There are more and more big canals and pipelines transporting fresh water from places where it is abundant to places where it is needed for drinking—or for industry and agriculture. Thirty-four such mega-systems are already in place and 76 are planned or are under construction; but—apart from the advantages of water transfer—the effects on humans and ecosystems are enormous. A first systematic review of these water transfer mega-projects (WTMPs) has now been conducted by Christiane Zarfl, Professor of Environmental Systems Analysis at the University of Tübingen, and her doctoral researcher Oleksandra Shumilova of the Leibniz-Institute of fresh water Ecology and Inland Fisheries (IGB) as well as colleagues from Freie Universität Berlin and the World Wildlife Fund. Their study was recently published in Frontiers in Environmental Science.