LATHROP, Calif. -- When Jack Robertson walks his dog atop the earthen levee just blocks from his home, the San Joaquin River rushes past on one side and rows of tract houses unfold on the other.
In Lathrop, a small community that mushroomed on a floodplain in California's Central Valley, 18,000 people live in the shadows of levees that once failed.
To pave the way for thousands more homes and a tripling of its population, the community is making levee repairs funded largely by $5 billion in state voter-approved flood control bonds.
In California, whose antiquated levee system is the nation's largest, such ambitious plans have raised the stakes in a long-running debate over how much should be built behind levees designed in large part to safeguard farmland, not the 1 million people and $69 billion in property now protected by them.
The planned development in Lathrop and other flood-prone places also has raised questions about whether the state's flood control spending is heading off a potentially disastrous problem or will exacerbate it in the long run.
After Hurricane Katrina on the Gulf Coast, California voters approved the bonds in 2006 for improvements to the most important and vulnerable levees and other flood infrastructure. The $5 billion is less than one-third of the $17 billion needed to completely shore up the state's flood protection system.
An AP analysis of the $3 billion spent so far shows the largest expenditures have focused on improving levees in flood-prone areas where development recently occurred and where much more growth is planned. In several cases, the levee projects were also partially financed by developers waiting to build more housing on the floodplains.
In addition to Lathrop 75 miles east of San Francisco, major repairs are taking place to the north in Plumas Lake in Yuba County and in West Sacramento, across the Sacramento River from the state capital, and the Natomas area of Sacramento itself.
Records show $629,290,000 in bond funds were spent in direct costs on these projects, not counting state-wide costs such as levee evaluations, floodplain mapping or flood notifications.
Critics say this is a poor way to spend the state's flood control dollars, because encouraging new development in floodplains puts more people and property at risk. And higher risk means ever-escalating demands for levee repairs, as well as greater rescue and rebuilding costs after flooding.
"It doesn't make economic sense," said Jeffrey Mount, geology professor at UC Davis. "The state should not be funding projects that induce growth and increase flood risk."
But the state has little power over local land use decisions, and local governments need tax revenue from new construction to help pay for levee repairs.
"Communities are caught in a vicious circle," said Mount. "To pay for their share of the cost of levee repairs, they need to have growth on the floodplain." Mount is a former state's levee safety board member who was critical of development and was fired by Gov. Arnold Schwarzenegger in 2005.
State water officials say the Central Valley's flood risk ranks among the highest in the nation and they are spending the bond money to protect existing communities. The levees built along the Sacramento and San Joaquin rivers, they say, are particularly vulnerable to warm rain on top of a heavy melting snowpack, which can fill reservoirs and rivers to overflowing within days.
Although courts have found the state financially liable for levee failures, officials acknowledge the state has exercised little control over years of rapid residential and commercial development on what once were lightly populated floodplains.
But they have begun taking steps to change that, said Mike Mierzwa, senior engineer at the California Department of Water Resources.
A state flood control plan released in December calls for limiting growth in undeveloped floodplains and encourages smarter land use planning. It advocates widening floodways and bypasses and purchasing conservation easements to prevent urban development.
The state also will require urban communities that want to do new development to achieve 200-year flood protection, double the federal standard, by 2025. That level of protection means a flood has a 0.5% chance of occurring in any given year. That corresponds to a 14 percent chance of flooding over the course of a 30-year mortgage.
"Moving to 200-year protection sets the bar a little higher," Mierzwa said. "It causes local communities to think about what they're doing out there, and focus less on protection and more on risk."
Experts say the state needs to do more to limit aggressive development behind levees.
"Climate change may bring larger floods, so we don't have any certainty about what level of protection we really need," said John Cain, director of conservation for California Flood Management at the nonprofit American Rivers. "One day, we could find out that gee, we were wrong, those people we allowed to buy houses behind that levee are in great danger."
Meanwhile, communities that are hungry for development race to have their levees meet the minimum federal 100-year flood standard, as they will be grandfathered in under the lower standard of protection. Once accredited, they are no longer considered to be in a "floodplain" – even if they have experienced frequent flooding.
That level of flood protection means that over the course of a 30-year mortgage, the chance of a 100-year flood occurring is about 1 in 4, or 26 percent.
In Lathrop, a new city hall and more than half dozen developments were built on land which most recently filled with water after the levees leaked during the 1997 flood. The levees, dating back to the mid-1800's, were improved – including recent widening and addition of seepage berms.
Eliud Nduti, a Kenyan immigrant who works as a Bay Area elevator mechanic, bought a house here two years ago. But he said he didn't realize Lathrop was behind a levee until he moved in.
"One day, I just drove up, parked my car and walked," he said. "I was really surprised. This levee is a concern for us, but we can't afford flood insurance."
Other residents, like Robertson, a retired computer company manager, said they feel safe and don't buy insurance because the levees meet the federal 100-year flood protection standard. Federal records show only 173 Lathrop residents, fewer than 1 percent, have flood insurance, which is not required.
In Lathrop, as in several other areas, developers eager to build more housing helped pay for the local share of levee repairs.
More repairs will be needed, said the local reclamation district secretary, Dante John Nomellini Sr. Future development will help raise money so the district can continue paying for more repairs, he said.
Nomellini said his district had little choice but to develop the floodplain and put more people at risk.
"If you have an existing population in place that you want to protect, not developing anymore is not going to help; it's going to hurt," he said. "You've got to increase the risk, because that's how you're going to get revenue to provide increased protection."