The Inundation of the Nile River

The nile is either the longest river on earth, or like the second longest. It's subject to an annual inundation caused by monsoon rains and melting snow in ethiopia. As a result, the nile river expands - it floods low lying lands as well as depositing thick layers of silt that are ideal for agricultural use. The ancient egyptians figured out how to irrigate their crops using dikes and canals where they would let water from the flooding nile soak before letting it run back into the river again.