Book Co. Pp. 393-408 Hartman, Kofraneck, Rubatzk, and Plocker. Because a very large percentage of the earth's land mass receives less than 20 inches of rain per year, the need for irrigation is very obvious. B. Farmers have irrigated crops for over 4,000 years. Records show that crops were irrigated along the Euphrates, Ganges, Nile and Tigris rivers as early as 2600 B.C. 2.
Great civilizations develop when the population no longer needs to lead a nomadic life-style.
A portion of the population produces all of the food so other members can perform other specialized activities ranging from making tools to establishing governments. Irrigation, no doubt, contributed to the founding of these great civilizations. Even though irrigation has been practiced for so many years, modern methods were started as little as 200 years ago. Selection of the right watering system can save labor and water, and assure increased crop yields. Each of these have characteristics which makes them useable in a specific situation.