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Home , Arabian Sea, Bharuch, Brahmaputra River, Ganga (goddess), Gangotri Glacier, Ghaghara

CHAPTER

DRAINAGE SYSTEM

ou have observed water flowing through 2006) in this class . Can you, then, explain the the , and even channels reason for water flowing from one direction to Yduring rainy season which drain the the other? Why do the rivers originating from the excess water. Had these channels not been in the northern and the Western there, large-scale flooding would have in the southern India flow towards the east occurred. Wherever channels are ill-defined or and discharge their waters in the Bay of ? choked, flooding is a common phenomenon.

The flow of water through well-defined channels is known as ‘drainage’ and the network of such channels is called a ‘drainage system’. The drainage pattern of an area is the outcome of the geological time period, nature and structure of rocks, topography, slope, amount of water flowing and the periodicity of the flow.

Do you have a near your village or city? Have you ever been there for boating or bathing? Figure 3.1 : A River in the Mountainous Is it perennial (always with water) or ephemeral (water during rainy season, and dry, otherwise)? A river drains the water collected from a Do you know that rivers flow in the same specific area, which is called its ‘catchment area’. direction? You have studied about slopes in the An area drained by a river and its other two textbooks of geography (NCERT, is called a . The boundary line

Important Drainage Patterns (i) The drainage pattern resembling the branches of a tree is known as “dendritic” the examples of which are the rivers of northern plain. (ii) When the rivers originate from a hill and flow in all directions, the drainage pattern is known as ‘radial’. The rivers originating from the Amarkantak range present a good example of it. (iii) When the primary tributaries of rivers flow parallel to each other and secondary tributaries join them at right angles, the pattern is known as ‘trellis’. (iv) When the rivers discharge their waters from all directions in a lake or depression, the pattern is know as ‘centripetal’. Find out some of the patterns in the topo sheet given in Chapter 5 of Practical Work in Geography– Part I (NCERT, 2006).

2021-22 22 INDIA : PHYSICAL ENVIRONMENT

Figure 3.2 : Major Rivers of India

2021-22 DRAINAGE SYSTEM 23 separating one drainage basin from the other in the . Identify these rivers of the is known as the watershed. The catchments of . large rivers are called river basins while those The Narmada and Tapi are two large rivers of small rivulets and rills are often referred to which are exceptions. They along with many as watersheds. There is, however, a slight small rivers discharge their waters in the difference between a river basin and a Arabian . watershed. Watersheds are small in area while Name these rivers of the western coastal the basins cover larger areas. region from the to the coast. River basins and watersheds are marked On the basis of the mode of origin, nature by unity. What happens in one part of the and characteristics, the Indian drainage may basin or watershed directly affects the other also be classified into the Himalayan drainage parts and the unit as a whole. That is why, they and the Peninsular drainage. Although it has are accepted as the most appropriate micro, the problem of including the , the meso or macro planning . Betwa, the Son, etc. which are much older in Indian drainage system may be divided on age and origin than other rivers that have their various bases. On the basis of discharge of water origin in the Himalayas, it is the most accepted (orientations to the sea), it may be grouped into: basis of classification. Hence, this scheme has (i) the drainage; and (ii) the Bay of been followed in this book. Bengal drainage. They are separated from each other through the ridge, the Aravalis and DRAINAGE SYSTEMS OF INDIA the Sahyadris (water divide is shown by a line Indian drainage system consists of a large in Figure 3.1). Nearly 77 per cent of the drainage number of small and big rivers. It is the outcome area consisting of the , the Brahmaputra, of the evolutionary process of the three major the , the , etc. is oriented physiographic units and the nature and towards the Bay of Bengal while 23 per cent characteristics of precipitation. comprising the Indus, the Narmada, the Tapi, the Mahi and the systems discharge THE HIMALAYAN DRAINAGE their waters in the Arabian Sea. On the basis of the size of the watershed, The Himalayan drainage system has evolved the drainage basins of India are grouped into through a long geological history. It mainly three categories: (i) Major river basins with includes the Ganga, the Indus and the more than 20,000 sq. km of catchment area. basins. Since these are fed It includes 14 drainage basins such as the both by melting of snow and precipitation, Ganga, the Brahmaputra, the Krishna, the rivers of this system are perennial. These rivers Tapi, the Narmada, the Mahi, the Pennar, the pass through the giant gorges carved out by Sabarmati, the Barak, etc. (Appendix III). (ii) the erosional activity carried on simultaneously Medium river basins with catchment area with the uplift of the Himalayas. Besides deep between 2,000-20,000 sq. km incorporating gorges, these rivers also form V-shaped valleys, 44 river basins such as the Kalindi, the Periyar, rapids and waterfalls in their mountainous the Meghna, etc. (iii) Minor river basins with catchment area of less than 2,000 sq. km include fairly good number of rivers flowing in the area of low rainfall. If you look at the Figure 3.1 you can see that many rivers have their sources in the Himalayas and discharge their waters either in the Bay of Bengal or in the Arabian Sea. Identify these rivers of North India. Large rivers flowing on the Peninsular plateau have their origin in the Western and discharge their waters Figure 3.3 : Rapids

