Transboundary Water Management in the Tista Basin: Some Issues and Concerns

As the Prime Minister is expected to visit Sikkim in January 2016, it is important for us to realize that Sikkim and Darjeeling together share nearly 70 percent of the Tista Basin area, one of the most contested basins geopolitically. Tista Basin is also one of the degraded basins of the World due to human overuse. More importantly, Bangladesh has been unhappy with India given the fact that India appropriates most of the basin water much before it enters Bangladesh, a lower riparian member of the Basin.

Transboundary Tista River flows the Eastern Himalayan landscape and is the fourth major river after the Ganges, Brahmaputra and Meghna in the Eastern South Asian region. It flows the entire length of Sikkim and carves out some of the profuse and verdant Himalayan temperate and tropical river valleys. As it flows down, the river forms border between Sikkim and West Bengal. It flows about 172 km in the hilly region of Sikkim and Darjeeling (India).  The river crisscrosses for about 98 km in the plains of West Bengal (India) and another 134 km in Bangladesh before joining Brahmaputra in Bangladesh. As it traverses down, Tista receives water from a large number of tributaries on either side of its course forming a complex and dynamic river basin and a unique eco-region often referred to as ‘Tista Eco-region’.

Regional Significance

Tista Basin forms a part of the larger Brahmaputra Basin in the Eastern Himalaya. The river drains a total geographical area of about 12159 km². Around 2004 km2 of the basin (about 17 percent) area lies in Bangladesh with the rest being in India. The Eastern Himalaya is considered as an important global ‘biodiversity hotspot’. The region besides being source of varied forms of natural/bio-resources also acts as a global ecological sink.

The basin currently is home to more than 30 million souls representing several social groups in Sikkim, northern West Bengal (India) and Bangladesh. Starting from the Lepcha Tribe, Ethnic Bhutias and the Ethnic Nepalis in Sikkim-Darjeeling Himalaya to the agrarian communities of North Bengal and Bangladesh, the region is the source of livelihood for several socio-cultural groups. Moreover, the basin has been source of etho-cultural and ethno-religious basis for many social groups in Darjeeling-Sikkim region since historic past.

Further, Tista is the only source of water to the agricultural crops of the thirsty Northern Bengal and North Western Bangladesh. Besides, other associated livelihood options including rafting, sand/stone mining and fishing to name only few have thrived across the basin since long. Tista basin, therefore, provides significant human and environmental security to the region and its geography milieu.

Water Exploitations across the Basin

As an international river, there have been serious issues on table with regard to the overall management in general and sharing of its water between India and Bangladesh in particular. Besides several existing and proposed mega hydro-dams along with numerous tunnels in the Sikkim-Darjeeling catchment, the Government of West Bengal has diverted almost entire Tista Water via artificial canals at Tista (Gajoldoba) Barrage in Jalpaiguri to irrigate its thirsty North Bengal leaving little or no water for Bangladesh.

India constructed the Gajoldoba Barrage in 1980s and started diverting its water for irrigation and transfer to the Mahananda River. India's irrigation plan with the Tista water is massive, to cover about 9.22 lakhs hectares of land in Cooch Behar, Jalpaiguri, Darjeeling, Uttar Dinajpur, Dakshin Dinajpur and Malda districts. Bangladesh completed the Tista Barrage in 1990s to supply water to about 6.32 lakhs hectares of its thirsty agricultural land in Niphamari, Rangpur, Dinajpur, Jaipurhat, Gaibandha and Bogra districts.

Overview of Hydro Power / Multipurpose Projects in the Tista Basin

Catchment		Projects	Remarks
Sikkim		·       Around 20 Mega Hydro Power Projects ·       More than 20 Mini and Micro Hydro Projects	Three-mega projects commissioned.  Others under various stages of construction
West Bengal	Darjeeling	·       Three Mega hydro Projects ·       Four more mega hydro projects proposed in July 2015	One project commissioned. One expected to be commissioned in early 2016
	Jalpaiguri	·       Tista Barrage project, Gajoldoba (Multipurpose)	Project work started in 1976, yet to be fully completed (partially completed)
Bangladesh		·       Tista Barrage Project, Duani, Lalmonirhat (Multipurpose)	Project work started in 1979 completed in 1998

Declining Water Flow in the Basin

Ironically, experts are still unclear about the quantity of water the Tista River carries due to official secrecy.  In India, data of international rivers are not accessible to the public and this limits water related research and water resource planning. Lack of river flow data also causes conflicts and unjustified claims by different parties. Due to lack of any data about river flows in upstream parts of rivers (like the Tista), it is impossible for downstream communities to ignore their claims or verify them.

