Temps de lecture :2 minutes
Some of the world’s greatest rivers are at risk of dying as a result of mismanagement, claims a new report from the campaign group WWF. The report (pdf) names the 10 rivers which are most at risk and outlines the factors that threaten them.
“It’s the scale of the problem which we are trying to underline,” says Tom Le Quesne, freshwater policy officer for WWF. “A river as huge as the Ganges in India is threatened with running out of water. Everywhere you go in the world, people are facing the same problem.”
Mike Acreman at the UK’s Centre for Ecology and Hydrology agrees that rivers are at risk, but adds that big organisations – including governments and the World Bank – are taking the problem seriously and are developing new tools to address it.
The most threatened rivers, according to WWF, are the Danube in Europe; the La Plata and Rio Grande/Rio Bravo in the Americas; the Nile/Lake Victoria system in Africa; the Murray-Darling in Australia; and the Yangtze, Mekong, Salween, Ganges and Indus, all in Asia.
When rivers are reduced to a trickle, says Le Quesne, seawater is no longer flushed out of estuaries and intrudes into groundwater and surface water. This in turn decreases the yields of shoreline crops. For example, he says, the sea reaches 40 kilometres up the Indus river estuary in Pakistan.
“The problem is totally solvable,” says Le Quesne. “There’s plenty of water in the world. It is a political problem.“
WWF is calling for rivers to be better managed, for more efficient irrigation of crops – the use of “drip systems” that deliver water directly to the planst – and for better monitoring of the water that is being used and to whom it is being distributed.
Mike Acreman points out that although the report’s intentions are good, it fails to mention the fact that “a lot is being done to address these problems”. He notes “environmental flows” in particular – a concept which has been developed to determine how much water needs to be left in a river in order to maintain its ecological health.
Acreman, who consults for the World Bank, says he has been encouraged to see the organisation use environmental flows to guide its projects. He cites a project to build a dam in Lesotho and pipe the copious amount of freshwater available in this mountainous country to the dry regions of South Africa. The World Bank agreed to fund the project only if a full environmental assessment was done. The conclusion of the assessment was that a great deal more water than expected needed to be left in the river’s natural course in order to supply the communities downstream, showing that the environmental flow concept can have real impact in protecting water resources.
20 March 2007
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