2ndInternational Conference on Emerging Trends in Engineering & Technology, April 12-13, 2013College of Engineering, Teerthanker Mahaveer University.River Kosi, Sorrow of India: An overviewMohd Danish1, Priyank Gupta1, Dr. Javed Alam2, Prof. Mohd. Muzammil3The Kosi River which is one of the largest tributaries of the river Ganges is infamous for floods, thus causes hugelosses in terms of both life and property. India, after Bangladesh, is the second in the world in loss due to floods,thus accounting for one-fifth of the deaths due to floods, globally. The Kosi River is considered as the sorrow ofBihar. It is one of the two major tributaries of the river Ganges(the other river being Gandak) draining the plains ofnorth Bihar. Despite a long history of flood control management in the basin for more than 5 decades, this Rivercontinues to bring a lot of misery through extensive flooding. Meandering is another bizarre behaviour of this riverwhich have shifted laterally about 112 km westward in the last 250 years. Due to this, the river which previouslyflowed near Purnea in the 18th century is now flowing to the west of Saharsa. The meandering behaviour of the KosiRiver has wasted an area of about 1,295 Sq. Km of land in Nepal and about 7,770 Sq. Km of land in Bihar, resultingin sand deposition. This wasted land was considered as the garden of Bihar and it was renowned for its rice-field andorchards. In the course of shifting it has wiped out many towns and villages inflicting heavy losses of human, cattlelife and property. The present paper presents an overview of the behaviour of River Kosi and its shifting pattern inits total reach with a focus on the structural and non-structural works carried out in this connection so far.Keywords: Kosi River, The Ganges, Watershed, Meandering1. IntroductionIndia is seventh largest country with geographical area32,87,263 km2(2.45% of the World’s land resources)and the second most populous country with over 1.2billion people (17.5 % of the World’s population) and itholds 4% of the world’s fresh water resources .Rivers in India are not only considered as a source ofwater but also it has been worshipped from centuries.The major river systems in India are Indus,Brahmaputra, Ganga, Yamuna, Narmada, Tapti,Godavari, Krishna, Cauvery and Mahanadi. The Gangesis the second largest river in the world in terms of waterdischarge and the Ganga-Brahmaputra river systemforms the largest delta in the world, known asSunderban. These are two of the various reasons forwhich Indian rivers are famous in the World. TheGanges has many tributaries and Kosi River is one ofthem. Kosi river has been the centre of attraction forIndia for several years due to various reasons, primarily,due to floods. Several researches have been done tocontrol this river and several techniques have also beenproposed and implemented but the Kosi has continuedto haunt common people every year.1. M. Tech. Student, Department of Civil Engineering,Aligarh Muslim University, Aligarh, India. Email:firstname.lastname@example.org , Email: email@example.com. Associate Professor, Department of Civil Engineering,Aligarh Muslim University, Aligarh, India. Email:firstname.lastname@example.org , mob: +91-98371694273. Professor, Department of Civil Engineering, AligarhMuslim University, Aligarh, India.Nayak  has studied the sediment management in Kosito control the river. Sinha et. al.  studied the floodingproblem in the Kosi river basin and presents an in-depthanalysis of flood hydrology. They also integrated thehydrological analysis with a GIS-based flood riskmapping in parts of the basin.2. Origin of Kosi RiverThe Kosi River flows between the boundary of Nepaland India and it is one of the largest tributaries of theGanges. The river along with its tributaries drains a totalarea of 69,300 km2up to its confluence with the Gangesin India. This also includes parts of Tibet, MountEverest region and the eastern third of Nepal. The riverbasin is surrounded by the ridges separating it from theBrahmaputra in the north, the Gandak in the west, theMahanadi in the east and the Ganges in the south. Fig. 1shows the satellite view of the Kosi River showing itsorigin from Nepal flowing into India along its path.3. Problems caused by the Kosi RiverKosi River has caused many problems to the commonpeople and to the country morale. These are discussed inthe following sections.3.1. Meandering of RiverA river that winds a course not in a straight line but in asinusoidal pattern is called a meandering river. Itscontinued action of secondary flow developed on theriver bends that cause further erosion on the outer bankand deposition on the inner bank. The meanderingaction increases the length of the river and tends to
