Driving northbound on the 101 Freeway from Ventura is a far different experience now than it was prior to Jan. 9, when a storm rolled through, mud slid from the hillsides, and 21 lives were lost. The days following the event forced closure of the freeway, and images of the path of destruction that tore through Montecito and parts of Santa Barbara County made international headlines. The damage can still be seen as residents continue working to return to normal.

Now, the U.S. Geological Survey is mapping changes to the beach and seafloor adjacent to the Montecito mudslides, including in their survey an area that stretches from Goleta to the beach at Mandalay Bay in Oxnard, in an effort to better understand long-term coastal changes. With these data, both Santa Barbara and Ventura Counties can better plan for future coastal living.

Dan Hoover, oceanographer with the USGS, wears a GPS-equipped backpack unit as he strolls the beach at Santa Cruz. The team of scientists mapping the coastline make use of these units, as well as GPS-equipped all-terrain vehicles and watercraft saddled with bathymetry equipment to determine nearshore depth.

The Jan. 9 mudslide dumped tons upon tons of mud and debris onto area beaches, but Hoover says that there is no accurate assessment of just how much material came down from the hillsides.

“That’s partly why we’re out there,” said Hoover. “If we keep going back, year after year over time, whatever got in there should move away and relax, and get spread out, and we should see that change.”

Hoover and his team began working on mapping the beach stretching from Goleta to Oxnard back in 2005, when, in the midst of drought, determining where debris and sediment come from and travel to was a slow, if not difficult, task. Hoover says that some estimates show that 1.5 million cubic yards of mud and sediment discharged into the ocean during the Jan. 9 event, but he adds that he doesn’t know how accurate that is.

The goal of the project, says Hoover, is to determine change over time; and though big events like the mudslide can leave imprints that often last for decades, influences such as those created by climate change and sea-level rise are also studied.

These data are provided to county planning divisions, who use them to determine coastal planning for the long term. Climate change models show that California may see up to a 66-inch rise in sea level during this century, according to a report released by the California Department of Public Health in 2017. With that in mind, counties are already burdened with planning for this real possibility. After the mudslide, planners are looking to update their prediction models.

Hoover says that events like the mudslide can be used as reminders for planners that, though rare, the possibility that they may occur should be included in county and city planning. As for the immediate effects, Hoover says that it will take some time to see just how big an impact the event had on the coast.

“This is the beginning of, hopefully, a long-term process of keeping an eye on things in the Montecito area,” said Hoover. “Hopefully, what we’ll see is the sediment on the bottom spreading out and moving to the southeast, down the beach slowly, and we’ll see it move to the Montecito area and, hopefully, pass through there to the Ventura coast.”