Water case studies Flashcards
(46 cards)
Change to river discharge of Tocantins River Brazil?
25% increase in river discharge between 1960 and 1997, coinciding with increased deforestation.
How does human activity affect evapotranspiration in the Amazon?
75% of intercepted water is returned to the atmosphere by evapotranspiration which reduces to around 25% when the forest is cleared.
What percent of the world’s rainforests does the Amazon contain?
60%
How many trees does the Amazon rainforest have?
400 billion trees that transport humidity inland from the Atlantic Ocean. This takes up to 20 billion tonnes of water vapour daily from the forest and dumps it as rain on central and southern Brazil.
Effects of drought in Brazil? (Hint: people, reserves, coffee)
Over 4 million people affected by rationing and power cuts.
17 major reserves dipped to critically low levels.
A 15% drop in Arabica coffee production drove global prices up by 50%.
Effect of deforestation on ecosystem resilience?
Deforestation has reduced ecosystem resilience and a positive feedback loop is caused by deforestation (reduced soil water storage and evapotranspiration lead to less rain).
How much of the Pantanal do seasonal floods cover?
Seasonal floods cover 80% of the Pantanal, changing terrestrial land to aquatic.
What did the 2014-15 drought in Pantanal do?
The 2014-15 drought increases tree mortality, reducing ecotourism and reducing habitats.
Wildlife became a major threat caused by cattle ranchers started fires that quickly spread out of control into the wetlands and surrounding forest during the drought.
Indus river regime?
Has high seasonal variability and most of the basin sits in a rain shadow and undergoes long periods of drought which are closely linked to El Nino events.
What effect did the Indus Water Treaty have?
The Indus Water Treaty grants India control over the three eastern rivers and Pakistan control of the three western rivers including the Indus river.
Source of water for the Indus River?
Primarily snow-fed from the Himalayan mountain ranges and receives a lot of water from the Asian monsoon rains.
Murray-Darling Basin river regime?
Has high seasonal variability and most of the basin sits in a rain shadow and undergoes long periods of drought which are closely linked to El Nino events.
Which area has become drier in Asutralia and since when?
The eastern areas (where most people live) have become drier since the 1970s.
What was the Big Dry and how did it pit “town against country”? (4 points)
The “Big Dry” was a 1 in 1000 year event affecting more than half of farmlands.
The drought issue pitted “town against country”, people against farmers.
The town blamed irrigators for mismanagement of water and believe farmers are over-abstracting water from Murray river.
Farmers believed the drought was due to lack of rain not agriculture. The Murray Basin produces 50% of Australia’s food so farming is essential. Minimal city restrictions on water use but farmers were close to ruin from drought.
Physical reasons for drought in the Sahel?
Occupies a transitional climate zone. Almost all rainfall is concentrated in the summer. Annual variability due to unusually warm sea temperatures weakening the West African monsoon.
Human influences on drought in Sahel?
Human factors don’t cause drought here but act like a positive feedback loop and enhance its impacts.
Snow melt in Siberia
Ice damming results in an intense rise in water levels, both upstream and downstream during break-up and flooding affected over 6,000 people.
What was the cause and effect of the Niger famine 2005?
Drought and locus infestation caused a famine in Niger 2005 as food production decreased by 15%. This made local food commodities unavailable and people consumed cereal seeds, leaving little in store for next year.
Flash flooding Cornwall
Boscastle experienced flash floods after thundery showers caused the small river in the village to overflow. Flood exacerbated by lack of flood control.
Monsoon rains in Southeast Asia
Caused by warm moist air bringing a humid climate and torrential rain.
Changing land use in Nepal and Tibet (flooding)
Deforestation in Nepal and Tibet is increasing the frequency and magnitude of floods in Bangladesh from the Ganges and Brahmaputra river.
Mismanagement of rivers (flooding)
The building of dams in India has increased the problem of sedimentation in Bangladesh.
How many people don’t have access to safe water or sanitation?
In 2015, 15% of the world’s people did not have reliable access to safe water and 25% lacked sanitation.
What does the OECD report predict about global water demand for manufacturing?
It would increase by 400% from 2000-2050.
