Land forms created by the river system

V-shaped valley

» A river flows with a greater velocity in the mountainous region and big, pointed fragments of rock also flow with a great speed along with the water.
» The river bed is scoured and down cutting starts, ultimately giving rise to a deep valley with steep sides. This valley is called a v-shaped valley.
» These valleys are found in mountainous regions.
» A deep and narrow valley with steep sides is called a gorge.
» The gorge of the river Ulhas in Thane district in Maharashtra and the gorge of the river Narmada at Bhedaghat near Jabalpur in Madhya Pradesh are well known.
» There are many gorges in the Himalayas.

Waterfall

» If there are both hard (resistant) and soft (less resistant) rocks in the course of the river, the less resistant rock is eroded faster.
» The resistant rock does not erode so easily. That is why, the river falls with a great speed from a cliff-like part of hard rock. This is called a waterfall.
» The Niagara Falls on the Niagara river is in North America.

Potholes

» In areas where the river bed consists of hard rock, the stones carried along with the river water due to the whirling impact of water.
» That is why holes of various shapes are formed in the rocky river bed. Such holes are called potholes.
» Many potholes are observed in the river bed of the Kukadi, Krishna, Godavari etc. in Maharashtra.

Meanders and ox-bow lakes

» Meanders are formed by lateral erosion. As the erosion increases over a period of time, the meanders in the river again starts flowing in a straight line.
» The loop previously formed then separates from the main course of the river. Water accumulates in this separated part.
» As this loop resembles on ox-bow it is called ox-bow lake. It formed due to impounding of water in the abandoned meander loop.

Fan-shaped plains

» In the region near the source of a river the tributaries joining the main river deposit materials carried by them on the banks of the main river.
» This deposition creates fan-like plains. They are called fan-shaped plains or alluvial fans.

Flood plains

» When, during the floods, the river-water overflows its banks and spreads in the surrounding areas, the silt carried by the water gets deposited in those areas. This creates flat plains on both the banks of the river. Plains created by this depositional work done during floods are called flood plains.
» The Gangetic Plain is a flood plain.

Natural levees

» When a river is over flooded, its water crosses its banks. At that time, the speed of the water is reduced, and the pebbles and stones carried by the river get deposited near the banks.
» On account of frequent floods, the area where these sediments are deposited near the bank of the river rises higher than the flood plain.
» This high wall is called a natural levee or natural embankment.
» Such levees are found on the banks of the Mississippi, the Huang-Ho etc, Southern bank of river Ganga.

Delta

» Delta was coined by Herodotus (the 'Father of History') after the Greek letter delta (A) because of the deltoid shape at the mouth of the Nile.
» A delta is a land form that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area or another river.

Delta region

» A river meets a sea or a lake. The silt carried by the river is deposited on the bed near its mouth.
» The area near the mouth of the river gets gradually filledup by this deposition and gets raised causing an obstruction for the river to flow in a single channel. It, therefore, splits into two branches and meets the sea.
» Over a period of time, there is deposition also at the mouth of these branches. In this manner, the main course of the river gets split into a network of small channels. These sub-channels are called distributaries.
» A triangular region of innumerable such distributaries is formed near the mouth of the river. This region is called the delta region.
» There are delta regions near the vent (opening) of the rivers Godavari, Ganga, Nile, Mississippi etc. Deltas are very fertile.
» The largest delta of the world is 'Ganges Delta’ /’Sunderbans Delta' (350 km).