What is Irrigation?

Irrigation was an innovation that resulted in mankind being able to cultivate crops, food, and livestock regularly, and thereby, become civilized. Irrigation ensured a steady supply of food for both humans and livestock and enabled humans to inhabit parts of the earth that do not naturally grow essential resources.

Development of Irrigation

Irrigation started in approximately 6000 BCE in both Egypt and Mesopotamia. These ancient societies rerouted the flooding Nile and Tigris/Euphrates rivers between July and December and after, the water would be drained back into the rivers. The first major irrigation project occurred around 3100 BCE in Egypt and involved the construction of dams and canals to divert the flood waters from the Nile into a man-made lake called "Moeris". Similar canal systems also existed in pre-Columbian America, Syria, China, and India.

King Hammurabi was the first to establish water regulations, including the distribution of water based on the acres farmed and the responsibilities of farmers to maintain canals on their property. The shadoof/shaduf, a large pole balanced on a crossbeam with a rope and bucket tied to one end and a counterweight on the other end, was invented around 1700 BCE. This device worked by pulling the rope to lower the bucket into a water source, then raising the bucket and swinging it around the pole to water fields or to move the water to another source. It allowed irrigation when there was no flooding and higher ground that needed to be farmed.

Around 700 BCE, the Egyptian water wheel was developed. Using similar technology to today’s water wheels, this device emptied water into aqueducts or troughs. This creation was the first lifting device not operated by humans. Not long after, the qanat became the first technique to use groundwater by building a vertical well into sloping ground. Tunnels dug horizontally through the well allowed water to travel by gravity. The Persian water wheel, also called the sakia, is the first known use of what we now know as a pump. This wheel was powered by oxen. Around 250 BCE, a Greek scholar invented the tambour, which was a screw in an empty tube that was rotated in order to scoop up water. Windmills were developed in 500 AD and evidence of their use exists in Persia (modern day Iran).

Around the world, irrigation appears to have started with canals and reservoirs, though many cultures' techniques varied. The Sinhalese of Sri Lanka have been dubbed the "masters of irrigation" and were the first to build artificial reservoirs. The Chinese used various methods, including chain pumps powered by foot pedals, hydraulic water wheels, or mechanical wheels moved by oxen. A Korean engineer invented the first rain gauge in 1441, allowing farmers to use their survey information better. In Arizona, United States, canals were used to water crops as early as 1200 BCE. Modern irrigation technology likely originated in the Mormon settlement of the Utah Great Salt Lake Basin around 1847.

Today, several types of irrigation systems are used, like surface irrigation, drip irrigation, sprinkler irrigation, sub-irrigation, and more. Agriculturists select the method most appropriate for the area, crops, and resources available. Irrigation changed human patterns by allowing humans to have a steady source of sustenance that could be cultivated on a mass scale. Additionally, it has allowed civilizations to survive, and even thrive, in harsh environments and to inhabit these areas permanently. However, it also impacted society in negative ways. The control of water and arable land has been monopolized by elites, and of course, technical challenges have arisen due to distribution, pollution, and drought. The development of irrigation contributed to the foundation of the "civilized" world and to the growth of engineering, particularly hydraulics.


Examples of the Effects of Irrigation