan has the backing of Oakley Vice Mayor Brad Nix.
BRAD NIX: There is no place which doesn't have some risk of harm from something. That's just the reality of life. What about tornadoes in the Midwest, what about hurricanes in Florida?
SPENCER MICHELS: But the inevitability of flooding has convinced geologist Jeffrey Mount to lobby not just for improving levees, but for state involvement in new development, since, he contends, local politicians are often swayed by developers.
JEFFREY MOUNT: There's tremendous amounts of money to be made by developing on the flood plains. And it is a ruse, an absolute ruse that there isn't room for development outside of the flood plains.
SPENCER MICHELS: All these problems, plus Katrina, have spurred the California legislature to look for solutions.
LOIS WOLK: There are people and communities that are in harm's way unless we invest in our flood infrastructure.
SPENCER MICHELS: Democratic Assemblywoman Lois Wolk is pushing for the state to provide guidelines for land use planning in flood plains.
LOIS WOLK: It is immoral, and frankly irresponsible, to continue to build in the flood plains -- to put our houses there, to put people there, to put schools there.
That is irresponsible, and it's fiscally irresponsible as well because the state is entirely responsible for what happens to those people, not only their lives, but their property.
SPENCER MICHELS: Her plan would make it more difficult to build in flood plains without stronger, state-imposed flood protection, a plan opposed by developers.
DON HOFER: Some regulatory oversight is obviously necessary. We've had that on this project. But does it mean that the state needs to control land use? I don't think so.
SPENCER MICHELS: The legislature will take up flood protection in early 2006. California is considering a bond issue to strengthen its levees, and is asking the federal government for help.
Meanwhile, perhaps 200,000 homes are slated to be built in the delta and near unpredictable rivers in the next few years.