Defence against sea level rise
There seems to be no doubt that in about 50 years' time the sea level is going to rise dangerously to swamp Bangladesh, killing and displacing millions of people and cause enormous damage to the delta-land. This problem is much more serious than the requirement of building a Rapid Mass Transit System (about 60skm in length) in Dhaka within 20 years at an estimated cost of about $100 million dollars per kilometre, which is well publicised and apparently in hand of the planners and the government. Although I am not an expert in offshore civil engineering matters, I cannot escape reading about extensive building of 'island worlds' in the shape of a 'palm tree' and the 'map of the world' around the coast of Dubai and the 'tulip' in the North Sea along the Netherlands coast. The latter is proposed to be a defence against rise in sea level due to global warming. So the technology for similarly holding back the sea in Bangladesh coast is available and the costs could and should be provided by the world's rich countries through IMF and WB for this purpose. Two 350 km long and 100m wide sea walls projecting about 3m above the highest calculated sea level, separated by about a kilometre of water between the sea-walls can be constructed from Teknaf to Talpatti (in Satkhira district). Inland seaports can be constructed within these walls with proper locks, and deep seaports and naval defence establishments can be constructed outside the outermost wall. Wind turbines can be judicially placed along these sea walls to generate electricity, dredge the basin and rivers, and windmills can pump out excess water from between the walls to the sea to keep the basin water level low. Many other economic uses can be made of the basin area enclosed by the walls and between the wall and the land mass, and the silt reclaimed from the rivers whether upland or near the basins can be used to make the general level of delta-land higher. These possibilities must be seriously investigated by Bangladesh authorities, in conjunction with neighbouring countries if necessary. Exploration and feasibility studies must be carried out without delay by experts in the field. In my opinion the cost per km would not be out of proportion to what is estimated for the Rapid Mass Transit System already proposed for Dhaka city and its surroundings.
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