The material welfare of the world's population depends on maintaining access to increasingly scarce water and energy resources. Water and energy in engineered and natural systems are intricately linked.

Extracting raw energy resources, cooling power plants, and powering the generators for hydroelectric energy all use water.

People also use natural waterways to dilute and disperse pollutants.

Extracting, purifying, pumping and transporting drinking water, heating water for domestic and other use, and treating and disposing of wastewater are all activities that use energy. In agricultural and industrial settings, both resources are essential to sustaining economic output.

To minimize resource depletion and maximize human and environmental benefits, it is essential to understand the interdependence of water and energy use.