Physical Case Study Flashcards
River exe location
South west England
Rises in the moorland of exmoor and travels 82.7km to reach sea at ex mouth
River exe catchment
601km
Why has the river exe got a large drainage density
Largely underlain by impermeable rock (84%)
How much of the catchment is grassland
67%
Annual rainfall for river exe
1295mm of rainfall annually
Land use % for river exe
67% grassland - farmland
15% woodland
10% arable land - crops
3% moors and peat bogs
How far above sea level is the source of river exe
514 metres
Location of Amazon rainforest
Covers large areas in the north of South America
Lies between cancer and Capricorn
Aprox 15•n to 15•s of equator
Size of Amazon rainforest
4% of earths surface
Climate of Amazon rainforest
27•C and roughly 2000+mm of annual precipitation
Amazon impact on carbon cycle
Accounts for 30-50% of global photosynthesis
Biodiversity of Amazon rainforest
Home to almost 20% of species on earth
Amazons impact on earths water
15% of global ocean water comes from the Amazon
Water cycle in Amazon
50% is used by plants and returned to the atmosphere
80% of rainfall is intercepted
Cause of deforestation in Amazon
Agriculture - 80%
Logging - mahogany
Road building - trans Amazon highway
Mineral extraction
Energy development
Settlement and population growth
Change in the Amazon
The Amazon basin has lost 17% of its primary rainforest in the last 50 years
Overall impacts of deforestation on the water cycle
Reduced evapotranspirstion
means less precipitation
Increased rates of runoff due to less trees
Soil is at risk of erosion which limits re growth
Mitigation on Amazon
Deforestation slowed by 75% between 2000 and 2021
Cattle ranching ban
Threat of prosecution
Protected areas
2006 soy moratorium
Eyjafjallajokull background
Constructive plate margin
North American and Eurasian plate diverge at a rate of 10-50 mm/year
Eyjafjallajokull nature of vulcanicity
Type of lava - basaltic
Viscosity - low
Shape - gentle sides, wide base, shield
Magnitude of eruptions - explosive
Hazards - ash, tephra, little lava, flooding
Primary impacts of Eyjafjallajokull
270 million cubic meters of ash ejected
110 million cubic meters of tephra
Very little lava
No deaths or injured
700 people evacuated
Secondary impacts of Eyjafjallajokull
Ash contaminated water supplies
20 farms were destroyed
150m thick ice cap was melted causing floods
2 bridges burst
Nepal earthquake of 2015 (Gorkha)
Magnitude -7.8
Date - April, 2015
Depth / focus - 15km - very shallow
80km north-west of Kathmandu
Vulnerability of Nepal to gorkha earthquake
Nepal GNI is £2730 per capita- its an lic
Kathmandu lies in a valley
Kathmandu has high population density
Infrastructure is poor
Impacts of gorkha earthquake
9000 fatalities
23,000 injuries
700,000 homes destoyed
200 killed in langtang landlides
5.17bn damage
Responses to gorkha earthquake
90% of Nepal’s military were deployed
The UN immediately released £15m
NGOs such as unicef brought in supplies
Background of hurricane Katrina
- New Orleans lies below sea level
- The levee system was not constructed to modern standards
- most of the population were not wealthy enough to leave
- 29th august 2005
- category 5 storm
Background of haiyan
- one of the strongest tropical storms ever recorded
- tacloban had experienced rapid rural-urban migration leading to high population
Primary impacts of hurricane Katrina
Over 1000 fatalities
More than 1 million became refugees
80% of New Orleans flooded
Primary impacts of typhoon haiyan
Over 6000 fatalities
2 million people made homeless
6 million displaced
Over 130,000 tonnes of rice lost
Responses of hurricane Katrina
Other countries responded, with Kuwait giving £500 million
Public donated 1.8 billion
1.2 million people evacuated the day before the storm
Responses of typhoon haiyan
The UN released £25 million in emergency funds
The uk deployed two navy ships supplying over 200,000 tonnes of aid
Background of Alberta wildfire
May 2016
Fire ignited in a remote forested area in fort mcmurray
The fire jumper a 1km river and was hard to control
Impacts of the Alberta wildfire
90,000 residents of fort mcmurray were evacuated
No fatalities or injuries
2400 homes and businesses were destroyed
600,000 hectares of land was destroyed
Response of Alberta wildfire
Was monitored using ground and satellite data
The complete evacuation was done on the 3rd of may
Red Cross and government both donated 50 million
Vulnerability of Philippines (MHE)
High population - 11 million people live on the coast of Manila
Poverty - 75% live in poverty
Lack of investment in hazard protection
Nature of hazards in Philippines
Tropical storms - 7-10 each year some very powerful e.g. haiyan
Earthquakes - 17 earthquakes above 5 magnitude between 2000 and 2013
20 active volcanoes
Physical vulnerability of New Orleans
50% lies below sea level
Lies in the gulf coast
City is surrounded by levees which acts a a bowl
How is the delta formed
Deposition from 3 rivers
Ganges
Meghna
Brahmaputra
Geography of the sundarbans
Larger channels tend to be straight, flow north to south and up to 2km wide
Smaller channels (khals) connect these large river
Khals drain land at low tide
Risks of sundarbans
Royal bengal tigers becoming an increasing threat due to deforestation and decreased habitat.
