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Abstract:
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From p. 1:
"Rapid urban population growth over the past 40 years has introduced important implications for the environment. Urban domestic and industrial consumers are using larger amounts of water and, consequently depleting the available sources. At the same time, they are degrading these resources with their wastes. Yet, urbanization and the consequent concentration of production are an essential part of economic development. They help lower unit costs for water supply systems and for many forms of sanitation services, including access to health services. However, in developing countries, the rate of investments needed to provide water supply and sanitation falls behind the urban growth, leading to a situation of intense pollution due to the concentration of industrial and domestic wastes. In these countries the problem is aggravated due to the unplanned way the cities grew. Migration induced by economic difficulties lead poor populations to settle in peri-urban areas with poor housing conditions and almost no urban infrastructure, creating large slum areas. The fact is that one of the greatest challenges posed by the fast urbanization rates and rapid population growth is to guarantee safe, adequate and reliable water supply, as well as adequate sanitation conditions, to all people and permanently. Beyond difficulties of reaching a large area with reliable service, a situation that is aggravated if the urban expansion was unplanned and chaotic, it also leads to severe strain on the water resources accessibility and on the environment due to the increase in the water demand and pollution loads. The challenge is augmented when megacities are concerned, but a selection of water management principles can be adopted to surpass such obstacles and recover part of the water supply system, as an ongoing case with the Guarapiranga reservoir of São Paulo, Brazil, illustrates."
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