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Robbing land from the sea March 25th, 2018 by

The low-lying Netherlands is famous for its polders, the land behind the dikes, reclaimed from the sea. Beginning about 1000 AD, people made dikes, or earthen dams, to protect communities from flooding. At first the water was simply drained through canals, but with time the land in the polders subsided, and by the 1400s water was being pumped out with windmills. Thanks to hard work, investment and some clever engineering, people still live in and farm the polders.

Much of Bangladesh is also right at sea level and densely populated. So why doesn’t Bangladesh have polders too? I wondered out-loud during a recent visit last October.

“But we do! Bangladesh has many polders,” my colleague Salahuddin retorted. He explained that there was a string of some 123 polders over much of southern Bangladesh, an area where several large rivers cut the delta into finger-like strips of lowland.

The polders were built between the 1960s and the 1980s, first by the provincial government of East Pakistan, and later by the Government of Bangladesh, after independence from Pakistan in 1971.

Each polder is ringed by a low earthen embankment (basically a dike), sometimes just two meters high and made by hand. The roughly oval-shaped polders are dozens of kilometers in circumference.

The Bangladeshi polders are drained by an ingenious network of canals, radiating like veins from the center of the polder to the edge, where the flow of water is controlled by a sluice gate in the embankment.The sluice gate is a concrete structure with metal doors that can be raised by a hand-crank to let the water out during the rainy season, and lowered during the dry season to keep out the saltwater.

Originally the wetlands of the delta region had been sparsely populated by fisher-farmers who grew low yielding rice varieties that tolerated brackish water. The polders soon became attractive places to live and settlers trickled in. The people who were born in the polders tended to stay there and so populations increased.

Some of the polders have benefited from some sort of project, and have been reasonably well managed. By 2018 the better polders are like gardens, with comfortable farm houses surrounded by shimmering green rice fields.

The polders have had their share of troubles. Sometimes one of the rivers changes course, depositing a bank of silt next to the sluice gate, so the water inside the polder cannot drain out.  Other problems are man-made. Loggers float timber down the canals, and when the logs reach the sluice gates, the workers take the easy route to the river. Instead of hoisting the logs around the sluice gate, the loggers force the timber through the delicate metal gates, twisting and denting them so they no longer open and close. Wealthy, powerful people sometimes block the drainage canals to raise fish in them. Or they string nets over the canal to catch fish. But this slows down the flow of water, allowing silt to settle and eventually block the canal. The canals are as wide as a highway, and can be just as difficult to maintain. So once the drainage canal stops working, villagers are unable to open them up again without help from outsiders.

The polders are essentially a government mega-project, which sounds at first like a recipe for disaster. But as one drives along the top of a polder embankment, the muddy river on one side and the tidy green fields and villages on the other, it is hard to ignore the fact that the government got something right.

Ironically, country that is flooded during the rainy season may be completely dry a few months later. Various initiatives are now promoting dry-season irrigation for high value crops besides rice, and the farmers in the polders are avidly buying motorized pumps. In many places the rich, black earth inside the polders is now producing two or three crops a year of rice, mung beans, mustard, watermelon and vegetables.

Such changes in the farming system are creating more wealth for the farmers in those polders that are well run. But it will take collaboration, for local government to protect the canals and embankments, for the private sector to provide farm supplies and buy the produce and especially for innovative farmers, to continue re-inventing the agriculture of this marvelous, human-made environment.

Further reading

In characteristic modesty it was some time before my friend Salahuddin told me that he had written his masters’ thesis on the polders of Bangladesh.

Salahuddin, Ahmad 1995 Operation and Maintenance of Small Scale Flood Control Projects: Case of Bangladesh Water Development Board. Master’s Thesis: Institute ofSocial Studies, The Hague.

See also Paul’s blog from last week on coastal Bangladesh: Floating vegetable gardens.


I am indebted to Md. Harun-ar-Rashid, Guy Jones and many others for enlightening me about polders on a recent trip to Bangladesh, supported by the Blue Gold Program, with funding from the Embassy of the Netherlands. Thanks to Harun-ar-Rashid, Ahmad Salauddin, Paul Van Mele and Eric Boa for reading and remarking on previous versions.

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