Coastal flooding due to eustatic sea level rise
Increased cyclones due to warmer seas and temperature
Increase coastal erosion due to eustratic sea level change
Over exploitation
Location and background of sundarbans
Coastal zone occupying worlds largest delta
Extends over southern Bangladesh and NE India w a population of over 4 million
Are a series of many islands with mangrove forests and swamps
Opportunities of sundarbans
Provide a wide range of goods and services for locals
Goods include
Wood, food, fishing materials
Services include
Protection
Value for tourism and education
Safety provided by sundarbans
Reduce force of tsunamis and cyclones by 90%
Value of sundarbans
Forests have a value of $12,000 per hectare
Adaptions to the challenges of sundarbans
Cyclone shelters being built
Introduction of salt tolerant rice
NGOS building latrines ( toilets above sea level )
Location of east Norfolk coast
Is located on the east coast on England
Includes the villages of happisburgh, bacton, sea palling and winterton
Happisburgh
Population of 1400 in 600 houses
Surrounded by low value agriculture land
Bacton
1200 people
Bacton gas terminal which processes North Sea gas
Sea palling
Low lying and has 650 people
Norfolk B-roads is located behind the village
Winterton on sea
1200 people
Geology of east Norfolk coast
Composed of glacial till, silt and clay
Cliffs are between 6-10 metres high
Rising sea levels will increase erosion rates
Coastal management of east Norfolk coast
TRADITIONAL APPROACH
Groynes, riprap and revetments introduced in the 50s after floods
Changes in government policy meant funding was no longer available for coastal management
In 1990 a storm destroyed 300 metres of wooden revetments
Coastal management of east Norfolk coast
SUSTAINABLE APPROACH
In 1996 a shoreline management plan SMP6 was created for the area
This used integrated coastal management
SMP6 covers a sub cell of sediment cell 3 - an area of the coast in which longshore drift is self contained
Stake holders in SMP6
Environment agency
North Norfolk district council
Local borough councils and regional coastal groups (locals):
Traditional approach was unsustainable due to several factors
Geology of the coast
Sizeable fetch and storms of the North Sea
Tidal ranges of over 5 metres
Frequent storm surges
Exmoor mores project
Restoration of peat bogs on Exmoor has resulted in a third less water leaving the moorland during heavy rainfall
By blocking up drainage ditches, the moorland can now hold more water and release it more slowly
Average rate of erosion on the east Norfolk coast
2 metres a year
Current strategy for bacton
Hold the line
Maintain the sea walls
New rip rap
Build fresh Groynes
Current strategy for happisburgh
Managed retreat due to low population and low value land
Impact of managed retreat on locals in Happisburgh
Population unhappy
Formed a group called coastal resident group
Local authority placed rock armour for a compromise
Failures of smp6 in east Norfolk coast
Failed to consider inland areas that are affected by erosion
Why are sundarbans island stable
Clay and silt are resistant to erosion
What are chars
Deposited sand at mouth of the rivers
How do mangroves develop
Vegetation succession on exposed sand
Causes and effects of flooding on the Bay of Bengal
Causes - eustatic sea level rise
Effects - high salinity of water
