Storm Barely Tests L.A. Drain Network

Think of underground Los Angeles as one vast storm drain, a catacomb of culverts, gutters, pipes, and, at the heart of it all, the mighty Los Angeles River.

Over the past two days, this network, cobbled together over dozens of years with a billion dollars in bond-issue money, has been put to its toughest test in months.

Who are we kidding? This was its only test in months.

Two days of the heavy-duty mist that we call rain has scarcely wet the edges of the Herculean drainage system built for 10- and 20- and 50-year torrents, for rainfall on an epic scale.

This little squall? Oh yawn. Oh puh-leez.

The people who supervise this labyrinthine system said Friday that they remain unperturbed by so niggling a dampness.

“To us this is just a drizzle,” said Bob Kimura, an engineer in the city’s Public Works Department, which handles flood control and tends its problem spots. “We designed for 10-year storms.”

So thoroughly did they design that their section of the city division, 100 strong in the 1970s, has been reduced to a squad of five. And two of them were off duty on Friday.

So thoroughly did they design that their chief chore in managing this storm-system-without-a-storm is to make sure that drought-dulled Southern Californians do not mistake their curbside catch basins for trash receptacles--and stuff them with old tires, Whopper boxes and sufficient drive-by garbage to clog any rainwater that might ever seek to trickle away.

“I don’t know why people think that’s a repository for their garbage and grass cuttings, but they seem to,” said Don Milne, the deputy director of the Los Angeles County Department of Public Works.

His department operates a network that’s wet and dry and spread all over.

It is the nation’s biggest drainage system in one of the nation’s driest regions. There are hundreds upon hundreds of miles of it, from 15-inch pipes to squared-off double concrete tunnels big enough for a pair of commuter trains to roll through side by side.

Flood or drought, maintenance crews annually check out the 80,000-plus catch basins around the county, raking out the gunk by Nov. 1 so that when the rain comes--if ever it does--the runoff can flow unimpeded.

“We don’t like to use the rains as opportunity to flush our drains. We try to keep them clean,” says Milne. “But when it hasn’t rained for six months or a year, just the stuff on the street . . . is enough” to create problems.

It was plain old garbage in the grates of catch basins that backed up rainwater on the right shoulder and right lane of the southbound Hollywood Freeway on Thursday, said Caltrans district maintenance engineer Richard Kermode.

The Caltrans people know if it has really been raining by checking bellwether spots on the freeways, like the one on the Santa Ana Freeway at Atlantic Blvd., a site that is lower than the land around it.

This week, it behaved like a lamb. Some years ago, though, when underground pumps failed, said Kermode, “there were cars actually floating in the lake created there.”

Inconsequential as the rainfall may have been, enough of it tumbled down the network of pipes and ducts--and into the flood control system that flows seaward--for the county to put its water-trapping devices to work.

At some of the system’s 28 “spreading grounds,” urban lakes that range from a couple of blocks across to 600 acres in size, the order went out Friday to inflate rubber dams and open water gates, diverting the rainwater as it churned down flood control channels to the sea.

The runoff stands in those “spreading grounds” to seep back into the ground water system, said Milne. One-sixth of the water the county uses in a year comes in that fashion, he said.

The dry land and “soft-bottom” channels suck up most of the water from a rain as light as this one. But paved watercourses like the Los Angeles River and the Arroyo Seco deliver the goods more or less intact.

So infrequent are really monumental rains that in past years, flood control workers have had to evict vagrants who took up residence in the concrete caves. They also have booted out strippers of stolen cars who found shelter there for their labors.

And they once displaced a hooker conducting business in a quiet culvert--costing her $75 in profits she stood to lose from clients she had already booked.