Irrigation was a Sumerian invention, which included major components like canals, gated ditches, levees, and gates. Its two purposes were to (1) to water the crops using w<span>ater carried from the Tigris and Euphrates Rivers to the fields where the crops were located, and (2) </span><span>to protect Mesopotamia, from the threat of flooding.</span>
Commonplace means not rare, where familiar means something that you're used to. For example, just because you're used to dragons doesn't mean its ordinary.
