TITLE:
Integrated Hydrodynamic-Ecological Assessment of Estuarine Barrage Operation Impacts on a Tropical Lagoon Ecosystem: A Case Study of Thao Long Dam in the Huong River-Tam Giang System, Vietnam
AUTHORS:
Nguyen Van Tuan, Truong Kim Cuong
KEYWORDS:
Estuarine Ecology, Salinity Range, Ecological Connectivity, Thao Long Dam Operation
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.14 No.6,
June
29,
2026
ABSTRACT: This study uses a sustainable coastal ecosystem approach to assess the impact of coastal river dams on ecosystems and aquatic environments, focusing on a case study model at the Thao Long saltwater intrusion control dam (Huong River basin) and the Tam Giang-Cau Hai lagoon system in Central Vietnam. Analysis results indicate that the operation of opening and closing the dam can create extreme changes in salinity levels, causing “freshwater shock,” increasing flow pressure and velocity downstream, and leading to stagnation and degradation of water quality upstream. Analysis of the physiological mechanisms, osmotic pressure regulation, and migration patterns of indicator species with high ecological and economic value in the area, including brown fish, sea bass, perch, shrimp, and native clams, shows that aquatic communities are vulnerable when salinity ranges exceed tolerance thresholds (commonly 15‰ - 32‰). The construction of a dam across the river mouth, such as the Thao Long Dam, which is closed during the dry season, also has negative impacts by disrupting the natural connection between the river and the sea, causing significant disturbances to the migration patterns, reproduction, life cycles, and diversity of common fish species in the Huong River estuary. This study contributes a novel integrated eco-hydraulic framework combining hydrodynamic modeling, salinity shock analysis, and ecological connectivity assessment for evaluating the impacts of estuarine barrage operations in tropical lagoon systems.