In OECD countries, rural population shrank throughout the second half of the 20th century, while urban population grew (OECD/China Development Research Foundation, 2010). However, empirical evidence shows that the proximity to urban centres can have positive impacts on the population grow'th rate of rural regions, as they can potentially benefit from better access to services and markets (Veneri and Ruiz, 2013, OECD, 2015c). Ensuring Sustainable Futures, OECD Studies on Water, OECD Publishing, Paris, http://dx.doi.org/10.1787/9789264230149-en.