Sharjah24 – AFP: More than 1.2 million barriers criss-cross Europe's rivers -- nearly twice as many as previously thought -- threatening some of the world's most diverse ecosystems, new research showed Wednesday.
Although the rivers have been dammed, forded or bridged for centuries, there is a surprising lack of detailed databases of the continent's waterways.
Most only list barriers of a certain height, above 10 metres, for example, leaving hundreds of thousands of smaller water breaks undocumented.
In a pan-European initiative, scientists collated more than 120 data bases on European rivers and ran tests to ensure no barrier was repeated in the final tally.
They found 629,955 unique barrier records -- a huge number demonstrating the extent to which human activity has influenced river ecosystems.
To compare the data with reality, the researchers then undertook a mammoth verification operation: they walked along more than 2,700 kilometres of European rivers, manually inputting any missing from records into the database.
The number of barriers recorded in field was on average 2.5 times higher than in existing inventories.
Extrapolating that discrepancy to continent-wide figures, the team estimated the true number of barriers across European rivers to be more than 1.2 million.
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