When people use freshwater beyond a physically sustainable rate, it sets off a cascade of impacts on ecosystems, people and the planet. These impacts include groundwater wells running dry, fish populations becoming stranded before they are able to spawn and protected wetland ecosystems turning into dry landscapes. Developments in computer models and satellites have fostered a new understanding of how freshwater is being redistributed around the planet and have made clear the central role that people play in this change. This human impact is so significant that organizations like the United States Geological Survey are redrawing their water cycle diagram to include the impacts of human actions.