Thursday, October 21, 2021

California is experiencing higher tides and more severe erosion

In what was another record-setting year in the Golden State, climate change is taking its toll on many of the island communities that are tourist magnets.

The likely reasons: Beach erosion, increased flash flooding and cold, deep winter storms. Researchers and scientists found that half of the 165 California counties experienced some sort of flooding between 2011 and 2015. And on at least one Southern California beach, floods have become commonplace.

The rainy winter that coincided with heavy storms recently caused serious damage to just a handful of beaches in southern California.

“These storms filled our beach with tons of sand, but it turned out to be very, very little,” said Brandon Mixon, senior coastal engineer for the Imperial Irrigation District. The institute placed rubber trash cans along the shorefront on La Laguna, one of many Southern California beaches where volunteers were called out to fill them with sand. A few hours later, the jetsam was washed out to sea. Mixon said he was shocked to see that the beach had been covered in sand that just days before had looked absolutely pristine.

Waves and debris begin to wash up onto La Laguna Beach in southern California. (Aaron Favila/AP)

“Imagine going to a beach that is almost pristine and everything is just swimming in it,” Mixon said. “You’re kind of in paradise, and then the next thing you know, someone has set off a commercial fishing boat and packed in all the sand. And the sand eventually fills your whole front lawn.”

When the area gets serious rain, Mixon said, there is literally no place for standing water. That, he added, has left the sand standing at the beach almost invisible for people walking or biking along the beach. Other small towns have also seen their beaches inundated, allowing cold water to leak inside shorelines.

The problem is exacerbated by increasing ocean temperatures, said Roy Spencer, a professor of atmospheric sciences at the University of California at Santa Barbara.

Shorelines rise and fall with the tides, though Mixon estimates that the coast itself gets some 4 inches of sand each year. But the waves can move up to 1 foot of that sand away during the two high tides that wash up on shore, he said. When the waves recede, they essentially block the sand from coming back.

“The warmer the water, the more dramatic the sea bed thins out, the farther north it recedes,” Spencer said.

“The high tides during those times have a sort of a tidal-wave action that actually involves the ocean floor,” he said.

The first high tide of a high season occurs in August. While rivers and lakes upstream push out storm runoff, and then run off into rivers like the Santa Ana, which feeds the ocean, so do storms sweeping up from the Pacific. And the storms that bring extremely high tides begin to get more frequent, Spencer said.

Irrigation districts have been thinking about how to protect beaches and shorelines. A project in Imperial County is in the works to provide inflatable barrier gates to prevent water from surging into protected shorelines. If those gates are needed, they can move to a new location along the coast at the first sign of severe storms. Another option, Spencer said, is removing sand from more expansive areas that were exposed by previous storms and moving it closer to protected shorelines.

“In drought years you’re going to have less sand and more erosion. In big storms, that’s going to be more severe erosion,” he said.

Spencer said he feels he’s “going to be drowned out eventually.”

While the extreme beach erosion and flooding have occurred in recent years, there have been more regular examples in California, at least when it comes to a place that tourists flock to.

In late January, researchers at the University of California at Berkeley’s sea level research center found that almost half of California’s 164 coastal counties saw moderate to severe flooding between 2011 and 2015. The rate of erosion in those counties, which are focused on the state’s southern coast, was 4.4 percent worse than it was during the past 15 years.

Those findings came in a report called “A Tides Warning: Coastal Erosion and Flooding in California.”

And they come amid a sea level that continues to rise.

“This is not some distant future disaster,” said Nick Bacari, a professor of civil and environmental engineering at UC Berkeley who was lead author of the report. “Our everyday reality is this sea

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