The trilemma of the water-pricing policy, the social function of water, and the threats to water security in a Metropolitan Region

The water security issue is worsened by the presence of the global threat of climate change that may inhibit global and local water availability. This study explores water security from the perspective of three impelling factors and was carried out in Bangkok Metropolitan Region (BMR), Thailand. We define the trilemma as three generally conflicting factors that bring different consequences because of water security. The study was organized by accounting time-independent hydrological budget in the region comprises of surface water, probable atmospheric water, and groundwater against current and future water demands with particular water qualities for different purposes. A sensitivity analysis has also been done. The study found that with current water resources development and water demand, the BMR would unlikely encounter water security issues, given the existing trilemma as a constraint. However, with a continuous increase in water demand and unchanged supply, water scarcity would likely be faced by BMR, as analysis suggests.