2021-22 24 INDIA : PHYSICAL ENVIRONMENT course. While entering the plains, they form the Potwar Plateau (), which acted depositional features like flat valleys, ox-bow as the water divide between the Indus and lakes, flood plains, braided channels, and Ganga drainage systems. Likewise, the down- deltas near the . In the Himalayan thrusting of the Malda gap area between the reaches, the course of these rivers is highly Rajmahal hills and the plateau tortous, but over the plains they display a during the mid-pleistocene period, diverted the strong meandering tendency and shift their Ganga and the Brahmaputra systems to flow courses frequently. River Kosi, also know as towards the Bay of Bengal. the ‘sorrow of ’, has been notorious for frequently changing its course. The Kosi brings THE RIVER SYSTEMS OF THE huge quantity of sediments from its upper HIMALAYAN DRAINAGE reaches and deposits it in the plains. The course gets blocked, and consequently, the The Himalayan drainage consists of several river changes its course. Why does the systems but the following are the major river bring such huge quantity of sediments river systems: from the upper reaches? Do you think that the discharge of the water in the rivers in The Indus System general and the Kosi in particular, remains the It is one of the largest river basins of the world, same, or does it fluctuate? When does the river covering an area of 11,65,000 sq. km (in India course receive the maximum quantity of water? it is 321, 289 sq. km and a total length of 2,880 What are the positive and negative effects of km (in India 1,114 km). The Indus also flooding? known as the Sindhu, is the westernmost of the Himalayan rivers in India. It originates EVOLUTION OF THE HIMALAYAN DRAINAGE from a glacier near Bokhar Chu (31°15' N latitude and 81°40' E longitude) in the There are difference of opinion about the Tibetan region at an altitude of 4,164 m in evolution of the Himalayan rivers. However, the Kailash Mountain range. In , it is geologists believe that a mighty river called known as ‘Singi Khamban; or Lion’s mouth. Shiwalik or Indo- traversed the entire After flowing in the northwest direction longitudinal extent of the Himalaya from between the Ladakh and Zaskar ranges, it to and onwards to Sind, and finally passes through Ladakh and Baltistan. It cuts discharged into the Gulf of Sind near lower across the Ladakh range, forming a Punjab during the Miocene period some 5-24 spectacular gorge near Gilgit in Jammu and million years ago (See the table of geological Kashmir. It enters into near Chilas times scale in Chapter 2 of Fundamentals of in the Dardistan region. Find out the area Physical Geography, NCERT, 2006). The known as Dardistan. remarkable continuity of the Shiwalik and its The Indus receives a number of Himalayan lacustrine origin and alluvial deposits tributaries such as the Shyok, the Gilgit, the consisting of sands, silt, clay, boulders and Zaskar, the Hunza, the Nubra, the Shigar, the conglomerates support this viewpoint. Gasting and the Dras. It finally emerges out of It is opined that in due course of time Indo– the hills near where it receives the Kabul Brahma river was dismembered into three main river on its right bank. The other important drainage systems: (i) the Indus and its five tributaries joining the right bank of the Indus tributaries in the western part; (ii) the Ganga are the Khurram, the Tochi, the Gomal, the and its Himalayan tributaries in the central Viboa and the Sangar. They all originate in the part; and (iii) the stretch of the Brahmaputra Sulaiman ranges. The river flows southward in Assam and its Himalayan tributaries in the and receives ‘Panjnad’ a little above Mithankot. eastern part. The dismemberment was The Panjnad is the name given to the five rivers probably due to the Pleistocene upheaval in of Punjab, namely the Satluj, the Beas, the Ravi, the western Himalayas, including the uplift of the Chenab and the . It finally discharges

