Making Corral stable


As the cracks in the asphalt on Corral Canyon Road continue to shift and widen each day and workers make near-constant repairs, geologists are trying to find a stable place to move the road. “It’s not getting worse, but it’s not getting any better,” said Malibu’s Public Works Director John Clement. “If we can move the road about 50 feet to the west, it should be, we believe, geotechnically stable.”

Winter storms activated two ancient landslides that lie beneath the road. Clement said one of those slides appears to have stabilized, but the other is active, and about 500 feet of the road must be moved.

“It looks fairly stable,” Clement said. But he quickly added that the new location could also be sitting on an even larger ancient slide, which some believe some runs beneath both slides. “If it’s down there, what’s the likelihood of it moving?” In addition, Clement said an earthquake fault runs through the property and he said he wants to “make sure that won’t cause any trouble.”

Hopes are a geotechnical investigation, being conducted right now by Bing Yen and Associates, will provide some answers. “We’re drilling borings and trenches to determine if there’s an ancient landslide,” said Mike Phipps, senior geologist for Bing Yen and Associates.

The Malibu Coast Fault Zone is located about 100 yards south of the

realignment area. Previous movement along the fault could have caused nearby ground to be fractured or sheared. “It just means that it’s been compressed and strained and the rock yields to the forces of nature,” said Phipps. “So far the conditions are as we anticipated. Conditions of being near the fault zone are pretty evident in the field. The rocks are pretty smashed up.

“Planes of weakness may be exposed. We’re looking for those and we’re looking at the geometry of the plane — to see whether they dip into the hill or out of the hill,” said Phipps. “The new road will have cut slopes and we need to be sure those are going to be stable. We don’t want to build a slope in there and have it fail under the road.” Phipps said there are measures that may need to be taken in order to make the land stable. “There’s conventional grading techniques that can be implemented if necessary.”

If the geotechnical report comes back favorably, the next hurdle will be acquiring the property, which is currently owned by L.A. City Water and Power. “It could be an actual purchase,” said Clement. “I’m hoping for a dollar. Or it could be some kind of permanent easement.

Clement added, “Everybody at Water and Power that we’re dealing with is very friendly and we have very good jurisdictional cooperation at this time.”

Clement said the California Coastal Commission agreed, after visiting the site, to give the city an emergency grading permit. “Obviously it’s a critical project,” Clement said.

Support appears to be coming from Los Angeles County as well. “We do have encouragement from Zev Yaroslavsky’s office to assist us in any way possible when we get to that point,” Clement said. “We have 200 homes that could be stranded if that road does collapse.”

Phipps estimated that the lab testing and reports should be completed within the next few weeks.

Clement said he can’t estimate how long negotiations will take but said that actual construction should take only a couple of weeks and would likely cost about $200,000. “Ideally, there will be no disruption of traffic,” he said.