A Bliss in the Bay of Bengal

Bangladesh is a deltaic country. The combined flow of the Jamuna, Padma and Meghna merged at Chandpur-  the spectacular river flow to the Bay of Bengal is the third highest of the world. After Chandpur, combined flow moves down to the Bay of Bengal through four principal mouths- Tetulia, Shahbazpur, Hatia, and Bamni. Many islands: Hatia, Sandip, and Nijhum Dwip are there. Many land mass are still in the way of being formation. Delta Plan 2100' gives us guide lines- how to reclaim new land from the sea.

The Meghna estuaries is dominated by many rivers, huge discharge of river water with high sediment, many islands, chars and sand bars, a shallow and wide water bodies, strong tidal actions and tropical cyclones. The adverse effects of global warming are increasing cyclone, sea level rise and saline water intrusion. Through minimizing land erosion and accelerating natural land reclamation- the country could expand the coasts beyond its original borders. Bank protection could save new alleviated lands from erosion.

Land reclamation is a process of creating or restoring new lands from the ocean in the face of erosion of char lands. Reclaiming of new land is fusible, as coastline of Noakhali have natural land formation process. Reclamation could be achieved through: a. bank protection to save alleviated char lands, b. polder by embankment/dike with drainage and irrigation, c. accelerating siltation and natural land reclamation by cross dam, d. artificial land reclamation by dam in sea areas.

Almost 2.4 billion tons of sediment passes to the Bay of Bengal each year through the Meghna. These coastal regions are still in formation of new char lands within river mouth. The char land formation is a welcoming situation. Many people make a living under those hazardous conditions- suddenly people are displaced

The coastline of Noakhali is best for reclamation of lands. The connection channel between Sandwip and Noakhali mainland are gradually silted up and creating new char lands. 'The Sandwip-Urir Char-Noakhali multi-disciplinary Cross Dam' project will give rise to more new lands. The cross dam would have only favorable effects on more sedimentation and will not block drainage of channel. A coastal land formation mega-project' could be taken including many Islands: Urir Char; Sonar Char, Swarna dweep, Char Fasson and other Islands at Bhola.

The coast-line configuration in the Meghna estuaries plays a role for building strong cyclones. Most areas are without tidal control- cyclone and storm surge with 5-7 ft high can damage ecosystems and kill many people and their livestock during pre and post monsoon period. During wet season, there is high tide - thus modern rice could not be cultivated in many coastal areas in wet season. During dry season- river discharge is lower than monsoon; saline water entire - paddy/crops could not be grown in high saline areas.

During the monsoon, a large volume of water and sediment comes through the Meghna estuary. At the same time- daily high and low tides comes from the sea. A tidal bore is a situation- where the flow of water from the river into the ocean reverses. Bores cause an abrupt increase in salinity and suspended sediment. The narrow channels at the south of Sandwip Island are trapping sediments around Urir Char and nearby islands to built new char lands.

Those alluvial low char lands below the sea level are prone to erosion. Land erosion is common natural phenomena. Only 40% of the char persists more than 5-6 years. If char is formed in a location; high flow of water from char side hit other sides- trends to erosion in other side.

The char lands economy is based on agriculture, fishing and livestock rearing. Education, health, and other support are minimal. There are lack of proper navigation, culvert, roads, embankment and drainage.

 As like Netherlands, large coastal embankments/dike and polders could be built in our coastal belt to restrict flow of tidal water. The research is needed on “cyclone and tidal hit protection measures (dike or dam). Reclaiming new lands is feasible, as more silt are being carried. Water reservoirs could be formed through surrounding low-lying areas by constructing dam (wall of reservoir) with land reclamation, rivers dredging, diking and poldering, drainage, irrigation and de-Stalinization. Hydro-dynamic modeling (flow, water depth, wave height) in the Meghna from Chandpur point to estuaries could be done.

