When Hwy 1 collapses by Big Sur, Caltrans engineers face unique challenges

California

BIG SUR, Calif. (KRON) — The last time a colossal landslide happened on Highway 1 south of Big Sur, the famously-scenic stretch of highway snaking along the Pacific Ocean was closed for more than a year.

The Mud Creek landslide of May 2017 was described by USGS researchers as “catastrophic.”

A total 6 million cubic yards of rock and soil slid off the mountain into the ocean and formed 15 acres of new coastline.

Following last week’s powerful January storm, Big Sur is once again cut off on the south side, this time at Rat Creek. More than 16 inches of rain triggered a steep slope to cave in, and the slip-out brought a huge chunk of Highway 1 down with it.

Rat Creek landslide / Photo by Caltrans

Rat Creek is located at PM 30.2 and is two miles south of the Esalen Institute.

It is about one mile south of the origin of the Dolan Fire in the Dolan Canyon area of Big Sur and is within the burn scar area.

Monterey County emergency officials knew that this part of the county, which was burned wildfires last summer, would be extremely prone to disasters during heavy winter rain events.

Mud Creek Landslide of 2017

Gov. Gavin Newsom declared a State of Emergency for Monterey County due to last week’s dramatic mudslides in Salinas and landslides along the coast.

A big question for Big Sur is, how will Caltrans engineers be able to repair Highway 1 before the summer tourism season arrives?

Kevin Drabinski, Public Information Officer for Caltrans District 5, told KRON4 on Sunday that crews are “still in assessment phase and no timeline for rebuilding.”

Caltrans does not have a number yet for the volume of earth that slid down the mountainside into the ocean below.

One Caltrans employee who witnessed the Rat Creek landslide told KRON4 that he does not think Rat Creek will be as lengthy of a rebuilding process as the Mud Creek slide.

The Mud Creek slide was the largest ever recorded in Big Sur’s history, so it’s no wonder that it took so long for engineers to reverse what Mother Nature had unleashed.

Rather than build a bridge or tunnel, engineers opted to rebuild the highway right along on the mountainside.

Caltrans’ “herculean” effort at Mud Creek faced several complications, including rocks that continued to fall even during construction.

The crew installed an interconnected drainage system to drain rainwater runoff and a 20-foot-high berm as a retaining wall. The project cost more than $50 million.

When Highway 1 collapsed at Rat Creek on Jan. 28, critics on Twitter questioned whether it was worth it for Caltrans to continue trying to maintain the world-famous stretch of highway. Twitter users asked KRON4, why not just build a new road in a new location?

Here is the good news for people who dream of driving the coast of California: Caltrans is committed to keeping this part of Highway 1 standing.

“We are committed to that ribbon of highway that runs along the Big Sur coast. It requires a relatively large amount of resources to maintain in summer, spring, fall and winter. We are committed to providing the resources to reopening this highway,” Drabinski said.

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