Drought and dams in biblical garden of Eden by Julia Harte | 16 Apr 2013 Iraq | Turkey The Ilısu Dam, an 11 billion-cubic-meter hydroelectric project on the Tigris River in Turkey will reduce the river’s downstream flow from 20 billion cubic meters to just 9, destroying about 670,000 hectares of arable land in Iraq. A National Geographic story of a disaster in the making. The Ilısu Dam, an 11 billion-cubic-meter hydroelectric project on the Tigris River in Turkey will reduce the river’s downstream flow from 20 billion cubic meters to just 9, destroying about 670,000 hectares of arable land in Iraq. A National Geographic story of a disaster in the making.