Coast Cam Tracks Beach Erosion

Beach erosion costs coastal communities millions in property losses each year and washes away tourism dollars as well. A recent report from the Federal Emergency Management Agency (FEMA) estimated that erosion could claim one in every four homes within 500 feet of the Atlantic, Gulf Coast, Pacific and Great Lakes shorelines during the next 60 years.

Yet scientists, too, are strapped for cash to study the ocean activity that causes erosion. The electronic sensors researchers commonly engage to monitor waves and currents cost between $5,000 and $20,000 apiece. A typical array uses about 30 sensors, bringing the total as high as $600,000. And installing them beneath the sea surfacea difficult process to begin withcan double the price. A new technique that uses video cameras and special software, however, promises to track the flow of near-shore waters just as well for a lot less. Thomas Lippmann of Ohio State University, who described the new system with his colleagues at a recent meeting of the American Geophysical Union, guesses the invention will cost no more than $100,000.

The new software analyzes video of the foam from breaking waves to model the dynamics below, calculating the speed and direction of the currents. Lippmann and his colleagues tested it on the beach at Duck, N.C., in the Outer Banks, setting up a single video camera on top of a 130-foot-tall tower to record a 500-meter stretch of surf. Because other scientists have studied the water at Duck using sensor arrays, Lippmann's group could readily compare their technique with the standard. They found that video-based data matched that collected by the sensors to within 10 percent. "If we could better measure and predict water circulation patterns," Lippmann says, "we could learn more about erosion, as well as other near-shore phenomena such as rip currents and undertow." The coast cam software combo should certainly help.