Work on River System 

(i) When the river tumbles at a steep angle over hard rocks or down a steep valley side, it forms a waterfall.
• (ii) As the river enters the plain, it twists and turns, forming large bends known as meanders.
• (iii) At this point in time, the meander loop cuts off from the river and forms a cut-off called an ox-bow lake.

• (iv) During flooding, the river deposits layer of fine soil and other materials called sediments along its banks. This leads to the formation of a flat fertile plain called a floodplain.
• (v) The raised banks along the river are called levees.
• (vi) The collection of sediments from all the mouths forms a delta.