Drainage System of India – Geography UGC NET – Notes

The Indian drainage system is made up of several small and major rivers. It is the result of the evolution of the three primary physiographic units, as well as the type and properties of precipitation. The Ganga, Indus, and Brahmaputra river basins are part of the Himalayan drainage system. The peninsular plateau is drained by the Narmada, Tapi, Mahanadi, Godavari, Krishna, and Kaveri rivers. The number, size, and shape of drainage basins changes, and the more information supplied, the larger and more comprehensive the topographic map becomes.

• The term drainage refers to a region’s river system. A drainage basin is an area drained by a single river system.
• A closer look at a map reveals that any elevated feature, such as a mountain or upland, divides two drainage basins. A water divide is a type of upland.
• River basins are the catchments of great rivers, whereas watersheds are the catchments of minor rivulets and rills.
• However, there is a distinction to be made between a river basin and a watershed.
• Watersheds are very modest in size, whereas basins span vast regions.
• River basins and watersheds are distinguished by their oneness. What happens in one area of the basin or watershed has a direct impact on the other portions and the entire unit.
• As a result, they are regarded as the most suited micro, meso, and macro planning zones.
• The Indian drainage system may be classified into several categories.
• It may be divided into two groups based on the discharge of water (orientations to the sea):
  • the Arabian Sea drainage
  • the Bay of Bengal drainage.

• Apart from their origins in India’s two primary physiographic areas, the Himalayan and Peninsular rivers differ in a variety of ways.
• The majority of Himalayan rivers are perennial. It implies they have access to water all year.
• These rivers are fed by rain as well as melting snow from the high mountains.
• Since their flow is dependent on rainfall, a vast number of Peninsular rivers are seasonal.
• Even the largest rivers have restricted the flow of water in their courses during the dry season.

The Himalayan Drainage System

• A river system is made up of a river and its tributaries.
• The Himalayan River systems rivers are supplied by both snowmelt and precipitation, making them perpetual.
• The Indus, Ganga, and Brahmaputra are the three great Himalayan rivers. These rivers are lengthy, with several big and significant tributaries.
• In their rugged journey, these rivers create V-shaped valleys, rapids, and waterfalls.
• They generate depositional features such as flat valleys, oxbow lakes, flood plains, braided channels, and deltas near the river mouth when they enter the plains.

Characteristics

• Drained by 19 major rivers, of which the Indus and the Brahmaputra are the largest, each having catchment basins in the mountains of about 260,000 square km in extent.
• Five of the 19 rivers, with a total catchment area of about 132,000 square km belong to the Indus system—the Jhelum, the Chenab, the Ravi, the Beas, and the Sutlej—and collectively define the vast region divided between Punjab state in India and Punjab province in Pakistan.
• Of the remaining rivers, nine belong to the Ganges system—the Ganges, Yamuna, Ramganga, Kali (Kali Gandak), Karnali, Rapti, Gandak, Baghmati, and Kosi rivers— draining roughly 218,000 square km)in the mountains.
• Three belong to the Brahmaputra system—the Tista, the Raidak, and the Manas— draining another 184,000 square km in the Himalayas.
• Mainly comprises the basin areas of the Indus, the Ganga and the Brahmaputra.
• The rivers are perennial in nature and are fed by rains during monsoon season as well as by the melting of the snow during summer season.
• Rivers are in their youthful stage.
• Carving out a number of erosional features like deep gorges, V-shaped valleys, rapids and water falls.
• Himalayan Rivers, which now belong to the three principal systems (the Indus, the Ganga and the Brahmaputra), have evolved through a long period of geological history.
• They originate on the southern slopes of the Tibetan Highlands and first flow parallel to the main axis of the mountains in longitudinal troughs.
• They take a sudden bend towards the south carving out deep gorges across the mountain ranges to reach the northern plains of India. Such deep gorges by the Indus, Satluj, Alaknanda, Gandak, Kosi and Brahamaputra suggest that they are older than the mountains themselves and have antecedent characteristics.

