Drainage

The streams within a drainage basin form certain patterns, depending on the slope of land, underlying structure as well as the climatic conditions of the area. The dendritic pattern develops where the river channel follows the slope of the terrain. The stream with its tributaries resembles the branches of a tree, thus the name is dendritic.

The Wular lake is located in Jammu and Kashmir, in contrast, is the result of the tectonic activity. It is the largest freshwater lake in India. Most of the fresh water lakes are in Himalayan region. They are of glacial origin. These freshwater lakes are formed when glaciers dug out a basin, which was later filled with snowmelt.

The Narmada rises in the Amarkantak hills in Madhya Pradesh, which flows towards the west in a rift valley formed due to faulting. On its way to sea, the Narmada creates many picturesque locations. The ‘Marble rocks’ near Jabalpur where the Narmada flows through a deep gorge, and the ‘Dhuadhar falls’ where the river plunges over steep rocks. The tributaries of the Narmada are very short and most of these join the main stream at right angles. It covers parts of Madhya Pradesh and Gujarat.

The main water divide in Peninsular India is formed by the Western Ghats, which runs from north to south close to western coast. The major rivers of the Peninsula such as the Mahanadi, the Godavari, the Krishna and the Kaveri flow eastwards and drain into the Bay of Bengal. The Godavari river is the largest Peninsular river which rises from the slopes of the Western Ghats in the Nasik district of Maharashtra and its length is about 1500 km, it is joined by a number of tributaries such as the Purna, the Wardha, the Pranitha, the Manjra, the Wainganga and the Penganga.

Lakes in the region of inland drainage are sometimes seasonal; for example, the Sambhar lake in Rajasthan, which is a salt water lake. Its water is used for producing salt. These lakes’ water is not suitable for drinking but it is used for some of domestic activities like cloth washing and cleaning the house. For irrigation purpose it is used in farming process.

The Tapi rises in the Satpura ranges, in the Betul district of Madhya Pradesh, and flows in a rift valley parallel to Narmada but it is much shorter in length. The coastal plains between Western Ghats and the Arabian sea are very narrow, hence, the coastal rivers are short.

Water divide is meant to an elevated area like mountain or upland that separates two drainage basins. It divides those elevated areas so that problem of water can be resolved easily among residents. For example: Ambala is located on the water divide between the Indus and the Ganga river systems. Here, elevated areas mean an area which is raised above the ground.

Basin is basically a natural depression in the surface of the land often with a lake at the bottom of it. In India, there are 20 river basins/draining areas, large and small. Among these small and large basins, the largest one is the Ganga basin.

Indus and Ganga both of them have their origin in the Himalayas, the river Indus rises near the Mansarovar Lake in Tibet and the Ganga originates at the Gangotri glacier in the Himalayas. The Indus flows through Baltistan and Gilgit and emerges from the mountains at Attock and the headwaters the Ganga, called Bhagirathi is fed by the Gangotri Glacier and joined by the Alaknanda at Devaprayag in Uttarakhand.

Bhagirathi and Alaknanda are the two headstreams of the Ganga, Bhagirathi is fed by the Gangotri Glacier and joined by the Alaknanda and by passing from here it meets at Devaprayag in Uttarakhand. At Haridwar the Ganga emerges from the mountains on to the plains. The Ganga is also joined by many tributaries from the Himalayas.

The Brahmaputra river in its Tibetan part have less slit because it is cold and a dry area. In India it passes through a region of high rainfall, here it carries a large volume of water and considerable amount of slit. But in Tibetan part of its there is less rainfall and that’s the reason of less slit and water. But during the rainy season, every year the river overflows its banks, that causes widespread devastation due to floods in Assam and Bangladesh. It collects huge volume of slit on its bed causing the river bed to rise and the river also shifts its channel frequently.

The Narmada and the Tapi are the only long rivers, which flow through trough, which flow west and make estuaries. The drainage basins of the peninsular rivers are small in size in comparison to other basins. Estuaries are the wide part of a river where it nears the sea; fresh and salt water mix and trough means a narrow depression (as in the earth or between ocean waves or in the ocean bed), also known as a channel along the eaves or on the roof; collects and carries away rainwater.

There are some economic benefits of rivers and lakes mentioned below:

Economic benefits of rivers:

(a) In a country like India where agriculture is dependent on the monsoons, then, in that case, these rivers provide water for irrigation and domestic purposes as well.

(b) Rivers carry slit and sediment which make the land fertile by carrying all the waste along with it and provide the most productive agricultural lands in the country.

(c) It also dilutes and transport wastes from settlements.

(d) Because of the help of rivers, the development of industries has been flourished along rivers as many industrial processes rely on water as raw material and for the generation of hydroelectricity.

(e) Rivers are helpful in providing means of transport and inland waterways.

(f) Rivers have been of fundamental importance throughout the human history and because of it recreation, tourist promotion and fishing are also being developed along waterfronts.

Economic benefits of lakes:

(a) Lakes are also of great to human beings. It helps in regulating the flow of a river.

(b) Lakes prevent flooding during heavy rainfall.

(c) It helps in maintaining an even flow of water during the dry season.

(d) It helps in moderating the climate of surrounding areas.

(e) It helps in maintaining the aquatic ecosystem.

(f) It also helps in developing tourism and providing recreation because of the enhancement of natural beauty due to the increasing number of lakes.

Natural Lakes: Wular, Dal, Loktak, Chilka, Barapani, Sambhar, Pulicat, Nainital Bhimtal.

Lakes created by Human-beings: Govind Sagar, Nagarjuna Sagar, Hirakund, Nizam Saga.

Apart from natural lakes, the damming of the rivers for the generation of hydel power has also led to the formation of lakes as Guru Gobind Sagar (Bhakra Nangal Project).

Rivers are important in many ways for the country’s economy; few of them are discussed below:

(a) As we all know that India is a country where agriculture is the major source of livelihood of the majority of its population and for agriculture water is the vital source.

(b) It carries silt and sediment which make the flood plains fertile and along this provide the most productive agricultural lands in the country.

(c) These rivers also dilute and transport wastes from settlements.

(d) Rivers have been helpful in development of industries as many industrial processes rely on water as a raw material.

(e) It also provides means of transport and inland waterways.

(f) Rivers make the country naturally beautiful which attracts tourists and many kind of employment is also provided like fishing.

(i) Rivers

(ii) Lakes

Across:

1. Nagarjuna Sagar is a river valley project, Name the river: Krishna

2. The longest river of India: Ganga

3. The river which originates from a place known as Beas Kund: Beas

4. The river which rises in the Betul district of Madhya Pradesh and flows westwards: Tapi

5. The river which is known as the ‘Sorrow’ of west Bengal: Damodar

6. The river on which the reservoir for Indira Gandhi Canal has been built: Satluj

7. The river whose source lies near Rohtang Pass: Ravi

8. The longest river of peninsular India: Godavari

Down:

9. A tributary of Indus originating from Himachal Pradesh: Chenab

10. The river flowing through fault drains into the Arabian Sea: Narmada

11. A river of south India, which receives rain water both in summer and winter: Kaveri

12. A river which flows through Laddakh, Gilgit and Pakistan: Indus

13. An important river of the Indian Desert: Lun

14. The river which joins Chenab in Pakistan: Jhelum

15. A river which rises at Yammunotri glacier: Yamuna