Threats to the Sundarbans Mangrove Wetland Ecosystems (original) (raw)
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Through their complex network of river channels, the Ganges, Brahmaputra and Meghna Rivers cover an area of about 1.76 million km 2 , their boundaries extend across different countries such as Bangladesh, Bhutan, China, India, and Nepal. The Sundarbans are found at the coast of the Ganges River and are known as the world's single largest mangrove forest with 3.5 percent of the world's mangroves covering an area of 6017 km 2 . The Sundarbans wetlands act as a natural shield that protects the coastal area from storm surges and cyclones in pre and post monsoon periods. However, due to increased in irrigation of agriculture, industrial activity and the diversion of Ganges water at Farakka Barrage (India) in early 1975, both siltation and salinity have increased in the Sundarbans which is threatening the Sundarbans ecosystems. Consequently the dominant Sundari (Heritiera fomes) and Goran (Ceriops decendra) are affected by top-dying disease which is recognized as a key management concern. The Ganges water sharing is not just a geo-technopolitical problem; it is also a humanitarian problem. So, interaction and educational awareness between concerned states are of great significant. The objective of this paper is to make a contribution towards the development and implementation of management plan for mangrove wetlands resources and to ensure that fresh water is supplied to the Sundarbans by the Ganges. Water salinity simulation and modeling would be a proper tool for decision making and allow planners to protect the Sundarbans ecosystems in future.
Bangladesh through its complex network of river systems drains an area of about 1.76 million sq. km ofthe catchment ofthe Ganges, the Brahmaputra and the Meghna of which only 7.5 percent lies in Bangladesh. The Sundarbans is situated in the Ganges catchment area which known as the single largest stretch ofproductive mangrove forest and unique ecosystems in the world. It is reprcsenting 3.5 percent of the world mangrove and consisting of an area 6017 sq. km. It provides direct employment opportunity to 600,000 people and 6 million people indirectly dependent. Since the diveßion of Ganges water at Farakka Barrage in India from early 1975, salinity levels have increased drastically in the coastal region in Bangladesh. The reduction ofGanges flows while the industries are facing serious problems in quality control of products and disastrous effects on agriculture, fisheries, navigation, hydro-morphology, drinking water, wetlands and mangrove ecosystems. The dominant flefi/iera fomes ard Ceriops decandra species are affected by top-dying disease which is recognised as key management concern. The Ganges water shadng is not just a geo-techno-political problem it is also a humanitarian problem. The objectives of this paper is to contribute to formulate a long-term management plan for mangrove wetlands resources through ensure to supply Ganges water into Sundarbans. GIS simulation and salinity model would be the proper tools for decision making and make recommendations for the future of Ganges water sharing conflict and protection of Sundarbans wetlands ecosystems.
The Sundarbans is situated in the Ganges transboundary catchment which is known as the single largest mangrove ecosystems in the world and covers 10,000 km² between Bangladesh and India. Since the diversion of Ganges water at Farakka Barrage in India from early 1975, salinity level has increased drastically in the south western part of Bangladesh. Due to reduction of fresh water flow urban drinking water supply, industrial production, agriculture, fisheries, navigation, hydromorphology and mangrove wetlands ecosystems have been affected. Urban area both surface and groundwater have become unfit for human consumption. In the consequences about 0.170 million hectares (20.4%) of new land, and almost 27 small towns have been affected by various degrees of salinity during the last three decades. The saline front defined by 6 dS/m iso-haline has penetrated up to 173 km north from the coast. The salinity has exceeded the recommended level 1 dS/m for potable water. It is a new threat to supply quality drinking water to the small towns in the south western region in Bangladesh. The dominant mangrove Heritiera fomes and Ceriops decendra species are affected by top dying disease which is recognised as key management concern. The Fourier Polynomial water salinity models on Sundarbans rivers are showing the cycling increasing behaviour. The findings of this study a potential contribution for making comprehensive management plan are for urban water supply, and protection of the mangrove wetlands ecosystems in the Sundarbans region.
