Subsid....en..c...e In Ba...n..gla...d...e...sh

As Bangladesh is built in the Ganges-Brahmaputra deltaic region it is naturally prone to the effects of subsidence. It experiences flooding and is in a seismically active area which means that given the right conditions the sediment of the delta to liquefy and fall, especially because the sediment would be extremely saturated during the monsoon season. The delta is in fact subsiding in some areas at about 2.2 cm per year and potentially at the same or faster rate in other areas. This is due to the isostatic adjustment of the underlying crust which is driven by the rise of the Himalayas. Isostasis is essentially how the lithosphere floats on top of the asthenosphere. Essentially, as the Himalayas are pushed further up in elevation by the Indian subcontinent subducting under the Asian continent, they erode (through various processes) and a bunch of that eroded material makes its way (usually via flooding) to the deltaic basin in Bangladesh. Over time that sediment accumulates at a faster rate than it washes out and as the weight of the sediment increases, the continent it is deposited upon will get pushed down a little. When the sediment gets washed away (which is does periodically) the continent sort of floats back up- this is called rebound.  Dewatering is another big contributor to the subsidence of the delta. As far as  I can tell from what I have read Bangladesh has recently gotten involved in some forms of coal mining which requires that the miners suck water from the water table in order to place mining equipment beneath the surface. This is basically how dewatering works. It is supposed make a sort of temporary  window for the equipment to be installed or for data to be collected but as would be expected, dewatering definitely has some permeant effects on the water table and on the layers of earth which are dried up in the process. As we all know, dried up sediment will fall without its regular amount of moisture to keep it up. Another contributor to subsidence is the practice of drawing up groundwater for drinking purposes. Bangladesh is facing a serious clean water problem. In the past drawing water up from wells has exposed people to arsenic poisoning but it is still cleaner than the water drawn from surface supplies, such as the rivers. Dhaka especially has been facing more and health issues caused by contaminated water sources. As sea level rises the soil in Bangladesh will become more saline as will the coastal bodies of water and eventually the delta and other areas further north. The more brackish the water become the less drinkable it will become and as the soil accrues more salt, it will become less fertile and the water table will become brackish as well, leaving Bangladesh fewer options for potable water. All of this would be caused by subsidence and the fact of the matter is that Bangladesh does not have either the infrastructure or the mitigation plan necessary to avoid the catastrophic results.

https://phulbarinews.wordpress.com/2008/06/24/dewatering-in-open-pit-mining-concern-or-benefit/

http://link.springer.com/chapter/10.1007/978-94-015-8719-8_9

http://www.sciencedirect.com/science/article/pii/S221209631300003X