Barrages vs reservoirs: Bangladesh's options in ensuring water security

After the heavy rainfall and consequent opening of Dumbur dam in India's Tripura, followed by the devastating floods in Feni, Cumilla and Noakhali, social media was flooded with posts proposing that Bangladesh build counter dams on the transboundary rivers that would supposedly hold back the water, preventing the floods.

Although this idea, as is, does not seem feasible, the idea of building a barrage on the Padma River to divert enough water to the southwestern part of Bangladesh has been in discussion for a long time. 

The Bangladesh part of the Teesta River also has a barrage project which facilitates supply of irrigation in the northern districts. Quite a few other Bangladeshi rivers also have dams and barrages on them as well, such as Karnaphuli and Feni.

Now the question is, in the context of climate change and associated increased precipitation as well as the withdrawal of water by upper riparian states–specially India–from the transboundary rivers, how will Bangladesh cope with the situation when the country suffers from both floods in the monsoon, and water scarcity in the lean season?

Experts differ on the proposed solutions.

"There are a lot of baors and beels (wetlands) in the southwestern region. They can be used as reservoirs. They should be maintained in a way so they can hold the monsoon water without polluting it."

Mohammad Azaz, chairman, River and Delta Research Centre

One of the much discussed projects is Ganges barrage project of Bangladesh. Due to the reduced freshwater flow from the Padma river caused by the Farakka Barrage in India, the southwestern part of Bangladesh suffers from increasing salinity intrusion, a scenario exacerbated by global warming and consequent sea level rise.

This is why the need to restore freshwater flow in the lower riparian rivers in the south west has been felt over the decades. 

Proposal of building a barrage on Padma river goes way back. In 1963, a consulting firm from New York,Tippetts-Abbett-McCarthy-Stratton,  proposed to the then Pakistan government to construct a counter-barrage to hold water in the monsoon and supply it to the Gorai and other rivers in the lean period.

In 2009, the Hasina government commissioned a feasibility study for the Ganges Barrage construction in Pangsha Upazila in Rajbari. It was completed in 2013, costing US$5 million (Tk43 crore). Construction was supposed to begin in 2014 and end in 2020. 

According to reports, Bangladesh waited for years to get India's 'clearance' to begin the barrage construction. In 2016, an Indian technical team even visited the Ganges Barrage site, but the Bangladesh government never got the nod. 

Reports also indicated that India was concerned that the proposed barrage in Bangladesh would adversely affect India.

The proposed project had a reservoir to augment the flow of water, in both dry and wet seasons, over the areas dependent on the flow of Padma. Some feared that the barrage could exacerbate the flooding in India.

In 2017, upon her return from Delhi visit, Sheikh Hasina called the project "faulty and suicidal." The government also announced that it would conduct fresh studies to find an alternative site and design for the project.

Earlier, China had also expressed interest to provide both financial and technical assistance to the project.

But none of these happened.

Most of the experts and activists were against constructing a barrage saying it would exacerbate the silting and destroy the river.

Mohammad Azaz, chairman of the River and Delta Research Centre (RDRC), still thinks it is a bad idea. The researcher and activist is in favour of using natural reservoirs to store water for the lean period.

"There are a lot of baors and beels (wetlands) in the southwestern region. They can be used as reservoirs. They should be maintained in a way so they can hold the monsoon water without polluting it," Azaz said.

He also mentioned that 67% of our land becomes wetland in the country. Much of it is transformed into farmland in the dry season, but enough beels still remain under water. The beels are mostly silted. If they are maintained, they can hold enough water. 

The researcher added that the wetlands are often encroached and filled for various purposes. He said this must be stopped.

"The beels cannot be filled. No one should be allowed to build houses on them. By preserving the wetlands we can mitigate the freshwater crisis in the lean season to a large scale."

Talking about the groundwater shortage in the northern areas, such as Barind Tract, The RDRC chairman stressed that we need to continue putting in efforts to ensure that the rivers get their fair share of water, and the canals connected to them need to be excavated. The canals will play a role to carry and distribute the monsoon water, he said. He also said that the 'water mafia' should be stopped.

"In the last 15 years, the water mafia has taken control of much of the groundwater sources in those areas. They own all the deep tubewells. This needs to be amended," Azaz said.

After being appointed the adviser to the Ministry of Environment, Forest, Climate Change and Water Resources, environmental lawyer and chief executive of Bangladesh Environmental Lawyers Association (BELA) Syeda Rizwana Hasan also talked about creating and maintaining water reservoirs instead of building barrages.

Can it solve the shortage of freshwater flow down south to hold back saline water? Ainun Nishat, water resource specialist and professor emeritus of BRAC University, says constructing the Ganges barrage is imperative.

"Under the Ganges water sharing treaty, we get 30-35 thousand cusec water through the river. 10-15 thousand cusecs of water from that should be diverted to the Bagerhat-Khulna-Satkhira region. For that we need an infrastructure – a barrage," the professor said.

"All the plans and designs of the barrage are ready. We need to complete the project on an urgent basis," he said. "There is no need to create any canal for this;  the existing river network of the area can be revitalised and used to distribute the water."

Professor Nishat said that while water sharing needs political will from all the parties, its management is often technical. He stressed the amalgamation of political and technical factors and knowledge in solving the water crisis. 

India has built many dams and barrages on the transboundary rivers flowing through Bangladesh, but has signed a water sharing treaty on only one river. The southwestern area suffers from the acute freshwater shortage despite the The Ganges Water Treaty. 

In 2026, the 30-year treaty will expire. No talks have been held over renewing the treaty. Other rivers, including the Teesta, remain outside any deal, allowing India for withdrawal of water on its discretion. 

The last 15 years has seen political concessions being made on Bangladesh's part without securing the fair share of river water. At a point, the issue of river sharing got totally excluded from the bilateral meetings and summits.

The discussion about alternatives such as holding water in reservoirs started during the Hasina government, when it was clear that India was not interested in sharing water of the transboundary rivers with Bangladesh in the lean period.