Will the Padma (Ganges) Barrage offer a solution to the problem?

From various sources, it is known so far that the Padma Barrage will be constructed at Pangsha in the Rajbari district. Its total length will be 2. 1 kilometers. It will include 78 spillways (water discharge gates, each 18 meters long and 12 meters wide) and 18 underflow outlets (each 18 meters long and 14. 5 meters wide). Additionally, there will be two fish passes.

It is estimated that the water level in the Ganges from Pankha (the entry point of the Ganges into Bangladesh from India) to Pangsha will be maintained at approximately 12 meters, storing around 2. 9 billion cubic meters of water. This water will be used to revive the Hisna-Matabhanga, Gorai-Modhumoti, Chandana-Barasia, Boral, and Ichamati rivers.

Among these, a flow of 7,600 cubic meters per second (cumecs) will be maintained through the Gorai-Modhumoti, and 300 cumecs each in Chandana and Hisna. ''Offtake'' structures will be constructed at the mouths of these rivers for this purpose. The project is expected to be implemented over seven years (2026-2033).

The feasibility study conducted in 2016 mainly focused on the benefits that could result from the barrage. Conversely, the potential negative impacts were either downplayed or completely ignored, such as the issue of siltation upstream due to the barrage.

The study states that when most of the gates of the barrage will be closed for 9 months a year to store water, only 15 per cent of the annual silt load will arrive. As a result, the upstream siltation will not be significant, and the riverbed will rise by just 3.28 feet in 60 years.

Firstly, this claim does not align with the experience at Farakka. Various studies on Farakka show that in some places, the riverbed upstream of Farakka has risen by about 20 feet over the past 52 years.

Secondly, the addition of the 18 underflow outlets in the proposed barrage might have made the study authors optimistic about silt discharge. It is noteworthy that with each outlet being 18X14.5 meters, the total width of these outlets will be 261 meters, which is only one-eighth of the total length of the barrage (2100 meters).

Moreover, Bangladesh's experience shows that theoretical calculations often do not hold in reality. As a result, there is a concern that these outlets may soon be clogged by silt. Being underwater, it would be challenging to clear these blocked passages.

Therefore, the optimistic outlook regarding minimal upstream siltation published in the study may not prove to be accurate. In that case, the upstream siltation would exceed the anticipated amount; the riverbed of the Ganges would continuously fill up, increasing the risk of floods and riverbank erosion. Conversely, due to reduced silt content downstream, the river would break its banks at a faster rate to regain its silt balance. Thus, there is a concern about increased bank erosion both upstream and downstream of the barrage.

More importantly, there is the danger of reduced water flow downstream. While there may be room for debate about the decrease in silt downstream, there is no room for such debate regarding the reduction in water. Because, the amount of water diverted to offset the needs of the Ganges' tributaries upstream would result in an equal reduction in water in the Ganges' branches and the Padma downstream, what in English is called a ''zero-sum game'' for Bangladesh. In other words, while water distribution can be varied upstream and downstream, the total amount of water cannot be changed.

In fact, the feasibility study makes this quite clear. It shows that due to the barrage, the water level will be maintained at nearly 12 meters up to Pangsha. But beyond Pangsha, this height will drop to just 1 to 5 meters depending on the month. Needless to say, this will have severe negative consequences. Yet, there is not a single sentence in the study about the potential impact of the proposed barrage downstream of Pangsha, as if the Padma River ends there!

Unfortunately, this stance of the BWDB mirrors India's attitude toward Bangladesh. We have previously observed that many in India feel that the Ganges ends at Farakka. There might be some justification for such an attitude from the Indian perspective since they are not overly concerned about the impact of Farakka on Bangladesh. For India, it's a ''positive-sum game'' —the more water they can extract, the more they gain, with nothing to lose. But the areas beyond Pangsha are still part of Bangladesh! Shouldn't the impact of the Padma Barrage on these areas be considered during project decision-making?

First, the scarcity of both surface and groundwater from Pangsha to Goalanda will intensify, resulting in reduced agricultural and fish production.

Secondly, the total flow of the Padma beyond Goalanda will reduce. One might argue that the total flow of the Padma might not reduce significantly due to the contribution from the Jamuna. However, it's known that India is continuously working to divert Brahmaputra's water westward under its river-linking project, utilising the Gajaldoba Barrage on the Teesta.

Further north, China's construction of successive dams on the Brahmaputra in Tibet is also reducing the amount of glacier meltwater. As a result, problems are already arising at the source mouths of rivers generated from the Jamuna, such as the Louhajang, Dhaleshwari, and Kaliganga. Due to the Padma Barrage, the flow of the Ichamati, Arial Khan, and other branches of the Padma, as well as various rivers in the Barisal division, will reduce beyond Goalanda.

