Higher-magnitude flood frequency increases in BD

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Staff Reporter :
The frequency of floods with higher magnitude have increased in Bangladesh at an alarming level, sending alerts to scientists who are now asking for immediate government interventions to save future crop damage.
Between 1972 and 2014, Bangladesh saw flooding with higher magnitude only in six years – 1974, 1987, 1988, 1998, 2004 and 2007.
Now the most worrisome news is that higher magnitude floods have ravaged the country for six consecutive years, starting in 2015, submerging more than 22% of the country’s total land.
A just-released study, conducted by a group of rice scientists, has drawn a conclusion that if the annual monsoonal floods and flash floods in Bangladesh drown land areas more than a 22% threshold level, rice production decreases at a rate of 70 tons per square kilometre.
Taking flood data from Bangladesh Water Development Board (BWDB) and other sources, the research group from Bangladesh Rice Research Institute (BRRI) shows that land areas more than the threshold level have been submerged in all six years
consecutively – in 2015, 2016, 2017, 2018, 2019 and 2020.
It is a new trend, they note, that never happened in the past as the country witnessed floods with higher magnitudes only six times in all those years between 1972 and 2014.
The researchers, who belong to the country’s premier rice research institute, found 10% loss in rice output due to this year’s repeated flooding that well crossed the threshold level.
They expressed a sense of urgency on the government taking immediate steps to excavate canals and re-excavate all filled-up and silted-up water bodies in flood-prone zones, in efforts to save crops from damage by recurring floods.
Experts say floods these days are submerging more croplands due to non-dredging of silted-up rivers. They say rivers overflow and submerge more areas during the height of monsoon, with silted-up canals and other water bodies losing capacity to hold waters.
The BRRI scientists say if the flooding of land remains within the band of 22%, farmers incur some loss but get better returns in post-flood cropping season with soil getting fertile.
“But, when floodwaters submerge more than 22% of land in the country, rice output decreases, on average, by 70 tons per square kilometre area,” states research findings.
The researchers, led by BRRI Director General Dr Md Shahjahan Kabir, also recommended continued government incentives to farmers in terms of farm mechanization and seeds and fertilizers.
To give the flood-affected farmers some support, they called for the government to ensure proper irrigation services from all state-run irrigation projects, a farmers-friendly paddy procurement policy and halting rice import in domestic paddy harvesting seasons.
The five-strong BRRI core research team members are its Director Dr Md Abu Bakr Siddique, head of its Agricultural Statistics Division, Dr Md Ismail Hossain, and three senior scientific officers – Md Abdur Rouf Sarkar and Dr Mohammad Chhiddikur Rahman from Agricultural Economics Division and Md Abdul Aziz from Agricultural Statistics Division.
Every year, on average, a fifth of cropland is affected by floods in Bangladesh. As a result, some crops are lost due to deluge, but in return, farmers also gain from increased productivity from the fertile alluvial soil derived from sediments.
But in years when repeated floods and flash floods submerge lands beyond 22% threshold level, Bangladesh substantially losses its annual rice output.
The researchers’ team, whose primary goal was to assess flood-induced crop losses in just-harvested Aman paddy, stumbled upon the worrisome findings that since 2015, floods in Bangladesh have been submerging more lands, thereby posing a threat to future food security.
With an annual output of 36 million tons, Bangladesh is world’s third-biggest producer of rice, after China and India.
Thanks to the population rise and rice-centric dietary habits, Bangladesh requires to grow an additional half a million tons on top of previous year’s output just to maintain the same level of self-sufficiency. But natural disasters like floods, cyclones and droughts often compel the country to rely on imports to bridge the demand-supply gap.
Bangladesh’s food department floated five international tenders in the last one month seeking to import 250,000 tons of rice to replenish public granaries. The government is anticipating that the import volume may hit half a million tons this fiscal year.
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