Archive for Facts and figures

Facts and figures about biological diversity

The leading causes of aquatic species decline and ecosystem degradation are physical alteration, habitat degradation and destruction, water withdrawal, overexploitation, pollution and the introduction of non-native species.

It is rare that a species or habitat is endangered by a single threat and to determine the root cause is very difficult, if not impossible to determine, because of the complexity of the systems involved.

While only 12 percent of species find their habitat within coastal or freshwater ecosystems, nearly all terrestrial species depend on water for their survival. In addition, in Europe, 25 percent of birds and 11 percent of mammals use freshwater wetlands in order to breed and feed.

Studies regarding global aquatic biodiversity only began in earnest in the early 1990s and there are still relatively few global assessments that have taken place.

More freshwater ecosystem species are threatened with extinction than either terrestrial or marine species. In one study, it was found that, on average, about 50 percent of freshwater species populations fell between 1970 and 2000.

According to the IUCN, there are over 3,000 freshwater species that are listed as threatened, over 1,000 are fish and nearly 1,900 are amphibian.

For larger freshwater species, four out of the five river dolphins and two out of the tree species of manatees and 40 freshwater turtles are threatened.

Information from:
2nd United Nations World Water Development Report: “Water, a shared responsibility”

Source: UNESCO Water Portal, June 2007

Facts and figures about qanats

Qanat (karez or foggara) irrigation systems are ancient (circa 800 BC) and consist of underground tunnels constructed into a cliff, scarp or base of a mountainous area, following an aquifer, or from rivers, to bring water out to the surface. The tunnels are straight and horizontal with a slope to allow the water to drain out into an oasis or irrigation system.

The volume of water produced by qanats depends on the type and extent of the aquifer, and its recharge rate. When tunnelling horizontally, air shafts 15-55 meters deep are constructed every 15-47 meters to remove the mined soil, clean the tunnels of silt, and aerate the tunnels.
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Facts and figures about Water and AIDS

Every year over 2.8 million people die from AIDS.


Improved nutrition and food security reduces susceptibility to diseases, including HIV/AIDS.


Improved water supply and sanitation reduces susceptibility to and severity of HIV/AIDS and other major diseases.


Safe access to drinking water and basic sanitation eases the pressure by other infections on the immune system of HIV/AIDS sufferers and allows for better health.


Interactions between epidemiological status and human vulnerability to subsequent stresses and shocks are well documented. For example, rural populations affected by HIV/AIDS are less able to cope with the stress of drought. Likewise, individuals living with chronic or terminal diseases are more vulnerable to emergency situations.



The section “Did You Know…?” is taken from the 2nd United Nations World Water Development Report: “Water, a shared responsibility”.

Facts and figures about water and industry

Water is used by industry in a myriad of ways: for cleaning, heating and cooling; for generating steam; for transporting dissolved substances or particulates; as a raw material; as a solvent; and as a constituent part of the product itself (e.g. in the beverage industry).

The water withdrawals for industry are:

·         World: 22% of total water use.

·         High-income countries: 59% of total water use.

·         Low-income countries: 8% of total water use.

Industries based on organic raw materials are the most significant contributors to the organic pollutant load with the food sector being the most important polluter. The contribution of the food sector to the production of organic water pollutant is:

·         High income countries: 40%

·         Low-income countries: 54%

In developing countries, 70% of industrial wastes are dumped untreated into waters where they pollute the usable water supply.

The annual water volume used by industry will rise from 752 km≥/year in 1995 to an estimated 1,170 km≥/year in 2025.

In 2025, the industrial component is expected to represent about 24% of total freshwater withdrawal.

Of major concern are the situations in which the industrial discharge is returned directly into the water cycle without adequate treatment. If the water is contaminated with heavy metals, chemicals or particulates, or loaded with organic matter, this obviously affects the quality of the receiving water body or aquifer. The toxicity levels and lack of oxygen in the water can damage or completely destroy the aquatic ecosystems downstream as well as lakes and dams, ultimately affecting riverine estuaries and marine coastal environments.

Past mining activities caused heavy arsenic contamination of groundwater and topsoil over 40 km≥ in Nakhon Si Thammarat province, Thailand. A study commissioned by the Japan International Cooperation Agency (JICA) in 2000 concluded that the contamination would last for the next 30 to 50 years. Testing of 1,000 samples showed arsenic contamination in some groundwater wells to be 50 to 100 times higher than the World Health Organization’s guideline value for drinking water (0.01 milligrams per litre).

In 1986 a fire destroyed a chemical store in Basel, Switzerland, near the borders of France and Germany. Chemicals reached the water in the Rhine River through the plant’s sewage system when huge amounts of water (10,000- 15,000 m3) were used to fight the fire. The store contained large quantities of 32 different chemicals, including insecticides and raw ingredients, and the water implications were identified through the presence of red dye in one of the substances, which turned the river red. The main wave of chemicals destroyed eels, fish and insects, as well as habitats for small animals on the riverbanks. The total eel population was destroyed for 500 kilometres downstream, from Basel in Switzerland down to Loreley in Germany. It took 3 months after the incident for the contaminant concentrations to drop to normal values.



Information from 2nd United Nations World Water Development Report ‘Water, a shared responsibility’, and from the ‘Water and Industry‘ facts and figures section of the World Water Assessment Programme (WWAP) website.

Facts and figures about water and salinization/desalination


Water, sanitation and hygiene are three intertwined determinants of the water/ill-health/poverty spectrum, considering hygiene in its broadest sense, including environmental as well as personal hygiene.

A lack of adequate sanitation is the most critical determinant of contamination of drinking water with micro-organisms.

More than 2.6 billion people – 40% of the world’s population – lack basic sanitation facilities.

Over 1 billion people around the world still use unsafe drinking water sources.

The diseases and conditions of ill-health directly associated with water, sanitation and hygiene include infectious diarrhoea (which, in turn, includes cholera, salmonellosis, shigellosis, amoebiasis and a number of other protozoal and viral infections), typhoid and paratyphoid fevers, acute hepatitis A, acute hepatitis E and F, fluorosis, arsenicosis, legionellosis, methaemoglobinaemia, schistosomiasis, trachoma, intestinal helminth infections (including ascariasis, trichuriasis and hookworm infection), dracunculiasis, scabies, dengue, filariases (including lymphatic filariasis and onchocerciasis), malaria, Japanese encephalitis, West Nile virus infection, yellow fever and impetigo.

Globally, between 1,085,000 and 2,187,000 deaths due to diarrhoeal diseases can be attributed to the ‘water, sanitation and hygiene’ risk factor, 90% of them among children under five.

Improvements in safe water supply, and in particular in hygiene and sanitation, could reduce the incidence of diarrhoea by about 20% and the number of deaths due to diarrhoea by more than 50%.

The simple act of washing hands at critical times (after using the toilet and handling infant faeces, before handling and eating food) can reduce diarrhoeal episodes by 33%.

Meeting the sanitation target means that an average of 140 million people per year need to gain access to sanitation every year until 2015. Compared to the average of 85 million per year that gained access between 1990 and 2002, this poses a huge challenge to governments and the international community alike.


The section “Did You Know…?” is taken from the 1st World Water Development Report ‘Water for People, Water for Life’, UNICEF Sanitation Statistics website and UNICEF’s Water, environment and sanitation programme website.