Integrated approach for drought and saline intrusion severity assessment on the coastal Mekong Delta of Vietnam contextualizing physical change to risk management and policy development

Drought and saline intrusion are common hazards that typically occur during dry seasons in the Mekong Delta of Vietnam (MDV), leading to significant socio-economic impacts such as water shortages, crop failures, and social unrest. Climate change exacerbated the impacts of these hazards, which have become more complex and unpredictable, particularly in coastal provinces in MDV. This study aims to explore the intricate relationships between drought and saline intrusion by utilizing the Streamflow Drought Index (SSI), Standardized Precipitation Evapotranspiration Index (SPEI), saline boundary 4 g/l, Pearson correlation (R), and p-values. Additionally, the study analyzes policy developments between the 2016 and 2020 droughts using document review and comparative approach methods. Overall, the results indicate that the 2020 drought was more severe than the 2016 drought. Hydrological drought shows a stronger connection with saline intrusion than meteorological drought in the MDV. Governance in drought and saline intrusion management in 2020 showed improvement compared to 2016. The management of aquaculture remained deficient, leading to more severe impacts of drought and saline intrusion on aquaculture in 2020 than in 2016. The findings of this study can complement risk information and assist decision-makers in effectively managing drought and saline intrusion hazards.