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The Grains of Truth

It just isn't normal to see an ATV (all-terrain vehicle) rumble through your favorite beach in the middle of the night. But strange looks and the occasional suspicious inquiry by the authorities come with the territory for Guza's research team as it conducts sand surveys at Southern California beaches.

Those who are taken aback by the ATV's midnight rumblings are little aware that this is no ordinary vehicle for off-roading joy rides. The technologically tricked-out ATV is equipped with some $35,000 worth of instrumentation, including a computer and GPS sensors that measure sand levels five times per second.

The ATV maneuvers up and down San Diego beaches in giant lawnmower-like patterns during surveys, meticulously documenting tracts of sand at Torrey Pines, Cardiff, and Camp Pendleton.

To gain access to the widest swath of beach available, the surveyors are governed by the tides. Sometimes that means the surveys can be conducted under a noon sun in summer, but sometimes it means 2 a.m. in winter darkness.

In addition to the ATV, high-tech tools used in the Southern California Beach Processes Study include a GPS-equipped Jet Ski that gives researchers valuable data about sand levels just offshore.

With LIDAR, the researchers determine sand levels twice a year on beaches from the Mexican border to Long Beach, Calif.

Guza admits that part of his scientific investigations are driven by raw "curiosity run amok." Even before he joined a leadership role in the program indeed, even before starting his scientific career on coastal processes he admits to a lifelong fascination with waves and beaches as a natural system.

He has studied beach erosion and sand levels as a long-term natural process, fluctuating through high-and-low cycles over thousands of years. In their natural state, beaches receive fresh sand input from rivers and cliffs. Today, however, especially in Southern California, beaches are deprived of this input because most rivers have been dammed and cliffs are being retained by armored structures and seawalls.

Recently, the science of understanding beach erosion has taken on new urgency as sand levels have plummeted in some areas dependent on beach tourism. Shoreline grains have become a precious commodity as millions of discerning tourists and their billions of dollars flock to beaches with inviting mounds of sand and eschew those without.

Like a detective using a new high-tech device at crime scenes to solve mysteries, Guza is using the precision of GPS to investigate the convoluted question of why sand appears and goes missing from one season to the next. He and his research team were able to follow the trail of a 2001 beach nourishment project that deposited 160,000 cubic meters (200,000 cubic yards) of sand at Torrey Pines. After a pounding storm in winter 2001, the surveys revealed that the newly infused sand retreated into the ocean to form a sandbar, but then moved back onto the beach the following summer, resulting in the much-desired wider beach.

But the surveys also can produce mixed messages. Surveys have shown that sand levels at Torrey Pines can change by six feet from summer to winter. After a November storm in 2001, the beach dropped 10 feet in two days. In contrast, over several years San Onofre beach 40 miles to the north has shown little or no change.

"Why?" asked Guza. "This is an interesting science question but it's also a very interesting beach management question. Finding out why beaches change or don't change could be valuable one day in finding a way to stabilize beaches that erode."

Next page: A Wave of Breakthroughs Emerges

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