On The Control Of Saltwater Intrusion: A Case Study For Binh Thuan Province, Vietnam

Saltwater intrusion is one of the major issues for coastal water resources management in the world since it has great impact on flora, fauna and the people that live along the estuary. Therefore, it is necessary to properly evaluate the process of saltwater intrusion of space and time. This paper aims to simulate saltwater intrusion in the Luy river basin in Binh Thuan province and propose measures to minimize its unwanted impacts in short-term and long-term. New Generation River modeling package, MIKE HYDRO River, in combination with advection-dispersion module was adopted to investigate the salinity intrusion. The model was well calibrated and validated based on surveyed data in June 2017 and March 2018. The salinity intrusion during validated period is the most severe since it is at the end of the dry season and during the spring tide. Especially, salinity had been measured along the Luy river in order to not only determine correctly the length of the river affected by salty water, i.e. the location with salinity concentration of 0.75 parts per thousand - where there is no risk of salinization to the plants, but also to validate the saltwater intrusion model in term of longitudinal profile. The result reveals that saline penetrates deeply into the Dong and Luy rivers, e.g. more than 8 km of seawater wedge length in the later one in present situation. Saline will intrude severely into the Dong, Luy, Mao and Oai Son rivers with the length of 13, 27.6, 10.8 and 13.1 km respectively, if considering low flow in dry season and sea level rise under RCP4.5 scenario in 2050. For minimizing unwanted impacts of salinity intrusion, suitable solution, i.e. structural measure, was selected. Precisely, two anti-salt weirs in the Dong and Luy rivers were proposed to be constructed at about 3 km from the estuary.