Debate on Clearing of L.A. River Grows

It was a quintessential Los Angeles moment. While ducks gamboled beneath graffiti in a concrete channel of the Los Angeles River and a Metrolink train passed overhead, two press conferences, designed to make the opposite points, took place Wednesday within 50 feet of each other.

The Army Corps of Engineers, smarting from accusations it had dragged its feet in allowing the channels to be cleared of vegetation for predicted El Nino storms, invited reporters to climb down the river’s concrete banks and watch workers remove brush.

A few yards away, state Sen. Tom Hayden (D-Los Angeles), flanked by representatives of Friends of the Los Angeles River and the Sierra Club, took the microphone to deplore the brush clearance.

Hayden scoffed at the idea that clearing vegetation from clogged flood-control channels would increase their capacity to carry water during heavy storms, and said Los Angeles County officials who had pushed for permission to do so were simply using the threat of El Nino to destroy valuable wetlands.

“The possibility of an El Nino event should not be used to destroy vegetation and habitat in the Los Angeles River,” Hayden said. That the Army Corps had sped the permit process to allow Los Angeles and seven other counties to clear out their concrete-lined, soft-bottomed channels--all engineered for flood controls--presents “a mortal threat to every river in the United States,” he said.

The Hayden press conference north of downtown Los Angeles attracted so much attention that the Army Corps canceled plans for a presentation by officials, deciding instead to fell a willow tree for the cameras.

“Don’t you know that there are bugs in those trees that the birds eat?” Marcia Hanscom, co-chairwoman of the L.A. River Task Force, chided a Corps official after the tree came down.

It was a clash not only of values, but of strategy.

To Hayden and the environmentalists, the way to prepare for storms is to develop a new, more natural system for flood control. Taking vegetation out of streams will not increase their capacity, they argue, but instead will only destroy valuable habitat for birds and other creatures.

Flood-control experts, however, say the vegetation takes up space, and therefore a channel’s capacity.

“When you have an area that’s taken up by vegetation, common sense tells you that area can’t be taken up by water,” said Jim Noyes, chief deputy director of public works. “If the water can’t go there, it will rise in height.”

Also, Noyes said, the presence of vegetation in a channel or stream slows the movement of water, which could cause the water to rise and overflow banks.

At the heart of the disagreement between the environmentalists and flood-control experts is Los Angeles’ system of concrete-lined channels, engineered roughly along the paths of streams and rivers in a series of projects from the 1930s through the 1970s.

At the time they were built, it was believed that by containing water in concrete channels, cities could avoid flooding and therefore build houses and other buildings right up to the banks.

But that only works, engineers say, if the channels are kept clear. So under contract agreements with the Army Corps and others, local governments, including the county, agreed to keep them free of brush, trees and debris.

Increased environmental regulation and money troubles at the county level, however, slowed the rate at which the channels were cleared. And so over recent years, reeds, willows and other plants have grown in channels with soft, or natural bottoms.

Last month Noyes told the Board of Supervisors the county had applied for permission to clear the brush nearly two years ago, but regulators had held up the process, allowing even more plants to grow.

With dozens of channels down to less than two-thirds of their original capacity, he said, severe flooding could occur if the growth was not cleared.

Under pressure from supervisors and others, the Army Corps sped up the process, and last week granted an emergency permit to allow the county to clear the channels.

But environmentalists want to preserve these plants, saying they are a habitat for birds and other creatures. Regulatory delays, these activists suggest, far from being problematic, are proof the system is working to protect valuable resources. They criticize the new emergency permit, saying it does not allow the public to comment on proposed work in the riverbed.

Like Hayden, many at Friends of the Los Angeles River and other organizations are critical of the flood-control system as a whole, saying that it never should have been built.

Instead of clearing the channels and continuing to rely on concrete, said Lewis MacAdams, spokesman for Friends of the Los Angeles River, the county should pull up asphalt parking lots throughout the region and allow the rain to soak into the earth.

That, he reasoned, would spur the flow of water into aquifers and reduce the need for extra space in the flood-control channels.

Hayden suggested removing asphalt playgrounds at area schools would serve a similar purpose.

Such actions might help, said Fred-Otto Egeler, spokesman for the Army Corps of Engineers, but neither the Army Corps nor the county has jurisdiction over those areas.

“It will help water percolate into the aquifer,” Egeler said. “That’s only logical. But then what are they going to do with all those thousands of cars?”