Flood Management In Ganga Brahmaputra Meghna Basin Environmental Sciences Essay

The Ganges, the Brahmaputra and the Meghna are the three major river systems which flow through both India and Bangladesh and make inundation jobs in the several basin countries during monsoon months in both the states about every twelvemonth. The basin scenario and besides the inundation scenario of the three rivers have been described in brief in the paper. It has been stated by the writer that the steps taken by the two states, both structural and non-structural, have shown positive consequences in a limited infinite merely without much consequence.

Specially, the job in Bangladesh has non been solved so far. The writer has suggested that joint steps are to be taken on the footing of common apprehension and regional co-operation between different affected states, specially between India and Bangladesh in order to understate the inundation jeopardies in both the states. Side-by-side peoples ' engagement on regional co-operative footing would understate the losingss due to inundations.

Introduction

The three major river systems, viz.

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, the Ganges, the Brahmaputra ( Jamuna every bit called in Bangladesh ) and the Meghna are common to the two states, India and Bangladesh, an undivided one prior to 1947. Due to the inordinate H2O flow in the monsoon months in these three rivers, which synchronise about every twelvemonth, the people of both the states suffer from untold wretchednesss due to the happening of inundations about every twelvemonth. Bangladesh, being the lower riparian state, suffers maximum due to such inundations doing tremendous loss of lives and belongingss. It is interesting to observe that though H2O is bit by bit going a scarce stuff globally, and its saving and proper use has become more and more of import, its copiousness in limited infinite and clip has become so destructive in this portion of South Asia.

Therefore, harnessing of this abundant natural resource for the benefit of this part has become an absolute necessity in the present geographical scenario of the two states.

This paper emphasises the necessity of regional co-operation between India, Nepal, Bangladesh and Bhutan and perchance China besides for the H2O resources direction through inundation extenuation, nutrient production and power development in the Ganga-Brahmaputra-Meghna basin ( GMB basin ) in the line of the Mekong Project of South and South-East Asia under the protections of ECAFE ( now ESCAP ) .

The River Basin Scenario

The three river basins are briefly described as under:

The Ganga: The chief Ganga River is the flow combination of the two rivers, viz. , the Alakananda and the Bhagirathi, which meet at Deva Prayag in Garwal territory of Uttaranchal State ( earlier Northern Uttar Pradesh ) of India within the mountain scope of the Himalayas. The original class of the river is on South- ward way, so it flows through eastern way and eventually in its last lap, it flows once more southbound and debouches into the sea. During its in-between class on eastern way, a figure of large and little feeders have joined on the northern side ( left bank ) from the Himalayan sub-basin, viz. , Ramaganga, Gomati, Ghagra, Gandak and Kosi, all of which have their beginnings within the mountain scope of the Himalayas in Nepal. Therefore, the part of flow of these feeders is from Nepal within the Himalayan scope and besides from the Indian dirt on the Southern side of the Himalayan foothills. There is another tributary, Mahayana which joins the river in Bangladesh ( FIG-1 ) .

On the Southern side ( Right bank ) , the feeders are Yamuna, which has joined the Ganga at Allahabad, and other major & A ; minor feeders are, Kehtons, Sone, Kiul and Punpun, which have beginnings from peninsular sub-basin. The mean one-year run-off of the Ganga below Allahabad is abount 150,000 million three-dimensional meter with the ratio of part between the Ganga and the Yamuna as 2: 3.

The catchment country of the Ganga river basin is divided in the ratio of 3:2 between the peninsular sub-basin and the Ganga sub-basin ; but the discharge part is merely the contrary, i.e. , 2:3. This has been possible due to the much higher strength of rainfall in the Himalayan mountain scope and besides at the pes of the Himalayas, compared to that of the peninsular parts. Therefore, hydrologically, the Himalayan Rivers are, of greater importance as respects H2O resources direction compared to the peninsular watercourse. Amongst the Himalayan watercourse, the Ghagra with its feeders contributes maximal run-off ( about 94,500 Mm3 ) and the Gomati contributes minimal run-off ( about 7,400 Mm3 ) . Amongst the peninsular watercourses, the Sone contributes maximal run-off ( about 32,000 Mm3 ) and the Kiul contributes the minimal run-off ( about 35,000 Mm3 ) .

James M. Coleman recorded the mean one-year discharge between 1979 and 1988 as 12,120 cumec ( 393,000 cusecs ) . Harmonizing to the inundation rhythm in the Ganges, the flow goes down from October every twelvemonth, becomes lower limit between last hebdomad of March and last hebdomad of April and becomes upper limit between last hebdomad of August and last hebdomad of September every twelvemonth.

