Water World Flashcards
What is the Sahel?
A narrow belt of semi-arid land immediately south of the Sahara desert
How often does rain fall in the Sahel?
Rain falls in only 1 or 2 months of the year and both the total amount of rainfall and the length of the rainy season very variable. Sometimes rain comes in torrential downpours and is then lost as surface runoff, causing flooding
How does drought affect the Sahel?
Drought causes seasonal rivers and waterholes to dry up and the water table to fall.
How does drought affect the farmers in the Sahel?
Drought spells disaster for the nomads who graze animals and for subsistence farmers who rely on rain to grow millet and maize. Grasses die and soil erosion and desertification follow due to overgrazing animals. People have been forced to migrate to cities
What is the impact of toxic waste from mines on water sources?
Heap-leach mining uses sodium cyanide which can contaminate rivers and groundwater. Banned in many US states but common in NICs
What is the impact of plant fertilisers on water sources?
Nitrates run off into rivers and lakes causing eutrophication which kills off animals because they are deprived of oxygen
What is the impact of chemical waste of water sources?
Water consumed in China contains dangerous levels of arsenic, fluorine and sulphates, often discharged by factories
What is the impact of radioactive waste of water sources?
Nuclear waste can remain dangerous for many thousands of years. Storing it in the ground is risky because of the chance of leaks.
What is the affect of deforestation in the Kehama district in north west Tanzania?
80% of people are farmers; deforestation has occurred for timber, land for tobacco plantations, fuel wood + subsistence farming
Without trees surface runoff increases and groundwater levels decrease
Major floods have increased
Cholera and diarrhoea have increased
What is the affect of over-abstraction of groundwater in India?
65% of crop water and 85% drinking water come from groundwater wells
Water tables are falling by 4m a year
Over 60% of groundwater supplies will be in a critical state by 2020
What are the costs of the Three Gorges Dam in China?
Cost $26 billion to build
Is increasingly dirty + polluted by industry
Over 1 million people had to be relocated as reservoir flooded
Many ancient monuments were flooded
Some animals, like the Chinese river dolphin have become extinct due to habitat loss
What are the benefits of the Three Gorges Dam in China?
Stops devastating flooding on the Yangtze river
Generates 22.5 gigawatts of electricity (clean energy)
River can be navigated far inland more easily
Water supply to people nearby is more reliable
