http://story.news.yahoo.com/news?tmpl=story&u=/nm/20040622/sc_nm/environment _damsgraphicembargo_dc&e=3&ncid=753 WWF: Dam Building Threatens World Rivers Tue Jun 22,12:42 AM ET By Ed Stoddard JOHANNESBURG, South Africa (Reuters) - Dam building poses a serious threat to some of the world's largest rivers, with China's Yangtze at greatest risk, WWF International said in a report released on Tuesday. The report, "Rivers at Risk," also said many of the benefits conferred by dams -- such as hydropower -- are canceled out by wasteful practices and environmental damage. "Much of the water provided by dams is lost, mainly due to inefficient ... irrigation systems, which globally waste up to 1,500 trillion liters of water annually. This is equivalent to 10 times the annual water consumption of the entire African continent," the report said. The report said 60 percent of the world's 227 largest rivers have been fragmented by dams. "(This) has led to the destruction of wetlands, a decline in freshwater species -- including river dolphins, fish, and birds -- and the forced displacement of tens of millions of people," WWF said. The report identified China's Yangtze River as most at risk, with 46 large dams planned or under construction along its waterways. The La Plata basin in South America and the Tigris and Euphrates basin in Turkey and the Middle East are also undergoing major dam works. "Degradation of the water sources in this (Tigris and Euphrates) basin is of particular concern for the biologically rich wetlands, such as the Mesopotamian marshlands in Iraq (news - web sites), that host a myriad of species," said the report. Some of the planet's most threatened mammals, such as the Ganges River dolphin, and dolphins and porpoises in the Yangtze, are at risk from habitat destruction associated with dam construction. "Dams disrupt the ecological balance of rivers by depleting them of oxygen and nutrients, and affecting the migration and reproduction of fish and other freshwater species," it said. The report says communities living downstream often suffer the most from dams, but the construction can be accomplished in an ecologically friendly way. "Good site selection, such as avoiding building dams on the main stem of a river system, and better dam design can play significant roles in minimizing impacts," it said.