ANAHEIM, CALIF. -- Using mathematical models to predict natural processes -- such as how well a sandy beach can weather randomly occurring storm buffeting -- is a commonplace but wrongheaded engineering practice that can cause real harm, according to a Duke University geologist who studies such coastal dynamics.
"Engineering models of Earth surface phenomena do not work, and I think it is very important that society recognizes this," said Orrin Pilkey, a professor of Earth and ocean science at Duke's Nicholas School of the Environment. "I think mathematical modeling in this sense is damaging our society."
Pilkey spoke in an interview before his talk on the same subject Monday at the annual meeting of the American Association for the Advancement of Science.
He is the outspoken director of Duke's Program for the Study of Developed Shorelines and the co-author of The Corps and the Shore (1996, Island Press), a book that criticizes the U.S. Army Corps of Engineers' use of predictive mathematical models such as "GENESIS" and "SBEACH"to model beaches.
Such models use mathematical equations to represent such factors as wave characteristics, the density and porosity of beach sand, the density of sea water and the beach's slope. The intended purpose is to predict how natural or artificial beaches will respond to various kinds of coastal engineering.
Some engineering models -- such as those assessing the performance of construction materials in a bridge or building -- are useful, Pilkey acknowledged. "Modeling steel and concrete is fine," he said. "But now engineers have stepped into natural systems and they want to model beaches. Well, they can't do that.
"In general, they can't model any natural systems with precision. But because beaches are so dynamic and because they can change so suddenly, it is very obvious and easy to see why modeling fails for them."