大规模围垦对香港维多利亚港水动力环流的影响

Effect of Large Scale Reclamation on Hydrodynamic Circulation in Victoria Harbour of Hong Kong

摘要:

运用一个已校正的珠江口三维水动力数学模型,研究现存的大规模围垦和进一步最大可能的中环围垦对香港维多利亚港（维港）水动力环流的影响.数值计算显示，与1975年（大规模围垦前）海岸线相比，现存的大规模围垦使维港的水动力有几点关键性变化：① 流量峰值降低了8%~17%，平均降低约11.5%；② 维港东部流速峰值由于流量的减少而减少,维港西部，尽管流量减少，但由于横断面剧减，流速峰值反而增加；③ 雨季由于珠江径流的作用,盐度垂向分布呈明显的二层结构，而在枯季则比较均匀；④ 枯、雨季的潮流冲洗时间分别增加约30%和

Abstract:

A calibrated threedimensional hydrodynamic model for the Pearl River Estuary is used to study the changes in hydrodynamic circulation in Victoria Harbour due to the existing reclamation and the maximum possible Central reclamation.Compared to the situation in 1975 （before large scale reclamation）,the numerical solutions show the following key changes after reclamation: The peak flow at all cross sections along Victoria Harbour decreases by about 8%~17% with an average value 11.5% in the existing reclamation.The peak velocity in the eastern harbour near Lei Yue Mun decreases after existing reclamation because of the reduction of flow,but it increases in the central and western harbour due to drastic reduction in harbour width.There is a clear twolayer vertical salinity distribution in wet season due to the runoff from the Pearl River,but a quite uniform vertical salinity structure in dry season.Flushing time in Victoria Harbour will increase by about 30% in dry season and 50% in wet season after reclamation due to the flow reduction.In present coastline,the flushing time ranges about 1.5~2.5 days in wet season and 5~7 days in dry season.The tidal flushing rate and flow discharge in the harbour will be practically unchanged after further maximum possible Central reclamation.