Sharing the water of the Ganges

A Map showing major rivers in Bangladesh, including the Padma River.

Descending from India's northern plains, the Ganges river forms a boundary of 129 kilometres between India and Bangladesh and flows for 113 km in Bangladesh. At Pakaur in India, the river begins its attrition with the branching away of its first distributary, the Bhagirathi River, which goes on to form the Hooghly River. About 10 kilometres from the border with Bangladesh the Farakka Barrage, built in 1974, controls the flow of the Ganges, diverting some of the water into a feeder canal linking the Hooghly to keep it relatively silt-free.[4]

After entering Bangladesh, the main branch of the Ganges is known as the Padma River until it is joined by the Jamuna River, the largest distributary of the Brahmaputra River, which descends from Assam and Northeast India. Further downstream, the Ganges is fed by the Meghna River, the second-largest distributary of the Brahmaputra, and takes on the Meghna's name as it enters the Meghna estuary. Fanning out into the 350 km wide Ganges Delta, it finally empties into the Bay of Bengal. A total of 54 rivers flow into Bangladesh from India.[5]

Indian Prime Minister Indira Gandhi and Bangladesh's founding leader Sheikh Mujibur Rahman signed the wide-ranging Indo-Bangladeshi Treaty of Friendship, Cooperation and Peace on 19 March 1972;[4] as per the treaty, the two nations established a Joint River Commission to work for the common interests and sharing of water resources, irrigation, floods and cyclones control.[2]

The Farakka Barrage is a dam on the Bhagirathi River located in the Indian state of West Bengal, roughly 10 km (6.2 mi) from the border with Bangladesh. India uses it to control the flow of the Ganges River. The dam was built to divert Ganges River water into the Hooghly River during the dry season, from January to June, to flush out the accumulating silt which in the 1950s and 1960s was a problem at Kolkata Port on the Hooghly River.[4] Bangladesh claimed that its rivers were drying up because of excess drawing of water by India.[5] In May 1974 a joint declaration was issued to resolve the water–sharing issue before the Farakka Barrage began operation.[3] This was followed by an interim agreement in 1975 to allow India to operate the feeder canals of the Barrage for short periods.[1][2]

However, India withdrew from the process of negotiations by September 1976 as both nations grew apart after the assassination of Sheikh Mujibur Rahman, the President of Bangladesh, in August 1975 during a military coup d'etat, and the related establishment of military rule in Bangladesh.[4] Bangladesh protested India's unilateral action at a summit of the Non-Aligned Movement (NAM), and at the 31st session of the United Nations General Assembly.[2] At the urging of other nations and the U.N., both India and Bangladesh agreed to resume dialogue, but with no results.[2]

The Ganges Delta spanning India and Bangladesh.

The formation of an Awami League government in 1996 under Sheikh Hasina Wajed, the daughter of Sheikh Mujib, led to a fresh thaw in relations and negotiations restarted. Both countries leaders met in the Indian capital on 12 December 1996 and signed a 30-year, comprehensive treaty.[1][2][3]

As per the 1996 treaty for sharing the Ganges waters at Farakka , the division is as follows:[6]

Both nations were able to co-operate in harnessing the water resources; the treaty also permits the construction of barrages and irrigation projects in Kushtia and the Gorai-Madhumati River in Bangladesh, draining the south-western districts and thus preserving the environment, natural and economic resources.[2]

The 1996 treaty established a long-term solution and considerably eased strains in Indo-Bangladeshi relations.[1][3] The 1996 treaty has been attacked by the Awami League's (AL) main rival, the Bangladesh Nationalist Party (BNP), which is regarded as hostile to India, but BNP not renege from the treaty when it came to power in 2001. The BNP and other Bangladeshi political factions allege that India is drawing excessive water and the amount allocated to Bangladesh is unjust and insufficient.[1][5] India in turn complains that the water allocated to Bangladesh leaves it with less water than necessary for the functioning of Kolkata Port and the National Thermal Power Corporation in Farakka.[5]

Other critics have also stressed environmental reasons for India to reconsider its drawing of water at Farraka. Alarming increases in deforestation and erosion at the upper levels of the Ganges River increases the deposition of silt at the lower level, which is already measured at 2 million tonnes annually, along with increased salinity, have led to desertification.[7] In Bangladesh, the diversion has raised salinity levels, contaminated fisheries, hindered navigation and posed a threat to water quality and public health.[8] Such silt levels are believed to be adversely affecting the Hooghly River and Kolkata Port.[1]