ABSTRACT

Rapid population growth over the past 60 years has led to accelerated global urbanization. With more than half of the world’s inhabitants now residing in cities, the human geography of the planet has shifted, condensing nearly 3.6 billion people into <1% of the total global land area (Schneider et al 2009, United Nations 2012). These urbanized areas represent hotspots of localized, concentrated development that place enormous pressure on natural resources, particularly freshwater supply. Globally, urban water use has increased five-fold since 1950, reflecting greater demands as more people move to urban centers and increase their per capita use, commensurate with higher standards of living (Richter et al 2013). Combined with water demands for agricultural irrigation, industrial production, and water to sustain environmental flows, water scarcity has become a global problem.