Imagine playing beside the ocean, when suddenly, the water drops. Where the water used to be, there are wriggling fish and ribbons of seaweed. What do you do?
Humans use lots of water. We need it for various activities, including agriculture, transport, washing, and recreation. Most important, we need to drink fresh water to stay alive. Today, in many regions around the world, fresh water comes straight to where we need it. But in some places, people must carry gallons of water from the closest stream, river, lake, or well to their homes.