Then, an integrated mega project could be implemented having 8 sub-projects: 1. Protecting entire sea site and char-lands from erosion by sea-wall 2.  Dredging and river training 3. Full tide control using dike/embankment/ polders with irrigation, drainage and de-Stalinization, 4. Natural & artificial land reclamation by dam construction 5. Sea side constriction of fresh water reservoirs for irrigation 6. Mangrove forestation for protection of cyclonic hit 7. Culverts & road constriction, navigation and drainage. 8. Human statement with good physical environment and eco- tourism.

Many islands including Urir Char were formed by the sediments derived from river system. The connection channel between Sandwip and Noakhali mainland are gradually building new char lands in a slow natural process. Reclamation of new areas is possible through rapid accreting natural reclamation process. 'The Sandwip-Urir Char-Noakhali multi-disciplinary Cross Dam Project' has been constracted to divert  flow into the areas between dam and shoreline for accelerating natural land formation -  will trap more sediment around Urir Char islands to give rise new lands.

In the Meghna river estuaries, huge quantities of sand have been deposited. A trailing suction hopper dredger could dredge sand/mud from the river beds for maintaining navigable waterways and the slurry of dredging could be pumped into pipes to deposit on nearby low-lands to form new lands. Using drugged material/sands- wall (dam) of fresh water reservoir could also be constructed and all the char lands could be surrounded by sea wall/dike/dam to form large polders and to keep tide/cyclone waters out.

Capacity building for char-land recovery is also important. Natural siltation, coastal reservoir and land reclamation could be expedited by cross dam/dike. A dike could protect the land from tidal flooding. A dike has water only in one side; a dam has water in both sides. Sea site dam/dikes and new lands could be built by transporting dredging mud from sea-beds to other areas using suction dredger. The coastal reservoir could be separated from the sea by building a surrounding dam (wall) in sea sites.

Entire sea site and char-lands protecting from erosion is must - strong dike/dam using more stones could provide high protection. The present coastal dike/dam/embankments have less effective lives in the face of cyclone hit. A pre-design dam construction and land reclamation process includes: site investigation, identifying viable fill/sand and hydrographical data. The dam construction works could be started from sea site. Central core of dam is made by an impermeable concrete - concrete and soils are then transferred to the dam areas. A gravity dam is usually made of concrete.

Accelerating natural land reclamation by cross dam and artificial land reclamation by filling-up the sea side areas using dredged materials is possible. Char land protection can be achieved by strong embankment/dike. But, land erosion is common natural phenomena there. River training and dike could save lands from erosion. The major objectives of river training are: safe passage of flood water without overtopping the banks by stabilizing river channel. River training in coastal rivers is needed for mitigating flood & tidal action.

Hatiya is an island at the mouth of the Meghna. Hatiya upazila could be used as a separate district head quarter for developing all the Islands. 'The Meghna Estuaries Development Authority' could be formed for implementing multi-purpose ‘coastal land reclamation project’. All the Islands will be connected with Hatiya by sea boats and ships. Navigation, drainage, culvert and road construction and eco-tourism could be expended. A distinctive image including hotels and mortals with a domestic airport could be developed for tourism, as like the Marina Bay of Singapore.

An environmental friendly coastal agricultural policy could be built up- emphasizing multipurpose use of char lands. Human statement with crops, fresh water fisheries, marine fisheries, buffalo and ships raring might be feasible. With tide and salinity control- salt tolerant Aman variety BRRI dhn78 could be grown in tidal saline prone areas. Climate resilient high-yielding rice variety development is needed. A regional station of BRRI and a 'Coastal Agriculture Research Institute' could also be built-up in an Island for developing salt tolerant crops.

Through accelerating land reclamation process- the country could expand coast borders for human settlement. It might open door to use char-lands in agriculture, and coastal tourism etc. The fresh-water reservoir will support drinking water and fisheries- fresh irrigation water could be used in 1 million hectares of coastal fallow dry season paddy lands. A group of talented engineers could work in land reclamation project- our concern lies with 100 years under ‘Delta Plan 2100’. With implementation of 'Land Reclamation Project' - Bangladesh could be an emerging economic power of 21st century.


Dr. A S M Masuduzzaman
is a Chief Scientific Officer,
Bangladesh Rice Research
Institute, Gazipur.