Rising Fear of El Nino : Flood control: System has been reinforced since devastating storm of 1983, but costly improvements still aren’t finished.

Nine years ago, Marie Holland watched from her hilltop home in Huntington Beach as floodwater gushed into hundreds of houses and businesses below.

“I moved to Orange County six months before the 1983 storms,” Holland said. “It was so severe that the water rushing through the gutters had actually lifted the manhole covers.”

Since then, she has moved down from the hill to a home a stone’s throw from an earthen flood control channel where major flood damage occurred that year. This year’s return of El Nino, Holland said, “makes me nervous.”

“Everyone on the beach has been asking us about El Nino,” said Mike Beuerlein of the Huntington Beach lifeguard marine safety division. “It seems that the red flag is popping up in people’s minds.”

On March 1, 1983, a tremendous rainfall--four inches in six hours in central Orange County, the most concentrated ever recorded there--closed the Santa Ana Freeway for 20 hours, flooded 1,000 homes both near the coast and inland, ripped off the end of the piers at Huntington Beach and Seal Beach, and caused as much as $160 million damage to public and private property countywide.

The storm was triggered by the El Nino condition, the accumulation of a vast pool of warm water in the eastern Pacific Ocean that stretches westward along the Equator. The energy generated by the warmth of the water disrupts global wind and precipitation patterns.

With El Nino officially formed now, according to the National Weather Service, local residents and officials are worried that the deadly storms which ripped through the Southland last week foreshadow another season of relentless tropical storms like that of 1983.

The heaviest rains of the past week measured 2.32 inches in central Orange County over seven hours Wednesday, extremely heavy but not comparable in severity to those of 1983. And in general, the flood control system held up well, officials said.

“The breaks in the storms were really the key,” said Francisco Alonso, a county flood control official who manned a pump station on the Huntington Beach channel this week. “The system is pretty much purged, and the channels are down. But if there was no break between storms, the system would not have time to recover, and then we would have more problems.”

Both residents and local officials worry that runoff in the network of channels and storm drains could rise past capacity under intense coastal rains.

“We need storm drains that can at least handle the average big storm every year,” said Robert Eichblatt, a Huntington Beach civil engineer who oversees the city network of storm drains.

Huntington Beach spends about $500,000 each year on flood control, but needs to spend an additional $40 million on storm drains and catch basins to provide adequate protection from heavy rains, Eichblatt said.

Those local drains feed about 245 miles of open channels which stand between residents and surging runoff, said Bill Reiter, director of maintenance programs for the county.

While cash-poor city governments struggle to maintain catch basins and storm drains to contain the street flooding in low-lying residential areas, the county has been working to upgrade and repair the network of flood channels to collect the runoff from those drains.

Those channels, which are banked by walls of cement or soil to steer runoff toward the ocean, criss-cross much of the county’s populated regions. The county’s Storm Operations Center has rainfall gauges planted in those channels to monitor water levels. Each gauge feeds information into a central computer that helps officials detect problems.

In 1983, “we did not have an alert system in,” said Mel Newman, storm center director. “But now we have improved reaction time and monitoring.”

The surprise of the 1983 storm inspired the installation of the computer system to improve reaction time, said Lane Waldner, supervisor of environmental studies at the County Environmental Management Agency.

The county spends about $20 million annually on flood control, according to Herb Nakasone, a county official. But a 1988 study by the Environmental Management Agency estimated that the county’s system was so riddled with deficiencies that it would take 25 years to rectify at a cost of about $1.3 billion.

Nonetheless, county officials said they are “pleasantly surprised” with how well most flood channels have handled the surging runoff of the recent storms.

“The channels are basically empty,” said Tom Connelie, manager of maintenance systems, after inspectors spent Thursday evening walking the channels. “The channel walls are still at their design height, but some erosion has left many levees not as thick.”

Crews were at work throughout the week clearing out channel bottoms, sandbagging the walls and unclogging storm drains that feed the channels in preparation for future storms.

