SAN DIEGO (CBS 8) - San Diego's coast is a precious resource for beachgoers, marine life and our county's economic well-being. It's also an ever-changing ecosystem threatened by erosion.
With 70-plus miles of pristine beauty, the San Diego coastline is constantly shifting.
"Beaches come and go under natural processes, sea level rises, sea level goes down," oceanographer Bob Guza said.
Heavy storms and cliff failures also contribute to coastal erosion. Guza monitors these changes over time.
It's not just Mother Nature that's to blame
"Human intervention and human interaction has changed a lot of the beaches," Guza said. "Many of the rivers in Southern California are dammed and this has cut off about half of the sand supply."
"These sea walls, this is to prevent erosion, and that's actually causing a problem. We're not having enough sand on our beaches," Birch Aquarium Executive Director Nigella Hillgarth said.
While nature and man-made forces collide, causing beach erosion, it's that same relationship scientists are looking to for solutions. Engineered sand replenishment is now underway on local beaches.
"If they hadn't done this so-called beach nourishment, there would be no beach and in fact this cobble that you see here, that would be what the beach would be made of," Guza said.
Scientists also monitor nature's own course.
"Just behind me, you can see a lot of the cliffs that actually slowly eroded to the ocean, and they've replenished our beaches, so it's a balance," Hillgarth said.
"If we want to have beaches, we can't take them for granted. We're going to have to watch them, observe them and potentially try to preserve them," Guza said.