One study points out that the peak discharge of Tista within Sikkim came down from 5000 cumec in 1972 to approximately 2200 cumec in 1998. Further, peak discharge at Coronation Bridge has come down from 5200 cumec in 1972 to approximately 3500 cumec during the same period. NHPC (2002) noted that the maximum observed discharge at Tista Bazar is 3650 cumec while the minimum discharge is recorded at 86 cumec. Further, Rudra (2003) pointed out that the mean annual discharge of the Tista at Anderson Bridge is about 580 cumec and it declines to 90 cumec in the lean months.

According to Central Water Commission (CWC), water flow in the Tista is already very low when it enters West Bengal from Sikkim due to construction of a series of hydroelectric projects in the upstream state and there are a few such projects in the West Bengal stretch of the river as well before the river flows down from the Himalaya to the plains.

Haque (2011) reported that the Tista River had an average historical flow of 7929 cumec maximum and 283 cumec minimum at Dalia (Bangladesh), upstream of the Tista Barrage in Bangladesh. He points out that, due to increasing withdrawal in the upstream (India), this flow has come down to about 1,000 cusec (28 cumec) and to even 500 cusec (14 cumec) during droughts. In addition, the Joint River Commission (JRC) in its last meet held in Dhaka displayed concerns over receiving only 6.5 per cent of the Tista water in Bangladesh which it said was the ‘lowest ever’.

Tista Water Sharing Concerns of Bangladesh

Bangladesh alleges that India is drawing water from the river unilaterally that has resulted in a grave deficit of the water levels and led to the drying up of the northern districts. As a lower riparian country of the basin, Bangladesh has been regularly voicing its concern for the equitable sharing of the transboundary Tista River for long. But it is still to be achieved despite several meetings between Bangladesh and Indian governments. Since 1972 Bangladesh has wanted a 50 per cent share of Tista river water. Tista is one of the 54 rivers on the India-Bangladesh border out of which only Ganga has a water-sharing agreement. The sharing of water on other important rivers including Tista has been under discussion for quite some time.

Given the number of hydropower dams and other forms of development planned upstream farmers down streams are not sure how long they will continue to get water when they need it. A recent Action Aid (2013) study conducted on 1140 families living in two unions of Lalmonirhat's Sadar upazila and two other unions of Kurigram's Ulipur upazila of Bangladesh highlights the following:

·      A total of 35 percent of the people dependent on Tista River lost their ancestral profession as fisherman, boatman and farmer in last two decades because of low flow of water in the river.

·      At least 25 percent people of both the riverbanks have become day labourers.

·      At least 42 percent people had to relocate their homesteads for 10 times due to riverbank erosion, losing of professions and for other reasons.

The study is about the impacts of Tista on the people living near its banks, their lifestyle, professions and culture. It brings out the life and living of people dependent on the river. In this context, we need to be heedful that any displacement of people within Bangladesh has the potential of creating newer conflicts between Bangladesh and India as well as converting some displaced into environmental refugees.

In the light of the current unscientific water management in the Upper Tista Catchment, Haque (2011) suggests that Bangladesh should demand the following:

·      Stopping of dam building in Sikkim that obstruct lean period flows in the Tista tributaries. 'Low Flow' hydroelectricity dams also obstruct the lean period flows.

·      No linking or release should be allowed to the Mahananda/Mechi River to the west or to the Jaldhaka River to the east. These links/releases lead to inter-basin water transfer.

·      The command area in the Indian Tista Irrigation Project  (Gajoldoba) must be reduced to a realistic size. A too large area shall end up with major conveyance loss and failure.

Regional Human Security Concerns

Such a glaring decline in the basin water particularly in the lower catchment (Bangladesh) has resulted in large-scale protests against India across the spaces of Bangladesh including Dhaka. Further, in the absence of reliable data and official agreement, technical issues regarding the quantity, division and share of the waters has become the bone of contention between India and Bangladesh.

We need to understand that upstream water usage determines downstream options in water management and therefore sets the stage either for conflict or cooperation. In this regard, experts often project that the next 10-15 years shall witness depressing intra and inter-State water disputes if policy makers both in India and Bangladesh do not come up with viable solutions for the sustainable management and sharing of Tista Water.