The river enters Bangladesh after about 50 kilometers below Farakka ( left side falls in Bangladesh ) and the feeders like Mahananda, Punarbhaba, Atrai ( Boral ) and Karatoya join the river Ganga on its left side. These rivers have their beginnings in India and the catchment country is spread in both India and Bangladesh. The river to the full runs into Bangladesh after about another 110 kilometer or so with Rajsahi territory on left side and Kustia territory on its right. The river joins the Brahaaputra after another 110 kilometer or near Goalanda Ghat in Bangladesh in the name of the Padma and farther down the combined discharge joins the Meghna at Chandpal ghat after going another 70km or so and the combined watercourse is called the Meghna. After another 90 kilometer or so the combined discharge falls into the Bay of Bengal. The entire length of the river Ganga/Padma from Deba Prayag to sea along the class is about 2,515 kilometers.

Historical events every bit good as old records show that the chief flow of the Ganga River used to flux through the Bhagirathi-Hooghly ( which is at present a distributory ) and the Ganga-Padma was an undistinguished distributory transporting chiefly the inundation discharge. Due to the continued procedure of siltation both in the river bottom and at the oral cavity, the flow became bit by bit undistinguished and finally it did non transport any discharge during thin Season months. However, this right arm continues to flux due souths through West Bengal for another 520 kilometer before it falls into the Bay of Benga.l near Saugar Island. The river has a figure of feeders on both Bankss, which contribute chiefly flood discharge doing the river a chief drainage channel during monsoon months. The entire length of the river Ganga from Deva Prayag to sea along this class is about 2,610 Km. Both the river classs are chiefly weaving channels.

The Brahmaputra: The Brahmaputra River has its beginning onthe northern incline of the Himalayas in China ( Tibet ) , where it is called as Tsan-Po. It flows towards E for a length of about 1,130 kilometers ( 700 stat mis ) and so turns towards South and enters Arunachal Pradesh province of India at its northern-most point and flows for about 480 Km ( 300 stat mis ) . Then it turns towards West and flows through Arunachal Pradesh, Assam and Meghalaya provinces for another about 650 Km ( 400 stat mis ) and so enters Bangladesh. At the boundary line, the river curves to the South and continues on this class for a length of about 240 Km ( l50 stat mis ) to its meeting with the Ganges. The entire length of the river from the beginning to the sea is about 2840 Km ( 1,760 stat mis ) . Within Bangladesh, the channel varies well in width runing from less than 2.0 Km to more than 12.0 Km. The Brahmaputra is classed as a braided channel as against the Ganges, which is fundamentally a meandering channel. During low flows the river becomes a multiple channel watercourse with sand bars in between and the channels switch back and Forth between the chief watercourse Bankss which are 6 Km to 12 Km apart. Plan position of the river shows many channels, shoals and islands, which indicate a river of low hydraulic efficiency with heavy deposit burden. ( FIG-2 ) .

The discharge of the river Brahmaputra is largely contributed by the snowmelt in China ( Tibet ) on the other side of the Himalayas before it enters Arunachal Pradesh. In Arunachal Pradesh, Assam and Meghalaya of India and Dinajpur and Mymenshingh territories of Bangladesh ( Northern side ) rainfall is rather heavy and this contributes significant sum of flow in the river. The river range between Bahadurabad ( where the river leaves India and enters Bangladesh ) and Aricha ( where the river joins the river Ganges ) is popularly known as Jamuna in Bangladesh.

The mean one-year discharge is about 19,200 cumecs ( 678,000 cusecs ) which is about twice that of the Ganges.

The Meghna: The Surma-Meghna river system flows on the E of the Brahmaputra river through Bangladesh. Out of the two chief subdivisions, the Surma River rises as the Barak, on the Southern inclines of the Nagaland-Manipur watershed in India. The Barak divides into two subdivisions within the Cachar territory of Assam in India. The Nortnern subdivision is called Surma, which flows through eastern side of Bangladesh by the side of Sylhet town and flows due souths. The southern subdivision of the Barak is called the Kushiara, which flows through India and so enters Bangladesh. At first the northen subdivision joins the Meghna near Kuliarchar and so the southern subdivision besides joins the Meghna river near Ajmiriganj. The lower Meghna is one of the largest rivers in the universe, as it is the oral cavity of the three great rivers- the Ganga-padma, the Brahmaputra and the Megbna. The entire length of the river may be about 930 Km ( 580 stat mis ) . The river is preponderantly a meandering channel, but in several ranges, particularly where little feeders contribute deposit, gold braid is apparent with sand islands bifurcating the river into two or more channels. The mean one-year discharge is of the order of 3,510 cumecs ( 124,000 cusecs ) , approximately one-third that of the Ganges.