2ndInternational Conference on Emerging Trends in Engineering & Technology, April 12-13, 2013College of Engineering, Teerthanker Mahaveer University.change its slope. Geometric features of meandering isshown in fig. 2Fig. 1 Satellite view of the Kosi River (source: GoogleMap)The Kosi River have shifted laterally about 112 kmwestward in the last 250 years. Due to this, the riverwhich previously flowed near Purnea in the 18th centuryis now flowing to the west of Saharsa. The meanderingbehaviour of the Kosi River has wasted an area of about1,295 Sq. Km of land in Nepal and about 7,770 Sq. Kmof land in Bihar, resulting in sand deposition.3.1.1.Theory of meanderingSeveral theories have been postulated to define thereason of meandering of rivers, they are summarised asfollows:126.96.36.199. Earth’s rotation theoryGilbert  and Neu  concluded that the shifting ofriver is mainly due the rotation of the earth but Quraishy has found that the tendency of the stream to shiftingof rivers to either left or right may be due to the erosionof the bank material whereas the force due to earth’srotation is very small to cause this shifting188.8.131.52. Disturbance theoriesAccording to this theory , the disturbance caused byvarious factors in a straight channel travels downstreamin such a way that it induce change in the flow pattern ofthe river.Fig. 2 Geometric features of a Meander (source:http://hydrotopics.wordpress.com/2010/10/05/how-and-why-rivers-meander/).184.108.40.206. Helicoidal-flow theoriesMany investigators have found by various studies thatthe meandering of the river is a result of helicoidal flowor secondary flow.220.127.116.11. Excess energy theorySeveral investigators have postulated that the energycontent of the river is responsible for the meanderingpattern of the river. Inglis  states that “meandering isnature’s way of damping out excess energy during awide range of varying flow conditions, the patterndepending upon the grade of material, the relationbetween the discharge and charge and the rate of changeof discharge and charge”.It may be concluded here that meander results from theprocesses of erosion and deposition in alluvial rivers butthere is no explanation as to why meanders also form onglaciers in the absence of sediment.3.1.2. Lateral migrationSome alluvial streams have been observed to undergolateral migration over a period of years. In general,larger streams seem to have larger rates of migration.Such changes have been found to occur in Yellow Riverin China and Kosi River in India. Table 1 gives theaverage rates of migration of the Kosi River from 1736to 1950. The flow pattern of Kosi River during differentperiod of years (as shown in fig. 3) clearly indicates thewestward movement of the river. In this region, groundalso has a transverse slope towards the west. Thus itmay also be concluded that the westward movementmay be due to the prevalent transverse slope of the
2ndInternational Conference on Emerging Trends in Engineering & Technology, April 12-13, 2013College of Engineering, Teerthanker Mahaveer University.country. Neil and John  studied the shifting of KosiRiver and concluded that its shifting is unidirectional.When alluvial channels flow at right angles to thecontours, they have the greatest possible slopes. Hence,if they continue to flow in this manner they may havethe greater tendency to erode and enlarge their channelsthereby relatively free from the problem of lateralmigration .Table: 1 Average Rates of Migration of the KosiRiver YearPeriod ofMovement inyearsApprox.distance movedin kmRate(km/yr)1736-177034 10.8 0.321770-182353 9.3 0.181823-185633 6.1 0.181856-188327 12.9 0.481883-190724 18.5 0.771907-192215 10.9 0.731922-193311 29.0 2.631933-195017 17.7 1.04Fig. 3 Different Course of Kosi river (source: Goleand Chitale 1966)The Kosi River has shifted laterally about 112 kmwestward in the last 250 years which is one of the majorproblems caused by this river. A satellite pictureshowing various migrations undergone by the Kosi isgiven in fig. 4.Fig. 4 satellite picture showing various migrationsundergone by the Kosi (source:ponce.tv/kosi_river_india.html)3.1.3. CutoffsThe meanders in an alluvial stream move graduallytowards the downstream, during this there is a gradualincrement in the length of the meanders which causeslateral movement to the meanders that can be checkedby increased frictional losses and bank resistance. Whenthe bend and the bank resistance becomes too large forcontinued stretching of loop it becomes easier for theflow to cut across the neck than to flow along the bendwhich results in a cutoff as shown in fig. 5.3.2. FloodsFlood is the main cause of misery for the people of Indiain general and for Bihar in particular. On August 182008, Kosi River burst out after heavy rainfall andflooded half of Bihar, wiping out villages, farms andleaving millions of people homeless or dead. The impactof flood on the people of Bihar after August 2008 floodis shown in Fig. 6.
