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.