Sundarbans Flashcards
location of sundarbans
area of Mangrove forest in southern Bangladesh and southern India
size of sundarbans
10,000 kilometres, contains largest Delta in the world
what rivers run through it?
Ganges, Brahmaputra and Meghna.
how is the land created ?
fluvial deposits of the three rivers running through it. the force of the tide shapes the landscape, which consists of interconnected river channels which flow across deposits of silt and mud.
what are Khals?
smaller interconnected channels which drain the land after each powerful Ebb tide
what are Chars?
roughly sand sized material is washed away to form banks at the mouth of the river. example: Dubiar Char
how are the mangrove forrests formed?
the SW prevailing wind blows sediment at coast to create large ranges of sand dunes. this creates lower energy environments behind the dunes in which small material can be deposited to form islands. if natural succession is allowed to occur, these will be colonised by halophytic plants and will eventually become the dense mangrove forest
opportunities for humans: goods
fuel construction materials fishing materials household items food and drink, textiles paper as well as medicines and feed for cattle
opportunities for humans: services
protection - mangrove forests and sand dunes dissipate wave energy to prevent shoreline erosion and act as a barrier against flooding and storm surgers caused by cyclones
provision - mangrove forests act as breeding ground for animals for food supply. helps with carbon capture which reduces the effect of global warming
maintenance - regular flooding creates nutrient rich soil
income/value - tourism for bengal tiger and other wildlife. rivers are of great cultural and religious significance
human challenges
over exploitation of vulnerbale coastal habitats causes a lowering of biodiversity (intensive fishing/ agriculture)
lack of understanding of environmental and economic importance
conflicts over resources
natural challenges
risk of being eaten by bengal tigers(50 people a year, around 100 tigers) or other wildlife
flooding due to glacio eustatic sea level rise
instability of islands
weather e.g cyclones
lack of accessability/remoteness
resilence to challenges: mangrove forest
provides shelter against storm winds, floods tsunamis and coastal erosion.
the 30 trees per 0.1 hectares reduces tsunami destructiveness by 90%
resilence to challenges: economic value
despite flood risk, high value due to traditional activites such as fishing, gathering timber and tannin production
one hectare mangrove = $12,000
could provide strong poverty resistance to one of the poorest economies in the world
Bangladesh ICZM scheme
created in 2005, to help local people pursue sustainable economic development. aimed to reduce poverty by increasing peoples resiliance through schemes such as micro credit schemes to help farmers improves production and reduce poverty gap.
what is the coastal embankment project?
5000 kilometres of embankments have been built in the form of 123 barrier dams.
problems with the coastal embankment project
led to greater deposition within drainage channels which lowers the carrying capacity of the channels and makes the ebankments less effective. also, less flooding can lead to less nutrient rich soil
how can the mangrove forests be a mitigation method?
dissipate wave energy to prevent erosion aswell as lowering the wave height to help create a strong barrier against flooding
what is Khas land?
government owned land protected so that farmers who have lost their land due to flooding can use it. other locals can also use it
what investment has their been?
flood/cyclone shelters - East Midnapore
infrastructure - roads, telecomunications, schools, hospitals.
these all help to mitigate the risks posed by natural disasters
why has the level resistance decreased recently?
poverty and marginalisation of some coastal communities have increased. this is due to the shrinking of the open acess resources, the degrading of the local ecosystem, the corruption of local and national political institutions, conflicts over land ownership and increasing deaths by tigers. Additionally, if wives are widdowed then they may face very limited opportunities in the male dominated society.
what does adapting to consequences mean?
learning to live with the effects of the natural disasters
what is the benefit of storm shelters/how many have been built?
2000 multi-storm shelters have been built. when not in use these shelters are used as markets or schools
what are Killas?
raised mounds to keep livestock safe as indigenous people rely on them.
how many killas have been built
1500, although this isnt nearly enough.
what have USAID done?
trained 30,000 people on increasing farm productivity. and using salt tolerant species of rice. also put in clean water storage tanks
what have the International Rice Research Institute (IRRI) done?
salt tolerant rice species to allow production in times of flooding.
however farmers cant afford them and they can only cope with 10% of the salinity in flood water
problems with salt tolerant rice strains
however farmers cant afford them and they can only cope with 10% of the salinity in flood water
what is hydrophonics?
they are floating farms. farmers collect plants such as hyacinth leaves and paddy stalks. these are beaten into shape to form a raft upon which seedlings are planted. low cost solution, only £73 per raft
issues with hydrophonics?
must be placed in tranquil water, safe from tides and waves. as the sea rises these areas will become less and less.
place specifics: Dhaka
300,000 - 400,000 migrants arrive each year partly due to sea rise
place specifics: Sagar Island
primary school destroyed in 2017, people had to move with it (0.5km inland) or become climate change refugees
place specifics: Khulna Division and West Bengal
areas most affected by sea level rise
what will the population be by 2050, and what will the increase be from 2021
population of 200 million, a 30 million increase from 2021.
what percentage of people live in coastal areas less than 10m above sea level?
10%
what is happening at Banaripara?
using hydrophonics and salt tolerant