The mean monthly discharge of the three rivers in Bangladesh is shown in Table -1.

The hydrological features of the three major river systems which flow chiefly through India and Bangladesh and the H2O resources development activities need to be associated have been briefly narrated. A conventional diagram of the three river systems with their inundation discharge is shown in Fig. 3.

From Fig.3 it can be seen that over 138,700 cumecs ( 4,900,000 cusecs ) of H2O flows into the bay of Bengal during inundations through a individual mercantile establishment of the Ganga-Brahmaputra-Meghna in Bangladesh. This is the largest in the universe for a individual mercantile establishment to the sea and exceeds even Amazon by about one -and- a -half times. Of the entire measure of H2O brought into Bangladesh, about 85 % is carried by this river system and these are chiefly responsible for inundations and flood in Bangladesh.

TABLE-I: Average monthly discharge of the rivers in Bangladesh ( 1934- : -1963 )

Calendar month

Ganges at Hardinge Bridge

Brahmaputra at Bahadurabad

Meghana at Bhairab Baral

Soap

Minute

Soap

Minute

Soap

Minute

January

5.10

2.29

6.60

4.36

0.65

0.51

February

4.76

1.90

4.98

3.40

0.54

0.37

March

3.60

1.61

5.97

3.77

1.10

0.51

April

2.97

1.25

8.61

5.15

1.13

0.74

May

3.14

1.39

24.04

7.98

2.49

1.39

June

9.68

2.35

38.65

26.50

5.38

3.37

July

29.59

10.76

45.36

33.55

9.12

5.69

August

52.58

23.61

55.52

30.72

9.14

6.68

September

56.03

25.03

48.50

24.15

9.51

6.43

October

42.30

8.35

32.28

14.07

8.10

5.27

November

16.53

4.39

14.98

8.49

5.01

1.78

December

6.74

2.86

9.37

5.66

1.27

0.79

Mean

16.36

7.81

21.74

17.98

3.94

3.00

The Flood Scenario

Both India and Bangladesh are on a regular basis affected by inundations due to the high discharges in the Ganga-Brahmaputra-Meghna river system. The chief causes of inundations are widespread heavy rainfall in the catchment countries and unequal capacity of the river channel to incorporate the inundation flow within the Bankss of the river. In the tidal range and delta country widespread flood occurs where high inundations in the river synchron1ses with the high tidal degrees from the sea. The planes of Uttar Pradesh, Bihar and West Bengal are affected by the spills from either parent river Ganga or by the spills from the tributories, viz. Ghagra, Gandak, Kosi etc.

India: During high inundations in Ghagra, Gandak and Kosi and their feeders, viz. , Sarju, Sarda, Rapti, Daha, Buri Gandak, Bagmati, Kamala etc. , big countries in Nepal, Uttar Pradesh and Bihar are inundated. When it synchronises with heavy precipitation in the downstream countries, the state of affairs aggravates. Floods of 1964,1967,1971,1972, 1979,1980,1986,1998 etc. , were rather terrible and largo countries were inundated each clip. The embankments, goads etc. , were badly damaged each clip and heavy outgo has been incurred to keep them. The discharge from the feeders is to a great extent silt-loaded during inundations which when deposited in favorable environment, make more jobs of inundations and the river channel oscillates between the two Bankss damaging the bing protective steps. It is reported that the Kosi River has increasingly shifted due wests by a distance of 112 Km in 225 old ages. However, after the building of Kosi Barrage and the inundation embankments, the inundation job has been minimised and westbound swing has been checked.

Looking at the class of the river Ganga in India, chief job of deluging in Uttar Pradesh is confined to the countries below the meeting of Yamuna and Ganga at Allahabad. In Bihar, it has been observed that when the Ganga River is at high phase, the discharge from the feeders gets blocked and causes widespread implosion therapy in the sub-basins and at the meeting points. The status is worsened when the inundation in the Ganga and its feeders synchronise.

