Caltrans — Highway 1/Mud Creek Emergency Restoration

After a winter of record rainfall totaling more than 100 inches in California’s southern Monterey County, a mudslide sent nearly six million cubic yards of material into the Pacific Ocean and buried State Route 1; the biggest landslide to ever hit the Big Sur coast. While millions of people witnessed the devastation, Caltrans engineers knew that previous methods used to evaluate and remove mudslide residue would no longer be environmentally-practical or safe. Working alongside geologists, they developed an innovative and environmentally-sound solution to combat the devastation caused by the mudslide, while restoring and reopening the highway. As part of this $54 million restoration project, geotechnical and surveying technology helped ensure worker safety, categorize the different types of materials involved in the mudslide, and ultimately develop remediation solutions. Land-based radar continuously monitored the active landslide for any movement. Solar-powered automated surveying equipment measured key points all over the landslide to track any displacement. Monitoring devices were drilled into the body of the landslide to analyze the material beneath the surface of the landslide. Finally, tapping into all of the data collected from years of experience working along the Big Sur coast, Caltrans developed the “ultimate solution” to protect the new peninsula from erosion caused by the powerful Pacific Ocean: a rock barrier over 40 feet tall and 2,000 feet long. Retaining walls made of rock and cable mesh was draped over the slopes above the highway would protect travelers from any additional rock fall. Highway 1/Mud Creek re-opened 14 months later in July 2018, restoring a vital link through Big Sur.