The 24th IAHR-APD Congress (24th IAHR-APD Congress)

166 / 2024-02-25 17:07:47

The Roles of different elevation of submerged dike on Ecological restoration engineering of Costal area：A case study of Qidong

submerged dike; Qidong coastal area; numerical analysis; ecological restoration

This paper focuses on the roles of different elevation of submerged dike on ecological restoration engineering of costal area. In this study, through numerical analysis of tidal current, wave and exchange period of water bodies for different elevation of the submerged dike in Qidong coastal area, the results show that when the elevation of the submerged dike is 2.0m, the maximum decrease of current is 0.2m/s within the range of 0m isobaths to the sea side of the submerge dike, but the maximum decrease of current is 0.5m/s within the range of 0m isobaths to the landside. The effective wave height reduced 54.3%~63.6%, and the exchange period of half water bodies increased to 15 days. The current of the flood and ebb tide is below 0.05m/s when the elevation of submerged dike is 1.8m. The wave attenuation is 45.1%~55.2%, and the exchange period of half water bodies is 4.25 days. The maximum current is ca. 0.21m/s and 0.10m/s when the elevation of submerged dike is 1.6m and 1.4m, while wave attenuation is 26.5%~44.7%. The exchange period of half water bodies is 3.0 days. The maximum current is ca. 0.32m/s and 0.43m/s while the elevation of submerged dike is 1.2m and 1.0m, and the wave attenuation is 10.6%~26.4%, the exchange period of half water bodies beside the submerge dike  is 2.5days. Different elevations of submerged dike play different roles in the coastal ecological protection and restoration. Therefore, selecting a proper elevation of submerged dike as an engineering is an important measure for coastal restoration.