SEA 



SCIENCE 



Does the Sand Go? 



By Elizabeth Burke • Photographs by Michael Halminski 



You've just eased yourself into a 

 beach chair and traded a bottle of 

 sunscreen for the fat, juicy novel you 

 found at your rental house. Everything 

 seems perfect. But when you think the 

 sweet tea in your cooler is the only thing 

 calling your name, you hear somebody 

 say, "I don't know where the sand 

 goes. Ask mom, she probably 

 knows!" 



"It goes away, like you 

 should," you holler back, burying 

 your toes in the sand and your nose 

 deeper in the novel. 



Ironically, for all the time we 

 spend at the beach, this is practi- 

 cally all we know about sand. 

 Questions like "Where does the 

 sand go?" are complicated, and 

 except for parental guesses, they 

 have remained largely unanswered 

 despite years of scientific study. 

 One reason is that tracking the 

 motion of a single grain of sand on 

 the beach, much less a wave full of 

 them, is nearly impossible. 



This past summer and fall, more 

 than 100 of the world's most accom- 

 plished oceanographers, coastal 

 geologists and engineers gathered on the 

 Outer Banks at the U.S. Army Corps of 

 Engineers Field Research Facility (FRF) 

 at Duck to conduct the largest coastal 

 field research project ever. Dubbed 

 SandyDuck '97, it was a series of 30 

 separate experiments designed to answer 

 the sorts of childlike questions that vex 

 even the experts. Most of the funding 

 came from three government agencies: 

 the Corps of Engineers, the Office of 

 Naval Research and the U.S. Geological 

 Survey. 



The scientists came to learn why 

 the beach looks different season to 

 season and year to year. They wanted to 

 understand what causes ripples, dunes 

 and sandbars. And after all the data is 

 analyzed, they hope to say where the 

 sand goes and to predict if and when it 



Peter Dickson gives perspective to the 

 size of the CRAB's wheels. 



will return. That knowledge can help 

 save property from the ravages of 

 storms and long-term erosion, says 

 coastal geologist Tom Drake of North 

 Carolina State University. 



"For years, oceanographers have 

 studied waves, and they always wished 

 the sand would stay put so that the 

 ocean would resemble a big laboratory 

 wave tank. Any change in the beach was 

 a tremendous nuisance," Drake says. 

 "At the same time, geologists studying 

 the sand and barrier islands were 

 wishing the ocean could be drained so 

 they could see the bottom." 



SandyDuck teamed these oceanog- 

 raphers and geologists, and together 



they used some ingenious methods for 

 looking at sand and waves and how they 

 affect one another. 



So, if you want to know more 

 about the path of a sand grain, what do 

 you do? 



If you're Oregon State University's 

 Rob Holman, you keep watch 

 from a distance — and a height of 

 120 feet. Holman, a pioneer in the 

 field of video imaging, has 

 mounted five video cameras on 

 the FRF's video tower to give him 

 a bird's-eye view of every wave 

 that comes ashore. But he does 

 more than just watch the waves 

 break; he uses the video images to 

 map changes in the sandbar over 

 time. 



"With the technology we 

 have now, we can measure how 

 each wave progresses," Holman 

 says. "We can also look at one 

 individual point on the beach and 

 see how the beach changes over 

 days or months." 



For Drake, the best view is in the 

 water. He uses a 3-foot-long, torpedo- 

 shaped side-scan sonar mounted on the 

 underside of the Army's Coastal 

 Research Amphibious Buggy (CRAB). 



"The side-scan sonar generates a 

 picture of the bottom using sound and 

 shows us the shape of dunelike features 

 called megaripples, rip-current channels 

 and offshore sandbars," Drake says. 

 "It's the same technology used to search 

 for shipwrecks like the Titanic or 

 downed aircraft." 



Researchers use the same tech- 

 niques and technology in another long- 



Continued 



COASTWATCH 23 



