Author’s book explores past and future of coast

To the human eye, Southern California’s coast might seem pretty static. But looking back over millions of years, periodic earthquakes, tsunamis and constant erosion have drastically altered the landscape.

MiraCosta oceanography professor Keith Meldahl drives that point home in his new book, “Surf, Sand and Stone: How Waves, Earthquakes and Other Forces Shape the Southern California Coast.” The book takes readers from San Diego to Santa Barbara, looking at how the coast came to be.

“The past tells us a number of things,” said Meldahl, an Encinitas resident. “You realize this area is extremely active geologically. The coastline has retreated hundreds of feet. That might not be apparent when you’re walking along the beach.”

Meldahl said understanding the past can help residents and government officials prepare for rising sea levels and an increase in coastal erosion. Given the large scale of sand loss across Southern California, a solution may require a mixture of beach replenishment projects and “managed retreat” — moving property back from the bluff, he added.

For this area, he favors sand replenishment, calling it the “least-bad scenario.”

“I don’t like the idea of spending millions of dollars on sand replenishment. However, it’s probably unrealistic here to move all property back from the bluff.”

That’s not to say the book is solely geared toward decision-makers or oceanographers. Rather, Meldahl wrote it to help the average person understand coastal forces and issues. He distilled past research into a digestible narrative, peppered with his anecdotes and pictures.

“It’s for anybody who’s interested in our coastline and the geology of waves, sand and beaches. It’s not a textbook.”

Of interest to surfers, his work also has a section on how waves form and how topography affects them. Another part recommends necessary supplies in the event of a natural disaster.

He wrote much of the book during a yearlong sabbatical, and the rest came during nights and weekends over the past two years. Meldahl said his passion for informing comes from his 18-year teaching career. “During class, I want to make science understandable and interesting.”

A geologist by training, Meldahl switched to oceanography when a teaching position opened up 18 years ago at MiraCosta.

“Oceanography wasn’t part of my thinking, but I realized — this is actually really fascinating.”

“Surf, Sand and Stone: How Waves, Earthquakes and Other Forces Shape the Southern California Coast” is available at amazon.com and ucpress.edu.