Scarred by saltwater, Madhumati River shows Bangladesh’s larger battle against climate change

Robin Chowdhury is a farmer in a remote village in the southern district of Gopalganj. For most of his life, he has relied on the Madhumati River for fresh water. But rising levels of salt in the river, one of the longest in Bangladesh, are putting both his health and livelihood at risk.

“It’s miserable,” said Robin, a resident of Gobra village in the district’s Sadar Upazila. “We have a fresh water crisis. I’ve gotten sick many times after drinking from the river. It’s so hard to get by.”

Robin isn’t alone. Rising salinity in the river has led to an outbreak of diarrhoea in Gopalganj and Tungipara that has overwhelmed the local authorities. His farm is in trouble too. Many farmers in the area have relied on the river for irrigation, but the high salt levels damage crops and the soil.

The salinity level of the Madhumati River, which flows 190 km through southwestern Bangladesh, has risen dramatically in the past five years. This year, the salinity level in the Madhumati was 2,100 parts per million (ppm), the highest in a decade, according to Dipak Chandra Talukder, an executive engineer of the Gopalganj Department of Public Health Engineering. In 2016, the level was 1,200 parts per million.

Part of this is due to climate change. As sea levels rise, the salt water flows back into rivers, raising their salt levels. This is even worse in the summer, when fresh water levels fall and salt water intrudes further. From March to June, at least 300,000 people in the area face a fresh water crisis.

The area is a microcosm of saltwater intrusion that scars Bangladesh’s southern and southwestern regions and offers glimpses into a larger battle against climate change.

This fresh water crisis is also a health crisis. “The human body can only stand salinity levels of around 600 ppm,” said Dipak Talukder.

Drinking water with higher salt levels can lead to diarrhoea, dysentery, high blood pressure, skin diseases and various other complications, says Gopalganj Civil Surgeon Sujat Ahmed.

He advised the local residents dependent on the river to get fresh water from ponds and deep tube wells, and to boil water before drinking. But this water is in limited supply, and local farmers have already been dipping into that supply for their irrigation needs.

This is echoed by a recent research from the World Bank. While most research has focused on inundation and losses from heightened storm surges, increased saltwater intrusion may actually pose the greatest threat to livelihoods and public health through its impacts on agriculture, aquaculture, infrastructure, coastal ecosystems and the availability of fresh water for household and commercial use, according to the report.

As the salinity of the Madhumati rises, it becomes less viable for irrigation as salt water can reduce crop yields and increase salt levels in the soil, reducing fertility, says Arabinda Kumar Roy, the deputy director of the Department of Agricultural Extension in Gopalganj. He advised farmers to use pondwater, or deep tube wells instead.

But farmers, like Manik Miah and Tarun Biswas from Tungipara, say local ponds and water bodies do not have enough fresh water for their crops, even if they fill them themselves. It is also more costly than using river water.

One way to increase the supply of fresh water is the water treatment plant that serves Gopalganj and Tungipara, according to engineer Dipak Talukder, but more plants must be built in order to meet the water needs of locals.

There is also the matter of environmental damage to consider.

“Salt water is not only harmful to the human body, it is also damaging to crops and the environment,” said Md Muhyminul Islam, an assistant professor of environmental science at Bangabandhu Sheikh Mujibur Rahman University of Science and Technology.

“If this salt water intrusion continues it will damage lives, livelihoods, agriculture and also pose a great threat to the biodiversity of the region.”