Evolution of blowouts in artificial foredunes on Pingtan Island, China

Abstract

AbstractThe appearance of a blowout can be an obvious sign of accelerated coastline retreat or dune erosion and in response to serious coastal erosion, an increasing number of artificial foredunes are being built. However, over time, numerous blowouts have also developed on artificial foredunes. To our knowledge, no studies have been reported on the evolution of blowouts in artificial foredunes, and in response we explore the aerodynamics and morphodynamics of artificial blowouts at different stages, by conducting field experiments on the Changjiang Ao coast of Pingtan Island, China. Where a foredune was built on an artificial clay structure, with topography and wind fields around three blowouts in different developmental stages measured, preliminary results revealed that: (1) the blowout morphology and airflow patterns show distinct seasonal changes; (2) the development of blowouts in artificial foredunes involves five stages, in contrast to the four stages observed in natural foredunes; and (3) blowout development is controlled by a two‐way feedback between aeolian processes and blowout morphological development, and the artificial structure can interfere with this feedback mechanism by altering the path of blowout development. The findings enhance our understanding of geomorphic process–response systems in artificial foredunes and provide a reference for coastal management and dune stabilization policy and practice.