Agricultural drought risk and local adaptation measures in the Upper Mun River Basin, Thailand

Northeast Thailand is one of the country's important agricultural regions. Yet, it is frequently grappled by droughts affecting crop production as most of the cultivation depends on rain-fed irrigation. This study employs a comprehensive framework for assessing the drought risk in the Mun River basin, including hazard, exposure, and vulnerability factors. Hazard is estimated using a multivariate approach considering drought duration and severity, while exposure and vulnerability are evaluated using eighteen proxy factors encompassing physical and socioeconomic aspects. Local adaptation measures adopted by farmers to cope with droughts are an integral part of the risk assessment framework. Factors are normalized to five equally spaced categories and are aggregated using weights obtained from AHP through a survey among 50 local experts. Further, an extensive survey was conducted among 122 farmers in two hotspots with high hazards but contrasting vulnerability to investigate adaptation practices. Experts in the region perceive a higher importance of adaptive capacity than drought susceptibility while defining vulnerability. The results show that people living in areas with high hazard levels and physical vulnerability also tend to have a higher adaptive capacity to manage water scarcity. Overall, 22% of the area is under high to very high drought risk. Specifically, 14% of the area in Nakhon Ratchasima, 15% in Buriram, 8% in Surin, and 19% in Si Sa Ket provinces have very high risk. Among two hotspots, Dan Khun Thot district farmers have diversified crops and practiced various adaptive measures to build their resilience against drought and have low vulnerability and risk. In contrast, adaptation measures are implemented to a far lesser extent in the Phlapphla Chai district and have high vulnerability and risk. The education level of farmers is found to be directly linked with the implementation of local adaptation measures. The disparity in the adaptive measures adopted in two districts highlights the significance of agricultural water management interventions. Access to climate information regarding droughts, building farm ponds, and crop management practices are the preferred adaptation measures taken by the farmers. The study recommends districts in each province identified as having high risk are prioritized and supported by the local government to improve farm-level water management practices and drought resilience. It is imperative as looming climate change will further exacerbate future droughts.