2ndInternational Conference on Emerging Trends in Engineering & Technology, April 12-13, 2013College of Engineering, Teerthanker Mahaveer University.Fig. 5 Aerial view of a cutoff (source:ponce.tv/kosi_river_india.html)The New York Times reported that it is the worst floodin the area in 50 years, prompting Prime Minister Dr.Manmohan Singh to declare a “National Calamity” on28 August. The Government earmarked $230 million inaid for the region. The Indian Army, National DisasterResponse Force (NDRF) and NGOs operated the biggestflood rescue operation in India in more than 50 years.Fig. 7 Impact of flood (source: www.ssvk.org)Death tolls rose from Indian Flood as more than 65people had been killed in monsoon rains. Villagers ateraw rice and flour mixed with polluted water in Bihar,amid hunger and diseases. Supal District was worst hitby floods and surging water swamped 1000 km2of farmlands, destroying wheat and paddycrops.4. River of SorrowThe two rivers in Asia, which are known as the rivers ofsorrow are namely Huang Ho in China and Kosi inIndia, both are called as sorrow of China and sorrow ofIndia respectively. Both the rivers are named as “Riverof Sorrow” because they had caused widespread humansuffering in the past. At present, the Kosi and theYellow River have nothing in common. The YellowRiver is already completely controlled and hence it doesnot pose any threat to people. The Kosi still remainstotally unregulated. At present, the embankments builton both sides of the Kosi temporarily helped to controlthis river. It is feared that very soon the Kosi wouldabandon its present course triggering off a new cycle ofdamages and destructions. After such incident, the Kosimight not anymore be only the sorrow of Bihar. It couldbe the sorrow of the West Bengal and Bangladesh apartfrom the terrible havoc the Kosi floods could be playingwith the safety of people in south-eastern Nepal.5. ConclusionThe nexus of Bihar flood is the Kosi River’s immensealluvial fan, extending some 180 Km from the river’sexit from the Himalayas and foothills in Nepal, down toits confluence with the Ganges in Bihar. The laws ofgeology and physics cause rivers to course back andforth across such fans. The .Problems posed by the Kosiare due to meandering and its westward shifting and canbe controlled by constructing a dam on the upstream i.e.in Nepal so that a controlled volume can be releaseddownstream.References Govt. of India, Ministry of Water Resources, “RiverBasin Atlas of India”, October 2012. Nayak J. N., “Sediment Management of the Kosi Riverin Nepal”, IAHS Publ. no. 236, July 1996. Sinha R. et. al. “Flood Risk Analysis in the Kosi RiverBasin, North Bihar Using Multi-Parametric Approachof Analytical Hierarchy Process (AHP)”, J. Indian Soc.Remote Sens. vol. 36, p.293–307, December 2008. Gilbert G.K. “The sufficiency of terrestrial rotation forthe deflection of streams”, Nat. Acad. Of Sci., Vol. 3,1884. Neu, H.A. “Transverse Flow in a river Due to Earth’sRotation”, JHD, Proc. ASCE, Vol. 93, No. HY-5,September 1967.
2ndInternational Conference on Emerging Trends in Engineering & Technology, April 12-13, 2013College of Engineering, Teerthanker Mahaveer University. Quraishy, M.S. “River Meandering and Earth’sRotation”, Current Science, October 1943. Garde R.J., Ranga Raju K.G. “Mechanics of SedimentTransportation and Alluvial Streams Problems”, ThirdEdition, New age International Publisher, 2000. Inglis, C.C. “The Behaviour and Control of rivers andCanals (with Aid of models)”, pt. I, CWINRS,Research Publication No. 13, 1949. Neil A. W John A. D, “Shifting of the Kosi River,northern India”,v 15 no. 3, p. 204-207, March 1987. Lane E.W. “Studies on the Problem of the Control ofthe Kosi River”, Cyclostyled Memoranda USBR No. 1and 2, July and August 1954. Gole, C.V. and S.V. Chitale “Inland Delta Buildingactivity of Kosi River”, JHD Proc. ASCE, Vol.92, No.HY-2, March 1966.