Construction of a proposed sewage system for Malibu, including a $38-million treatment plant in Corral Canyon, would periodically disrupt traffic on already-clogged Pacific Coast Highway for two years, according to a county consultants' report.
Pipes would cross the Malibu Coast Fault in three spots and run through numerous landslide areas.
Corral Creek, about three miles west of Malibu Canyon Road, would be lined with concrete. Once the plant began operating, a year-round stream of treated waste water would flow across Corral Beach to the sea.
Individual property owners served by the system would be assessed fees ranging from $13,000 to $26,000 apiece to finance the plant, pipes and hookups, the report says.
The Corral Canyon proposal has been recommended by consultants from James M. Montgomery Consulting Engineers as the best of 16 options for disposing of Malibu's waste. The recommendation was made public during meetings with Malibu residents early in the year.
Montgomery's report, delivered to the county this week, offers the first detailed look at the potential impact of the suggested sewage system on the delicate Malibu environment, as well as its effect on property owners' pocketbooks.
A hearing on the report will be held Aug. 5 in Malibu, said Brian Scanlon, county sewer maintenance superintendent. The location and time have not been determined, Scanlon said.
The sewage issue has been an emotional one for 20 years in Malibu's coastal terrace, where more than 80% of the waste water is treated in septic tanks. Six small, private sewage systems also operate there.
Three times, residents have rejected sewer bond issues. Critics contend that sewers will lead to overdevelopment in the geologically unstable, environmentally fragile region. Opponents of the sewer system also resent being forced to pay for it.
The consultant's report says public acceptance of the Corral Canyon proposal would be "marginal." Indeed, about 200 people have joined a committee questioning the current push for sewers.
But the county Health Department has declared that continued reliance on septic systems will be dangerous. So the project can proceed and property owners can be taxed, despite their objections, as long as four of the five county supervisors approve it, the consultants' report says.
Over the past decade, 45.5% of beachfront septic systems have had breakdowns and 23.2% of the septic systems off the beach in the Malibu coastal area have failed, said Frank A. Grant, the consultant's project director.
Many of the septic tanks were built in the 1950s, when regulations for the systems were not as stringent as they are now, the report says.
The consultants estimate that without a regional sewage system, 42% of the existing septic tank systems would fail over the next 20 years and 33% of those installed during that period would also break down, leading to nuisance, odor and potential disease.
A regional sewage system is required, the report says, to protect public health, accommodate future construction permitted under the nearly complete local coastal program and protect against landslides by keeping septic system water out of the soil.
Besides, "no project does not mean no development," the report says. "Existing lots could be built upon with septic systems." Pepperdine University's plans for doubling the number of students at the Malibu campus and a planned 300-room hotel could also proceed by using an existing private treatment plant, the report says.
The county expects to open a sewage system that serves Malibu from Topanga Canyon on the east to Latigo Shores on the west by 1991. An expansion farther west to Point Dume would follow about 20 years later.
Owners of 3,500 lots in higher-density neighborhoods along a 25-mile strip of coastline would ultimately be affected. The first phase, which is about two-thirds of the project, would include 4,700 residential units once development reaches the maximum allowed under the local coastal program. And 794 acres of commercial land also would be served.
The consultants examined a range of options for a sewage system, from pumping waste water to the Tapia treatment plant in the Santa Monica Mountains to scattering several small treatment plants throughout Malibu.
The Corral Canyon proposal, which would cost more than $60 million to build and operate, is the least expensive and most practical choice, the consultants concluded.
The system would include a two-part pipeline, with 2.4 million gallons of sewage each day flowing west of Big Rock Mesa to the new plant and 300,000 gallons per day flowing east of Big Rock to the Hyperion plant in El Segundo, operated by the city of Los Angeles. By the time the system's second phase is complete, the canyon plant would treat 3.6 million gallons of sewage each day.