Thirdly, reduced water flow in the Padma will also result in decreased water in the Meghna estuary, consequently allowing salinity to penetrate further inland. Given the low land elevation in the northeastern Haor region, salinity from the Meghna estuary could easily reach up to the Haor area.

Therefore, it's clear that advancing the Padma Barrage project without considering the multifaceted negative impacts downstream of Pangsha will reflect a one-sided evaluation of the project, as well as increase regional disparities.

Notably, by implementing the Padma Barrage Project, Bangladesh will, in effect, fulfill India's desires. India has always wanted Bangladesh to construct the Padma Barrage, as it could then argue that whatever water Bangladesh receives is sufficient to meet all its needs (through the Padma Barrage).

In this way, India would escape from accusations by Bangladesh concerning the share of the Ganges water. That's why India has been so eager to provide financial and technical assistance to Bangladesh for constructing the Padma Barrage. Hence, how constructing the Padma Barrage signifies Bangladesh's independent foreign policy is puzzling.
Thus, Bangladesh should adopt an alternative strategy to address the issues of Ganges-dependent areas, encompassing two aspects: regional-international, and domestic.

In the regional-international arena, first, Bangladesh must intensify efforts to secure its share of the Ganges from India. The initial step toward this goal would be signing the 1997 UN Convention on the use of international watercourses. It was previously suggested that the Awami League government had not signed the convention due to its submissive policy towards India. However, even the subsequent caretaker government did not sign the UN convention despite signing many agreements.

Ratifying this convention will serve as evidence of the current BNP government's independent foreign policy. This convention provides multiple protections for the interests of downstream countries. Regardless of whether India recognises it or not, signing the convention will empower Bangladesh to engage in discussions with India from a superior moral and legal standing, supported by the UN.

Secondly, as the 30-year term of the Bangladesh-India Treaty signed on 12 December 1996, regarding sharing the Ganges water, will soon end, Bangladesh must begin to prepare for negotiations with India concerning its renewal. It's notable that the Mujib-Indira Treaty of 1974 provided a provision for a minimum of 40,500 cusecs water for Bangladesh during the dry season. The Ganges Treaty signed during former President Ziaur Rahman's tenure in 1977 guaranteed 27,000 cusecs for Bangladesh. However, the current treaty does not guarantee a ''minimum flow. ''

Hence, the guarantee must be re-established in the renewed treaty and set at a minimum of 35,000 cusecs. To save the Sundarbans, this flow is necessary. Accordingly, attempts must be made to secure the support of all relevant international circles, including UNESCO. Efforts should be made to privately contact and garner the support of environmental and river-conserving groups within India.

The second aspect of the strategy to solve the issues of Ganges-dependent areas will focus internally on altering attitudes and behaviours towards rivers. A paradigm shift from the current approach of enclosure to an open approach towards rivers is needed. The BWDB should be completely restructured by replacing supporters of the enclosure approach and those involved in corruption.

The new BWDB's task will be to free all rivers across the country, especially those in the southwest, from all types of sluice gates, flap gates, regulators, narrow bridges, culverts, etc. All the rivers must be liberated from encroachment according to CS maps, and the encroachers must be penalised.

All polders should be opened so that river water can freely enter and exit, freeing millions of people from waterlogging and water entrapment. All embankments should be converted into seasonal embankments. This comprehensive reform initiative will ensure the unimpeded flow of Ganges water through the Sundarbans to the Bay of Bengal, thereby revitalising Ganges-dependent areas.

Notably, the utility of canal-based irrigation on the surface has diminished over time. Shallow tube well-based irrigation has played a pivotal role in agricultural production in Bangladesh in recent times. For this, the renewal of groundwater is essential. Revitalising rivers will aid in achieving this goal. There's no need for a Tk 640 billion project for this. Due to the mega projects of the previous Awami League government, Bangladesh's economy is already burdened. The aim should be to achieve greater outcomes at lower costs.

If Bangladesh advances along these two avenues—regional-international and domestic—the revitalisation of Ganges-dependent areas will be assured; the Padma River will be safeguarded from distortion; regional disparities will not worsen; the Meghna estuary will remain healthy; and a positive ecological shift in Bangladesh's environmental conservation will occur. Therefore, the government should refrain from unilaterally proceeding with the Ganges barrage project; more time should be taken to reach a decision, providing the public an opportunity to voice their opinions. It must be remembered that, ultimately, it is the people who will repay the loan for this project.

#Dr. Nazrul Islam is a professor at the Asian Growth Research Institute and former head of development research at the United Nations.

*The opinions are the author's own.

#This article, originally published in Prothom Alo print and online editions, has been rewritten in English by Rabiul Islam