Assessing the Water-Energy-Food Nexus under Climate and Socio-economic Change in Vu Gia – Thu Bon River Basin, Vietnam

The Vu Gia – Thu Bon River Basin (VGTBRB), Central Vietnam’s largest river basin (about 10,350 km²), flows through Quang Nam Province and Da Nang City. It supplies water for multiple purposes, including hydropower generation (with around 20 operational upstream hydropower plants), irrigation, and domestic use (accounting for almost 70% of domestic use for Da Nang). While this multifunctional role supports the regional socio-economic development, the basin is increasingly challenged by intensifying water, energy, and food (WEF) demands driven by population growth, urban expansion, tourism development, and salinity intrusion, highlighting the need for an integrated Water-Energy-Food nexus approach.

Despite growing global research on the WEF nexus, no comprehensive statistical WEF nexus models have been developed for the VGTBRB. Previous studies in the region have largely focused on individual sectors, overlooking the role of salinity intrusion and its implications for water demand, food production, and tourism-related resource use. This study addresses this gap by employing a WEF nexus framework combined with System Dynamics Modelling (SDM) to capture sectoral interactions, feedback mechanisms, and trade-offs in water allocation under future climate and socio-economic scenarios. The analysis incorporates historical data from 2010 to 2024 for model calibration and validation, and projections for 2025–2050 aligned with climate change scenarios and the regional Master Plan for 2021–2030 with a vision to 2050.

Results indicate pronounced seasonal variability in water demand, critical feedback between temperature and domestic water use, and interactions between rainfall and water use that influence the risks of salinity intrusion at downstream water supply intakes. In addition, a positive relationship is identified between tourism growth and water demand, particularly during dry seasons, which exacerbates water stress.

By explicitly integrating salinity and tourism dynamics, this study pioneers a WEF nexus-based modelling approach for the VGTBRB. The findings provide policy-relevant insights to enhance water system resilience under climate and socio-economic change, support progress towards the Sustainable Development Goals, and inform integrated resource governance in a tourism-dependent, salinity-affected river basin.