Studieson the influence of coastline change on tidal prism and water exchange of Laizhou Bay

ZHU Jinlong; SUN Wei; CHEN Shaowei; FENG Yinyin; WEI Xiao; LIU Ning; XU Yandong; WANG Wanguan; LI Zimo

doi:10.13984/j.cnki.cn37-1141.2024.03.002

Abstract：Since the 21st century,the coastline of Laizhou Bay has changed significantly due to coastal reclamation activities such as port dam construction and aquaculture dikes,which have caused the change of the hydrodynamic environment of the bay.In order to investigate the response of the tidal prism and water exchange capacity of Laizhou Bay to its coastline change during the past 20 years,the influence of the coastline change on tidal prism and water exchange capacity was analyzed with two-di-mensional flow and advection-diffusion models for the two typical years,2000 and 2020.The results showed that from 2000 to 2020,aquaculture dikes have caused an increase in the potential energy of tid-al waves,and the maximum possible tidal range of Laizhou Bay also shows an increasing trend.The head of the bay between Weifang Port and Guangli Port increased significantly with the maximum in-crease of 8 cm.The spring tidal prism was decreased by 2.91％,the neap tidal prism by 1.42％and the mean tidal prism by 2.33％,and decreased bay area was the main reason for the decrease of tidal prism.The decrease in the sea area of the bay has led to a reduction in its self-cleaning capacity and wa-ter exchange,increasing the bay half-life time by 15 days.As for the local water exchange capacity,the water exchange capacity in the western part of the bay was decreased by port dam construction and a deposition trend of the Yellow River Estuary,resulting in an increase of half-life time in the western part of the bay by 40 d.