Experts Cite Danger of Building in Basin

Flood control experts say Monday’s devastating flood should serve as a vivid warning to government officials considering proposals to allow more building in the Sepulveda Basin.

Monday’s flood stranded 48 people, but it might have been much worse, they say, if building projects proposed since 1980, and still awaiting action, had been in the path of the floodwaters.

Those proposals include an arts park--complete with museum and subterranean theaters--and commuter rail lines.

“I kind of think what happened will raise the consciousness of the decision makers and people proposing these sort of things,” said Joe Evelyn, chief hydrologist for the U.S. Army Corps of Engineers, which is in charge of constructing and maintaining Los Angeles’ drainage system.

In the ideal maps-and-charts world of federal water engineers, the Sepulveda Basin would be little more than a 2,000-acre open area--a drain into the Los Angeles River for the giant Jacuzzi-shaped San Fernando Valley.

Development of any sort runs directly contrary to those uses. “When you construct a facility to provide flood control, you’re looking to be able to inundate the area behind the dam when it’s necessary to do so,” Evelyn said. “Our policy is to only allow things that are compatible with inundation.”

As buildings, roads and parking lots have covered most of the rest of the Valley floor, the need to keep the Sepulveda Basin development-free has increased because there is nowhere else for the water to go, he said.

That’s why flood damage to a city of Los Angeles sewage treatment plant or city golf courses--repairs for which could cost the city more than $1 million--elicits little sympathy from Evelyn.

On Tuesday, city Golf Director Steve Ball estimated that it could cost up to $500,000 to clean silt and debris from the three golf courses damaged in the flood. Public works officials said it could cost another $500,000 for repairs to the Tillman sewage treatment plant, utilities and roads.

There also are as-yet undetermined costs of restoring baseball diamonds and soccer fields, replacing carpets in a small golf office that was flooded and repairing a few waterlogged park vehicles.

All evidence, Evelyn said, that in a densely populated area like Los Angeles, political pressure can smother policy and prudence.

“In less populated areas, the land resources are available and it’s much easier for us to say, ‘Why put it here?’ ” Evelyn said. “You can’t do that in L.A.”

History also indicates that memories about bad weather are quickly clouded in the face of dwindling open space for building and for recreation.

Although Monday’s storm dropped nearly seven inches of rain in communities whose storm water feeds into the basin--much of it concentrated in several huge downpours at midday--it was far from unprecedented. Meteorologists reported that a bigger storm passed through the Valley in 1980 and one within drops of being as large arrived in 1983.

Yet the Tillman sewage treatment plant was operating in the basin by 1985 and an expansion of it started in 1988, over the strong objections of the Corps. Other proposals considered and rejected, though not because of flood concerns, were polo fields and a permanent site for the San Fernando Valley Fair.

“In a couple of sunny weekends, all of a sudden the politicians and anybody who wants to build there will forget,” said Gerald Silver, president of the Homeowners of Encino. “People just begin to salivate when they see this open space.”

Silver and others criticized the Corps of Engineers for preaching against development, then acquiescing to political pressure. The corps also helps pay for some of the less intrusive recreation developments through a matching grants program.

In 1980, the Cultural Foundation, a private Woodland Hills group, proposed filling a corner of the basin with a $70-million arts park complex to include a children’s arts center, a visual arts center, an outdoor amphitheater, a natural history museum and two subterranean theaters that together could hold up to 2,300 people.

Evelyn said the corps has long been concerned about the arts park’s potential for attracting large numbers of people who would have to be evacuated in a flood.

“We’ve always thought that was incompatible--not a safe thing to do,” he said.

On Tuesday, representatives of the Cultural Foundation proudly pointed out that the northwest corner of the basin, where they hope to locate the arts park, remained above the flood line.

“If areas around Burbank Boulevard were under close to 15 feet of water and the area around Arts Park wasn’t under water, that should be good news,” said Ross Hopkins, interim executive director of the foundation. “My fear is that this might delay things, but my expectation is that this should not affect our project.”

The project, however, continues to have fund-raising difficulties. The project has not yet been approved by the City Council but is supported by West Valley Councilwoman Joy Picus.

The Sepulveda Dam was constructed in 1941 because of several devastating floods in the Valley, including one in 1938 after a storm that dropped 7.74 inches on the Valley floor and killed 49 people.

Based on historical weather statistics, a storm far worse than Monday’s--one of the 100-year variety--is yet to come.

Monday’s flood filled the basin to only about 55% of its 17,400-acre-foot capacity, Evelyn said. But “one day there will be an event that’s more than twice as large as Monday’s” that hydrological charts indicate will send water across the top of the dam, over the San Diego Freeway and into Encino and Sherman Oaks neighborhoods.

Times staff writer David Wharton contributed to this story.