Indicator-to-impact links to help improve agricultural drought preparedness in Thailand

Droughts in Thailand are becoming more severe due to climate change. Developing a reliable drought monitoring and early warning system (DMEWS) is essential to strengthen a country's resilience to droughts. However, for a DMEWS to be valuable, the drought indicators provided to stakeholders must have relevance to tangible impacts on the ground. Here, we analyse drought indicator-to-impact relationships in Thailand, using a combination of correlation analysis and machine learning techniques (random forest). In the correlation analysis, we study the link between meteorological drought indicators and high-resolution remote sensing vegetation indices used as proxies for crop yield and forest growth impacts. Our analysis shows that this link varies depending on land use, season and region. The random forest models built to estimate regional crop productivity allow a more in-depth analysis of the crop- and region-specific importance of different drought indicators. The results highlight seasonal patterns of drought vulnerability for individual crops, usually linked to their growing season, although the effects are somewhat attenuated in irrigated regions. Integration of the approaches provides new, detailed knowledge of crop- and region-specific indicator-to-impact links, which can form the basis of targeted mitigation actions in an improved DMEWS in Thailand and could be applied to other parts of Southeast Asia and beyond.</p

Evaluation of the inequality of water resources

In this study, Lorenz curves and Gini coefficients, which have been used for income distribution problems, were applied to quantify the distribution of water resources. This method was used to test water inequality in the Mae Chaem river basin, as well as the rest of Thailand. The Lorenz curves and Gini coefficients of the Mae Chaem river basin were compared to those for all of Thailand to understand water resources inequality in small-scale basins and large areas. The Gini coefficients of both the streamflow discharge per unit area (potential water resources) and water availability to population in the Mae Chaem river basin are significantly smaller than in Thailand as a whole. The dry season results for Thailand show that both the potential water resources and water availability to population were higher in 2000 than in 1989. This is a result of changes in the water availability to the population related to changing land use, especially deforestation throughout Thailand

Assessment of water conflict in Mae Chaem River Basin, Northern Thailand

For this study, we conducted a quantitative water resources assessment of the Mae Chaem River Basin, Thailand, an area with dry season water scarcity and water use conflicts between upstream and downstream inhabitants. The block-wise TOPMODEL with the Muskingum–Cunge flow routing method (BTOPMC) was used to predict run-off in 21 sub-basins and Geographic Information System (GIS) was employed to collect information for crop water demand evaluation. Four sub-basins exhibited critical water conditions in 2000. The conversion of forestlands into agricultural lands during the past decade has engendered water scarcity in the dry season and flooding in the wet season