• On average freshwater species populations were reduced by half between 1970 and 2005, a sharper decline than for other biomes.
• As of 2000 there were more than 50,000 large dams in operation.
• Some 589 large dams were built in Asia from 1999 to 2001.
• Of the world’s 292 largest river systems in 2005 (accounting for 60% of the world’s runoff), more than a third (105) were considered to be strongly affected by fragmentation, and 68 moderately affected.

The section “Did You Know…?” is taken from the 3rd World Water Development Report “Water in a Changing World“.

Source: http://www.unesco.org/