Our Science Heritage
People cannot live without fresh water. Their body cells and body processes depend on a continual supply of fresh water. Also, the food that people eat requires water to grow.
Civilizations could not develop without the invention of farming. With farming, people could stay in one place and raise their own food rather than relocate depending on the availability of natural foods.
Evidence indicates that people in the Middle East began raising grain, goats, and sheep about 11 000 years ago. Crops were raised and animals domesticated about 9500 years ago in Southeast Asia and about 8500 years ago in what is now Mexico.
About 5000 years ago, four major civilizations arose. Each of those civilizations developed in a river valley that contained fertile soil for farming and fresh water for irrigation and for use by people. The four river valleys are the Nile (in present-day Egypt), the Tigris and the Euphrates (in present-day Iraq), the Indus (in present-day Pakistan), and the
Hwang Ho, or Yellow River (located in present-day China).
Scientists who study the past feel that there is a connection between the rise and fall of civilizations and the way they used their land and other natural resources. In the case of the Sumerians, who lived in the valley between the Tigris and the Euphrates Rivers, there is evidence that they destroyed their farmlands by poor irrigation practices.
Water and Ancient Civilizations
They increased the salt content of the soil to a point where crops could no longer be raised (a problem that still occurs in areas that water their crops by irrigation).