A "100-year flood," which would swamp most of Long Beach and all or part of 15 other Southeast and South Bay cities, can be stopped by constructing concrete walls up to five feet high atop levees along 21 miles of the Rio Hondo and Los Angeles rivers, federal officials say.
That $300-million solution, proposed by the Army Corps of Engineers, will be outlined today in public meetings at Lakewood City Hall and in the Los Angeles Area Chamber of Commerce headquarters in downtown Los Angeles.
The proposal, which caps 15 years of study by the corps, is part of a two-pronged federal program designed to eventually contain the two rivers within their banks even after torrential rains--and to provide flood insurance for property owners in a vast, newly defined flood plain in the meantime.
On March 21, in a second meeting, local officials from the 16 cities will be briefed on the expanded federal flood insurance program. All but two of the cities are already participants in the existing insurance program.
Because the program requires flood insurance on any new construction within the flood plain and on homes purchased with federally insured loans, some local officials have already said they are concerned that it could slow home sales and drive away commercial projects.
Flood insurance on affected homes with a $185,000 loan would range from $240 to $530 a year, depending on risk, federal officials said.
In addition to the insurance requirements, the flood program says new buildings must be constructed above the level a 100-year flood would reach.
"The expanded insurance program could be in place within two years, the officials said. Insurance requirements would be repealed when the corps' flood-control improvements are completed, perhaps within a decade, since the risk of flooding would be virtually eliminated, they said.
That the Long Beach, Southeast and South Bay areas need much more protection than previously thought from a 100-year flood--one with a 1% chance of occurring in any single year--was announced by the Corps of Engineers in September, 1987.
The corps concluded that the 100-year flood plain of the 2,000-square-mile Los Angeles County Drainage Area was about 50% larger than it had estimated only two years before.
Engineers now estimate that a 100-year flood would blanket up to 82 square miles with water two to eight feet deep, causing up to $2.25 billion in damage. They say that the flood would damage about 120,000 buildings, including the homes of about 625,000 people.
Though small parts of the San Fernando Valley and downtown Los Angeles would be inundated, the bulk of the flood's devastation would be absorbed by the communities that straddle the lower Los Angeles River and the Rio Hondo south of the Whittier Narrows Dam, the corps reported.
As a result, the construction plan the corps is now recommending focuses on flooding in southern Los Angeles County.
Cities in the flood plain are Bellflower, Bell Gardens, Carson, Cerritos, Compton, Downey, Gardena, Lakewood, Long Beach, Los Angeles, Lynwood, Montebello, Paramount, Pico Rivera, Signal Hill and Torrance. Unincorporated parts of Los Angeles County are also included.
Under the corps' plan, levees along the two rivers, which now are between 20 and 25 feet high, would be raised an average of three to five feet. The plan also calls for raising 24 bridges to accommodate the higher channel and shoring up existing levees where they are weakest.
"It's a pretty benign plan in that we're not taking any land," said Jon Sweeten, assistant project manager for the Corps of Engineers. "The public won't be impacted."
The project was chosen because it protects the most property for the lowest cost, which is the basic federal criterion for judging flood-control proposals, Sweeten said. It would prevent damage of about $2 billion at a cost of $300 million, he said.
From a cost-benefit standpoint the project should rank high, said Cliff Ford, a corps design specialist. Most flood-control projects show benefits 1 to 1 1/2 times their costs, he said.
Comments from today's hearing will be considered in preparing a final proposal that will be submitted to Congress within a year, Sweeten said. Congress will then consider it along with numerous other projects from across the country.
Congress would fund between 50% and 75% of the project, with the rest coming from the state and from Los Angeles County flood-control funds. Construction alone would take up to seven years, Sweeten said.
Some city officials expressed skepticism about the project this week. "The federal government is planning everything for the great disaster that never happens," said Pico Rivera City Manager Dennis Courtemarche. But several others predicted that the corps' proposal will receive strong support.
"It certainly sounds like a good, economical solution," said Carson City Engineer George Schultz.