New Age, July 15, 2009
BANGLADESH is the lowest riparian country of more than 53 trans-boundary rivers. Four-fifths of Bangladesh is made up of the combined delta of the Ganges, Brahmaputra, Meghna and Barak river systems – one of the largest river basins in the world. India has 400 storage dams of various sizes and the major reservoirs have a total capacity of 2,221 billion cubic feet. Upstream diversion due to the Farakka Barrage on the Ganges in India has adversely affected the hydrology, river morphology, agriculture, domestic and municipal water supply, fishery, forestry, wildlife, industry, navigation, public health and biodiversity in north-western districts of Bangladesh. Now India has started another intervention on the international river Barak at Tipaimukh and will construct a dam at Fulertal (100 kilometres downstream from Tipaimukh) by 2012. This dam construction originally started in 2007 but had to be postponed due to protest by the surrounding villagers and pressure from international bodies. With the construction of Tipaimukh dam, India would be diverting the Barak’s water flow from its north to its south and east. It will have adverse impacts on nature and livelihood in the north-eastern districts in Bangladesh. The Barak feeds not only the Surma-Kushiara in Sylhet but also flows into the Meghna, one of the three major rivers in Bangladesh.
The proposed Tipaimukh dam is a 390m long and 162.5m high earthen core rock filled dam at downstream of the confluence of Barak and Tuivai rivers near Tipaimukh village in Manipur state of India. To produce an estimated 1,500MW electric power, the dam will permanently submerge an area of 275.50 square kilometres in India. The dam will establish a reservoir behind the dam that will catch water in the rainy season and release it in the dry season. A list of benefits such as high-class tourism, free power sharing, resettlement and rehabilitation package has been offered by the Indian project proponent (North East Electric Power Corporation) to appease the people of Manipur state.
The geology on Tipaimukh and its adjoining areas are basically made up of the Surma Group of rocks that are well characterised by folds and faults with regional strike. All these faults and fractures can cause localised shifting or deflection at the confluence of the rivers Barak and Tuivai. Such faults are potentially active and may be focal and/or epicentres of future earthquakes. The north-eastern part of India is one of the highest earthquake-prone areas in the world due to its tectonic setting. The Tipaimukh dam site has been identified at the highest-risk seismically hazardous zone. Analysis of earthquake epicentres of the Tipaimukh dam site reveals hundreds of earthquakes in the past 100-200 years. It is found that within 100km radius of Tipaimukh two earthquakes of +7M magnitude have taken placed in the past 150 years, the last in 1957 at an aerial distance of about 75km from the dam site. The expert appraisal committee of India revealed that the design of the dam contains many errors, and omissions, and falls short of compliance of standards set by the scientific and academic community in India and the world.
As part of the project planning process, India conducted detailed studies, completed the final design and environment impact assessment without consultation with Bangladesh as a downstream stakeholder. The Indian government has not clearly stated the amounts of water that will be stopped or diverted with the construction of the Tipaimukh dam. About 7 to 8 per cent of the total water of Bangladesh is obtained through the river Barak to Surma-Kushiara river basins. Agriculture, irrigation navigation, drinking water supply, fisheries, wildlife in numerous haors (wetlands) and low-lying areas in entire Sylhet division, some areas of Comilla and Mymensingh districts, and some peripheral areas of Dhaka division depends on this water.
Along with the people of India, civil society groups, government and non-governmental organisations in Bangladesh have protested against the downstream impacts of Tipaimukh dam. The following adverse impacts on nature and livelihood in Bangladesh have been identified:
The erosion just downstream of the Tipaimukh Dam would be excessively high and this erosion would continue as long as hundred kilometres downstream or more in the Surma-Kushiara system. The probable deposition during late monsoon and post-monsoon season will raise the overall bed level of the rivers, and for an extreme case it would block the mouth of certain tributaries originating from the Kushiara. Bed level would rise and will induce the average monsoon flood to become moderate to severe flood in the Surma-Kushiara floodplain. On the other hand, Sylhet and Moulvibazar have unique natural monsoon-flooding pattern.
In post-dam scenario, 30,123 hectares of inundated areas in Sylhet and 5,220 hectares in Moulvibazar would be reduced due to change of flooding pattern. About 71 per cent of the upper Surma-Kushiara basin area would no longer be flooded. The Kushiara would cut its connection with its right bank floodplain for around 65 kilometres and this part will become ‘reservoir river’ rather than a most valuable ‘floodplain river’. The Kushiara-Bardal haor (wetland) on the left bank of the Kushiara would become completely dry. The Kawardighi haor (wetland) would also lose around 2,979 ha (26 per cent).
Hydrology and wetlands
The Tipaimukh dam would lead to hydrological drought and environmental degradation. According to the Institute of Water Modelling, an autonomous research institute in Bangladesh, once the Tipaimukh dam is fully functional, average annual monsoon inflow from the Barak to the Surma-Kushiyara-Meghna system would be reduced around 10 per cent in June, 23 per cent in July, 16 per cent in August and 15 per cent in September. Water level would fall by more than a metre on average in July on the Kushiara and 0.75 metre on the Surma. During a relatively drier monsoon year, the dam would have more impact on the availability of monsoon water in the Barak-Surma-Kushiara than the average annual monsoon year.
Groundwater and irrigation
Millions of people are dependent on hundreds of water bodies fed by the Barak for agricultural activities. The dam would cause the Surma and Kushiara to run dry from November to May. Shortage of water in these few months would decrease the boost of groundwater. Over the years this would lower the groundwater level, which in turn would affect all dugouts and shallow tube-wells. Agriculture dependent on both surface as well as groundwater would also be affected. Arable land will decrease and production of crops will fall, leading to an increase in poverty.