Reportedly, in July 2015, excess unannounced water was released from hydro project dams of Sikkim causing flash floods in villages located on both banks of the Tista downstream in Darjeeling and Jalpaiguri districts of West Bengal. Considering this problem, the chief minister of West Bengal advised the north Bengal development minister to visit Sikkim and apprise the chief minister of Sikkim on the matter so that such release of water can be regulated. The West Bengal government is expecting to develop a communication mechanism so that it is informed about such discharge of water. This surely is a pointer to the potential future intra-state disputes in the region!

There is, therefore, an urgent need to re-look India’s local/regional water management/diplomacy strategy and neighbourhood policy. However, both India and Bangladesh are yet to ratify the UN Water Course Convention, 1987 that talks about the need for resolution by adopting equitable, non-discriminatory guiding principles for sharing of international water resources. The convention also urges all riparian States to cooperate on the basis of sovereign equality, territorial integrity, mutual benefit and good faith in order to attain optimal utilisation of an international watercourse.

Vimal Khawas teaches in the Department of Geography, Sikkim University.

This essay is part of research uptake activities of the larger research work being conducted under project ‘Hydropower development in the context of climate change: Exploring conflicts and fostering cooperation across scales and boundaries in the Eastern Himalayas’ funded by Netherlands Organisation for Scientific Research (NWO) and DFID (Department for International Development), United Kingdom. 

Note: Published in Sikkim Express, December 17, 2015

Natural Disasters and Hydro-Excitement in the Upper Tista Catchment: A Serious Concern!

Vimal Khawas

Trans-boundary Tista Basin forms a part of the larger Brahmaputra Basin in the Eastern Himalaya. The river drains a total geographical area of about 12159 km². Around 2004 km2 of the basin (about 17 percent) area lies in Bangladesh with the rest being in India. In recent times, traditional symbiotic and intimate human-environment relationship in the Tista Basin has been increasingly put to danger by diverse undercurrents of development. This has resulted in imbalances in the environment and various ecological systems there in. Besides other forms of development including improper expansion of agriculture and irrigation, unscientific construction of roads and buildings and unplanned urbanization, Central and Provincial Governments of India are vehemently underway with series of hydropower projects particularly within Sikkim-Darjeeling catchment of the basin.

Drivers

The mega hydropower projects proposed in the area are part of the Government of India’s program of dam construction to create another 200 billion cubic metres of storage through the 50000 MW hydroelectric initiatives launched in 2003. Considering huge untapped hydro potential of the Tista and its numerous perennial tributaries, Central and Provincial governments see huge opportunity to mobilize flow of capital investment through public, private or joint sector.

Therefore, apart from development of various small, mini and micro-hydel projects, several mega projects have been awarded to NHPC, NTPC and private developers in the last one and half decades. From these projects, the State governments of Sikkim and West Bengal will get 12 percent of free power. Reportedly, Sikkim hopes to yield approximately INR 2000 crores per annum by tapping into ‘the enormous hydroelectric potential’ of the basin within the State. Besides contributing to the growth and development of the country, Sikkim visualizes of a prosperous Sikkim with the revenue earned.

However, the number of mega projects in Sikkim allotted to public and private sectors has been lowered radically from around 27 in 2007 to 16 in 2015. Important reasons cited by the government include critical social, ecological, geological and financial considerations. Reportedly, the Sikkim-Nepal earthquake of September 2011 played significant role in bringing down sizeable numbers of hydro-projects in the Sikkim Himalaya. The data recorded in the official documents indicate that number of ongoing mega projects came down from around 25 in 2010 to about 18 by 2012. Accordingly, the identified hydro capacity of the Sikkim Himalaya has been lowered from over 5200 MW to around 4200 MW as per the recent reassessment study of the Central Electricity Authority (CEA, 2014).  In the Darjeeling region, out of three mega projects one (TDLP III) is already commissioned. Others are in various stages of construction. Further, the Chief Minister of West Bengal has recently announced four more projects in Darjeeling region of the Tista basin. Consequently, the Sikkim-Darjeeling catchment is now expected to produce over 6000 MW of electricity within the next few decades.

The biggest concerns at the moment are the varied impacts of such gigantic development ventures on the regional environmental security in this fragile region and its neighbourhood. The recent tectonic events in Sikkim (2011) and Nepal (2015) and the consequent disasters have further challenged the very idea and future of mega hydropower dams in the region. These seem to have either been overlooked or their impacts underplayed by respective EIA reports. 

