Evolution of blowouts in artificial foredunes on Pingtan Island, China

• Published in: Earth surface processes and landforms Vol. 47; no. 10; pp. 2597 - 2611
• Main Authors: Zhang, Shaoyun, Qiu, Xing, Fu, Shuyi, Fu, Jingjing, Chen, Shouxu, Tian, Wei, Huang, Dequan, Dong, Yuxiang
• Format: Journal Article
• Language: English
• Published: Bognor Regis Wiley Subscription Services, Inc 01.08.2022
• Subjects: Aerodynamics; Air flow; blowout; Blowouts; Coastal erosion; Coastal management; Coastal zone management; Developmental stages; Dune stabilization; Dunes; Eolian processes; Evolution; Feedback; Field tests; form‐flow feedback; Geomorphology; morphological change; Seasonal variation; Seasonal variations; surface airflow; Wind fields; China
• ISSN: 0197-9337; 1096-9837
• DOI: 10.1002/esp.5397

The 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. The 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. The formation and evolution of blowouts on the artificial foredune are explored for the first time, with the comparison to natural foredune blowouts. It is found that the evolution speed of the artificial foredune blowout is significantly larger than that of the natural foredune blowout.