The chief Ganga below Rajmahal upto Jalangi Bazar in Malda and murshidabad territories of West Bengal has a history of implosion therapy and bank eroding. Due to the rambling nature of the deep channel, the left bank of the river upstream of bombardment has been under onslaught taking to the breach of inundation embankment and implosion therapy of the huge country. The inundations of 1960, 1968, 1979, 1987, 1988, 1996, 1998 etc. , were rather terrible and afloat huge countries of land in Malda territory. Similarly, the right bank downstream of bombardment in Murshidabad territory is often overtopped due to high inundations deluging the more developed countries and bank eroding is endangering the bing rail and route communications. Coming down to the Bhagirathi-Hooghly class, the feeders, viz. , Pagla-Bansloi, Mayurakshi, Ajay, Damadar and Raldi have joined the river on its right bank and Jalangi and Churni have joined on the left bank. While the right bank feeders have beginnings in the hill ranges of Bihar and run out into the Bhagirathi, the left bank feeders are fed by the Ganga H2O and its ain catchment H2O during monsoon months which are discharged into the parent river. The widespread rainfall in the catchment countries of sub-basins of the feeders in Bihar tableland and in South Bengal create inundations really frequently in basin countries before run outing into the parent river. In Case this inundation is synchronised with the inundations in the Ganga River every bit good as the high tides from the sea, congestion occurs in the drainage and this aggravates the inundation state of affairs. During the old ages 1968,1971,1978,1980,1986,1987,1988, 1990,1995,1998 and 2000 there were heavy inundations in the Bhagira thi-Hooghly basin countries. Out of these old ages, the inundations of 1978 and 2000 were most terrible doing large-scale amendss in South Bengal. During 2000 inundations, approximately 24,000 Km countries with a population of about 21.8 million were affected. The inundation was so terrible and public agitation was so self-generated that the concerned sections were forced to fix several studies on the causes of inundations and its jobs.

Bangladesh: The combined discharge of three river systems of the Ganga, Brahmaputra and Meghna comes down through Bangladesh district with a favorable physical environment and during the monsoon months spills over the embankments and inundations the basin and sub-basin countries about every twelvemonth. From the conventional diagram, it can be seen that over 138,700 cumecs ( 4,900,000 cusecs ) of H2O flows into the Bay of Bengal during inundation via the lower individual mercantile establishment. Every twelvemonth H2O degree in the three chief rivers rises and by and large overtops their Bankss deluging huge piece of lands of land. Flows of approximately 56,600 cumecs ( 2,000,000 cusecs ) on the Ganges or the Brahmaputra and 8,500 cumecs ( 300,000 cusecs ) on Meghna are by and large sufficient to do the channels to overrun their Bankss. As an illustration, during 1955 inundations about 38 % of the entire land country in Bangladesh ( so East Pakisthan ) was inundated by floodwaters. Severe inundations have occurred in 1954, 1956, 1962, 1964, 1970, 1972, 1976, 1980, 1987,1988 and.1998. Each inundation consequences in transportation of big measures of suspended deposits into the next inundation field.

The two back-to-back inundations of 1987 and 1988, which were remarkably terrible deluging more than 40 % of the land country of Bangladesh, generated widespread concern amongst common people and the Bangladesh Government was compared to the readying of the several proficient studies on the inundation job.

Scenario on Regional Co-operation

It has been highlighted that the three river systems are responsible for the happening of inundations in the States of Uttar Pradesh, Bihar and West Bengal in India and Bangladesh. The inundation occurs in a limited clip frame of 2 to 3 monsoon months when the infinite becomes limitless due to the favorable hydrological environment. The state of affairs is worst in Bangladesh due to the combination of discharge in three major rivers. Individual attempts of each state to extenuate the inundation jeopardies by following preventative steps by manner of both structural every bit good as non-structural steps did non turn out much effectual so though the inundation jeopardies could be minimised efficaciously in a limited infinite, particularly in India.

But in Bangladesh inundations continue to stay as a threat boulder clay now without many effectual steps. The structural steps adopted in India are building of dikes, reservoirs and bombardment, building of inundation leeves by jacketing the river basins, protective steps of riverside by revetment, goad, and bed bars either separately or in combination. The non-structural steps are beforehand pre-flood warnings, post-flood deliverance and rehabilitation steps etc.

The inundation jeopardies of the two states can possibly be mitigated by joint attempts of the two states at appropriate proficient every bit good as administrative degrees. In the bing geographical scenario of the two states, being largely covered by the inundation fields of the different rivers arising from the largest mountain scope of the universe, it is impossible to avoid inundations wholly. The people of the two states will hold to populate with the inundations. However, its strength, badness and often can possibly be minimised with the joint attempts of the two states.