Earthquake

There are concerns that building hydro-dams may lead to river-induced seismicity in this geologically young and seismically active region. The Darjeeling-Sikkim catchment of the basin is located in the high-risk seismic zone IV of the Indian seismic zoning map and therefore had been active seismic region in historical times. Recent major earthquakes in Nepal (April 2015) and Sikkim (September 2011) measuring 7.8 and 6.8 in magnitudes have clearly exposed the region’s wherewithal with regard to earthquake disaster. The Nepal earthquake of April 25, 2015 and series of aftershocks thereafter have reportedly damaged about 14 hydropower plants across Nepal resulting in a loss of 150 megawatt (MW) of electricity. In this regard, Sunkoshi Hydropower plant has apparently suffered serious damage with its 3-km canal suffering from multiple leakages. Environmentalists, activists and researchers in the region have long been warning against too many constructions of mega dam projects in the upper Tista catchment.

The fragile geology coupled with mega hydro-dams could induce earthquakes and the resultant landslides and flash floods could result into a disaster.  The central government, provincial governments and hydropower companies may, however, dismiss the earthquake related concerns as fear mongering. Yet, a contingency plan for disaster management in the event of earthquake is a far cry for almost all the hydro-projects in the area! Scholars across the world have reported the performance of various types of dams under earthquake shaking. Their studies show that concrete dams may be subject to severe cracking, movement and opening of joints that may render the dam unserviceable or may require major repairs.

Landslides

It may further be noted that Sikkim-Darjeeling segment of the Tista basin is featured by a number of active and dormant landslides. A cursory glance at landslide statistics gives us a fearful idea of the enormity of damage done and the ever-present threat to life and property in the region. In the last one-century more than 10000 slides have been registered in Darjeeling region alone. Thousands of lives have been lost and the overall economic development of basin negatively impacted.  Mention should be made that heavy and spontaneous rain on June 30 and July 01, 2015 triggered a string of landslides across Darjeeling Himalaya killing over 40 people. According to Praful Rao, President, Save the Hills, ‘Kalimpong was pummeled by torrents of rain starting from approximately 20:00 hrs. I watched the clouding as it formed over us and remained almost stationery much like the clouding over Uttarakhand in 2013. Kalimpong received almost half (226 mm) the entire July month's average rainfall (548.7mm) in the 06 hours’. Darjeeling Together, an initiative of the people of Darjeeling to help the people affected by the recent landslides, has placed the following preliminary figures on the immediate impacts of landslides: villages affected: 165, people affected: 94797, houses damaged: 1907, people in relief camps: 2360. Initial report of the district administration has calculated property loss to the tune of INR 12 crores in the Darjeeling region.

According to a recent study of Wadia Institute of Himalayan Geology (Dehradun), the Sikkim Earthquake (2011) triggered several hundred landslides in Sikkim, Darjeeling, Nepal, Tibet and Bhutan Himalaya. In the Indian Territory, the earthquake-triggered landslides were reported as far as 100 km away from the earthquake rupture zone. Within Sikkim, the study reported over 350 new landslides in the post earthquake period.

Notably, after water impoundment and pondage by the dam, water level in the area rises considerably. As a consequence, the strength parameters of the slope mass weakens and it may become susceptible to destabilization thus triggering new landslides and further destabilisation of already active slides. A live example of such a situation is seen along the National Highway between Tista Bazar and 27 Mile near Rambi in Darjeeling region where TDLP-III regularly impounds water for several weeks, although NHPC claims to be a run-of-river project (RoR), threating livelihood security of the riparian settlements.

River Erosion

Of all the Himalayan Rivers, Tista reportedly has the highest sediment yield.  The effects of erosion and sedimentation provide favorable conditions to river shifting. River Kosi has shifted by about 150 km to the west during the last two centuries. According to Hunter’s statistical account of Bengal, Tista originally was a river of Ganga basin. In 1787, due to incessant rain followed by heavy flood and devastating earthquake Tista shifted its course to Brahmaputra basin. If such sudden river capture occurs today, thousands of villages will be swept away in a gigantic flash flood inflicting incalculable human and environmental disasters.

This is no great news for a region already facing the cost of shortsighted mountain development.

Note:    This article can be published by others after obtaining permission from the author.