Necessity of Regional Co-operation - The Ganga: Water Use in the Indian Subcontinent - page 264

Meghna near Bhairab Bazar, used to be the main Brahmaputra, once upon a time; the
present course, insignificant at that time, was known as Yamuna. Further down, there
is one more distributary, Dhaleswari which leaves the left bank of the Brahmaputra
and joins the Meghna, south of Dhaka city.
As stated, the Tsan Po/Brahmaputra is about 2840 km, or 1760 mile, long -
longer than the Ganga in any of its courses. Up to Aricha, where it merges with the
Ganga, the total drainage area is about 581,000, or 0.581 million sq. km, of which
293,000 sq. km is in Tibet, 241,000 sq. km is in India and only 47,000 sq. km
is in Bangladesh. The catchment area of the river above Bahadurabad is about
536,600 sq. km. The discharge observation station at Bahadurabad recorded the
highest flow of 71,320 cumecs, or 2519,000 cusecs, in 1958 and the lowest of 3,280
cumecs, or 116,000 cusecs, in 1960. The average annual discharge is about 19,200
cumecs, or 678,000 cusecs, which is nearly twice that of the Ganga. The first flood-
peak occurs generally in mid-June and carries huge sediment load in both monsoon
and lean seasons. During floods, the channel transports nearly 5 million tonnes of
sediment in a day. The annual silt run-off Bahadurabad is about 735 million tonnes.
The Meghna
The Surma-Meghna flows on the east of the Brahmaputra through Bangladesh. The
Surma rises as the Barak on the southern slope of the Nagaland-Manipur watershed
in India. The Barak divides into two branches within Cachar district of Assam. The
northern branch is called Surma which flows through east of Bangladesh beside
Sylhet town and flows southward. The southern branch is called the Kushiara which
flows through India and then enters Bangladesh. At first, the northern branch joins
the Meghna near Kuliarchar and then the southern branch also joins the Meghna,
near Ajmiriganj. The upper Meghna up to Shaitnol is a small river, whereas the
lower Meghna below Shaitnol is one of the largest rivers in the world, as it is the
mouth of three long rivers - the Ganga-Padma, the Brahmaputra and the Meghna.
The last receives the old Brahmaputra on its right bank at Bhairab Bazar. Its total
length is about 930 km, or 580 miles. It is predominantly a meandering channel,
but in several reaches, especially where small tributaries leave sediment, braiding is
evident and sand islands divide the river into two or more channels.
The maximum flood discharge, recorded in the Meghna, is of the order of 12,220
cumecs, or 431,500 cusecs, in 1960; the average annual discharge is of the order of
3,510 cumecs, or 124,000 cusecs, i.e. about one-third the Ganga's. Even though the
river has a lower discharge than of the Ganga and the Brahmaputra, it leaves about
0.20 million tonnes of sediment in a day during floods.
There are about 50 other small and medium-size rivers which flow through both
the countries and with which the interest of both the countries are involved. However
the hydrological data of most of these rivers are available. Therefore, the following
discussion on regional cooperation will be confined to these three major rivers. A
schematic diagram of them when they are in spate is shown in Fig. 14.2.