Deep Bay (DB) is a semi-enclosed bay that opens to the middle part of the Pearl River Estuary (PRE), the largest estuarine wetland area in the world. Like many rivers around the world, the Pearl River has in recent years experienced more frequent and more severe flow variations. It was hypothesized that Pearl River flow variation would affect the environment of DB, where locates large area of Ramsar wetlands of international importance. The anthropogenic factor of land reclamation was also hypothesized to alter the Pearl River flow and thus affect DB and the PRE environment. Simulations were performed to model water and salt transport processes under different scenarios of Pearl River flow variation and land reclamation. It was found that the Pearl River had a strong governing role on the hydrodynamics of DB, especially in the wet season. The simulation results indicated that in the wet season, the waters at the mouth of DB and DB as a whole were respectively composed of 50–80% and 31–37% of water discharged from the Pearl River. Moreover, it was shown that a 20% increase in Pearl River flow in the wet season would result in 0.2% and 3.3% more Pearl River water flushing into the bay before and after reclamation, respectively. Therefore, reclamation is predicted to stress the coastal ecosystem in DB, as it will enhance the intrusion of pollutants from the Pearl River into the bay head. However, it would benefit the removal and dilution of pollutants directly discharged into the bay from the Shenzhen River. Our results confirm that the hydrodynamic interconnection of bay and estuary in an estuarine system is complex, and should be carefully examined when assessing the environmental impacts of climate change and anthropogenic engineering projects.

后海湾（DB）是半封闭的海湾，通向珠江口（PRE）的中部，珠江口是世界上最大的河口湿地地区。像世界上许多河流一样，珠江近年来的流量变化更加频繁和严重。据推测，珠江水流的变化会影响到DB的环境，因为DB所在的地区具有国际重要性。还假设了开垦的人为因素会改变珠江水流，从而影响DB和PRE环境。进行了模拟，以模拟珠江流量变化和土地开垦的不同情况下的水盐运输过程。研究发现，珠江对DB的水动力具有重要的控制作用，尤其是在雨季。模拟结果表明，在雨季，珠江口和珠江口总体上的水分别由珠江排放的水的50-80％和31-37％组成。此外，研究表明，在潮湿季节珠江流量增加20％会分别导致填海前后海湾地区的珠江水冲洗量分别增加0.2％和3.3％。因此，预计填海将给DB的沿海生态系统带来压力，因为这将增加污染物从珠江进入湾头的入侵。但是，这将有利于去除和稀释从深圳河直接排入海湾的污染物。我们的结果证实，河口系统中海湾与河口的水动力互连是复杂的，