2021-22 DRAINAGE SYSTEM 25 into the Arabian Sea, east of . The The Ganga System Indus flows in India only through Jammu and The Ganga is the most important river of Kashmir. India both from the point of view of its basin The Jhelum, an important of the and cultural significance. It rises in the Indus, rises from a spring at Verinag situated glacier near Gaumukh (3,900 m) at the foot of the Pir Panjal in the south-eastern in the of . part of the of Kashmir. It flows through Here, it is known as the Bhagirathi. It cuts Srinagar and the Wular lake before entering through the Central and the Lesser Pakistan through a deep narrow gorge. It joins Himalayas in narrow gorges. At Devprayag, the Chenab near Jhang in Pakistan. the Bhagirathi meets the Alaknanda; The Chenab is the largest tributary of the hereafter, it is known as the Ganga. The Indus. It is formed by two streams, the Alaknanda has its source in the Satopanth and the Bhaga, which join at glacier above . The Alaknanda Tandi near Keylong in . consists of the Dhauli and the Ganga Hence, it is also known as Chandrabhaga. which meet at Joshimath or Vishnu Prayag. The river flows for 1,180 km before entering The other tributaries of Alaknanda such as into Pakistan. the Pindar joins it at Prayag The Ravi is another important tributary of while Mandakini or Ganga meets it at the Indus. It rises west of the Rohtang pass in Rudra Prayag. The Ganga enters the plains the Kullu hills of Himachal Pradesh and flows at . From here, it flows first to through the Chamba valley of the state. Before the south, then to the south-east and east entering Pakistan and joining the Chenab near Sarai Sidhu, it drains the area lying between the southeastern part of the Pir Panjal and the Do you Know? Dhauladhar ranges. ‘Namami Gange Programme’, is an The Beas is another important tributary of Integrated Conservation Mission, approved the Indus, originating from the Beas Kund near as “Flagship Programme” by the Union the Rohtang Pass at an elevation of 4,000 m Government in June 2014 with the twin above the mean sea level. The river flows objectives of effective abatement of pollution, through the Kullu valley and forms gorges at conservation and rejuvenation of the Kati and Largi in the Dhaoladhar range. It National River Ganga. enters the Punjab plains where it meets the Main pillars of the Namami Gange Satluj near Harike. Programme are: The Satluj originates in the ‘Raksas tal’ near • Sewerage Treatment Infrastructure • River-Front Development Mansarovar at an altitude of 4,555 m in Tibet • River-Surface Cleaning where it is known as Langchen Khambab. It • Bio-Diversity flows almost parallel to the Indus for about 400 • Afforestation km before entering India, and comes out of a • Public Awareness gorge at Rupar. It passes through the Shipki • Industrial Effluent Monitoring La on the Himalayan ranges and enters the • Ganga Gram You may explore about this project at Punjab plains. It is an antecedent river. It is a http://nmcg.nic.in/NamamiGanga.aspx# very important tributary as it feeds the canal system of the Bhakra Nangal project.

