What is the history of irrigation?
The history of irrigation is not like a set evolutionary line, and thus the respective developments throughout the world are uniquely characterized by their respective environments. Many of the ancient river valley civilizations practiced irrigation so that they could weather out times of draught.
Archaelogical investigation has identified evidence of irrigation in Mesopotamia and Egypt as far back as the 6th millenium BCE, where barley was grown in areas where the natural rainfall was insufficient to support such a crop.
Contrasting the examples of Mesopotamia and Egypt, Mesopotamia had extensive irrigation systems because of untimely droughts and floods. On the otherhand, Egypt had annual floods -flooding of the Nile river- whose flood periods could be easily calculated.
Historically, surface irrigation dominated most forms of irrigation; it is only recently (late 19th century) that more complex forms of irrigation such as sprinkler irrigation and lateral move irrigation were introduced.