V. THE ISSUES RELATED TO WATER RESOURCES
1 Drought
According to the researchers, the ability of the current supply of fresh water is a serious problem worldwide. There are at least 80 countries in the deserts and semi-deserts (about 40% of the world population) of the two continents of Asia and Africa prone to drought and crop failure so often do not provide enough food to feed their citizens from the well to the village. Prolonged drought in the region has made 273 rivers dry, 413 tanks and makes 3.19 million people with 1.58 million livestock short of drinking water falling into severe. In the 1970s drought disaster threatened about 24, 4 million people every year and has killed more than 23,000 people, the consequences still last until 1980. 1985 over 154 million people in 21 countries in Africa Chau fell into famine due to drought, in addition to the excessive population growth and the war spread, on the other hand is also due to the management and use of natural resources and agricultural development less efficient. In these countries, the poor have to spend time trying to find water is often in the rivers and streams have been polluted and the water to get the women and children have to walk 16 km - 25 km only a day and a tank full of water on the way back (Miller, 1988). The civil war lasted with drought occurred more than 60 years has made the lives of 12 million people in Somalia are severely threatened.
2 Flooding
In contrast, in other countries armed relative rainfall large is a large amount of rainwater received in just a short time in years. For example, in India, 90% of the rainfall concentrated in mid June to September often cause flooding. In the early 1970s, catastrophic flooding has threatened on 15, 4 million people every year and kills 4,700 average, average damages of $ 15 billion, this result still extended to 1980. Originally leading to flooding is caused by human deforestation, burning forests for farmland, mining, urban sprawl ... Although flooding is considered a deadly natural disaster and damaging flowers color and property of people but after the flood, caused by the deposition of silt increases soil fertility (Miller, 1988). To prevent and reduce the ravages of floods in this country, many measures are implemented as cropping of drainage, construction of dams and reservoirs, afforestation on barren hills, forests retain watershed.
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