2021-22 26 INDIA : PHYSICAL ENVIRONMENT before splitting into two , namely its tributaries – Tila, Seti and Beri, it comes the Bhagirathi and the Padma. The river has out of the mountain, cutting a deep gorge at a length of 2,525 km. It is shared by Shishapani. The river Sarda (Kali or Kali Uttarakhand (110 km) and Ganga) joins it in the plain before it finally meets (1,450 km), Bihar (445 km) and the Ganga at . (520 km). The Ganga basin covers about 8.6 The Kosi is an antecedent river with its lakh sq. km area in India alone. The Ganga source to the north of Mount Everest in Tibet, river system is the largest in India having a where its main stream Arun rises. After number of perennial and non-perennial rivers crossing the Central Himalayas in , it is originating in the Himalayas in the north and joined by the Son Kosi from the West and the the Peninsula in the south, respectively. The Tamur Kosi from the east. It forms Sapt Kosi Son is its major right bank tributary. The after uniting with the river Arun. important left bank tributaries are the The is comparatively a small Ramganga, the Gomati, the , the river rising in the Garhwal hills near Gairsain. Gandak, the Kosi and the Mahananda. The It changes its course to the southwest direction river finally discharges itself into the Bay of after crossing the Shiwalik and enters into the Bengal near the Sagar Island. plains of Uttar Pradesh near Najibabad. Finally, The , the western most and the it joins the Ganga near . longest tributary of the Ganga, has its source The Damodar occupies the eastern margins in the glacier on the western slopes of the Chotanagpur Plateau where it flows of Banderpunch range (6,316 km). It joins the through a rift valley and finally joins the Hugli. Ganga at Prayag (). It is joined by The Barakar is its main tributary. Once known the Chambal, the Sind, the Betwa and the Ken as the ‘sorrow of Bengal’, the Damodar has on its right bank which originates from the been now tamed by the Damodar Valley Peninsular plateau while the Hindan, the Rind, corporation, a multipurpose project. the Sengar, the , etc. join it on its left bank. Much of its water feeds the western and The Sarda or Saryu river rises in the Milam eastern Yamuna and the canals for glacier in the Nepal Himalayas where it is purposes. known as the Goriganga. Along the Indo-Nepal border, it is called Kali or Chauk, where it joins Name the states which are drained by the Ghaghara. the river Yamuna. The Mahananda is another important tributary of the Ganga rising in the Darjiling The Chambal rises near in the hills. It joins the Ganga as its last left bank plateau of and flows tributary in West Bengal. northwards through a gorge up wards of Kota The Son is a large south bank tributary of in , where the Gandhisagar has the Ganga, originating in the Amarkantak been constructed. From Kota, it traverses down plateau. After forming a series of waterfalls at to Bundi, Sawai Madhopur and Dholpur, and the edge of the plateau, it reaches Arrah, west finally joins the Yamuna. The Chambal is of Patna, to join the Ganga. famous for its badland topography called the Chambal ravines. The Brahmaputra System The Gandak comprises two streams, The Brahmaputra, one of the largest rivers namely Kaligandak and Trishulganga. It rises of the world, has its origin in the in the Nepal Himalayas between the Chemayungdung glacier of the Kailash range and Mount Everest and drains the central part near the Mansarovar lake. From here, it of Nepal. It enters the Ganga plain in traverses eastward longitudinally for a Champaran district of Bihar and joins the distance of nearly 1,200 km in a dry and Ganga at Sonpur near Patna. flat region of southern Tibet, where it is The Ghaghara originates in the glaciers of known as the Tsangpo, which means ‘the Mapchachungo. After collecting the waters of

2021-22 DRAINAGE SYSTEM 27 purifier.’ The Rango Tsangpo is the major course, absence of meanders and non- right bank tributary of this river in Tibet. It perennial flow of water. The Narmada and the emerges as a turbulent and dynamic river Tapi which flow through the rift valley are, after carving out a deep gorge in the Central however, exceptions. Himalayas near (7,755 m). The river emerges from the foothills under The Evolution of Peninsular Drainage the name of Siang or Dihang. It enters India System west of town in . Three major geological events in the distant Flowing southwest, it receives its main left past have shaped the present drainage bank tributaries, viz., Dibang or Sikang and systems of Peninsular India: (i) Subsidence Lohit; thereafter, it is known as the of the western flank of the Peninsula leading Brahmaputra. to its submergence below the sea during the The Brahmaputra receives numerous early tertiary period. Generally, it has tributaries in its 750 km long journey through disturbed the symmetrical plan of the river the Assam valley. Its major left bank on either side of the original watershed. tributaries are the Burhi Dihing and Dhansari (ii) Upheaval of the Himalayas when the (South) whereas the important right bank northern flank of the Peninsular block was tributaries are the Subansiri, Kameng, Manas subjected to subsidence and the consequent and Sankosh. The Subansiri which has its trough faulting. The Narmada and The Tapi origin in Tibet, is an antecedent river. The flow in trough faults and fill the original Brahmaputra enters into near cracks with their detritus materials. Hence, and flows southward. In Bangladesh, there is a lack of alluvial and deltaic deposits the Tista joins it on its right bank from where in these rivers. (iii) Slight tilting of the the river is known as the Jamuna. It finally Peninsular block from northwest to the merges with the river Padma, which falls in the southeastern direction gave orientation to the Bay of Bengal. The Brahmaputra is well-known entire drainage system towards the Bay of for floods, channel shifting and bank erosion. Bengal during the same period. This is due to the fact that most of its tributaries are large, and bring large quantity of sediments River Systems of the Peninsular Drainage owing to heavy rainfall in its catchment area. There are a large number of river systems in THE PENINSULAR DRAINAGE SYSTEM the Peninsular drainage. A brief account of the major Peninsular river systems is given below: The Peninsular drainage system is older than The Mahanadi rises near Sihawa in Raipur the Himalayan one. This is evident from the district of Chhattisgarh and runs through broad, largely-graded shallow valleys, and the to discharge its water into the Bay of maturity of the rivers. The Bengal. It is 851 km long and its catchment area running close to the western coast act as the spreads over 1.42 lakh sq. km. Some water divide between the major Peninsular navigation is carried on in the lower course of rivers, discharging their water in the Bay of this river. Fifty three per cent of the drainage Bengal and as small rivulets joining the basin of this river lies in Madhya Pradesh and Arabian Sea. Most of the major Peninsular Chhattisgarh, while 47 per cent lies in Odisha. rivers except Narmada and Tapi flow from west The Godavari is the largest Peninsular river to east. The Chambal, the Sind, the Betwa, the system. It is also called the Dakshin Ganga. It Ken, the Son, originating in the northern part rises in the Nasik district of and of the Peninsula belong to the Ganga river discharges its water into the Bay of Bengal. Its system. The other major river systems of the tributaries run through the states of Peninsular drainage are – the Mahanadi the Maharashtra, Madhya Pradesh, Chhattisgarh, Godavari, the Krishna and the . Odisha and . It is 1,465 km Peninsular rivers are characterised by fixed long with a catchment area spreading over 3.13

