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CORVALLIS - About 80 dump truck loads of sand from the Oregon Coast are sloshing back and forth this summer in the Hinsdale Wave Research Laboratory at Oregon State University, being observed by technology so precise that researchers can literally track movements of the sand one grain at a time.

Sea levels are continuing their inexorable rise, coastal erosion concerns are growing and global warming threatens to accentuate this process. In response, a major four-year, $2 million initiative is under way at OSU and six other institutions to learn about sediment transport processes on coastal beaches that have been observed for decades but never really understood.

This is summertime, so most beaches in the U.S. are being replenished by gentle ocean waves and currents. Next winter, violent storms may strip away much of the material they are now depositing. But the mechanisms that control this long-known process remain a mystery, experts say.

"No one really knows how wind, waves, currents and tides combine to move all this sand," said Dan Cox, an OSU associate professor of civil engineering and coordinator of this Cross-Shore Sediment Transport Experiment. "But in the marine environment, sand is one of our most basic natural resources and it's essential that we learn more about it."

Millions of cubic yards of sand routinely move back and forth on the ocean shores, and also along the shoreline. However, there are so many variables that may control or influence this process that it has been nearly impossible in the past to gain a real scientific understanding of it. The wave research laboratory at OSU, part of the university's College of Engineering, is changing that.

"We're at a cusp of discovery on this issue right now, and the wide-ranging expertise of people who are involved from all over the nation will make it happen," Cox said. "Our large wave flume, in combination with some state-of-the-art instrumentation, is going to give us the data to significantly improve our computer models and understanding of sand movement."

The huge tanks in the wave research laboratory allow scientists to simulate natural sand movement processes on a large scale while still studying them with the latest technology. Among the tools being used is particle image velocimetry, in which high resolution cameras and lasers allow researchers to "connect the dots" between images of moving sand and literally observe the flow field as the sand grains move.

It's the first time technology of this type has ever been used in large-scale wave studies, the researchers said.

"You might think we would know by now what is going on, but there's still a poor understanding of how sand gets swept off the bottom of the ocean and moved by waves and currents," Cox said. "Now with this technology we can literally see it as it moves."

The issues involved are important. The world's sea levels are rising about a centimeter every decade, with significant implications for coastal erosion.

"That may not sound like a very fast sea level rise, but any vertical increase in the water level is magnified many times in its horizontal impact on the shoreline, especially in low-lying areas," Cox said. "In some places in Texas they are losing 10 feet of coastline every year, and studies show that 86 percent of the coasts in the U.S. are eroding."

A fundamental understanding of sand movement, shoreline stability and other topics will ultimately help address more applied problems, Cox said. In future research, the program may also examine the movement of sand up and down the coastline, in addition to the seasonal in-and-out movement.

"Right now at the mouth of the Columbia River, for instance, there has been interest in using some of the sand that's being dredged there to replenish other Oregon coastal beaches," Cox said. "But if we did that, no one really knows if it would work or where the sand would go. These are some of the kind of questions it would be nice to have an answer for."

This program is being funded by the National Science Foundation and Office of Naval Research, and involves OSU, Ohio State University, the University of Florida, University of Delaware, Woods Hole Oceanographic Institution, Naval Post Graduate School, and Cornell University. Several scientists from Japan are also participating. The program is also being used to provide summer research experiences for undergraduate studies, who do such work as profiling the shape of the beach after it is affected by wave action.

"About half of the population of the United States lives within 50 miles of a coastline, beaches that are steadily being eroded," Cox said. "We still don't know what processes are at work here, but this work will help find the answers."