**3. Policy context – Megacities and water**

A number of accounts suggest that global freshwater supplies are increasingly facing severe *stress*: a growing imbalance between available supplies within various regions on one hand, and demands on those supplies by multiple users on the other. Water stress is generally attributed to population growth, climate variability (including extreme drought), and inadequately maintained and/or deteriorating water supply and treatment infrastructure. Experts view stress as caused by demographic, climatological, and socio-economic factors intersecting in various ways (World Meteorological Organization, 1997; World Resources Institute, 1998; Alcamo, et. al., 2003; World Water Council, 2005).

While these three factors are compelling sources of stress, a more nuanced cause is rapid *urbanization*, exemplified by the phenomenal growth of so-called "megacities" composed of tens-of-millions of people. Megacities are a sprouting phenomenon in developing nations, especially, where cities and towns already comprise some 80% of the planet's urban populace. More than two-thirds of the world's urban residents live in cities in Africa, Asia, and Latin America. Moreover, since 1950, the urban population of these regions has grown five-fold, while in Africa and Asia alone, urban population is expected to double by 2030 (Satterthwaite, 2000; UNPF, 2007).

Large cities generally, and megacities in particular, contribute to water stress in two ways: 1) they are often located some distance from the water sources needed to maintain their growth; thus they must divert water from outlying rural areas which, in turn, often produce the food and fiber to support them; and, 2) soaring birthrates and in-migration (the latter often from these same outlying areas) place extra burdens upon water infrastructure, and generate severe health and hygiene problems. Both of these contributors underscore the complex ways demography, economics and climate factors interact.

Aqueduct, completed in 1940. While the Owens Valley case revolves around a powerful, growing city initially diverting water from a modest agrarian region in order to support future growth, and then restoring a portion of that region's water under federal order, the latter cases revolve around endangered species protection and climate variability,

For New York City, the chief focus of our discussion is the Croton and Catskill watersheds the former is the city's original regional water source, dating to the 1840s, while the second was developed in the late 19th Century. In more recent years, both watersheds have been part of the so-called *New York City Watershed Protection Plan* designed to protect the city's water supply from sewage and runoff-induced contamination through adopting cooperative land use controls and other measures. These watersheds are the source of fully one-half of the city's water supply. Additional case material from the Delaware River, an interstate stream which New York relies upon for the other half of its water supply, is also discussed. Section 3 sets the stage for comparison by first considering two vital questions: 1) how do megacities affect water supply and quality in their nested regions; and, 2) why are Los Angeles and New York good cases for studying these issues? Despite being located in a highly-developed society, and perceived as having safe, well-managed water systems, this was not always the case. Beyond this, as we shall see, Los Angeles and New York share important challenges with regards to infrastructure, the need to conserve water, and climate change which may translate into lessons for other megacities facing similar problems.

A number of accounts suggest that global freshwater supplies are increasingly facing severe *stress*: a growing imbalance between available supplies within various regions on one hand, and demands on those supplies by multiple users on the other. Water stress is generally attributed to population growth, climate variability (including extreme drought), and inadequately maintained and/or deteriorating water supply and treatment infrastructure. Experts view stress as caused by demographic, climatological, and socio-economic factors intersecting in various ways (World Meteorological Organization, 1997; World Resources

While these three factors are compelling sources of stress, a more nuanced cause is rapid *urbanization*, exemplified by the phenomenal growth of so-called "megacities" composed of tens-of-millions of people. Megacities are a sprouting phenomenon in developing nations, especially, where cities and towns already comprise some 80% of the planet's urban populace. More than two-thirds of the world's urban residents live in cities in Africa, Asia, and Latin America. Moreover, since 1950, the urban population of these regions has grown five-fold, while in Africa and Asia alone, urban population is expected to double by 2030

Large cities generally, and megacities in particular, contribute to water stress in two ways: 1) they are often located some distance from the water sources needed to maintain their growth; thus they must divert water from outlying rural areas which, in turn, often produce the food and fiber to support them; and, 2) soaring birthrates and in-migration (the latter often from these same outlying areas) place extra burdens upon water infrastructure, and generate severe health and hygiene problems. Both of these contributors underscore the

respectively, as factors that compel change in urban water policy.

**3. Policy context – Megacities and water** 

(Satterthwaite, 2000; UNPF, 2007).

Institute, 1998; Alcamo, et. al., 2003; World Water Council, 2005).

complex ways demography, economics and climate factors interact.

Urban-related water stressors can be more precisely de-constructed as three-fold problems. First, large cities generate huge volumes of wastewater which are costly to treat and, if left untreated, can contaminate local wells and streams. Second, the *spatial* "footprint" caused by sprawling horizontal urban development and annexation imposes numerous water-related problems, including paving of city streets and commercial districts (contributing to pollutant runoff and diminished groundwater recharge), and consumption of water for parks and outdoor residential use (increasing evapo-transpiration and taxing local supplies).

Third, while greater concentration of people in cities may lower unit costs for many forms of water infrastructure (Satterthwaite, 2000) the need to expand water supply and treatment networks over vast distances increases the likelihood of distribution system leaks and other failures. All these problems have been observed in a number of Third World megacities, and underscore how urbanization exacerbates climate change impacts on scarce water supplies; imposes extraordinary pressures on surrounding regions; and, outraces infrastructural capacity (UN, 2009: 32; Adekalu, et. al., 2002; Downs, Mazari-Hiriart, Dominguez-Mora, & Suffet, 2000; Gandy, 2008; Tortajada and Casteian, 2003; Yusuf, 2007; and Zérah, 2008).
