<P> A river civilization or river culture is an agricultural nation or civilization situated beside a river . A river gives the inhabitants a source of water for drinking and agriculture . Additional benefits include fishing, fertile soil due to annual flooding, and ease of transportation . </P> <P> The first great civilizations all grew up in river valleys, The oldest known civilization, 3300 to 2500 BCE, was along the Tigris and Euphrates rivers in the Middle East; the name given to that civilization, Mesopotamia, means "land between the rivers". The Nile valley in Egypt had been home to agricultural settlements as early as 5500 BCE, but the growth of Egypt as a civilization began around 3100 BCE . A third civilization grew up along the Indus River around 2600 BCE, in parts of what are now India and Pakistan . The fourth great river civilization emerged around 1700 BCE along the Yellow River in China, also known as the Huang - He River Civilization . </P> <P> Civilizations tended to grow up in river valleys for a number of reasons. The most obvious is access to a usually reliable source of water for agriculture and human needs . Plentiful water, and the enrichment of the soil due to annual floods, made it possible to grow excess crops beyond what was needed to sustain an agricultural village . This allowed for some members of the community to engage in non-agricultural activities such as construction of buildings and cities (the root of the word "civilization"), metal working, trade, and social organization . </P>

When did the human settlements came about in the nile valley