RISING WATER SALINITY: A THREAT TO MANGROVES OF INDIAN SUNDARBANS
Mangroves constitute an important ecosystem because of their global extent and high productivity. These plants thrive in the intertidal zones of the tropics and subtropics that are characterized by regular tidal inun-dation and fluctuating salinity. Mangrove species are well adapted, both morphologically and physiologically, to survive under saline conditions, but in hypersaline environment their growth is reduced. The present chapter is a critical analysis on the impact of salinity on the growth of a common mangrove species (Hertiera fomes). The analysis has been carried out in the framework of Indian Sundarbans, which has contrasting salinity profiles in different segments owing to barrage discharge and siltation phenomena. Analysis of the decadal profile of salinity indicates a gradual lowering in the western Indian Sundarbans due to Farrakka barrage discharge and runoff from catchments. The central sector, Water Insecurity: A Social Dilemma Community, Environment and Disaster Risk Management, Volume 13, 167À183
CHAPTER 8 RISING WATER SALINITY: A THREAT TO MANGROVES OF INDIAN SUNDARBANS
Mangroves constitute an important ecosystem because of their global extent and high productivity. These plants thrive in the intertidal zones of the tropics and subtropics that are characterized by regular tidal inundation and fluctuating salinity. Mangrove species are well adapted, both morphologically and physiologically, to survive under saline conditions, but in hypersaline environment their growth is reduced. The present chapter is a critical analysis on the impact of salinity on the growth of a common mangrove species (Hertiera fomes). The analysis has been carried out in the framework of Indian Sundarbans, which has contrasting salinity profiles in different segments owing to barrage discharge and siltation phenomena. Analysis of the decadal profile of salinity indicates a gradual lowering in the western Indian Sundarbans due to Farrakka barrage discharge and runoff from catchments. The central sector,
Aquatic Salinization and Mangrove Species in a Changing Climate: Impact in the Indian Sundarbans
Policy Research Working Papers
The Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about development issues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry the names of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not necessarily represent the views of the International Bank for Reconstruction and Development/World Bank and its affiliated organizations, or those of the Executive Directors of the World Bank or the governments they represent.
Mangrove wetland ecosystems in Ganges-Brahmaputra delta in Bangladesh
Frontiers of Earth Science in China, 2008
The Sundarbans is one of the productive mangrove wetland ecosystems in the Ganges-Brahmaputra delta in Bangladesh. The delta is undergoing rapid ecological changes due to human activity. In the present study, surface water salinity data from 13 rivers of the Sundarbans were collected in order to investigate the saline water intrusion in the mangrove wetlands. Results demonstrate that saline water has penetrated the upstream area as river water salinity has increased significantly in 1976 compared to the year 1968. The soil and river water salinity data also shows that it has crossed the water salinity threshold line in most parts of the Sundarbans wetlands. These observations are due to the construction of Farakka Barrage in 1975, which reduced the water discharge of the Ganges River from 3700 m 3 /s in 1962 to 364 m 3 /s in 2006. The shortage of freshwater discharge to the deltaic area is trailing active ecosystems function, especially in the dry season in the south western region in Bangladesh. The objective of this study is to understand and analyze the present degraded mangrove wetland ecosystems and their negative impacts. The findings of this study would contribute to the formulation of the mangrove wetland ecosystems management plan in the Ganges delta of Bangladesh.
2005
Abstract. The Sundarban, covering about one million ha in the delta of the rivers Ganga, Brahmaputra and Megh-na is shared between Bangladesh (~60 %) and India (~40 %), and is the world’s largest coastal wetland. The area experiences a subtropical monsoonal climate with an annual rainfall of 1,600–1,800 mm and severe cy-clonic storms. Enormous amounts of sediments carried by the rivers contribute to its expansion and dynamics. Salinity gradients change over a wide range of spatial and temporal scales. The biodiversity includes about 350 spe-cies of vascular plants, 250 fi shes and 300 birds, besides numerous species of phytoplankton, fungi, bacteria, zoo-plankton, benthic invertebrates, molluscs, reptiles, am-phibians and mammals. Species composition and com-munity structure vary east to west, and along the