When water becomes scarce, its quality often deteriorates

Droughts and heat waves cause great economic damage. To reduce water scarcity, hydrologist Michelle van Vliet advocates a better understanding of the interaction between water quality and water use. Water scarcity is more than just a physical lack of water. Growing water scarcity has three causes: decreasing water availability, increasing water use and deteriorating water quality, making it unsuitable for certain uses or functions. Droughts and heat waves are particularly critical because they have an amplifying effect on all three of these causes. Each of these three components alone contributes to water scarcity, but they also do so together by interacting with each other. For example, reduced water availability during a drought increases water scarcity directly, but also indirectly because less water is available to dilute potential pollutants, which in turn leads to a deterioration in water quality.