English

An environmental scientist providing clean water to the city of Philadelphia explains how this water is used to fight fires and to provide water for our homes, parks, and swimming pools. He shows us that river water provided by rain and runoff from farms is dirty and needs to be purified before human beings can use it.

Despite its wonders, Earth's water cycle does not spread water evenly around the planet. The Ogallala Aquifer’s huge underground reservoir of water gives the relatively dry Central Plains states such as Nebraska a large but limited irrigation source. But the aquifer's water is being used up faster than it is beng replenished.