Case Studies Flashcards
Flooding: Mississippi and Missouri
1993
Flooding: Mississippi and Missouri
Causes 5
Heavily saturated ground 400-750% increase in precipitation over the plains between April and August Building on flood plains Levees collapsing--> downstream Navigation--> dams built on tributaries
Flooding: Mississippi and Missouri
Impacts 7
$15-20 billion in damage 30,000m flooded 32 deaths 15 million acres of farm land destroyed "Ghost Towns"--> depopulation Emotional trauma Levee breakages
Flooding: Mississippi and Missouri
Management 4
People relocated
Dams, dykes, and levees built
River straightening–> moves faster
Dredging
Flooding: Boscastle
Boscastle Cornwall, 16th August 2004
Flooding: Boscastle
Causes 9
Impermeable bed rock upland on Bodmin moor
Thin soil and lack of vegetation –> 70% of vegetation removed in the last 200 years
Steep converging topography
3 fluvial systems joining
High tide
Debris forming dams under bridges
Saturated ground–> wet summer
89mm of rain in one hour–> river rise of 2 m
14 cars trapped debris –> a 3m river rise
Flooding: Boscastle
Impacts 5
75 cars, 5 caravans, 6 buildings and boats washed into the sea 100 + houses and businesses destroyed 150 people rescued from roofs and trees 4 foot bridges washed away £20 million in damages
Flooding: Boscastle
Management 4
River bed lowered by 0.75m
River widened
4.6 million defense scheme in 2008
Routine river clearing
Flooding: Harbertonford 3
River Harbourne
Flooded 21 in the past 60 years
Over £50,000 damage
Flooding: Harbertonford
Management: Palmer Earth Dam 7
2km upstream form the village 60 year lifespan Can hold a 1/400 year flood £850,000 4.1ha reservoir storage Afforestation 600mm drop in river bed level
Flooding: Harbertonford
Management: Storm drain 4
25 year lifespan
£4000
Overflow culvert
Speeds water up
Biomes: grassland
Serengeti, Tanzania
Biomes: grassland
Formation 5
Too much rain to be a desert Too little rain to be a rain forest ITCZ, 21st June tropic of Cancer ITCZ, 21st December tropic of Capricorn Effects convection cells, and therefore precipitation
Biomes: grassland
Characteristics
50-127cm of rain
2 seasons–> long dry winter, wet summer
Lions, zebras, elephants, giraffes, ungulates
Grass, acacia trees
Biomes: desert (warm)
Sahara
Biomes: desert (warm)
Formation 3
High pressure due to convection cells
Increased solar radiation
Little rain and clouds
Biomes: desert (warm)
Characteristics 2
Less than 35 cm of rain
Few plants and animals–> cacti and snakes
Biomes: desert (warm)
Threat of Climate Change 5
Desertification
Extinction of species–> Addax, Barbary sheep
Over the past 25 years 9/12 deserts studied have warmed faster than surrounding areas
Culture loss–> Tuareg Nomads
Temperature increase, water decrease
Causes of Climate Change (Natural) Volcanoes:
Volcanic aerosol reflects solar radiation, reducing the heat the earth receives.
Causes of Climate Change (Natural) Volcanoes:
Mount Tambora 7
1815
Indonesia
VEI-7
Led to the “Year without Summer”
Eruption column reached the stratosphere at 43km
0.5°C decrease in temperature
Sulfate concentration in ice cores increases
Causes of Climate Change (Natural) Oceans:
Long term 5
Laurentide ice sheet
Ice sheet melted in North America adding cold freshwater to the Atlantic
Stopped the convection currents that produce the Gulf Stream
Led to the European ice age–> Younger Dryas
500 years for the Gulf Stress to restart
Causes of Climate Change (Natural) Oceans:
Short term: El Nino 5
Dramatic reduction in trade winds
Convection cell breaks down
Warm water in the western tropical Pacific Ocean shifts eastward along the equator toward the coast of South America
South America receives more precipitation
Rest of the world deviates from the norm
Causes of Climate Change (Natural) Oceans:
Short term: La Nina 3
Trade winds are more intense
More rainfall in the west Pacific
Drought along the South American coast
Causes of Climate Change (Natural) Oceans:
Short term: El Nino Effects 9
1997-98= strongest El Nino in 100 years Heatwaves in India and TExas Floods in Bangladesh and China South Asia= late monsoon season Indonesia= forest fires Harvest failure= Africa Malaria increased Bleaching of coral reefs £50 billion total damage