Evolution of the Himalayan Drainage

• There are differences of opinion about the evolution of the Himalayan Rivers.
• However, geologists believe that a mighty river called Shiwalik or Indo-Brahma traversed the entire longitudinal extent of the Himalaya from Assam to Punjab and onwards to Sind, and finally discharged into the Gulf of Sind near lower Punjab during the Miocene period some 5-24 million years ago .
• The remarkable continuity of the Shiwalik and its lacustrine origin and alluvial deposits consisting of sands, silt, clay, boulders and conglomerates support this viewpoint.
• It is opined that in due course of time IndoBrahma River was dismembered into three main drainage systems:
  1. The Indus and its five tributaries in the western part;
  2. The Ganga and its Himalayan tributaries in the central part.
  3. The stretch of the Brahmaputra in Assam and its Himalayan tributaries in the eastern part.
• The dismemberment was probably due to the Pleistocene upheaval in the western Himalayas, including the uplift of the Potwar Plateau (Delhi Ridge), which acted as the water divide between the Indus and Ganga drainage systems.
• Likewise, the down-thrusting of the Malda gap area between the Rajmahal hills and the Meghalaya plateau during the mid-pleistocene period, diverted the Ganga and the Brahmaputra systems to flow towards the Bay of Bengal.

Indus River System

The Indus river is one of the world’s largest river basins. It is also known as Sindhu. The river flows through China(Tibet region), India, and Pakistan. In Tibet, it is known as Singi Khambai or Lion’s mouth.

• It originates from a glacier near Bokhar Chu in the Tibetan region at an altitude of 4,164 m in the Kailash Mountain range near the Mansarovar Lake.
• The river flows northwest and enters in Ladakh region in India from a place called Demchok, after entering India Indus river flows in between Karakoram and Ladakh range but more closer to the Ladakh range. At a place called Dungti, the river takes a sharp southwest turn and cuts through the Ladakh range and then takes a northwestern course and continues to flow towards the Leh region of Ladakh between Ladhak Range and Zaskar Range. After reaching Leh river countinues the northwestern course and reaches the town of Batalik which is in the Kargil district.
  • It is joined by the Zaskar River at Leh.
  • Near Skardu, it is joined by the Shyok at an elevation of about 2,700 m.
  • The Gilgit, Gartang, Dras, Shiger, Hunza are the other Himalayan tributaries of the Indus.
• Now the Indus river enters into the Baltistan region through the city of sakardu and countinues to flow northwest towards the city of Gilgit, Upon reaching the city of Gilgit the river takes a south bend and then turns west and then fully enters the northwest frontier province of Pakistan which is called Khyber Pakhtunkhawa.
  • The Kabul River empties into the Indus River near Attock, Pakistan. It is the main river in eastern Afghanistan and the Khyber Pakhtunkhwa province of Pakistan.
• The river then takes a southwestern course and countinues to flow across the Khyber Pakhtunkhwa province.
• It then flows through the plain in western and southern Punjab province of Pakistan, the river countinues to head towards the Sindhu province of Pakistan.
• Just above Mithankot, the Indus receives from Panjnad (Panchnad), the accumulated waters of the five eastern tributaries—the Jhelum, the Chenab, the Ravi, the Beas, and the Satluj.
• In Sindh Province river accumulates a lot of sediments and forms the Indus river delta before draining into the Arabian sea near Karachi.
• The blind Indus River Dolphin, a sub-species of dolphin, is found only in the Indus River.

Tributaries of Indus River

Shyok River:

• Rising from the Karakoram Range, it flows through the Northern Ladakh region in J&K
• It has a length of about 550km.
• A tributary of the Indus River, it originates from the Rimo Glacier.
• The river widens at the confluence with the Nubra River
• Shyok River marks the south-eastern fringe of the Karakoram ranges by forming a V-shaped bend around it.

Nubra River:

• It is the main tributary of the Shyok River.
• It originated from the Nubra Glacier, in a depression to the east of Saltoro Kangri Peak
• Nubra River meanders towards the southeast to join the Shyok River downstream of Shyok Valley at the base of the Ladakh range
• Nubra Valley, situated at an altitude of 3048m, is formed out of the Nubra River
• The catchment area is devoid of vegetation and human habitation due to high elevation and lack of rainfall.

Shigar River:

• It is a small right-bank tributary of the Indus River in its course through the Ladakh region of J&K
• It rises from the Hispar Glacier.
• It joins Indus at Skardu.
• The Shigar River descends down a very steep gradient
• Its entire catchment has been influenced by the action of glaciers.

Gilgit River:

• It is an important right-bank tributary of the Indus River in its course through the Ladakh region of J&K
• It originates from a glacier near the extreme northwestern boundary of the Himalayas
• The entire catchment area of the Gilgit River is bleak and desolate
• Bunji is the main human settlement along the river
• Ghizar and Hunza are the major right and left bank tributaries respectively.