Eight thousand years ago, farmers in Egypt discovered that by building embankments and dams along the Nile, they could trap the rising waters to grow more crops. This was one of the first irrigation systems to be invented, but it was not the last.
Over time, engineers, farmers and civilizations have designed some pretty ingenious irrigation systems. This is because irrigation does much more than help crops grow. It also enables landscape maintenance, revegetation of desert soils, reduces dust, helps raise livestock, and manages wastewater disposal, mining and drainage.
These crucial irrigation systems allowed early civilizations to grow and develop further. Today, irrigated agriculture covers 275 million hectares (about 680 million acres) of land and accounts for 40% of the world's food production. We now have new, more efficient irrigation systems that put water exactly where it is needed most, and we are only going to get better.
via Interesting Engineering