Artificial levees are 'earthen mounds' built on the river banks to increase the 'volume of water' the channel can hold.
EXPLANATION:
A levee or stop bank is called as a 'natural or artificial wall' or a bank which is used to protect the flooded water in a certain area and these Levees are made from the compact earth.
There are two type of levee, artificial and natural. Artificial levee often seems to get damaged which may cause breach.