Meghna River one of the major rivers in Bangladesh, specially famous for its great estuary that discharges the flows of the Ganges-Padma, the Brahmaputra-Jamuna and the Meghna itself. The downstream of surma river from Ajmiriganj is often referred to as the Meghna. The matter would be simpler but for the fact that from Madna downstream for about 26 km (in a straight line) one of the two channels of the Surma-Meghna is known as the dhaleshwari. The channel from Ajmiriganj down to the confluence with the Dhanu is referred to as the Surma. This confluence is five kilometres east of Kuliarchar and north of Bhairab Bazar. Downstream from this point, the river is referred to as the Meghna.
The Meghna has two distinct parts. The Upper Meghna from Kuliarchar to Shatnol is a comparatively small river. The Lower Meghna below Shatnol is one of the largest rivers in the world because of its wide estuary mouth. The Lower Meghna is at times treated as a separate river.
The Meghna receives the old brahmaputra on its right at Bhairab Bazar. A little above the confluence, the Meghna has a railway bridge-'Bhairab Bridge'-and a road bridge-'Bangladesh-UK-Friendship Bridge' over it. The width of the river there is three-quarters of a kilometre. Several small channels branching off from the Meghna and meandering through the lowland bordering the Tippera Surface receive the flow of a number of hilly streams and rejoin the main river downstream. The most important of these offshoots is the titas, which takes off south of Ghatalpar and after meandering through two long-bends extending over 240 km rejoins the Meghna through two channels in Nabinagar upazila. Other offshoots of the Meghna are the Pagli, Kathalia, Dhonagoda, Matlab and Udhamdi. The Meghna and these offshoots receive water of a number of hilly streams from the Tripura Hills. The important hill streams are the gumti, Kakrai, Kagni, dakatia, Hawrah, Sonaiburi, Harimangal, Pagli, Kurulia, Balujuri, Sonaichhari, Handachora, Jangalia and. All of these are liable to flash floods. The Gumti, Kakrai and Hawrah are the most destructive rivers. They have silted their beds to the extent that they now flow above the mean level of the land when brimful. Numbers of embankments have been built to contain them. But every other year one or the other of these streams overflows and causes considerable damage to crops, livestock and homestead.
The Meghna receives Tippera Surface streams from the east and flows from the enlarged Dhaleshwari from the west. At the confluence, just north of Shatnol, the Meghna is about five kilometres wide. Dhaleshwari comes down in a brown stream and meets the clear blue-green Meghna. For many kilometres the waters do not seem to mix, for half the river water remains brown and the other half blue-green. The boatmen are fond of pointing out this peculiarity.
Sixteen kilometres from Shatnol, the combined flow of the Ganges and Brahmaputra-Jamuna, known as the padma, meets the Meghna at a 11 km wide confluence in the rainy season near Chandpur. From this point southwards the Meghna is marked as the Lower Meghna, becoming one of the broadest rivers and largest estuaries in the world.
Lower Meghna is the combined stream of the Padma and the Meghna (Upper Meghna), reinforced by the Dhaleshwari. All the three rivers are large. The Dhaleshwari-Meghna and the Padma are each 5 km wide at the confluence. The Lower Meghna has several small chars (braid-bars) in it, which create two main channels, of which the large eastern one is 5 to 8 km wide. The western channel is about 2 km in width. Near Muladi the 1.5 km wide Safipur river is an offshoot from the right-bank. Further south, the Lower Meghna shifts into three channels: west to east flowing tentulia (Ilsha) river, the Shahbazpur and the Bamni. The Ilsha is a 5 to 6.5 km wide channel separating Bhola Island from the Barisal mainland.
West of the mouth of the Ilsha is the Rabnabad islands. Shahbazpur Channel, 5 to 8 km wide, separates Bhola from Ramgati and Hatiya islands and at its mouth are the Manpura islands. Bamni now is said to be nonexistent. previously it used to flow between the islands of Ramgati and Char Lakshmi and the Noakhali mainland, and was at times the main outlet for Meghna. The tides and their bores always affected it considerably, and this channel narrowed or widened in an unpredictable manner. After eroding a considerable part of the mainland in the 1940s, it suddenly shoaled to such an extent, just west of Noakhali town, that in winter there was a land bridge from the mainland to Ramgati Island. To make this a permanent feature, a large earthen cross dam was built. To accelerate the accretion of chars, a second cross dam was built linking Noakhali mainland and Char Jabbar which rapidly built up nearly 260 sq km of land.
The estuary of the Lower Meghna is usually taken to stretch from the Rabnabad islands to the Kumira coast, a distance of 153 km. The water is, however, saline for half of the year as far north, as a line could be drawn from the middle of Bhola to the north of Sandwip. The estuary of the Lower Meghna may be considered as extending between the Ilsha (Tentulia) and Shahbazpur rivers which together have a width of about 40 km at the sea-face. The volume of the estuarine discharge is not known, but at Chandpur the mean discharge from June to October is around 2.5 million cusec. The mean maximum in this period of the year is about four million cusec. The winter flow is about one-eighth of it although the river is even then several kilometres wide. The low flow is due to the stream's sluggishness. In maximum flood, the Lower Meghna's flow is no less than five million cusec. It is also estimated that from May to October its daily load of sediments is nearly four million tons. The annual load of sediments carried by it is about 1,500 million tons and annual water discharge about 875 million acre-feet (MAF). In comparison, the Congo, La Plata and Yangtse rivers have a total annual flow of 1,022, 636 and 559 MAF respectively. The Lower Meghna, as the major outlet of the combined Ganges, Brahmaputra and Meghna has therefore somewhat less outflow than the Congo, which is second only to the Amazon.
The Lower Meghna (160 km) is measured from the south of Chandpur to as far as the Tentulia. The flow is estimated for a point mid-way between Chandpur and Mehendiganj. The total length of the Surma-Meghna is about 670 km. The length of the Upper Meghna is measured up to Chandpur, but the discharge is measured at Bhairab Bazar.
A larger number of settlements, towns, ports and industries have sprung up on both the banks of the Meghna. Narsingdi, Chandpur, Barisal and Bhola are the district towns that stand on the banks of the Meghna. Kuliarchar, Bhairab Bazar, Chandpur (Puran Bazar), Ramdaspur, Kalupur and Daulatkhan are important riverports and business centres. The Ashuganj thermal power plant and the Fenchuganj fertiliser factory are located on the banks of this river.
The Meghna is a flood-prone river. The bangladesh water development board (BWDB) has implemented the Meghna Valley Project and constructed embankments along the riverbanks. These embankments are protecting greater Sylhet, Mymensingh and Comilla districts from floods. By constructing dams at different places a total of 180,000 ha of land has been brought under irrigation. About 125 km of dams have been constructed in the southern region of Bangladesh under the coastal enbankment project. These are helping to control floods and keep salinity off. These dams are also playing an important role in land reclamation. [Masud Hasan Chowdhury]
See map in surma-meghna river system.