Indian damming of the Ganges by the Farakka Barrage has resulted in the largest irrigation network in Bangladesh being unable to supply enough water to the land. The dam was constructed in 1974, some 11 miles inside the border, partly to improve navigability of the Hooghly River feeding Calcutta. When the dry season peaked in April 1993, pumps in Bangladesh could not be operated because of the drastic fall in the volume of water traditionally expected from the Ganges. The diversion amounted to approximately 70% of the dry season flow. Decreasing flows have also resulted in a rise in salinity over large areas. No agreement between India and Bangladesh on water share has been in force since 1982.