Mighty rivers that inspired religions, civilisations and explorers are among the ten most threatened in the world.

Rivers such as the Nile, the Indus and the Ganges are dying because of stresses put on them by mankind, the WWF says in a report published today.

Each of the ten river systems identified in the report is beset by man-made problems, including water being siphoned off, dams destroying ecosystems and pollution. They flow across six continents and the damage threatens the lives of people and wildlife, the WWF says.

The ten most endangered river basins are said to be the Danube, Yangtze, Rio Grande, Salween, Nile, Indus, Ganges, Plata, Mekong and Murray-Darling. About 41 per cent of the world’s population live in threatened river systems, and of the 10,000 species of freshwater animals and plants at least 20 per cent are already extinct.

“In the last 50 years we have altered ecosystems more rapidly and extensively than in any other period in history,” the report states. “Physical alteration, habitat loss and degradation, water extraction, overexploitation, pollution, and the introduction of invasive species threaten the planet’s freshwater ecosystems.”

Most river basins face multiple threats, and to draw up a list of the ten most endangered, the conservation charity used published reports and the judgment of its own experts. The list comprises river systems that have already suffered extensive damage and freshwater networks likely to be markedly changed over the next decade.

The Danube was named as one of those that has already been severely damaged, having lost 80 per cent of its wetlands and floodplains.

In Asia, the Salween is one of only 21 of the world’s 177 longest rivers that still run freely from source to the sea. However, 16 large dams are planned for the river, and the alteration in the landscape could prove disastrous for wildlife.

Water extraction for agriculture, industry and domestic use is such a problem for the Rio Grande and the Ganges that there are shortages farther downstream, flow levels having fallen sharply.

Flow in the Ganges and the Indus is expected to be further reduced because of the disappearance of Himalayan glaciers, a trend attributed to global warming. “With climate warming, many glaciers will no longer exist to moderate the flow of these rivers,” the report says.

Australia’s Murray and Darling river system is under pressure from introduced species that are outcompeting native fish, which have suffered 90 per cent reductions in numbers in the past two centuries.

Overfishing is cited as another serious problem for rivers, notably the Mekong, which drains an area in Asia twice the size of Germany.

Similarly, pollution from rapid economic development is blamed for the deterioration of the Yangtze. “The Yangtze used to be so clear that you could see a pen sink to the bottom. Now it has become so dirty that it is not fit for drinking,” the report says.

The WWF called on governments and businesses to take better care of their water supplies to ensure that they remain sustainable resources for people and wildlife.

David Tickner, head of the organisation’s freshwater programme, said: “Unabated development is jeopardising nature’s ability to meet our growing demands. The world is facing a massive freshwater crisis, which has the potential to be every bit as devastating as climate change.

“Conservation of rivers and wetlands and security of water flows must be seen as part and parcel of national security, health and economic success.”

1: Rio Grande

Flows through: US and Mexico
Length: 1,890 miles. Drains area of 235,000 square miles
Key threats: water extraction, salination, invasive species
Dependent wildlife: 69 of the 121 fish species found nowhere else

2: Yangtze

Flows through: China
Length: 3,910 miles Drains area of 695,000 square miles
Key threats: pollution, 105 planned dams, overfishing
Dependent wildlife: 350 fish species including Yangtze Sturgeon, 160 amphibian species, Finless Porpoise, Chinese Alligator, Giant Panda, and the largest salamander in the world (Audrias davidianus)

3: Mekong

Flows through: China, Laos, Burma, Vietnam, Thailand, Cambodia
Length: 2,860 miles. Drains area of 311,000 square miles
Key threats: overfishing, 149 dams planned, deforestation, pollution
Dependent wildlife: Mekong giant catfish (the world’s largest freshwater fish), 160 amphibian species, estimated 1,700 fish species, Irrawaddy river dolphin

4: Salween

Flows through: China, Burma, Thailand
Length: 1,740 miles. Drains area of 105,000 square miles
Key threats: 16 proposed dams
Dependent wildlife: the fishing cat, Siamese crocodile, small panda, wild donkey of Dulong, 92 amphibian species, and 47 of its 143 fish species are found nowhere else

5: Murray-Darling basin

Flows through: Australia
Length: 2,100 miles. Drains area of 405,000 square miles
Key threats: invasive species, salinisation, climate change
Dependent wildlife: Silver perch, freshwater catfish, Murray cod, crayfish and freshwater snails, 16 mammal and 35 bird species

6: Ganges

Flows through: India, but also drains from Nepal and China
Length: 1,560 miles. Drains area of 392,000 square miles
Key threats: water extraction, 14 proposed dams, climate change
Dependent wildlife: Ganges river dolphin, freshwater shark (Glyphis gangeticus), 140 fish species and 90 amphibian species

7: Indus

Flows through: Pakistan, but also drains from Afghanistan, India and China
Length: 1,800 miles. Drains area of 418,000 square miles
Key threats: climate change, water extraction, pollution, 6 proposed dams
Dependent wildlife: Indus river dolphin, 22 of 147 species of fish are found nowhere else, 25 amphibian species

8: La Plata basin - includes Paraguay, Paraná and Uruguay rivers

Flows through: Paraguay, Brazil, Uraguay, Bolivia, and Argentina
Length: 2,500 miles. Drains area of 1,160,000 square miles
Key threats: 27 proposed dams, dredging, overfishing, climate change, pollution
Dependent wildlife: La Plata river dolphin, ocelots, 85 of 350 species of fish are found nowhere else, more than 1,600 species of flowering plants. Fills the Pantanal, the largest freshwater wetland in the world

9: Nile

Flows through: Egypt, Sudan, Ethiopia, Uganda, and drains from Tanzania, Burundi, Rwanda, Democratic Republic of Congo, Eritrea and Kenya.
Length: 4,160 miles. Drains area of 1,257,000 square miles
Key threats: climate change, extraction, invasive species
Dependent wildlife: Nile crocodile, 26 of its 129 fish species are found nowhere else, 137 amphibian species

10: Danube

Flows through: Germany, Austria, Slovakia, Hungary, Serbia, Romania and Bulgaria
Length: 1,730 miles. Drains area of 310,000 square miles
Key threats: 8 proposed dams, shipping infrastructure, flood protection measures, pollution, invasive species
Dependent wildlife: 7 of its 103 fish species and 18 of its 88 freshwater molluscs are found nowhere else

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