Saltwater Intrusion Analysis and Control for Complex River Network Using Multi-Source Tracer-Aided Modeling Simulation

The escalating sea-level rise associated with global climate change increasingly threatens estuary regions with salinity intrusion, particularly in complex river network systems where both ecological integrity and socio-economic development are at risk. While tracer techniques are commonly employed in salinity intrusion research, numerical models capable of quantifying multi-source contributions and tracing intrusion pathways in such complex settings remain underdeveloped. This study introduces a multi-source tracer-aided modeling approach to analyze and mitigate salinity intrusion, enabling quantification of the relative contributions of various salinity sources at targeted locations. Using the Telemac-2D hydrodynamic model, we simulated salinity intrusion in the Xinbu Island estuary, Hainan Province, China. A multi-source particle tracer method was implemented to delineate intrusion pathways, leading to the formulation of targeted control strategies based on simulation outcomes. Results demonstrate that measures informed by source proportion and intrusion path analysis are highly effective: under discharge conditions of 181 m3/s and 296 m3/s, salinity levels in the northern river network were significantly reduced. This study provides a valuable framework for addressing similar salinity challenges in vulnerable estuarine environments worldwide.