river kosi, sorrow of india an overview

2nd International Conference on Emerging Trends in Engineering & Technology, April 12-13, 2013 College of Engineering, Teerthanker Mahaveer University.

River Kosi, Sorrow of India: An overview

Mohd Danish1, Priyank Gupta

1, Dr. Javed Alam

2, Prof. Mohd. Muzammil

3

The Kosi River which is one of the largest tributaries of the river Ganges is infamous for floods, thus causes huge

losses 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 of

Bihar. It is one of the two major tributaries of the river Ganges(the other river being Gandak) draining the plains of

north Bihar. Despite a long history of flood control management in the basin for more than 5 decades, this River continues to bring a lot of misery through extensive flooding. Meandering is another bizarre behaviour of this river

which have shifted laterally about 112 km westward in the last 250 years. Due to this, the river which previously

flowed near Purnea in the 18th century is now flowing to the west of Saharsa. The meandering behaviour of the Kosi River has wasted an area of about 1,295 Sq. Km of land in Nepal and about 7,770 Sq. Km of land in Bihar, resulting

in sand deposition. This wasted land was considered as the garden of Bihar and it was renowned for its rice-field and

orchards. In the course of shifting it has wiped out many towns and villages inflicting heavy losses of human, cattle

life and property. The present paper presents an overview of the behaviour of River Kosi and its shifting pattern in its 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, Meandering

1. Introduction

India is seventh largest country with geographical area

32,87,263 km2 (2.45% of the World’s land resources)

and the second most populous country with over 1.2 billion people (17.5 % of the World’s population) and it

holds 4% of the world’s fresh water resources [1].

Rivers in India are not only considered as a source of water 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 Ganges

is the second largest river in the world in terms of water

discharge and the Ganga-Brahmaputra river system

forms the largest delta in the world, known as Sunderban. These are two of the various reasons for

which Indian rivers are famous in the World. The

Ganges has many tributaries and Kosi River is one of them. Kosi river has been the centre of attraction for

India for several years due to various reasons, primarily,

due to floods. Several researches have been done to

control this river and several techniques have also been proposed and implemented but the Kosi has continued

to haunt common people every year.

1. M. Tech. Student, Department of Civil Engineering, Aligarh Muslim University, Aligarh, India. Email:

[email protected] , Email: [email protected]

2. Associate Professor, Department of Civil Engineering, Aligarh Muslim University, Aligarh, India. Email:

[email protected] , mob: +91-9837169427 3. Professor, Department of Civil Engineering, Aligarh

Muslim University, Aligarh, India.

Nayak [2] has studied the sediment management in Kosi

to control the river. Sinha et. al. [3] studied the flooding problem in the Kosi river basin and presents an in-depth

analysis of flood hydrology. They also integrated the

hydrological analysis with a GIS-based flood risk

mapping in parts of the basin.

2. Origin of Kosi River

The Kosi River flows between the boundary of Nepal and India and it is one of the largest tributaries of the

Ganges. The river along with its tributaries drains a total

area of 69,300 km2 up to its confluence with the Ganges

in India. This also includes parts of Tibet, Mount Everest region and the eastern third of Nepal. The river

basin is surrounded by the ridges separating it from the

Brahmaputra in the north, the Gandak in the west, the Mahanadi in the east and the Ganges in the south. Fig. 1

shows the satellite view of the Kosi River showing its

origin from Nepal flowing into India along its path.

3. Problems caused by the Kosi River

Kosi River has caused many problems to the common people and to the country morale. These are discussed in the following sections.

3.1. Meandering of River

A river that winds a course not in a straight line but in a sinusoidal pattern is called a meandering river. Its

continued action of secondary flow developed on the

river bends that cause further erosion on the outer bank and deposition on the inner bank. The meandering

action increases the length of the river and tends to

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change its slope. Geometric features of meandering is

shown in fig. 2

Fig. 1 Satellite view of the Kosi River (source: Google

Map)

The Kosi River have shifted laterally about 112 km

westward in the last 250 years. Due to this, the river

which previously flowed near Purnea in the 18th century

is now flowing to the west of Saharsa. The meandering behaviour of the Kosi River has wasted an area of about

1,295 Sq. Km of land in Nepal and about 7,770 Sq. Km

of land in Bihar, resulting in sand deposition.