In this connexion, it may be recalled that in the Joint Rivers Commission ( JRC ) , the two states had placed separate proposals in 1978 for augmentation of the Ganga river flow at Farakka. While Bangladesh proposal concentrated on storage of Ganga H2O itself during inundations by building dikes and reservoirs to be located largely in Nepal, Indian proposal was based on inter-basin transportation of H2O from the Brahmaputra basin to the Ganga basin through a link canal as the Brahmaputra has plentifulness of H2O largely untapped. This inter-basin transportation of H2O would be executable as the Brahmaputra basin Furthermore, this would besides understate the inundation jeopardies as the inundations in the Brahmaputra came in progress of more than two months compared to the Ganges. However, none of the proposals could be materialised due to the expostulations from either side on assorted evidences. Both the proposals had their virtues and demerits every bit good. Now, if we can follow a proposal in between, i.e. , storage reservoirs in both the Ganga and the Brahmaputra basins and a link canal fall ining the two rivers at a suited location for inter-basin transportation of H2O, it may be possible to understate the inundation jeopardies in both the states besides other benefits like irrigation, hydro-power coevals, pilotage and other manner of communicating etc. This purpose is to be achieved by common apprehension and regional co-operation between the two neighbouring states. Besides, a web of progress warning system about the inundations in the two states would understate the losingss, aid in the procedure of deliverance and rehabilitation etc. of the affected people. After the black inundations in Bangladesh in 1988, the Indian Government expressed concern about the amendss and showed involvement in regional co-operation for inundation extenuation in both the states through joint action program. Bangladesh Government besides came closer to India and had negotiations on river co-operation. However, batch of clip has passed without much end product and the clip has come now for a joint action program on flood extenuation.

The joint action program on inundation sector would dwell of:

Structural steps: -

-Construction of storage dikes and reservoirs at suited location.

-Inter-basin transportation of H2O for irrigation, inundation extenuation etc. , by building link canal fall ining the Ganga and the Brahmaputra.

-Construction of embankments, drainage constructions as required to forestall inundations.

B ) Non-structural steps:

-A combined web of progress pre-flood warning system to be spread in both urban and rural countries.

-A combined web of post-flood activities for deliverance, alleviation and rehabilitation operations.

degree Celsius ) Common Peoples ' engagement in flood direction:

-An action program for exchange of positions between the people of the two states for avoiding any misinterpretation.

-Active engagement of the people to understate losingss, e.g. building of progress inundation shelters for people every bit good as for cowss.

-Storage of sufficient nutrient and imbibing H2O before happening of inundations.

-Active engagement in deliverance and relief operations.

-To prevent harm to the embankments and unauthorized building in inundation field, side incline of embankment etc.

-To aid and co-operate on the care of bing embankments

-To follow the bing regulations and ordinances for bar and extenuation of inundations.

Some possible possibilities for regional co-operation are shown in Table -2.

Table -2: Potential Possibilities for Regional Co-operation.

States Involved

Potential Fieldss of cooperation

River basin

1. Nepal and India

Construction of storage reservoirs

Flood extenuation

Irrigation

Hydro-power genration

The Ganges and its feeders

2. Bhutan and India

Construction of storage reservoirs

Flood extenuation

Hydro-power coevals

Mahananda, Tista and their feeders.

3. India and Bangladesh

Construction of storage reservoirs

Flood extenuation

Hydro-power coevals

Irrigation

Inter-basin transportation

Guaranteed minimal flow

The Ganges, the Brahmaputra, the Meghana and all their feeders.

4. International expertness ( in instance of utmost necessity )

Technical expertness

Financing

Interceding difference if any

-

As has been stated earlier, `` the people of both India and Bangladesh, being the lower riparian states of the river basins, will hold to populate with inundations. But corporate attempts on the footing of regional co-operation would surely assist in understating the inundation jeopardies and losingss thereof.

Decision

The scenario of the three river basins, their inundation scenario and some facets of regional co-operative for extenuation of inundation jeopardies have been highlighted in the paper. The building of dikes, reservoirs, embankments on the footing of regional apprehension and co-operation between India and Bangladesh are of import structural steps to be taken for understating inundation jeopardies. Besides, non-structural steps, such as, a web of progress warning system, coordinated post-flood activities are perfectly necessary for understating the losingss due to inundations. Side-by-side peoples ' engagement on regional co-operative footing for extenuating inundation jeopardies in both the states will surely understate the jobs.