A large-scale waterway regulation project, which is the main approach for people to manage coastal and estuary area will be imperative due to the high-speed economic development in Guangdong Province. The project will change the topography in the estuary region and influence the hydrodynamic conditions there. The Modaomen waterway, as the main access to the sea of Xijiang River, plays a key role in connecting outer sea. During recent years, a remarkable deterioration of tide intrusion occurred resulting in negative effect on water resource utilization in industry, agriculture and local people’s lives and therefore it is of great significance to study on the tide intrusion caused by dredging project.
This paper analyses measured Modaomen hydrological data and exhibits the temporal and spatial distribution of salinity and characteristics of fresh and salinity water mixing, as well as the correlation between salinity, water level and suspended sediment concentration in the Modaomen region. Based on the establishment of high-precision three-dimensional salinity mathematical model in Modaomen region, this paper calculates various engineering plans and examines the changes of flow field and tidal saltwater intrusion, which provides elementary base for implementation of the waterway regulation engineering. During the process of calculation, the terrain, the border and validation data that adopted in this paper is relatively new and have high reliability.
The study indicates that the salinity degree has a merely minor increase after projects indeed in the estuary to provide situation for tide intrusion. However, the influence is little and it fails to be the chief reasons responsible for the depravation of tide intrusion in the Modaomen estuary recent years.