3.1.1. Theory of meandering

Several theories have been postulated to define the

reason of meandering of rivers, they are summarised as follows:

3.1.1.1. Earth’s rotation theory

Gilbert [4] and Neu [5] concluded that the shifting of river is mainly due the rotation of the earth but Quraishy

[6] has found that the tendency of the stream to shifting

of rivers to either left or right may be due to the erosion of the bank material whereas the force due to earth’s

rotation is very small to cause this shifting

3.1.1.2. Disturbance theories

According to this theory [7], the disturbance caused by various factors in a straight channel travels downstream

in such a way that it induce change in the flow pattern of

the river.

Fig. 2 Geometric features of a Meander (source:

http://hydrotopics.wordpress.com/2010/10/05/how-

and-why-rivers-meander/).

3.1.1.3. Helicoidal-flow theories

Many investigators have found by various studies that the meandering of the river is a result of helicoidal flow

or secondary flow.

3.1.1.4. Excess energy theory

Several investigators have postulated that the energy content of the river is responsible for the meandering

pattern of the river. Inglis [8] states that “meandering is nature’s way of damping out excess energy during a

wide range of varying flow conditions, the pattern

depending upon the grade of material, the relation

between the discharge and charge and the rate of change of discharge and charge”.

It may be concluded here that meander results from the processes of erosion and deposition in alluvial rivers but there is no explanation as to why meanders also form on

glaciers in the absence of sediment.

3.1.2. Lateral migration

Some alluvial streams have been observed to undergo

lateral 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 River

in China and Kosi River in India. Table 1 gives the

average rates of migration of the Kosi River from 1736

to 1950. The flow pattern of Kosi River during different

period of years (as shown in fig. 3) clearly indicates the

westward movement of the river. In this region, ground

also has a transverse slope towards the west. Thus it

may also be concluded that the westward movement

may be due to the prevalent transverse slope of the


country. Neil and John [9] studied the shifting of Kosi

River and concluded that its shifting is unidirectional.

When alluvial channels flow at right angles to the

contours, they have the greatest possible slopes. Hence,

if they continue to flow in this manner they may have

the greater tendency to erode and enlarge their channels

thereby relatively free from the problem of lateral

migration [10].

Table: 1 Average Rates of Migration of the Kosi

River [11]

Year

Period of

Movement in

years

Approx.

distance moved

in km

Rate

(km/yr)

1736-1770

34 10.8 0.32

1770-

1823 53 9.3 0.18

1823-1856

33 6.1 0.18

1856-1883

27 12.9 0.48

1883-

1907 24 18.5 0.77

1907-1922

15 10.9 0.73

1922-1933

11 29.0 2.63

1933-

1950 17 17.7 1.04

Fig. 3 Different Course of Kosi river (source: Gole

and Chitale 1966)

The Kosi River has shifted laterally about 112 km

westward in the last 250 years which is one of the major

problems caused by this river. A satellite picture

showing various migrations undergone by the Kosi is

given in fig. 4.

Fig. 4 satellite picture showing various migrations

undergone by the Kosi (source:

ponce.tv/kosi_river_india.html)

3.1.3. Cutoffs

The meanders in an alluvial stream move gradually

towards the downstream, during this there is a gradual

increment in the length of the meanders which causes

lateral movement to the meanders that can be checked

by increased frictional losses and bank resistance. When

the bend and the bank resistance becomes too large for

continued stretching of loop it becomes easier for the

flow to cut across the neck than to flow along the bend

which results in a cutoff as shown in fig. 5.

3.2. Floods

Flood is the main cause of misery for the people of India

in general and for Bihar in particular. On August 18

2008, Kosi River burst out after heavy rainfall and

flooded half of Bihar, wiping out villages, farms and

leaving millions of people homeless or dead. The impact

of flood on the people of Bihar after August 2008 flood

is shown in Fig. 6.