Biodiversity and ecology
ONE of the most serious and least studied consequences of large dams is the long-term health impacts due to drastic changes in the ecological balance, displacement and loss of livelihood and sudden alterations in the demographic character of the area. These factors have not been considered at all in the process of the Tipaimukh project planning phase. It is a well-known fact that the construction of dams invariably destroys the natural riverine ecosystem. As a result, it affects the habitat of rare and endangered flora and fauna in wetland. Construction of a high dam will obstruct the migratory path of fish and other aquatic fauna, prevent the exchange of micronutrients and silt between the upper and lower reaches of a river and have an overall adverse affect on the riverine food chain. Above impacts would destroy the natural integrity of the ecosystem, losing riverine habitat and species, and a lack of enrichment of land with the nutrient-full silt. This would lead to the ultimate decline in the natural productivity of the two most abundant resources of Bangladesh – land and water.
Dam break and human catastrophes
A detailed study by the World Dam Commission published in 2000 states that the adverse impacts of any large dams are irreversible for the lower riparian region. A study on the trends of earthquakes reveals that they mostly take place in regions which have experienced earthquakes in the past. If the Tipaimukh Dam were to break, its ‘billions’ of impounded cubic metres of water will cause catastrophic floods because of its colossal structure. The faults and fractures around the Tipaimukh Dam axis belong to the category that may undergo strike-slip and extensional movements. If the dam axis is displaced by a few centimetres, serious damage may occur causing a dam disaster leading to huge loss of lives and property.
The erosion and sedimentation just downstream of the Tipaimukh Dam would be excessively high and would continue as long as over 600 kilometres downstream in Bangladesh. This excessive erosion downstream of the dam would increase the overall siltation and water turbidity in the Surma-Kushiara system. These will adversely affect the water quality of the entire Surma-Kushiara-Meghna system in Bangladesh.
The Tipaimukh dam will permanently submerge an area of 275.50 square kilometres in India. The dam will have warming impact due to methane degassing from the reservoir. Mass human displacement, land use change on macro and micro climate and carbon emissions of large dam construction itself is enough to reconsider constructing of Tipaimukh dam.
Violation of laws and agreement
International rivers are naturally well designated and they flow through many countries. There are international rules and conventions that guide modes of sharing waters of such rivers between countries in the riparian regions. The UN International Water Management Convention 1997 adopted two key issues, in gist stated by two words – ‘no harm’ and ‘equitable sharing’. To elaborate the implications of the two set of terms, one can safely state that the upper riparian country must not do harm to lower riparian country by withdrawing or diverting normal natural flow of water. If any such withdrawal and diversion is at all to be done, such mode must have prior sanction of the lower riparian country subject to the condition of mutually agreed equitable sharing.
Under this convention, hiding any information by the upper riparian countries about the use of common rivers is considered as violation of the UN convention. The International Convention on Joint River Water also states that without the consent of the downstream river nation, no single country alone can control the multi-nation rivers. But India does not care about these international laws despite being a signatory to this convention. The Tipaimukh Dam project was entirely developed and approved without informing the government of Bangladesh or involving its people in any meaningful exercise to assess the downstream impacts of the dam. Bangladesh was not invited to participate, fully and actively, in the decision-making process as a key stakeholder. This is clearly a gross violation of co-riparian rights of Bangladesh.
The unilateral construction of Tipaimukh dam by India on this international river Barak is a violation of UN Convention on the Law of Non-navigational Uses of International Watercourses. At a Joint River Commission meeting in September 2005, India formally assured Bangladesh that they would not divert any water for their irrigation project. If India constructs the dam without the consent of Bangladesh, it will also be violation of article 9 of the Bangladesh-India Ganges Water Sharing Treaty 1996. Interestingly, a dam across the Barak was first mooted in 1928. Yet, India has failed to produce all the necessary data and research on the impacts of the dam on the people and the environment of both countries.
Economists have estimated that Bangladesh will lose up to $32 billion in a year due to the Tipaimukh dam construction. Taking into account the above impacts and recently developing objections in the both countries, the following actions should be undertaken to reach an amicable solution of this dispute:
Indian government needs to undertake a fresh review despite advancing the dam construction works. Invite Bangladesh to take part in the whole decision making process before it is too late.
India must provide access to all technical information (design, drawing, environment impact assessment) to Bangladesh to measure the total impacts of the Tipaimukh Dam on Bangladesh.
A joint team should be formed to study the adverse ecological and environmental impacts on both countries.
Bangladesh must ratify the UN convention as soon as possible in order to take advantage and for it to be effective.
As the proposed site is one of the highest potential earthquake areas in the world, so impacts from its tectonic setting risk must need to be investigated seriously.
Draw the international community’s (Asian Development Bank, World Bank, UNEP) attention to save our people and nature of Bangladesh.
The Bangladesh government, political leaders, civil society bodies, environmentalists need to join under a common umbrella to stop India constructing the Tipaimukh Dam.
The World Commission on Dams report has shown that Indian dams do more harm than help. Therefore, as per the report’s recommendation consider replacing dam-based hydroelectricity with a ‘run-of-the-river’ type project.
Abridged from a paper presented at a seminar at the Australian National University on July 3. Dr Nargis A Banu is an environmental scientist with Sydney Water Corporation, Australia.