A levee protecting eastern Manteca has a provisional bill of health from federal officials.
The Federal Emergency Management Agency had eyed the levee as a possible problem spot. But it issued the provisional approval, according to a recently released map.
Local levee officials must provide the federal agency with proof the levee would hold in a 100-year flood, the kind estimated at a 1 percent chance of happening each year.
Reclamation District 17, which owns the levee, has until Aug. 23, 2009, to provide that data. In the meantime, it is listed as provisionally accredited on a preliminary new map.
The area includes luxury homes on the former site of the Manteca waterslides east of the city, a subdivision north of Woodward Road and east of McKinley Avenue within the city, and areas designated for development in the city's general plan.
Even protected, the areas are within the so-called 0.2 percent annual flood zone -- that is, an area with a 1 in 500 chance of flooding every year.
"One thing we need to emphasize to people, something we have always wanted to emphasize and particularly after Katrina, is that levees are not perfect," said Jim Stone, deputy public works director and flood-plain administrator for the city of Manteca. "Levees do fail. And because they fail or because a storm comes along that is so big the levee can't handle it, people who live behind levees should be aware there is some risk. None of our levees are designed to provide protection from the 500-year flood."
The maps show that a 1-in-500 chance flood would reach even farther west in pockets north and south of the Highway 120 Bypass. The maps are a preliminary version of updated flood maps being prepared by FEMA for insurance purposes, which are expected to be final next year. When the maps are done, those living in areas within the 100-year flood area will be required to carry flood insurance.
But Stone encourages homeowners anywhere within even the 500-year flood zone and nearby to buy insurance. For homeowners in a low-risk area, insurance runs about $317 a year for coverage of $250,000 on a house and $100,000 on its contents, according to an estimate provided on FEMA's Web site. The premium jumps to $2,462 a year in high-risk areas.
"All we have are calculations about where the water might go," Stone said. "We don't know exactly how nature is going to perform. So if people have a lot of equity in their home, they might want to think about getting that protection."
The levee, which runs between Stockton and Manteca, is known for seepage. But that isn't necessarily a problem unless the flow carries with it soil from the levee, and the reclamation district maintains that the levee meets requirements.
In accordance with the levee's 1990 accreditation, workers watch for soil flow and shore up the levee with sandbags and gravel blankets when necessary. Stone said the district and cities also are working to improve the levee.
Stone said the city is planning information sessions within a month or two.
San Joaquin County will have maps available for viewing from 1 to 5 p.m. today and 10 a.m. to 2 p.m. Friday in Conference Room A at its office at 1810 E. Hazelton Ave. in Stockton. Maps also can be found online at www.sjgov.org/pubworks/firmpanels.htm.
Bee staff writer Inga Miller can be reached at email@example.com or 578-2324.