This map shows the source watersheds of 534 cities."Although the 100 largest cities in the world occupy less than 1 percent of our planet’s land area, their source watersheds — the rivers, forests and other ecosystems from which they get their water— cover over 12 percent. [...] The availability and quality of that water supply, and hence the costs to move and treat it, depend heavily on how land in those source watersheds is used." (Nature Conservancy, 2015). For more information, access the Urban Water Blueprint report here: http://www.iwa-network.org/wp-content/uploads/2016/06/Urban-Water-Blueprint-Report.pdfYou can also visit the Urban Water Blueprint website here: http://water.nature.org/waterblueprint/#/intro=true