Shrimp aquaculture activities weakened the embankments in the coastal regions, which in turn left the polders vulnerable against tidal surge during cyclone Amphan, locals and disaster management experts say.
Polders -- a name borrowed from the Dutch which refers to low-lying land surrounded by mud walls -- were created by the Dutch in the coastal belt of Bangladesh in the 1960s with a view to protecting farmlands from saline water intrusion. There are 139 polders in the country at present, with 5,700 kilometre dikes.
However, in the 1980s, when the World Bank and other development agencies funded and promoted shrimp aquaculture in Bangladesh, shrimp farmers started to cut gaps in the embankments to allow saline water inside the polders.
Two consecutive cyclones that hit Bangladesh in 2007 and 2009, respectively Sidr and Aila, devastated the already weakened embankments. Cutting the embankments is strictly prohibited.
There are ill-maintained sluice gates on the polder dikes, but they are inadequate for the large number of shrimp farms. Therefore, shrimp farmers continued to place pipelines boring holes through the dikes.
This puts embankments in danger, Ataur Rahman, a local resident of Satkhira's Shyamnagar upazila told The Business Standard. Around 60-70 percent land of Padmapukur union, where Ataur lives, has been flooded by cyclone Amphan.
Three days after the cyclone, he had to move his family to Khulna city, as his home remained under saline water with no immediate respite in view. Moreover, more water is now entering Ataur's polder due to the ongoing spring tide.
"When water is released from shrimp farms, they wash away mud from around the embankments, and weakens them," said Ataur. Also, where there is saline water, mud crabs thrive there and dig holes in the embankments, further weakening those, Ataur added. Water rushes in the polders through breached parts during storm surges, but does not go out easily.
Mentioning a study conducted by ThinkAhead Bangladesh, Khaled Hossain, a disaster management expert based in Dhaka, endorsed Ataur's views. Khaled said a comparison of after effects of cyclone Aila on Barguna district's Patharghata upazila and Bagerhat's Southkhali union of Sharankhola upazila evidently suggested that shrimp cultivation has a negative impact on the embankments.
"We took a small group of locals from Southkhali to Patharghata, and a group from Patharghata to Southkhali. As we asked them to observe and identify the possible causes as to why Patharghata was less effected by the tidal surge, they all identified shrimp cultivation practices as a reason behind eroded embankments in Southkhali," Khaled said. Water surge does more harm than wind during a cyclone, he explained.
After Sidr and Aila, no serious repairing was carried out to the damaged embankments, so they breached again in Amphan.
Although Ataur Rahman and his likes want shrimp farming and saline water intrusion are stopped, there is little resistance against the shrimp farmers. Partly because leasing out farmlands to shrimp farmers pays better than rice cultivation, and also because shrimp farmers are often very powerful.
But that has not always been the case. In the past, people in several polders resisted attempts to open polders to saline water for shrimp aquaculture. In 1990, people of polder 22 launched a movement against a local shrimp boss when landless leader Karunamoyee Sardar was shot and killed. This polder has remained shrimp-free for a long time, and after cyclone Aila, people of this polder reported a little or no salinity intrusion from storm surge.
Gawher Nayeem Wahra, convenor of Disaster Forum, however,opined that blaming shrimp farmers alone will shift the focus from the governance issue.
"This is an overall governance problem. The embankments have been in damaged and fragile state for a long time, why were not those taken care of in time?" Gawher questioned. He added that preparation for a cyclone is not limited to relief distribution.
"We were not prepared. The embankments had collapsed few hours before the cyclone struck with full force."
Nayeem Wahra suggested that people are given the ownership of the embankments. Then, they will maintain those embankments themselves. He also cited the example of an eight-kilometre-long embankment in Charfassion under Bhola district that people have been residing on and maintaining for 20 years.
Meanwhile, after Amphan, people in several locations in Khulna and Satkhira have joined hands to repair devastated embankments themselves.