Coast case studies Flashcards
What are a few facts about old man hoy?
- Vegetation helps it to stabilise
- Horizontal bedding planes
- Slight seaward dip
- Base stack is igneous basalt
- Blocks at the bottom from former arch
What are a few facts about Flamborough head?
- Base of cliff is where undercutting occurs forming wave cut notch- undercutting until cliff collapses
- Surface of wave-cut platform uneven due to differential erosion
- Limestone cliffs
What are a few facts about a spit?
- Spurn point a sand and shingle spit 5.5km long and 50 miles wide
- Spit forms sweeping curve which continues the line of the coast because of different prevailing wind
- The energy in the waves transporting materials reduces where north sea meets Humber estuary causing deposition
- LSD moves east to south, so prevailing wind is from south east
What are a few facts about a tombolo?
- Tombolo which connects two land masses is 500m long and is subject to waves form different directions
- In winter sand is lost from the centre and builds up at the ends and is summer opposite occurs
- During low tides it can be 70m wide and during high spring tide it can be submerged
What are a few facts about a barrier beach?
- 18-mile-wide shingle barrier beach stretching from west Bay to Portland
- In some places 15ft high and 200m wide
- Behind is a shallow tidal lagoon and barrier beach protects it (Submergent)
- Longshore drift going from east to west, so prevailing wind is from southeast
What are a few facts about a cuspate foreland?
- Formed as prevailing wind brings sediment through LSD together in opposite directions
- Headland cuspate foreland off the coast of Kent and mostly made up of shingle
- Some cuspate forelands may be stabilised by vegetation, while others migrate down the shoreline
What are a few facts about a hooked spit?
- Formed be LSD from the west
- The salt marsh has formed behind Hurst castle spit, which has formed because of LSD from the West
- Key haven salt marsh are under threat from the construction of groynes down current (to the west) which were designed to trap sediment.
What are a few facts about UK sediment cell 2?
- Starts at Flamborough head and finishes at the wash
- Transfers- Longshore drift south to southeast towards the wash, Offshore currents into the North Sea.
- Inputs- Holderness coast cliffs, Flamborough head and the Humber estuary.
- Sinks- Spurn head spit, beaches to the south of Grimsby
California Coastal flooding case study
- California coast stretches 1,264 miles, so hard to manage
- More than half of California people reside in coastal regions
- California has two natural bays SF bay and SD bay
Subsidence: - 80% of water extraction is from farmers – increases subsidence as water is removed from the ground – CA sinking by 1 foot per year
El Nino: - Happens in tropical Pacific Ocean- fluctuation in earth’s climate system weather trade winds mean more warm sea in eastern pacific- more low-pressure systems- which leads to lots of erosion and flooding
Waves: - Hurricane Marie 2014- Storm surge can add 50-100% of existing water
- Areas like laguna beach lots of beach replenishment but exposed to lots of waves on the coast-High risk to coastal flooding
- Santa Monica prioritised for coastal management- large amount of beach replenishment – Better protection and more successful
- Santa Barbara- high risk of flooding and coastal recession
- San Francisco bay natural wetlands- Salt marsh removed for development- low lying estuarine region
- Land subsidence on estuary led to higher flood risk
Bangladesh coastal flooding case study
Mangrove swamps protect Bangladesh from storm surge because they absorb wave energy
- Bangladesh is vulnerable because only above sea level by 5-8m near Dhaka- Vulnerable to storm surge
- Waves funnelled into one area most wave energy hitting one area- Bay of Bengal- more vulnerable to storm surge
- Mangrove swamps removed for development less wave energy dissipated- more vulnerable
- Sundarbans only protected mangrove forest while others damaged/removed
- Mangrove forests income generation and food security
- Increasing industrial development- gradually deteriorating mangrove ecosystem
Maldives coastal flooding case study
Economic impacts:
- Loss of tourism (about 33%of GDP)
- Makana national airport may be shut down due to flooding cutting of international tourism- 1 million travelled in 2015
- Coastal flooding may also damage fish processing plants- reducing Maldives fish exports (10% of GDP)
Social impacts:
- Houses could be damaged or destroyed and severe flooding can make entire communities homeless
- Supplies of freshwater are already low on many of the islands and at a risk of being polluted by sea water- many have tp rely on rainwater and desalinisation plant (economic)
Environmental impacts:
- Coastal flooding wears away beach at very rapid rate- Destroying habitats
- Soil on most islands shallow and can be easily washed away- most plants unable to grow
Dawlish storm surge case study
- 1.2 billion pounds lost
After winter 2013: - 25000 tonnes of collapsed cliff removed at Teignmouth
- Hundreds of tonnes of debris removed
- Line was shut for 2 months
- £35m reduction in holiday spending
Holderness coast- skip sea- East riding of Yorkshire case study
- No national scheme to compensate people losing their homes
- Local council have to cover the demolition of the houses- limited money given to those moving
- Offering up to £1000 in relocation expenses and up to £200 in hardship expenses
- Council expects 100 homes to be lost in next few decades
Kiribati-nation under threat due to climate change- case study
- Risk of being inhabitable due to sea level rise
- Seawalls have been broken
- United states responsible for ¼ of CO2 emissions
- 40% of people live near the coast
- People of Kiribati trapped 6ft above sea level- salt water can poison ground and sources
- People leaving
- Purchasing land in Fiji for civilisation
- People of Kiribati being rejected as climate refugees
- 145 million people live only 3ft above sea level or less
- Also affects developing countries through flooding- lots of floods in New Orleans and San Francisco
- Trump withdrew from Paris climate agreement
Australia- consequences of coastal recession case study
Causes of risk:
- 3mm of sea level rise per year
- Overall, 1.2m of sea level rise
- Many mega cities on low-lying areas
- Sea level stable until 19th century- Industrial revolution
- 13cm of flooding could have big risk
Social impacts:
- 250,000 houses at risk
- May lose 7-5 hospitals
- Increase in unemployment- fisheries- 30 billion GDP and tourism
Economic impacts:
- Loss of potential 120 ports and 5 power stations
- 0.5m sea level rise = 2.8 billion in damage
- $3.9 million a year spent on beach nourishment
Environmental impacts:
- Affects natural ecosystems – Freshwater habitats
- Ground water affected by salt intrusion
