Drainage Patterns and Drainage Systems of India PDF

Drainage Patterns and Drainage Systems of India drishtiias.com/printpdf/drainage-patterns-and-drainage-systems-of-india Drainage: The flow of water through well-defined channels is known as ‘drainage’ and the network of such channels is called a ‘drainage system’. Dr...

Drainage Patterns and Drainage Systems of India drishtiias.com/printpdf/drainage-patterns-and-drainage-systems-of-india Drainage: The flow of water through well-defined channels is known as ‘drainage’ and the network of such channels is called a ‘drainage system’. Drainage Pattern: It refers to the system of flow of surface water mainly through the forms of rivers and basins. The drainage system depends upon factors such as slope of land, geological structure, amount of volume of water and velocity of water. Types of Drainage Patterns Dendritic Drainage Pattern: It is the most common form and resembles the branching pattern of tree roots. The dendritic pattern develops where the river channel follows the slope of the terrain. The pattern develops in areas where the rock beneath the stream has no particular structure and can be eroded equally easily in all directions. Tributaries join larger streams at acute angles (less than 90°). E.g. The rivers of the northern plains; Indus, Ganga and Brahmaputra. 1/7 Parallel drainage pattern: It develops in regions of parallel, elongated landforms where there is a pronounced slope to the surface. Tributary streams tend to stretch out in a parallel-like fashion following the slope of the surface. E.g. The rivers originating in the Western Ghats; Godavari, Kaveri, Krishna, and Tungabhadra. Trellis Drainage Pattern: Trellis drainage develops in folded topography where hard and soft rocks exist parallel to each other. Down-turned folds called synclines form valleys in which reside the main channel of the stream. Such a pattern is formed when the primary tributaries of main rivers flow parallel to each other and secondary tributaries join them at right angles. E.g. The rivers in the upper part of the Himalayan region; Indus, Ganga and Brahmaputra. 2/7  Rectangular Drainage Pattern: The rectangular drainage pattern is found in regions that have undergone faulting. It develops on a strongly joined rocky terrain. Streams follow the path of least resistance and thus are concentrated in places where exposed rock is the weakest. The tributary streams make sharp bends and enter the main stream at high angles. E.g. Streams found in the Vindhya mountain range; Chambal, Betwa and Ken. Folding and Faulting When the Earth’s crust is pushed together via compression forces, it can experience geological processes called folding and faulting. Folding occurs when the Earth’s crust bends away from a flat surface. A bend upward results in an anticline and a bend downward results in a syncline. Faulting happens when the Earth’s crust completely breaks and slides past each other. Whether the Earth’s crust experiences a fold or fault will depend on the material it is made out of in that area. A fold is more likely to happen with flexible material and it is what causes mountains to form, whereas a fault will happen with more brittle material and is what causes earthquakes to occur. 3/7  Radial Drainage Pattern: The radial drainage pattern develops around a central elevated point and is common to conically shaped features such as volcanoes. When the rivers originate from a hill and flow in all directions, the drainage pattern is known as ‘radial’. E.g. The rivers originating from the Amarkantak range; Narmada and Son (tributary of Ganga). Centripetal Drainage Pattern: It is just the opposite of the radial as streams flow toward a central depression. During wetter portions of the year, these streams feed ephemeral lakes, which evaporate away during dry periods. Sometimes, salt flats are also created in these dry lake beds as salt dissolved in the lake water precipitates out of solution and is left behind when the water evaporates away. E.g. Loktak lake in Manipur. Drainage System of India Himalayan Drainage System: About: Rivers of this system are fed both by melting of snow and precipitation and hence, are perennial. These rivers form V-shaped valleys, rapids and waterfalls in their mountainous course. While entering the plains, they form depositional features like flat valleys, ox-bow lakes, flood plains, braided channels and deltas near the river mouth. 