Study calls Ventura County beach Southern California’s fastest growing

A new study shows a stretch of Ventura County’s coast was Southern California’s fastest growing beach in recent decades.

Researchers used satellite-based measurements to examine changes along the shoreline from 1984 to 2024. Those changes varied from year to year and spot to spot. But in all of Southern California, they found beaches had grown by 500 acres over 40 years.

“We see areas that have widening beaches and we see areas that have narrowing or eroding beaches,” said Jonathan Warrick, a research geologist at the U.S. Geological Survey and the study’s lead author.

But as a whole, the region added more sand than it lost. The sand, however, piled up in some areas while others showed “very significant” erosion problems, Warrick said.

The Ventura County shoreline has some of those quickly eroding spots, including a beach near Mugu Lagoon. The region’s fastest growing stretch also is local, located in the Oxnard area. South of the Santa Clara River and north of Channel Islands Harbor, the stretch of sand includes McGrath State Beach. The McGrath campground remains closed but the beach is open and accessible from Mandalay or Surfers Knoll.

Warrick attributed the build up at least partly to the river, which he said can carry an abundance of sand downstream.

What local beaches got smaller?

A group of researchers, including from the USGS and UC Irvine, participated in the study. The findings were published recently in Nature Communications, a scientific journal.

Where the sand ends up depends on a variety of factors, according to the research. Sediment may flow down the coast or come from creeks and rivers. But those natural flows can be blocked by upstream dams or jetties and harbors built along the coast.

Those structures can mess with sand allowing it to build up in some spots and cause erosion in others, said Sean Anderson, professor of environmental science and resource management at CSU Channel Islands.

For decades, though, officials have replenished beaches around much of the state, he said.

In some cases, agencies work to mechanically move sand around obstacles, pumping it onto eroding beaches. The study, however, says those efforts may not always be effective in getting enough sand to vulnerable spots.

Locally, the deep underwater canyon that allows shipping into the Port of Hueneme blocks the flow of sand down the coast to places like Hueneme Beach.

For decades, agencies have regularly dredged sand from around the mouth of Channel Islands Harbor and replenished beaches down the coast. Still, the area north of Channel Islands Harbor has grown bigger over time, as have others elsewhere in Southern California.

The sand appears to be building up at a higher rate than it has been pumped out, Warrick said.

What will happen to beaches in the future?

California beaches, worth billions for the state’s economy, are incredibly important and people have the ability to help sustain that resource, Anderson said.

But those efforts likely will become increasingly difficult over the next several decades, he said.

In the past, beaches may have shifted inland as sea levels rose. But now, there’s development along the coast, from the Pacific Coast Highway to homes and railroads, creating a hard landward edge for the shoreline.

That means the area left for beaches could shrink as sea level rise becomes more pronounced, according to Anderson.

“The rules of the game are changing,” he said.

To read the full report, visit nature.com/ncomms/.

Cheri Carlson covers the environment and county government for the Ventura County Star. Reach her at [email protected].

This article originally appeared on Ventura County Star: Ventura County beach called the fastest growing in Southern California