Coasts case studies Flashcards
what is the Portland bill to Selsey bill sediment cell
- a coastal management area located on the south coast of the UK
- one of the 11 sediment cells identified in the UK
what is the Nile delta how has its coastline receded
- A region in northern egypt where the nile empties into the mediterranean sea
- receding at an average rate of 1.2 metres a year - one of the highest coastal erosion rates in the world
what physical factors are causing the nile delta to recede
sea level rise - causing more frequent and intense coastal flooding and erosion
natural subsidence - located on a soft and compressible sedimentary basin which is naturally sinking ; exacerbating the effects of sea level rise
Storm surges - vulnerable to storm surges because of its low lying topography and location (situated in an area where several large scale weather systems converge)
what human factors are causing the nile delta to recede
dam construction - construction of dams (aswan dam- reduced sediment supply from 130 million tonnes to 15 million tonnes a year) upstream have reduced amount of sediment that is transported downstream to the delta - not receiving enough to keep equilibrium
water diversion - diversion of water from the nile for irrigation is also reducing the amount of sediment
groundwater over extraction - causing lank to sink and exacerbating effects of sea level rise and natural subsidence
urbanisation development- rapid pop growth of delta region have led to construction of infrastructure in vulnerable areas - reduced natural protection provided by coastal ecosystems like mangroves and wetlands
over fishing and pollution - also contributing to loss of coastal ecosystems
climate change- burning of fossil fuels and deforestation causing sea level rise and more frequent intense storms
where is Bangladesh
country in south east asia
situated at delta of 3 rivers which flow into the bay of bengal in the south
what physical factors make bangladesh vulnerable to storm surges
low lying topography - only a few metres above sea levels - most areas only 1-3 metres above
geographical location - area frequently affected by severe weather events
shape of the coast - funnel shaped - concentrates force of incoming storm surges making them more destructive - bay also has shallow water allowing surges to travel further inland
river delta - countrys river delta has complex network of channels creeks and islands which are easily inundated by storm surges
what human factors make Bangladesh vulnerable to storm surges
population density - high population density especially along coast so increased risk of casualties and damage
urbanisation - resulted in construction of infrastructure in areas that are vulnerable making them more susceptible to damage
deforestation - has contributed to soil erosion and land loss reducing natural barriers to storm surges
agricultural practices - has lead to soil erosion which can increase risk of land loss during a storm surge
poor infrastructure - poorly maintained drainage systems and flood barriers
climate change -burning of fossil fuels and deforestation - leading to more frequent and intense storms and sea level rise
where is the maldives
small island nation located in indian ocean
what physical factors make the Maldives vulnerable to flooding
topography - one of lowest lying in the world- average elevation of 1.5 metres and highest point of 2.4 metres - vulnerable to sea level rise and storm surges - IPCC- sea level predicted to rise 50m by 2100 which would inundate 77% of its land area
what human factors make the maldives vulnerable to flooding
coral reef degradation - play a crucial role in protecting the maldives from wave action and storm surges - degradation caused by climate change overfishing and pollution is reducing their effectiveness
rapid population growth - led to construction of infrastructure in areas that are vulnerable - now more susceptible to damage
overdevelopment - infrastructure led to filling of wetlands and mangroves- natural barriers to flooding
lagoon dredging - removing more natural barriers
deforestation - contributes to soil erosion and land loss - removing natural barriers
climate change- human activities leading to more frequent and intense storms
poor infrastructure - poorly managed drainage systems and flood barriers
whats being done to prevent the maldives from flooding
building sea walls
promoting sustainable tourism - reducing carbon emissions from transportation
developing early warning systems - give time for preparation and evacuation
investing in renewable energy -decrease dependence on fossil fuels and decrease greenhouse gas emissions
encouraging sustainable development - preserving wetlands and mangroves
whats being done to reduce how vulnerable bangladesh is to storm surges
building and maintaining coastal embankments
developing early warning systems
establishing cyclone shelters - built in coastal areas for people during storms to prevent injury/death
promoting community based disaster risk reduction
encouraging sustainable land use - such as afforestation to reduce soil erosion and strengthen natural barriers against flooding
investing in climate resilient infrastructure - such as bridges and roads to ensure essential services not disrupted by storms
what was the 2013 north sea storm surge
- a major flooding event that affected parts of netherlands , germany and the UK
what caused the 2013 north sea storm surge
- low pressure system developed in the north atlantic and moved towards the north sea
- brought strong winds and heavy rainfall - led to significant rise in sea level
what physical factors contributed to the 2013 north sea storm surge
high tide - coincided with high tide which made an even higher sea level increase
coastal geography - north sea is shallow with a funnel shape that will concentrate power towards coastlines
what human factors contributed to the 2013 north sea storm surge
land use changes - deforestation , urbanisation and agriculture increase runoff and reduce capacity of ecosystems to absorb water
climate change - increased severity of weather events
impacts of the 2013 north sea storm surge
- reached 6.3m in places
-18,000 evacuated
-1400 properties flooded with no deaths - major impacts avoided due to thames barrier better sea defences and better forecasting ( compared to 1953 surge that caused over 2400 deaths
why is happisburgh an example of policy decisions leading to conflict
- the SMP decision here is ‘do nothing’
-this was against wishes of local residents , especially those on beach road where several homes have been lost
-house values are very low which has meant residents are unable to afford to move - campaigning by the CCAG (coastal concern action group) raised awareness nationally - a council bid for government money led to a 3 million grant
- grant was spent giving beach road residents grants to help them move
- beach road houses demolished to make buffer zone between village and cliffs - council constructed new homes on nesrby farmland so community stayed same size
what is the reason for the ‘do nothing’ approach in happisburgh
that sea defences over time would create a headland that would limit transfer of sediment downdrift so those areas would become even more vulnerable
what schemes were implemented in chittagong , bangladesh
- embankments to raise roads above normal sea level
-twenty five tropical storm shelters - new market areas with sheds raised on platforms above predicted 2050 sea level
what are the positives of the project in chittagong
generation of jobs ( reducing poverty )
reduction in road flooding to 5 days year from 20
what are the negatives of the project in chittagong
200 people relocated for roads realignment
embankments were slow to be constructed
natural habitats disturbed
what is the SMP decision at hornsea (holderness coast) and why
policy decision at hornsea is to hold the line
- its a regional economic centre with a pop of around 8500 people
- has important historical sites
- inland is Hornsea mere , a very important lake for birds that is identified as a special protection area and an SSSI
what is protecting mappleton
two rock groynes rip rap and cliff regrading
what did the SMP for mappleton state in 2010
that for this area the economic case for defending it is marginal
why is this a problem for mappleton in the future
- places of no active intervention could -
lose up to 400m of land by 2105
by 20105 the main coastal road is likely to be destroyed - by 2055 around 200 hectares of farmland lost
- would turn parts of mappleton into high risk locations - properties hard to sell
what is the problem with sustainable management in the maldives
- isolated islands likely will be ignored in favour of the capital and making new artificial islands
- sustainable management of traditional income sources such as fishing , and resources such as mangroves could be overlooked in favour of protecting urban and tourism development
- potential for CONFLICT
what is being done to help isolated islands in the maldives
- organisation mangroves for the future working with maldivian communities to teach importance of maintaining coastal swamps as a natural defence
- global environment facility has priovided small grants to islanders to help them develop sustainable and organic farming as an alternative food and income source to coral reef fish (threatened)
