Water and Urbanization
Between 2009 and 2050, the world population is expected to increase by 2.3 billion, from 6.8 to 9.1 billion. At the same time, urban populations are projected to increase by 2.9 billion, from 3.4 billion in 2009 to 6.3 billion total in 2050. Thus, the urban areas of the world are expected to absorb all of the population growth over the next four decades, while also drawing in some of the rural population. Furthermore, most of the population growth expected in urban areas will be concentrated in the cities and towns of less developed regions.
By 2030, it is anticipated that the urban population in developing and developed countries will amount to 3.9 billion and 1 billion respectively. Population growth is therefore becoming largely an urban phenomenon concentrated in the developing world.
Slums generally present a set of unique problems, including poor housing conditions, inadequate access to safe water and sanitation, overcrowding and insecure tenure; thus, the welfare of those living in these areas are seriously impacted.
Worldwide, 87% of the population gets its drinking water from improved sources, and the corresponding figure for developing regions is also high at 84%. Access is far greater, however, in urban areas (at 96%), while only 81% of rural populations have access to improved sources. However, these estimates do not take into consideration service quality (e.g. intermittent supply, disinfection) or affordability.
In 2011, a reported 2.5 billion people in the world did not use improved sanitation facilities. A comparison of the latest estimates from 2008 with those of 2000 indicates a deterioration in both water and sanitation coverage in urban areas. Over those eight years, in cities and towns of all sizes, the number of people without access to tap water at home or in the immediate vicinity increased by 114 million, and the number of people without access to private sanitary toilets (basic sanitation) increased by 134 million. In both cases, this means an increase of 20% in the number of individuals living in cities who lack access to basic facilities.
Urban settlements are also the main source of point-source pollution. Urban wastewater is particularly threatening when combined with untreated industrial waste. In many fast-growing cities (small and medium-sized cities with populations of less than 500,000), wastewater infrastructure is non-existent, inadequate or outdated.
However, promising initiatives are emerging worldwide to address the need for improved and comprehensive urban water planning, technologies, investment and associated operations in the cities of the future.
Sources: World Water Development Report 2012; Joint Monitoring Programme on Water Supply and Sanitation 2013 Update.