THE WORK OF RIVERS AND PRODUCED LANDFORMS (FLUVIAL LANDFORMS)

                     THE WORK OF RIVERS AND PRODUCED LANDFORMS

                                                   (FLUVIAL LANDFORMS)

The landforms formed by the river water are called riverine landscape.  The river function is the most important of the exogenous processes.  The water obtained due to rain or melting of snow starts flowing in the form of narrow currents on natural pulses.  These streams grow together and form the river.  Therefore, the river is the only natural means of transporting ground floor water to the ocean or a large lake.  The place where the river takes birth is called the origin or source of the river, and the place where the river falls into the ocean or a big lake is called the mouth or estuary of the river.  The path through which the stream of the river passes is called its valley.  In the development of river basins, when tributaries come from the main river, a whole drainage basin is formed.  The higher part between two runoff vasines is called the Watershed or Water Divide.  In India, the mountain range of the Western Ghats acts as a water divider because the rivers flowing to its east fall into the Bay of Bengal while to its west the flowing rivers fall into the Arabian Sea.  The entire area through which the river flows and receives water, It is called Catehment Area.
             
                                                     Work of River

The river performs three types of functions which include erosion, transport and deposit. 
1.Erosion - It is called erosion of the river when the river crosses its edges and foothills.
2. Transport - The river carries the powder generated by erosion in the direction of its water flow.  This is called transportation.
3. Deposition - The river deposits sediment (sediment) in a lowland region.  This is called the deposition work.

                                                 Erosional Work of River
The erosion work of the river is of two types: (1) mechanical and (2) chemical.  In mechanical activity, the river cuts its banks and sediments with the help of its water force.  In chemical reaction, the river dissolves the soluble elements in the rocks in water and erodes the rocks.  The river completes its erosion through Hydraulic Action, Abrasion or Corrasion methods.       
Elements that affect river erosion -
The following elements affect the river erosion:
1. Volume of Water 2.velocity of water 3.Nature of Rocks

Transportational Work of River

The depression generated by the erosion of the river starts flowing along the river's water, it is called the river's flow.  The depression that the river carries is called the River Load of the river water.  The River Load ranges from small rocks to fine chicks.

Factors affecting transport -

1. Velocity of Water - Of all the factors that affect the transport activity of the river, the delay of water is the most important. When the velocity of water increases in the river, it increases the power to transport significantly.  is.  According to Gilbert sir, the power of transportation increases in proportion to the sixth power of the speed. If the water becomes double, then the power to transport will be (2) - 2 x 2x2x2x 2x2 = 64 times.

2. Volume of Water - If the normal amount of water flowing in the river doubles when the other conditions are normal, then the power to transport in it will also be doubled.
3. Size of the River Load - Fine rock particles can be carried far and wide while large ones rocks blocks can be flown only a short distance away.

Depositional Work of River

When the river cannot carry its river load any further, it starts depositing it at the bottom, sides and mouth.  The decrease in the river's carrying capacity comes due to many reasons, such as a decrease in the slope of the valley, a decrease in the velocity of the river, an increase in the amount of water in the river and an increase in the amount of depression.  In the process of deposition, firstly, big stone blocks are deposited and after that medium and small rock particles start to sit.  Fine depression lasts around the mouth.  Only a quarter of the total depression carried by the river reaches the sea.

Landforms Produced By River

The route of the river from the origin to the mouth in three parts Can be divided
(A) Upper part of river valley (b) Intermediate part of river valley (C) Lower part of river valley
Through erosion, transportation and deposition activities, the river creates a variety of topography in different parts of its route.

Landforms produced in the upper part of River Valley

The upper part of the river valley starts from its source located in the mountainous region.  In this part, the river flows on a steep gradient, due to which its velocity and depression carry power is high.  At this stage, the major work of the river is erosion by which the river forms the following figures.

(I) V shaped valley - The river deepens its base through erosion forms, As a result, a V-shaped valley is formed.  It has two classes based on size. 

Gorges. A gorge is a very narrow, deep and steepsided valley. According to Worcester, "These are valleys whose walls are very sleep and high inproportion to their width.The narrow and extremely deep V-shaped valley is called the Gorge.  In high mountain areas, when the river flows over the resistant rocks, due to the high velocity, it keeps cutting the valley and deepening its valley while the work of lateral erosion is less.  Due to the hardness of the rocks, the upper parts of the valley edges fall down into the valley due to weather-weathering, but the lower parts are free from the effects of weathering.  Therefore the gorges are relatively wide from above.In the Himalayas, the Indus, the Satluj and the Brahmaputra form spectacular and frightening megaliths.  The Indus River flows through a 17,000-foot deep gorge in the Himalayas.  Apart from these, the gorges of Narmada, Kosi and Gandak rivers are also notable. 

. Canyon - In terms of texture there is no significant difference between the Gorge and the Canyon, yet it is larger, deeper and narrower than the Canyon Gorge.  This valley is like the I (I) letter of English with its two sides. They are very sharp.  Canyons are generally found in high mountain areas with arid and semi-arid climates because the valley does not widen due to less rainfall in such areas, but the perennial river continues to cut its bottom vertically and deepen.  Grand Canyon, built by the Colorado River in the US, is 483 km 2088 meters deep and 6 to 16 km wide.

Pot Holes - Rolling rock formations on the solid rock bottom along the river route form pits.  In these pits, when the river water rotates in the form of whirlpools, the pebbles and stones lying in the pits act as drills.  Such trenches built in the river bed are called Jalaj Gatika .  The bottom of these pits is wide and the mouth is narrow.  In some places, these troughs are found at the bottom from which they seem as if nature has created a bridge.  Most of the water sockets are above the rapids and below the waterfall.  The deeper deep water socket is called the Plung Pool. 

5. Waterfall - When the river is on the rocky ledge If it falls directly below the upper part, it is called waterfall.  Somewhere in the valley of the river there are soft and hard rocks are separated.  Due to erosion of the river, soft rocks are cut quickly, while hard rocks are weakened at low speed.  Therefore, the different erosion rate of rocks by the river is the main reason for the formation of normal water falls.  Waterfalls are also formed due to earthquakes, volcanoes and land transmission.  When the water of rivers falls down from the top of the cliff at a very high velocity, at a place, it is called 'waterfall'. In this, the layers of hard and soft rocks of the river route are built in horizontal or vertical.  The river water cuts the soft rock, but does not cut the hard rock.  As a result, water starts falling from its upper part downwards. The part of the river in which the flow of water exceeds the normal velocity is called Kshiprika.  Following conditions are required for the construction of waterfalls Necessary. 

(1) Difference in hardness of rocks.  (II) When the strata in the rocks are inclined towards the origin.
(III) When the rocks are tilted towards the mouth.  (IV) When the layers of rocks are in horizontal state.  (V) When the layers of rocks are in vertical direction.