Dams Come Under Attack And Are Blamed For Poor Water Quality and Detrimental Effect on Biodiversity


News has come out of Washington that the large scale dams are beginning to have a detrimental effect on both biodiversity and the quality of water. The information has come about after there has been research carried out on thousands of projects from around the world.

Researchers from International Rivers have been focusing their work on the most substantial river basins and as a watchdog group, have managed to get data from 6,000 of the 50,000 large dams supposed to be in the existence. They found that once a dam was more than 15 meters high, the water quality dropped and there was a high level of mercury found as well as areas of trapped sediment

As a result of their findings, they are asking that governments come up with a system that can work to change this. They have published an online database called “State of the World’s Rivers” and a spokesperson said “Many of the world’s great river basins have been dammed to the point of serious decline.”

Although the group admit that this is not new data but it is the first time that that it has been used to give an overall view. The projects coordinator Zachary Hurwitz said “By and large most governments, particularly in the developing world, do not have the capacity to track this type of data, so in that sense they’re flying blind in setting policy around dam construction.


The figures show that out of the 5 most fragmented river systems are in East Asia and South Asia, but there are four others in Europe and the USA, meaning 1st world countries are not exempt. The concern however comes with Brazil, India and China as they are planning to build more and more dams. Brazil intends to build 650 and many species could be damaged through this.

Hurwitz continued “Precisely those basins that are least fragmented are currently being targeted for a great expansion of dam-building. But if we look at the experience and data from areas of high historical dam-building………..those worrying trends are likely to be repeated in the least-fragmented basins if this proliferation of dam-building continues.”

While it seems that there is clear evidence that Dams are a problem, the International Commission on Large Dams takes a different view. President Adama Nombre questions the idea that there can be an alternative “What would be those alternatives? Fossil fuel plants consuming coal or gas. Without explicitly saying it, the authors use a purely financial reasoning to bring us toward a carbon-emitting electric system.”

Further comments have not yet been received from International Rivers

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