Welcome to Geodesh! This is a personal effort to report and highlight the current and possible future issues around water supply, climate change and environments in the Ganges-Brahmaputra-Meghna (GBM) Delta in Bangladesh and other Asian Mega Deltas.
The GBM Delta and other Asian Mega Deltas are currently facing various water and environment related problems of which groundwater contamination by elevated arsenic is recognised as the world's largest mass poisoning in history. Millions of people in Bangladesh and other Asian countries are exposed to dangerous levels of arsenic through drinking water that comes from alluvial aquifers formed by young sediments deposited by major river systems originated in the Himalayas and Indo-Burman Mountains.
Groundwater which occurs at shallow depths in most places of these deltas has been used for drinking and irrigation purposes. Greatest dependence on this natural resource is observed in the GBM Delta in Bangladesh and West Bengal (India). Megacities like Dhaka and Kolkata in the GBM Delta are now facing serious crisis of public water supply. Many areas in Bangladesh are also experiencing lack of irrigation water supply during the dry season threatening Boro rice cultivation. These problems have already intensified from seasonal to perennial in nature and will likely become serious threats to biophysical environments and urban civilisations in future.
Additionally, climate change and rising sea levels in the Bay of Bengal and Indian Ocean will exacerbate public water supply and environmental flows by increasing water salinity in coastal areas, particularly in and around Surdarbans - the largest mangrove forest in the world. Sea-level rise in other Asian Mega Deltas may impose similar environmental problems although dependence on groundwater is currently low in the Irrawaddy, Chao Phraya, Mekong, and Red River Deltas. Changing patterns in the monsoon rainfall associated with global warming may negatively impact groundwater recharge in many areas in these deltas that are currently under water-stress.
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This website is designed and maintained by Dr. M. Shamsudduha, UCL Institute for Risk & Disaster Reduction, London, UK
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