4/7 Indus River System: It is one of the largest river basins of the world. It is also known as the Sindhu and is the westernmost of the Himalayan rivers in India. It originates from a glacier near Bokhar Chu in the Tibetan region in the Kailash Mountain range. In Tibet, it is known as ‘Singi Khamban’; or Lion’s mouth. The Indus flows in India only through the Leh district in the Union Territory of Ladakh. Important tributaries of the Indus are Sutlej, Ravi, Jhelum, Chenab (largest tributary of Indus) and Beas. Ganga River System: It rises in the Gangotri glacier near Gaumukh (3,900 m) in Uttarakhand where it is known as Bhagirathi. At Devprayag, the Bhagirathi meets the Alaknanda; hereafter, it is known as the Ganga. The Ganga enters the Northern plains at Haridwar. Ganga flows through the states of Uttarakhand, Uttar Pradesh, Bihar and West Bengal. Son is the major right bank tributary and the important left bank tributaries are Ramganga, Gomati, Ghaghara, Gandak, Kosi and Mahananda. Yamuna is the western most and the longest tributary of the Ganga and has its source in the Yamunotri glacier. Ganga flows into the Bay of Bengal near the Sagar Island. Brahmaputra River System: It is one of the largest rivers of the world and has its origin in the Chemayungdung glacier (Kailash range) near the Mansarovar lake. In southern Tibet, it is known as the Tsangpo, which means ‘the purifier.’ The river emerges from the foothills of Himalayas under the name of Siang or Dihang. It enters India west of Sadiya town in Arunachal Pradesh. Its main left bank tributaries are Dibang or Sikang, Lohit, Burhi Dihing and Dhansari. Important right bank tributaries are the Subansiri, Kameng, Manas and Sankosh. In Bangladesh, it merges with the river Padma, which falls in the Bay of Bengal. 5/7 Peninsular Drainage System About: The peninsular rivers are characterised by fixed course, absence of meanders and nonperennial flow of water. The drainage system is older than the Himalayan one. The Western Ghats running close to the western coast act as the water divide between the major Peninsular rivers. Most of the major Peninsular rivers except Narmada and Tapi flow from west to east. The other major river systems of the Peninsular drainage are Mahanadi, Godavari, Krishna and Kaveri. 6/7 Narmada: It is the largest west flowing river of the peninsular region flowing through a rift valley between the Vindhya (north) and the Satpura Range (south). It rises from Maikala range near Amarkantak in Madhya Pradesh. Major Tributaries of the river are Hiran, Orsang, Barna and Kolar. The Narmada basin covers parts of Madhya Pradesh, Maharashtra and Gujarat. The Sardar Sarovar Project has been constructed on this river. Tapi: Another important westward flowing river, originates from the Betul district of Madhya Pradesh in the Satpura ranges. It flows in a rift valley parallel to the Narmada but is much shorter in length. Its basin covers parts of Madhya Pradesh, Gujarat and Maharashtra. Mahanadi: It rises in Raipur district of Chhattisgarh and runs through Odisha to discharge its water into the Bay of Bengal. 53% of the drainage basin of this river lies in Madhya Pradesh and Chhattisgarh, while 47% lies in Odisha. Major tributaries: Seonath, Hasdeo, Mand, Ib, Jonking and Tel rivers. Its basin is bounded by the Central India hills on the north, by the Eastern Ghats on the south and east and by the Maikala range on the west. Godavari: It is the largest Peninsular river system and is also called the “Dakshin Ganga”. It rises in the Nasik district of Maharashtra and discharges its water into the Bay of Bengal. Its tributaries run through the states of Maharashtra, Madhya Pradesh, Chhattisgarh, Odisha and Andhra Pradesh. Penganga, Indravati, Pranhita, and Manjra are its principal tributaries. Krishna: Krishna is the second largest east flowing Peninsular river which rises near Mahabaleshwar in Sahyadri. Koyna, Tungbhadra and Bhima are its major tributaries. It flows through the states Maharashtra, Karnataka, Telangana and Andhra Pradesh before flowing into the Bay of Bengal. Kaveri: Kaveri rises in Brahmagiri hills of Kodagu district in Karnataka. It is a sacred river of southern India. Its important tributaries are Arkavathi, Hemavathi, Bhavani, Kabini and Amravati. It flows in a southeasterly direction through the states of Karnataka, Kerala and Tamil Nadu and drains into Bay of Bengal through Pondicherry. 7/7