Water salinity investigation in the Sundarbans rivers in Bangladesh

Bangladesh, through its complex network of river systems, drains an area of about 1.76 million km 2 of the catchments of the Ganges, the Brahmaputra and the Meghna, of which only 7.5% lies in Bangladesh. The Sundarbans is situated in the Ganges catchment area, which is known as the single largest mangrove forest and unique ecosystem in the world. It has an area 6017 km 2 and a natural shield that protects the coastal area from storm surges and cyclones. It also plays a potential role in the regional economy and ecosystems. Since the diversion of Ganges water at Farakka Barrage in India from early 1975, as a result the water and soil salinity has penetrated. Consequently, both siltation and increased salinity have degraded water quality in the Sundarbans rivers, and threats for mangrove ecosystems. At present, ground water use in the study area is less because of high salinity intrusion. For salinity investigation, time series data for four years (13 rivers) were used for water salinity modelling. The objectives of this paper are to investigate the water salinity approximation in the Sundarbans rivers, which will be considered as a tool for decision making. It will make a contribution to develop an interdisciplinary management plan and to ensure that fresh water is supplied to the Sundarbans by the Ganges for the protection of mangrove ecosystems.