issue 207 - May 1990
By the end of the century global consumption of water will be ten times greater
than it was in 1900.¹ Yet many people in the Third World are still without adequate
water and sanitation. Here are the facts on water and waste worldwide.
Two-thirds of the world's households use a water source outside the home - and the water haulers are invariably women. A person needs 5 litres a day for drinking and cooking; 25 more to stay clean. The most a woman can carry in comfort is 15 litres.9 Water is heavy: many pots and buckets carried on the head weigh 12 kilograms when full; 18-litre plastic jerrycans now commonly in use weigh 20 kilograms. It is not uncommon for women in some parts of Africa to spend five hours a day on hauling water.10
WATER RICH, WATER POOR
The annual renewable supply of water available for use is around 3,000 cubic metres per person. Under current climatic and population-growth conditions 70% the supply per head will drop to 2,230 cubic metres by the year 2000. This is an alarming drop but is still more than enough given that our annual water-use in 1990 (averaged worldwide) is 750 cubic metres per person. Nevertheless, because the world's water is unevenly distributed, some countries will experience a 'water gap' by the end of the century.2
Heavy demand on water for irrigation - especially in Asia - is lowering water tables, putting city and even village supplies under pressure. Most irrigation methods are extremely inefficient, wasting two-thirds of water used and causing both waterlogging and land degradation. Competition between farmers and citydwellers - as well as between nations - is bound to increase.3
A DECADE OF PROGRESS
The UN International Drinking Water Supply and Sanitation Decade was launched to provide 'water and sanitation for all by 1990'. This ambitious target was never realizable and 300 million more people lack sanitation in 1990 than in 1980. But in percentage terms there has been some progress, especially with water: 50% of people in rural areas now have an adequate water supply compared with only 30% ten years ago. 5,7
Proper hygiene and sanitation is at least as important as clean water in combatting the worst water- and dirt-related diseases.11
Examples: diarrhoeas and dysenteries, including cholera, e. coli diarrhoea, salmonellosis, giardiasis, amoebic dysentery, enteric fevers such as typhoid, poliomyelitis, hepatitis A, ascariasis, trichuriasis.
Disease toll: 5 million children under the age of five die annually of dehydration caused by diarrhoea; around 100 million people suffer diarrhoea at any one time.12
Prevention: Sometimes the bug is carried in the drinking water and passed on that way but dirty hands or food are at least as often to blame. Washing is very important.
Examples: schistosomiasis (bilharzia), transmitted by water snails; guinea worm (dracunculiasis), transmitted by water flea.
Disease toll: 200 million people suffer from the lassitude of schistosomiasis, mostly those living by slow-moving bodies of water;13 10 million suffer from guinea worm and are out of action for the painful weeks of the worm's emergence through the skin.
Prevention: Avoid wading in the water or imbibing it; clear the snails or fleas from the water source; strain drinking water.
Examples: malaria, sleeping sickness, river blindness, yellow fever. All are spread by flying insects - certain species of fly and mosquito - which breed in or bite near water.
Disease toll: Each year 800 million people suffer from malaria, one of the most pervasive and debilitating of the world's endemic diseases. It kills one million children under two in Africa each year. One million people suffer from river blindness (onchocerciasis) carried by blackfly, of which 340,000 are already blind.14
Prevention: The vectors - the flies and mosquitoes - have to be controlled by spraying and drainage; or the parasites they carry eradicated by eliminating the disease in humans.15
THE QUANTITY KEY
80% of disease in developing countries is related to poor drinking water and sanitation. Water quantity is even more important than quality when it comes to health - because a lot of water is needed to keep the body and household clean. The key to increasing the water consumption of the poor is giving them easier access to a supply. Until their distance from a source is reduced to less than five minutes' walk, water consumption does not rise significantly.8
HOUSEHOLD WATER CONSUMPTION²
Households with dishwashers, washing machines, and sprinklers: 1,000 litres a head per day
Households with a piped supply and taps: 100-350 litres a head per day
Households using a public hydrant in the street: 20-70 litres a head per day
Households depending on a stream or handpump several miles distant: 2-5 litres a head per day
1 Investigations of land water resources, A Shiklomanov. Source. UNESCO, 1990.
2 Water for Agriculture, Sandra Postel (Worldwatch 1989).
3 Water: Rethinking Management in an Age of Scarcity, Sandra Postel (Worldwatch 1984).
4 World Health Statistics Annual 1988, WHO.
5 Towards the Targets, WHO 1988.
6 Water and Sanitation for Health: Towards the Year 2000, UNDP.
7 UNICEF and the 1990s: The Water and Sanitation Sector Workplan for t990-t995, UNICEF 1989.
8 Health aspects of water and sanitation, Sandy Cairncross, Waterlines, Vol 7, no 1.1988.
9 Women, A World Report Debbie Taylor et al, UN/Methuen 1985.
10 Women and Water in the Developing World, WaterAid Fact Sheet 1989.
11 Environmental Health Engineering in the Tropics, Sandy Cairncross and Richard G Feacham (John Wiley, 1988).
12 State of the Worlds Children Report, UNICEF 1989.
13 Water, Sanitation, Health - For All?, Earthscan 1981.
14 Source, Vol. I No 2, UNDP, September 1989.
15 Illustrations from Sanitation Without Water, SIDA (the overseas-aid arm of the Swedish government),1980.