No doubt, eventually, it will get cleaned up and Highway 1 will reopen. But what that's going to take and how much it's going to cost are still big open questions for Caltrans and the state of California as experts assess this newly formed section of Big Sur's coastline that is currently impassable, after what some are calling the biggest landslide in state history. Last Saturday's landslide at Mud Creek was less of a natural disaster as just an inevitable part of the landscape in this part of California, and it was something that some geologists had been expecting for a long time. It's also just one of multiple rockslides and landslides that regularly batter and reconfigure this part of the scenic coastal highway, but this one could present special challenges that Caltrans hasn't dealt with in three decades, since a similarly large but not nearly as large landslide took out part of the highway north of here in 1983. One Caltrans engineer, Rick Silva, tells the LA Times, "It might be a once-in-a-career slide," but he and other engineers feel they're up to the challenge and have knowledge about these hills gained from the work that took over 14 months to complete after the '83 slide.
The Mud Creek slide dumped an estimated 1.5 million tons of rock, mud, and debris over what was formerly a third-of-a-mile stretch of Highway 1, and created a skirt-like new outcropping of coast below it, where waves are now lapping at it and stirring up more mud. The slide has indefinitely cut off traffic from the south into Big Sur, where traffic from the north was already cut off by the collapse of Pfeiffer Canyon Bridge earlier this year. That bridge is expected to have a replacement later this year, possibly by late September, but meanwhile the highway in the southern section of Big Sur has multiple slide areas to contend with before it can fully reopen, the largest of which is now presenting a daunting puzzle for engineers who will have several options some of them crazily expensive for removing the debris and rebuilding a working road here.
As the Chronicle reports, after a stormy and extremely wet winter in California, Caltrans is already looking at $1 billion in road and bridge repairs, almost three times the average they've spent per year in the last five years. That price tag will only rise as solutions take shape for the Mud Creek slide.
First up on the list of priorities will be determining how much more sliding is going to occur as the LA Times reports, via field inspectors, "Listen closely, and you’ll hear a sound of water running like rain through the rocks and dirt. The slide at Mud Creek is still moving."
The slide was caused by groundwater seepage after the winter's rains, and by groundwater percolating up from the soil in springs, which engineers had already been observing for weeks before the slide part of the reason why workers had been removed from the area last week and why no one was around when the slide took place, or was injured or buried by it.
The LAT also gets into the problem of Paul's Slide, a consistently shifting hillside that was also in motion last week, leading to a different road closure north of this one. One lane in that section of Highway 1 had already tumbled into the ocean, and that section of the road will also need to be rebuilt over the coming months.
Complicating matters further is the fact that Mother Nature just did something Caltrans engineers won't be permitted to do as they figure out how to dig out from under all this debris: dumping rocks and dirt into the ocean. As the LAT notes, crews cleaning up after the 1983 slide were able to push debris down into what was a cove, turning it into a beach, but regulations now prohibit that in what is considered part of the Monterey Bay National Marine Sanctuary.
So will they be trying to dig out and remove (or blow up) potentially enormous boulders now in the path of Highway 1? Will Caltrans decide, like they did with Devil's Slide near Pacifica, that the only long-term solution will be to build a tunnel that future slides can just pass over? (The Devil's Slide tunnel, completed in 2013, cost $400 million.) All options appear currently on the table.