Running through the network of city-maintained drains and county-maintained channels is the Santa Ana River, which has been identified by the Army Corps of Engineers as posing the greatest flood threat west of the Mississippi River. The Santa Ana flood plain covers nearly all of western Orange County, stretching north into Santa Ana and Anaheim.

More than $1.4 billion will be spent on the Santa Ana River project, now under way. Improvements include increasing the river channel capacity and raising the height of the Prado Dam near Corona.

The project is designed to increase channel capacity to hold the precipitation from potentially disastrous storms which batter the mountains of San Bernardino and Riverside counties.

But river improvements are no panacea for harnessing intense, coastal rains like those of the past week. In fact, the Santa Ana River channel was not severely tested by the 1983 rains, according to an Environmental Management Agency study.

Rather, coastal downpours feed the network of city storm drains and county flood channels.

Nine years ago, flooding was concentrated in Huntington Beach, where three earthen channels cut through the city and spill into the ocean at the mouth of the Santa Ana River.

Much of the flooding occurred after surging waters breached those channels, which have since been improved with concrete linings.

Officials say that unless millions are spent to further improve those channels in Huntington Beach’s Talbert Valley system, the threat of widespread damage will never disappear. If the rainfall that fell Wednesday had doubled in intensity, officials say none of the improvements which proved effective would have prevented a repeat of 1983.

Despite the success of the Talbert Valley system this week, officials say that the channels still need improvements which would require more than five years to complete at a cost to county taxpayers of about $60 million.

“We are planning (further) improvements in that area,” said Phillip Jones, senior civil engineer in county flood control design. “But if a storm hit the same area as the 1983 storm did, we’d have the same problems as last time.”

Putting Flood Preparation to the Test

Powerful coastal rainstorms caused by the unusual El Nino weather condition flooded 1,100 homes and caused $160 million in damage on March 1, 1983. Last week, the flood control system stood up to new El Nino-driven storms, but officials still worry that improvements made in the last nine years may not be enough to prevent major flooding.

1983 VS. LAST WEEK

1) Huntington Beach

1983: 700 homes flooded when three major earthen channels suffered failures.

Changes: Concrete-lining added to a portion of one channel where major flooding occurred. Work begun to expand overflow basin in area. When complete in 1994, pumping station will transfer water to Santa Ana River.

Last week: Runoff in dirt-walled channels flowed smoothly to the ocean. Some erosion occurred, but no residential damage.

2) Carbon Creek Channel

1983: 71 Cypress homes evacuated as channel overflowed.

Changes: $8 million spent to concrete-line stretch from Moody Street to Walker Lane and to upgrade overflow basins.

Last week: No problems reported.

3) Santa Ana-Delhi Channel

1983: Water spilled over dirt banks from Bristol Street to Mesa Drive.

Changes: $12 million spent to concrete-line and eliminate channel bottlenecks.

Last Week: Some erosion where lining project continues near Bristol, but no damage.

4) Anaheim-Barber City Channel

1983: Overflowed at Rancho Road and Graham Street. Seven residences suffered minor damage.

Changes: $8.6 million spent to concrete-line portions of channel and eliminate bottlenecks.

Last Week: No problems reported.

5) Oso Creek Channel

1983: Channel flooded onto stretch of Camino Capistrano at Avery Parkway.

Changes: $4.5 million spent to raise levees and improve concrete-line channel.

Last Week: No problems reported.

WHAT IS “EL NINO”?

A phenomenon known as El Nino can fuel powerful and wet winter storms in California. The condition develops near South America.

1) Warm water: For unknown reasons, a much larger area of warm water than normal develops off coast of South America.

2) Jet stream changes course: Expanse of warm water can alter global weather patterns. The subtropical jet stream, normally well south of California, may approach the state.

3) Moisture feeds storms: Jet stream carries moist, tropical air from central Pacific to California. This air fuels winter storms that come down from Alaska, making them drop more rain than normal.

Source: Orange County Environmental Management Agency; March 5, 1983, Red Cross Damage Report; WeatherData

Researched by BOB ELSTON and DANNY SULLIVAN / Los Angeles Times