2021-22 28 INDIA : PHYSICAL ENVIRONMENT lakh sq. km 49 per cent of this, lies in The Tapi is the other important westward Maharashtra, 20 per cent in Madhya Pradesh flowing river. It originates from Multai in the Betul and Chhattisgarh, and the rest in Andhra district of Madhya Pradesh. It is 724 km long Pradesh. The Penganga, the Indravati, the and drains an area of 65,145 sq. km. Nearly 79 Pranhita, and the Manjra are its principal per cent of its basin lies in Maharashtra, 15 per tributaries. The Godavari is subjected to heavy cent in Madhya Pradesh and the remaining floods in its lower reaches to the south of 6 per cent in . Polavaram, where it forms a picturesque gorge. Luni is the largest river system of It is navigable only in the deltaic stretch. The Rajasthan, west of Aravali. It originates near river after Rajamundri splits into several Pushkar in two branches, i.e. the branches forming a large delta. and the Sabarmati, which join with each other The Krishna is the second largest east- at Govindgarh. From here, the river comes out flowing Peninsular river which rises near of Aravali and is known as Luni. It flows in Sahyadri. Its total length is towards the west till Telwara and then takes a 1,401 km. The Koyna, the Tungbhadra and southwest direction to join the Rann of the are its major tributaries. Of the total Kuchchh. The entire river system is ephemeral. catchment area of the Krishna, 27 per cent lies in Maharashtra, 44 per cent in and Smaller Rivers Flowing Towards the West 29 per cent in Andhra Pradesh and Telangana. The Kaveri rises in hills The rivers flowing towards the Arabian sea (1,341m) of Kogadu district in Karnataka. Its have short courses. Why do they have short length is 800 km and it drains an area of courses? Find out the smaller rivers of 81,155 sq. km. Since the upper catchment Gujarat. The Shetruniji is one such river area receives rainfall during the southwest which rises near Dalkahwa in . season (summer) and the lower part The Bhadra originates near Aniali village in during the northeast monsoon season (winter), district. The Dhadhar rises near the river carries water throughout the year with Ghantar village in . comparatively less fluctuation than the other Sabarmati and Mahi are the two famous rivers Peninsular rivers. About 3 per cent of the Kaveri of Gujarat. basin falls in , 41 per cent in Karnataka Find out the places of of these and 56 per cent in . Its important rivers. Find out some important west tributaries are the Kabini, the Bhavani and the flowing rivers of Maharashtra. Amravati. The Narmada originates on the western flank The rises from the Trimbak hills of the Amarkantak plateau at a height of about in Nasik district at an elevation of 670 m. The 1,057 m. Flowing in a rift valley between the Kalinadi rises from Belgaum district and falls Satpura in the south and the Vindhyan range in the Bay. The source of Bedti river in the north, it forms a picturesque gorge in lies in Hubli Dharwar and traverses a course marble rocks and Dhuandhar waterfall near of 161 km. The is another important Jabalpur. After flowing a distance of about river in Karnataka flowing towards the west. 1,312 km, it meets the Arabian sea south of The Sharavati originates in Shimoga district , forming a broad 27 km long estuary. of Karnataka and drains a catchment area of Its catchment area is about 98,796 sq. km. The 2,209 sq. km. Sardar Sarovar Project has been constructed on this river. Find out the name of the river on which the Gersoppa (Jog) fall is found. Collect information about conservation mission named has two important rivers which can be “Namami Narmade” and discuss mentioned here. One is Mandovi and the other with your peers. is Juari. You can locate them on the map.

