The hydraulic head measures the water pressure expressed in terms of height. For instance the pressure on the bottom of a lake filled with a water column of 10 m, will receive a water pressure of 10 m expressed as hydraulic head.
Perspectives are different frameworks from which to explore the knowledge around sustainable sanitation and water management. Perspectives are like filters: they compile and structure the information that relate to a given focus theme, region or context. This allows you to quickly navigate to the content of your particular interest while promoting the holistic understanding of sustainable sanitation and water management.