Impact of Large-Scale Reclamation on Hydrodynamics and Flushing in Victoria Harbour, Hong Kong

Kuang, C.P.; Huang, J.; Lee, J.H.W., and Gu, J. 2013. Impact of large-scale reclamation on hydrodynamics and flushing in Victoria Harbour, Hong Kong. A three-dimensional (3D) hydrodynamic model for the Pearl River Estuary based on Delft3D is established and calibrated to study the changes in tidal circulation and flushing in Victoria Harbour. The tidal circulation and flushing were simulated by this 3D model under the existing reclamation conditions, including Central Reclamation Phases I, II, and III (CRI, CRII, and CRIII), and Wan Chai Reclamation Phase I (WRI). The model is also applied to predict the hydrodynamic changes after the reclamation of proposed Wan Chai Development Phase II (WDII) to be constructed in 2017. Compared to the coastline in 1975 (before large-scale reclamation), the numerical results show that the following changes have taken place after the existing reclamation: (1) The peak flow at all cross sections along Victoria Harbour decreases by about 9–25%, with an average value of about 15% for the existing reclamation; (2) the peak velocity in the eastern harbour near Lei Yue Mun decreases after the existing reclamation because of the reduction of flow, but it increases in the central and western harbour due to the significant narrowing in harbour width; (3) flushing time in Victoria Harbour increases by about 25–40% in the wet season and increases by almost 15–30% in the dry season as a result of the changes of the flow discharge and tidal range. After the reclamation of WDII, the flushing rate and flow discharge in Victoria Harbour only change slightly compared with that under the existing reclamation condition. Another finding is that for the present coastline, the flushing time ranges about 1.5–2.5 days in the wet season and 5–7 days in the dry season.