No longer moving mountains, CalTrans works with massive Big Sur slide

Aug 10, 2017

The landslide at Mud Creek – about 25 miles north of Hearst Castle – is the largest ever on the Central Coast. It buried and broke apart a section of California's famed State Route One. To fix it, CalTrans has decided to build a road over the massive slide.

This week, KAZU's Krista Almanzan visited the work site to find out how that became the solution.

Joe Erwin and I stand on land that didn’t exist before the Mud Creek Slide.  The ocean is at our backs.  In front of us, a semi-truck hauling enormous boulders makes its way down an access road carved into this new hillside.

“You know when you first see it you are overwhelmed by how big it is.  And you think what can we possible do,” says Joe Erwin, Project Manager with CalTrans.

The landslide wiped out this quarter mile stretch of Highway 1 back in May.  It's near the border of Monterey and San Luis Obispo Counties and roughly 25 miles north of Hearst Castle.  

The slide brought down enough dirt and rock to add about 15 acres of new land to the coast. That land is now the construction site for the rebuild. Erwin says back in the day, the solution for repairing the highway would’ve been pretty obvious.

“Go and start at the top of that mountain with a team of bulldozers and just start pushing material into the ocean until we got back to where the original highway was. That’s how we used to do it in the 80s,” he says.

That was before CalTrans adopted the Big Sur Coast Highway Management Plan in 2004.  Because of that, CalTrans tries to work with landslides and protect the Monterey Bay National Marine Sanctuary.

So those boulders being hauled in will shore up the new slope and keep more dirt from going into the ocean.

“This is critical black abalone habitat. There is pristine national marine sanctuary just in this area, right off the coast  So we don’t want to contribute to the degradation of those natural resources,” says Erwin.

I ask, does that make the repair more difficult?  “It definitely constrains your options. But CalTrans, even before this landslide occurred, we had already taken the approach that we aren’t trying to move mountains anymore in Big Sur,” says Erwin.

They weighed options like building a tunnel, but that would take too long.  And there’s not enough space to add a bridge.  So the answer is rebuilding the highway on this new piece of land.

As for building on a landslide, Erwin says, the land is stable.  “It was such a large mass that once it came down and came to rest that it almost self-consolidated and stabilized itself,” says Erwin.

“Very interested in what they’re doing up here,” says Jim Ramey who is also on site for a tour.  He owns the Ragged Point Inn and Resort just south of here.  

He says business is way down since January. That’s how long the highway has been closed here because Mud Creek was already unstable before the mountainside collapsed.

“A lot of people are on the road to drive it through.  So that’s a significant number of the people that we see.  But we do see a lot of people still coming up to take in the beauty of the area,” says Ramey.

CalTrans expects to have a timeline and cost estimate for the rebuild by the end of August.