Fig. 5 Aerial view of a cutoff (source:

ponce.tv/kosi_river_india.html)

The New York Times reported that it is the worst flood

in the area in 50 years, prompting Prime Minister Dr.

Manmohan Singh to declare a “National Calamity” on

28 August. The Government earmarked $230 million in

aid for the region. The Indian Army, National Disaster

Response Force (NDRF) and NGOs operated the biggest

flood 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 65

people had been killed in monsoon rains. Villagers ate

raw rice and flour mixed with polluted water in Bihar,

amid hunger and diseases. Supal District was worst hit

by floods and surging water swamped 1000 km2 of farm

lands, destroying wheat and paddycrops.

4. River of Sorrow

The two rivers in Asia, which are known as the rivers of

sorrow are namely Huang Ho in China and Kosi in

India, both are called as sorrow of China and sorrow of

India respectively. Both the rivers are named as “River

of Sorrow” because they had caused widespread human

suffering in the past. At present, the Kosi and the

Yellow River have nothing in common. The Yellow

River is already completely controlled and hence it does

not pose any threat to people. The Kosi still remains

totally unregulated. At present, the embankments built

on both sides of the Kosi temporarily helped to control

this river. It is feared that very soon the Kosi would

abandon its present course triggering off a new cycle of

damages and destructions. After such incident, the Kosi

might not anymore be only the sorrow of Bihar. It could

be the sorrow of the West Bengal and Bangladesh apart

from the terrible havoc the Kosi floods could be playing

with the safety of people in south-eastern Nepal.

5. Conclusion

The nexus of Bihar flood is the Kosi River’s immense

alluvial fan, extending some 180 Km from the river’s

exit from the Himalayas and foothills in Nepal, down to

its confluence with the Ganges in Bihar. The laws of

geology and physics cause rivers to course back and

forth across such fans. The .Problems posed by the Kosi

are due to meandering and its westward shifting and can

be controlled by constructing a dam on the upstream i.e.

in Nepal so that a controlled volume can be released

downstream.

References

[1] Govt. of India, Ministry of Water Resources, “River

Basin Atlas of India”, October 2012.

[2] Nayak J. N., “Sediment Management of the Kosi River

in Nepal”, IAHS Publ. no. 236, July 1996.

[3] Sinha R. et. al. “Flood Risk Analysis in the Kosi River

Basin, North Bihar Using Multi-Parametric Approach

of Analytical Hierarchy Process (AHP)”, J. Indian Soc.

Remote Sens. vol. 36, p.293–307, December 2008.

[4] Gilbert G.K. “The sufficiency of terrestrial rotation for

the deflection of streams”, Nat. Acad. Of Sci., Vol. 3,

1884.

[5] Neu, H.A. “Transverse Flow in a river Due to Earth’s

Rotation”, JHD, Proc. ASCE, Vol. 93, No. HY-5,

September 1967.

http://www.ssvk.org/


[6] Quraishy, M.S. “River Meandering and Earth’s

Rotation”, Current Science, October 1943.

[7] Garde R.J., Ranga Raju K.G. “Mechanics of Sediment

Transportation and Alluvial Streams Problems”, Third

Edition, New age International Publisher, 2000.

[8] Inglis, C.C. “The Behaviour and Control of rivers and

Canals (with Aid of models)”, pt. I, CWINRS,

Research Publication No. 13, 1949.

[9] Neil A. W John A. D, “Shifting of the Kosi River,

northern India”,v 15 no. 3, p. 204-207, March 1987.

[10] Lane E.W. “Studies on the Problem of the Control of

the Kosi River”, Cyclostyled Memoranda USBR No. 1

and 2, July and August 1954.

[11] Gole, C.V. and S.V. Chitale “Inland Delta Building

activity of Kosi River”, JHD Proc. ASCE, Vol.92, No.

HY-2, March 1966.

river kosi, sorrow of india an overview

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