Journal of East China Normal University(Natural Sc ›› 2019, Vol. 2019 ›› Issue (4): 202-211.doi: 10.3969/j.issn.1000-5641.2019.04.019

• Estuary and Coastal Research • Previous Articles    

Study on the safety of sea dikes against coastal erosion in a strong tidal estuary

LI Lu1,2, LIU Xin-cheng1,2, SONG Yong-gang1,2, ZHAO Geng-run1,2   

  1. 1. Shanghai Water Engineering Design and Research Institute Co. Ltd., Shanghai 200061, China;
    2. Shanghai Engineering Research Center of Coastal Zones, Shanghai 200061, China
  • Received:2018-07-29 Online:2019-07-25 Published:2019-07-18

Abstract: High resolution bathymetric data along the Huadianhuiba sea dike, a typical eroding coast on the northern coastline of Hangzhou Bay, was collected to analyze seabed evolution. A wave model covering the Changjiang Estuary and Hangzhou Bay was built to obtain the wave elements along the sea dike. Then, sensitivity analyses were carried out to calculate the impacts of coastal erosion on the wave elements, the required crest elevation, and the intensity of the seaside dike revetment. The results indicate that under a design condition of a 200 year return period with increasing water depth in front of the sea dike, the mean wave height and wave period are almost stable, while the wave length and H1% are significantly increased. The increased wave length, due to the topography deepening, is found to be a major factor for the subsequent wave run-up, which reduces the defense standard of sea dikes at crest elevation. In addition, the required intensity of the seaside dike revetment increases significantly with the depth of water in front of the sea dike. This indicates that a safety margin should be accounted for in design of the sea dike.

Key words: coastal erosion, safety of sea dike, wave elements, crest elevation, intensity of the seaside dike revetment

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