coastal systems -sundarbans (case study) Flashcards
(18 cards)
what is the case beyond the UK called?
.sundarbans
what is the sundarbans?
.an ecosystem that offers a wide range of vital ecological services eg -cyclone protection, wildlife habitat, food and natural resource provision, carbon sequestration
how many people is the sundarbans home to?
7.2 million people
.half the population live below the poverty line
where is the sundarbans?
.covers southern Bangladesh and India
what are the key characteristics of the sundarbans?
.formed from sediment deposited by three rivers that flow in the Bay of Bengal
.extends over 10,000km2
.network of tidal waterways, mudflats and small islands of salt-tolerant mangrove forests
.wide range of animals, including 260 bird species and the Bengal tiger
what are mangrove forests?
.group of trees and shrubs that live in the coastal intertidal
.trees that grow in areas with low-oxygen soil, where slow-moving waters allow fine sediments to accumulate
.grow at tropical and subtropical latitudes near the equator as they cannot withstand cold temperatures
what are the characteristics of mangrove forests?
.prop’ roots: dense and tangled that absorb the energy of tropical storms
.roots are adapted to salt water and the daily rise and fall of tides, so most mangroves get flooded at least twice per day -halophytes
.the root system of mangroves also makes these forests attractive to fish and other organisms seeking food and shelter from predators
what are the coastal processes affecting the sundarbans?
.tidal action
.erosion
.deposition
what does tidal action result in for the sundarbans?
.strong tidal current flows north at high tide and south at low tide twice a day -this frequent movement of water creates large, straight channels that are 2km wide
. inundates the forest areas with sea water from the Bay of Bengal twice a day.
.at low tide, all water drains from the forest areas -creating the extensive network of interconnecting smaller channels, known as khals.
how does erosion effect the sundarbans?
.network of channels are made up of clays and silts -which are quite resistant to erosion
.prop roots of the mangrove forests dissipate energy creating low-energy coastal environments -reducing erosion from storm surges, currents, waves, and tides
so the interconnected river channels remain static and rarely move
how does deposition affect the sundarbans?
.mangrove prop roots slow the movement of tidal waters, causing sediment to be deposited and build up a muddy riverbed/seabed
.non -cohesive sediment like sands are deposited on banks at the river mouths.
.south westerly prevailing wind blows deposited sand into sand dunes
how do dunes act as protection for fine sediment?
.dunes act as protection for fine sediment as it allows it to be deposited further and over time, new islands are developed
.over time, vegetation is established on these islands which leads to a climatic climax of mangrove forests
what are the opportunities by living in the sundarbans?
.services -flat fertile land is ideal for growing crops, particularly rice
.services -mangroves are a natural
defence against flooding; 30 trees can reduce the destructive force of a tsunami or cyclone by up to 90%
.goods -cargo ships transport goods such as oil and food in for people to buy and trade
what are the risks of living in the sundarbans?
.natural -area is affected by cyclones -13 supercyclones in the past 23 years
.natural -flooding can lead to salinisation making it hard to grow crops -soil salinity increased 6x over 30 years
.human -growing population means more fuel and farmland is needed, so mangroves are being removed, over 20 years110 km2 of mangroves disappeared
how are the risks overcome?
.resilience
.mitigation
.adaptation
how are the risks overcome through mitigation?
.protect and replant mangrove
.cyclone shelters and early warning systems
.communities can use open access natural resources such as khas land, fisheries and forests -government owned land that is protected for use by local populations
how is resilience used in order to overcome the risks of living in the sundarbans?
.build roads and bridges to improve access
.training in sustainable fishing and farming -fertile soils and ecological diversity provides a plentiful supply of a large range of nutritious foods
how is adaptation used to overcome the risks of living in the sundarbans?
.salt-resistant rice crops – using a new variety of rice than can be submerged in salt water for two weeks
.build houses and cyclone shelters on stilts
.sustainable farming - USAID has provided 30,000 farmers with sustainable farming techniques
.education and disaster preparation from NGO’s reduces impacts of hazards
