Discovering The Global Past Chapter 1

In chapter one of Discovering the Global Past  it discusses the importance of water in early civilizations. Specifically its main question being "How did the need for steady supply of water affect the technological, economic, political and legal development of ancient societies?"
In Mesopotamia, farmers relied on different types of irrigation to keep the land useful.  If irrigation wasnot maintained the land would be a waste. Egypt did not get much rain and it forced many to rely on the Nile River like many did in China with the Yellow River due to the lack of rain.
Because the irrigation system began so long ago, historians relied on the remains of the land to identify how the natives preserved their land. When historians discovered the first civilizations writings they learned the importrance of the irrigations systems based off the evidence of the writings.