Irrigation, in short, is when water is brought to crops/lands (Benjamin A. Jones). This is done so crops can grow, land can become arable, etc (Benjamin A. Jones). Irrigation can also improve environmental factors by controlling run-off when it comes to watering crops, meaning by only allowing so much water to be used when watering crops so the fertilizers and pesticides won’t run-off into freshwater resources (Podonnell). Irrigation may also be a way to prevent flooding by building ditches, dams, walls, etc. The most used irrigation system is the surface irrigation method, where water is brought to crops through canals, dams, furrows, etc, which is about 85 percent of the entire world’s irrigation use (Fruit Growers).

Mesopotamia invented irrigation for several different reasons. An example of this would be when the Sumerians built dams, ditches, canals, etc, to prevent flood waters from drowning crops, livestock, people, and houses from washing away. The Sumerians would also use irrigation to control water levels for farming. This meant that when the water levels were too low there would be a drought and crops would dry out, and when the water levels were too high, damaging flooding was likely. Controlling these would be extremely important to keep agriculture, and their economy, going smoothly. These floods and droughts were unpredictable, so irrigation was a big help with agriculture, and to the Sumerians. 

Irrigation has had many positive effects over the hundreds of years it has been performed and adapted. An example of one is that when irrigation is done in areas where precipitation is irregular, meaning it doesn't have a normal cycle, nor regular amount of rainfall, irrigation has shown to improve crop health and growth (Kim Rutledge). Irrigation has also shown that it can give a regular schedule when it comes to farmers planting and harvesting crops, giving people a reliable food source (Kim Rutledge).