What it's about:
Bangladesh has battled against rising sea levels for decades. The vast river delta suffers from annual river flooding, as cyclones blowing in from the Bay of Bengal cause banks to burst.
To combat the water threat, the South Asian country has developed a range of defence mechanisms, including storm shelters, salt-resistant crops and 139 polders near the coast to protect farmland from flooding.
But the polders are now sinking rapidly and struggling to keep out the tide, forcing Bangladeshis to reassess their approach to tackling the water crisis, according to an article funded by the Pulitzer Center.
The idea of dismantling some of the barriers, and allowing the water in, was first suggested by U.S. geologist Steve Goodbred in 2009. Controlled flooding could result in long-term benefits, he argued after discovering that land just outside the polders had risen 10 centimetres above high tide because of natural sediment deposition.
Farmers in southwest Bangladesh started experimenting with Goodbred’s proposal, cutting gaps in the banks and letting water in. The results were clearly visible: within a few years, the land inside the polders had risen by over a metre and the waterlogging ceased.
Government officials quickly followed suit, adopting a strategy of “tidal river management”. In 2015, a construction crew cut through the bank of a polder surrounding the Kobadak River, turning the area inside into a wetland.
The results appear promising. Parts of the beel have gained half a metre of land and the river channel has deepened, allowing the water to drain from surrounding polders.
Why it's noteworthy:
By 2100, sea levels around Bangladesh are projected to rise by between 0.4 and 1.5 metres, and extremely high water surges - which today occur once a decade - are predicted to take place up to 15 times a year, according to the Pulitzer Center report.
The country’s current defences are unable to keep the water out. In 2009, a huge polder collapsed when Cyclone Aila struck. The disaster killed more than 150 people and left Bangladesh with over $270 million in damages.
Bangladesh has realised that to prevent future crises, it must learn to accommodate the water pounding its coastline. Controlled flooding could provide the solution the waterlogged country has been seeking for decades.
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