2021-22 DRAINAGE SYSTEM 29

Kerala has a narrow coastline. The longest right. The Subarnrekha, the Baitarni, the river of Kerala, Bharathapuzha rises near Brahmani, the Vamsadhara, the Penner, the Annamalai hills. It is also known as . Palar and the Vaigai are important rivers. Find It drains an area of 5,397 sq. km. Compare its out these rivers from the atlas. catchment area with that of the Sharavati river of Karnataka. Teachers may explain the comparative importance of east flowing small rivers The Periyar is the second largest river of Kerala. Its catchment area is 5,243 sq. km. River Catchment area sq. km You can see that there is a marginal difference in the catchment area of the Bhartapuzha and Subarnarekha 19,296 Baitarni 12,789 the Periyar rivers. Brahmani 39,033 Another river of Kerala worth mentioning is Penner 55,213 the which falls in the Vemobanad Palar 17,870 lake after traversing a course of 177 km.

Teachers may explain the comparative RIVER REGIMES importance of west flowing small rivers Do you know that the quantity of water River Catchment area flowing in a river channel is not the same sq. km throughout the year? It varies from season Sabarmati 21,674 to season. In which season do you expect the Mahi 34,842 Dhandhar 2,770 maximum flow in Ganga and Kaveri? The Kalinadi 5,179 pattern of flow of water in a river channel over Sharavati 2,029 a year is known as its regime. The north Indian Bharathapuzha 5,397 rivers originating from the Himalayas are Periyar 5,243 perennial as they are fed by glaciers through snow melt and also receive rainfall water during Small Rivers Flowing towards the East rainy season. The rivers of South India do not There are a large number of rivers flowing originate from glaciers and their flow pattern towards the east along with their tributaries. witnesses fluctuations. The flow increases Can you name some of these rivers? There are considerably during monsoon rains. Thus, the small rivers which join the Bay of Bengal, regime of the rivers of South India is controlled though small, these are important in their own by rainfall which also varies from one part of

Table 3.1 : Comparison between the Himalayan and the Peninsular River

Sl. No. Aspects Himalayan River Peninsular River 1. Place of origin Himalayan mountain covered with Peninsular plateau and central highland glaciers 2. Nature of flow Perennial; receive water from glacier Seasonal; dependent on monsoon and rainfall rainfall 3. Type of drainage Antecedent and consequent leading to Super imposed, rejuvenated resulting dendritic pattern in plains in trellis, radial and rectangular patterns 4. Nature of river Long course, flowing through the Smaller, fixed course with well-adjusted rugged mountains experiencing valleys headward erosion and river capturing; In plains meandering and shifting of course

5. Catchment area Very large basins Relatively smaller basin 6. Age of the river Young and youthful, active and Old rivers with graded profile, and have deepening in the valleys almost reached their base levels

