Impact of the South-to-North Water Diversion Project on saltwater intrusion and freshwater resources in the Changjiang Estuary

doi:10.3969/j.issn.1000-5641.201941031

Abstract

Abstract: The South-to-North Water Diversion Project is an interbasin water diversion project, whose impact on changes in freshwater resources in the Changjiang Estuary is of widespread interest. In this paper, we used a 3D numerical model of estuarine saltwater intrusion to study the impact on saltwater intrusion and freshwater resources in the Changjiang Estuary from both short-term and long-term perspectives. The study, moreover, was focused on the eastern and middle route water transfer schemes of the Project. The results indicate that during the neap-spring tide period in mid-to-late February, the unavailable water intake time, corresponding to salinity greater than 0.45 at the water inlets of the Dongfengxisha, Chenhang, and Qingcaosha is 7.74, 3.08, and 2.72 days, respectively. In the case of a short-term water transfer scheme at river discharge of 1 000 m³/s, saltwater intrusion is intensified, especially at the river mouths of the North Channel, North and South Passages, and in the upper reaches of the North Branch, where salinity rise is most noticeable and a large area shows a salinity rise greater than 0.5; meanwhile, the supply of freshwater in the South Branch decreases. During the neap-spring tide period in mid-to-late February, the unavailable water intake time at the water inlets of the Dongfengxisha, Chenhang and Qingcaosha Reservoirs increases by 1.43, 2.14 and 2.13 days, respectively. In the case of long-term water transfer schemes at river discharge of 1 600 m³/s, the salinity rise in the entire estuary is even more noticeable; a large area of salinity rise greater than 1 shows up on the river mouths of the North Channel, North and South Passages, and a small area of salinity rise greater than 1.5. The supply of freshwater in the South Branch also decreases. During the neap-spring tide period in mid-to-late February, the unavailable water intake time at the water inlets of Dongfengxisha, Chenhang, and Qingcaosha Reservoirs increases by 1.49, 3.08, and 3.08 days, respectively.

Key words: Changjiang Estuary, South-to-North Water Diversion Project, saltwater intrusion, freshwater resource, numerical model

CLC Number:

P731.2

SU Aiping, Lü Hanghang, WU Yufan. Impact of the South-to-North Water Diversion Project on saltwater intrusion and freshwater resources in the Changjiang Estuary[J]. Journal of East China Normal University(Natural Science), 2020, 2020(3): 32-42.

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