coasts case study Flashcards
(27 cards)
portland bill to selsey bill
proof of land level rise emergence coasts and examples (2)
raised beaches- little Gruinard (NW scotland)
abandoned cliff line- Kings cave (have caves cut by marine erosion but are now left higher and dry + unaffected by marine erosion
proof of sea level rise submergence coasts (5)
- Ria
- Fjord
- Barrier island
- Dalmation coasts
- tectonic activity
what is a ria and an example
Ria- are submerged river valleys- lowest part of the river’s coarse and the floodplains may be completely drowned but tops of valley course remain exposed (Kingsbridge Ria- south devon)
what is a Fjord and an example
Fjord- are submerged glacial valleys- have very steep sides and the water in a fjord is very deep (Milford Sound- New Zealand)
what is a barrier island and an example
Barrier islands- formed initially as lines of coastal sand dunes attatched to the shore. sea level rise floods the land behind form a lagoon, leaving the dunes as islands (East coast of America)
what is a dalmation coast and an example
Dalmation coasts- form where there are hills running parallel to the coast. rising sea levels submerge the area to create long narrow islands arranged in lines. (dalmation coast-Croatia)
whats tectonic activity to prove sea level rise and an example
tectonic activity raised beaches- a series of storm beach ridges. The ridge very close to the shore is the present storm beach ridge. then there is previous inland ridges (New Zealand)
how is holderness coast at risk of coastal retreat
- average it loses 2m of a coastline every year
- lack of physical protection of cliffs by narrow and low beaches
- has boulder clay that can easily be eroded
- 30 villages been lost to sea over 2000 yrs
coastal recession occured at the river nile delta
- aswam High Dam- discharge (amount of water in the river) decreased from 25 billion m3 to 10 billion m3
- Sediment volume fell from 130 million tonnes. To 15 million.
- Water withdrawals for industry, cities and agriculture from the reservoir Lake Nasser.
- water in reservoir flows very slowly allowing more sediment to be deposited.
- the Aswan high dam trapped 98% of the Nile’s sediment upstream. caused less natural beach replenishment.
- Saltwater intrusion into farmland → damaging agriculture, economy, and making land less stable.
what are the impacts of coastal recession occured at the river nile delta
what management has been done
- Loss of fertile farmland: threatens food security in a region with major reliance on agriculture.
- Urban risk: Alexandria, a major city (over 5 million people), is at risk from rising seas and storm surges.
- Projected land loss: up to 33% of the Nile Delta could be underwater by 2100 if current trends continue.
- Seawalls, gabions, and revetments have been built around key cities like Alexandria.
- ➔ Groynes installed to trap sand and stabilise beaches.
2013 north sea storm surge characteristics
wind speeds over 140mph
15 fatalites accross the uk, holland, germany
factors inceasing vulnerability in the 2013 north sea storm surge
- north sea becomes shallower in southern England, leads to higher wave heights in the South
- north sea is open to the Atlantic and the coastline is funnel shaped therefore low lying coastal settlements are at great risk of flooding
why is Bangladesh vulnerable to coastal flooding
(6)
- much of country is low-lying river delta only 1-3m above sea level
- storm surges meet outflowing river discharge
- have intense rainfall
- almost all coastline consists of unconsolidated delta sediment (susceptible to erosion
- deforestation of coastal mangrove (removed vegetation stabalised coastal swamps
- triangular shape of the Bay of Bengal concentrates a cyclone storm surge
what have Bangladesh done to reduce the impact of coastal flooding
- improved warnings
- construction of cyclone shelters
- better aid response
effects of cyclones in Bangladesh (5)
- many meters of coastal erosion
- reshape whole stretchlines of coastline
- river channels in the delta can shift dramatically,
- eroding farmland
- creates new areas of deposition elswewhere
what are the Dynamic Pressures of Bangladesh
- Most densely populated country in the world.
- 46% of the population lives below 10m (within LECZ)
- Lies on the floodplain of 3 major rivers
- Low levels of development (0.614 HDI)
issues for tuvalu
- its highest point is only 4.5m above sea level
- water supply is limited and at risk from salt water incursion
- have small economies based on tourism and fishing (easily disrupted)
- high population densities
- lack the funds to finance coastal defences to protect huge lengths of coastline.
what are the social impacts of the 1953 storm surge in the Netherlands
- 1,800 deaths
- 100,000 evacuated
- outbreaks of many diseases
what are the economic impacts of the 1953 storm surge in the Netherlands
- 3,000km road destroyed
- 300 bridges damaged
- cost of infrastructure repair to be €450 million
what are the environmental impacts of the 1953 storm surge in the Netherlands
- 200,000 hectares of farmland destroyed
- 30,000 livestock drowned
- large coastal erosion
delta worken netherlands response to the storm surge
- series of dams, storm surge barriers, and dikes designed to protect the Netherland’s from the North Sea
- cost approximately 5 billion euros.
national flood warning system also developed and new evacuation plans
managing lyme regis
sustainable management in the maldives (3)
- sustainable management of traditional income sources such as fishing and resources isoverlooked in favour of protecting urban anf tourism develolped
- MFF is working with Maldivian communites to educate on importance of coastal mangrove swamps as natural defence against coastal erosion and flooding
- GEF provided small grants to islanders to help develop sustainable and organic farming as an alternative food and income source to coral reef fish