2021-22 30 INDIA : PHYSICAL ENVIRONMENT the Peninsular plateau to the other. the dry season. During the rainy season, much The discharge is the volume of water flowing of the water is wasted in floods and flows down in a river measured over time. It is measured to the sea. Similarly, when there is a flood in one either in cusecs (cubic feet per second) or part of the country, the other area suffers from cumecs (cubic metres per second). drought. Why does this happen? Is it the The Ganga has its minimum flow during problem of availability of water resource or that the January-June period. The maximum flow of its management? Can you suggest some is attained either in August or in September. measures to mitigate the problems of floods and After September, there is a steady fall in the droughts simultaneously occuring in different flow. The river, thus, has a monsoon regime parts of the country? (See Chapter 7 of the book). during the rainy season. Can these problems be solved or minimised There are striking differences in the river by trasfering the surplus water from one basin regimes in the eastern and the western parts to the water deficit basins? Do we have some of the Ganga Basin. The Ganga maintains a schemes of inter-basin linkage? sizeable flow in the early part of summer due to snow melt before the monsoon rains begin. Teachers may explain the following The mean maximum discharge of the Ganga examples at Farakka is about 55,000 cusecs while the • Periyar Diversion Scheme mean minimum is only 1,300 cusecs. What • Canal Project factors are responsible for such a large • Kurnool-Cuddapah Canal difference? • Beas-Satluj Link Canal The two Peninsular rivers display • Ganga-Kaveri Link Canal interesting differences in their regimes compared to the Himalayan rivers. The Have you read in the newspapers about the Narmada has a very low volume of discharge linking of rivers? Do you think that digging a from January to July but it suddenly rises in canal is enough to transfer water from the Ganga August when the maximum flow is attained. basin to the Peninsular river? What is the major The fall in October is as spectacular as the rise problem? Consult Chapter 2 of this book and in August. The flow of water in the Narmada, find out the difficulties posed by the as recorded at Garudeshwar, shows that the unevenness of the terrain. How can the water maximum flow is of the order of 2,300 cusecs, be lifted from the plain area to the plateau area? while the minimum flow is only 15 cusecs. The Is there sufficient surplus water in the north Godavari has the minimum discharge in May, Indian rivers which can be transferred on a and the maximum in July-August. After regular basis? Organise a debate on the whole August, there is a sharp fall in water flow issue and prepare a write up. How do you rank although the volume of flow in October and the following problems in using river water? November is higher than that in any of the (i) No availability in sufficient quantity months from January to May. The mean (ii) River water pollution maximum discharge of the Godavari at (iii) Load of silt in the river water Polavaram is 3,200 cusecs while the mean (iv) Uneven seasonal flow of water minimum flow is only 50 cusecs. These figures (v) River water disputes between states give an idea of the regime of the river. (vi) Shrinking of channels due to the extension of settlements towards the thalweg. EXTENT OF USABILITY OF RIVER WATER Why are the rivers polluted? Have you seen The rivers of India carry huge volumes of water the dirty waters of cities entering into the per year but it is unevenly distributed both in rivers? Where do the industrial affluents and time and space. There are perennial rivers wastes get disposed of ? Most of the carrying water throughout the year while the grounds are on the banks of rivers and the non-perennial rivers have very little water during dead bodies are sometimes thrown in the

2021-22 DRAINAGE SYSTEM 31 rivers. On the occasion of some festivals, the Ganga Action Plan, or about a campaign for flowers and statues are immersed in the rivers. cleaning the Yamuna at Delhi? Collect Large scale bathing and washing of clothes materials on schemes for making rivers also pollute river waters. How can the rivers pollution free and organise the materials in a be made pollution free? Have you read about write up.

EXERCISES

1. Choose the right answer from the four alternatives given below. (i) Which one of the following rivers was known as the ‘Sorrow of Bengal’? (a) The Gandak (c) The Kosi (b) The Son (d) The Damodar (ii) Which one of the following rivers has the largest river basin in India? (a) The Indus (c) The Ganga (b) The Brahmaputra (d) The Krishna (iii) Which one of the following rivers is not included in ‘Panchnad’? (a) The Ravi (c) The Indus (b) The Chenab (d) The Jhelum (iv) Which one of the following rivers flows in a rift valley? (a) The Son (c) The Yamuna (b) The Narmada (d) The Luni (v) Which one of the following is the place of confluence of the Alaknanda and the Bhagirathi? (a) Vishnu Prayag (c) Karan Prayag (b) Rudra Prayag (d) Prayag 2. State the differences between the following. (i) River Basin and Watershed (ii) Dendritic and Trellis drainage pattern (iii) Radial and Centripetal drainage pattern (iv) Delta and Estuary 3. Answer the following questions in about 30 words. (i) What are the socio-economic advantages of inter-linking of rivers in India? (ii) Write three characterstics of the Peninsular river. 4. Answer the following questions in not more than 125 words. (i) What are the important characteristic features of north Indian rivers? How are these different from Peninsular rivers? (ii) Suppose you are travelling from Haridwar to along the foothills of the Himalayas. Name the important rivers you will come across. Describe the characteristics of any one of them. Project/Activity Study the Appendix III and answer the following questions. (i) Which river has the largest proportion of catchment area in the country? (ii) Make a comparative bar diagram on a graph paper to show the length of the courses of the rivers.

2021-22