Although Bangladesh is a ‘river nation’, most of its rivers originate outside the country. 80 percent of the rivers flowing through Bangladesh originate from a neighboring country; especially India. Because of this, the flow and availability of water has become a complex and risky issue for Bangladesh. This is compounded by the pressures of rapid urbanization, agriculture, and global warming.
A recent analysis has shown that four of the 10 major rivers flowing through Bangladesh are no longer within their normal and safe operating limits. This means that the water flow in these rivers is not even at the minimum level required for river-based society and nature. These four rivers are the Padma, the Old Brahmaputra, the Gorai and the Halda. As a result, not only is the supply of safe food and water at risk, but the livelihoods of millions of fishermen, farmers and ordinary people in the region are also at risk. The flow of water in the remaining six rivers is also dangerously decreasing. The main reason for this is the construction of dams, hydroelectric projects and large-scale water extraction for agricultural purposes upstream.The concept of a river’s Safe Operating Space was introduced by scientists at Stockholm University in 2009. It states that there are a total of nine environmental limits, including global warming, water use, and biodiversity loss, that become dangerous for humanity if crossed. An updated study published in 2023 said that the world has already crossed six of the nine limits.
Bangladesh is one of the world’s largest and most densely populated deltas, home to about 170 million people. This research on the safe operating limits of rivers is therefore very relevant. As the demand for water from rapidly growing cities like Dhaka has increased, so have the pressures on food, fish, and world-renowned biodiversity-rich forests like the Sundarbans.
The flow of Bangladesh’s rivers has been steadily decreasing over the past three decades in all seasons except winter. Analysis shows that existing political agreements have failed to address this problem. Despite the Ganga Water Sharing Treaty signed in 1996, the ‘health and social dependence’ of the Padma River is critically endangered today. The rivers of this region have been the driving force behind the culture, environment and economy of South Asia for thousands of years. Not only humans, but many animals that depend on the rivers are also under threat today. For example, the hilsa fish, which is popular for its taste and tender texture and provides about 12 percent of the country’s total fish production. But this fish is now extinct there due to reduced water flow in the upper reaches of the Padma River.
The salinity of the Gorai River has increased due to the withdrawal of excess water through the Farakka Barrage in the Indian state of West Bengal. 
A normal river needs a balance between salt and fresh water. But as the river’s flow has decreased, salinity has now increased dramatically in coastal areas. This is affecting freshwater fish farms, agricultural production, and aquatic animals like the Padma dolphin.
The existence of the Sundarbans is under threat today due to the downstream flow of the river and the increase in salinity. If this forest is destroyed, not only the regional climate of Bangladesh but also India and Nepal will be disrupted. At the same time, a huge amount of carbon stored in the forest will be released into the atmosphere, which will further accelerate climate change and the melting of the Himalayan ice.
The path to overcoming this problem is not easy. We need to work together across national boundaries and ensure sustainable river management. International support and fair agreements are also needed to ensure that rivers remain within their safe management limits and that river-dependent ecosystems survive.
The rivers flowing through Bangladesh’s delta region flow not only through India but also through China, Nepal, and Pakistan. The political realities of these countries make transboundary agreements difficult, even though they could pave the way for meeting the water needs of 700 million people.
Yet there are some hopeful examples. For example, the Mekong River Agreement between Cambodia, Laos, Thailand and Vietnam is a viable model that could be followed by bilateral or multilateral agreements with India and Nepal on the Ganges and China and Bhutan on the Yamuna.
One possible solution could be a ‘tax-based water sharing system.’ In this, the country that uses more water pays more tax and the revenue is shared among the other partner countries. However, this agreement should be based on the historical flow of the river-not on current dams or projected future flows.
On the other hand, stopping deforestation, diversifying land use, and restoring wetlands will increase resilience to climate crises such as floods and droughts and ensure water security in the Bangladesh delta region. Finally, ensuring safe management limits for rivers means securing the future of our society.