Historic Paradigms of Urban Water/Stormwater/Wastewater Management and Drivers for Change

Abstract

Since the onset of urbanization millennia ago, cities were connected to water resources, which were their lifeline. Without this connection to water, there would be no cities and, ultimately, no life. When water became scarce, cities were abandoned, and sometimes entire civilizations vanished, as exemplified by the history of the indigenous Hohokam and Anasazi peoples living in the southwestern U.S. in the 15th century, in communities of more than a thousand people-communities that lasted for about a thousand years, but were abandoned, most likely because of extensive drought and the failure of their irrigation systems. Obviously, there were several reasons other than water scarcity causing ancient cities to become ghost towns, then ruins, and finally archeological excavations, centuries or millennia later. Some were related to loss of soil fertility caused by a lack of water for irrigation or poor irrigation practices, which resulted in famine; epidemics of water-borne diseases; exhaustion of the natural resource that was being extracted; or contaminated water, for example, by lead in ancient Rome. Water scarcity is sometimes a result of poor city management and institutions that were inadequate to deal with the multiplicity of conflicting uses and demands for water. Urban waters provided navigation, fish and other seafood, power to mills, laundry, recreation for kings and other nobility, defense during siege by invading armies, and religious significance in some countries and cultures (e.g., India) where certain bodies of water are worshiped.Water also cleans cities; in historic cities, rainfall washed away the deposits on the streets containing garbage, manure from animals, and human fecal matter. Rainfall and ensuing runoff were-and still are, in many urban areas in some countriesthe main and often the only means of disposal of accumulated malodorous solids. During antiquity and the Middle Ages, rivers in sparsely settled rural areas were Terrible epidemics plagued medieval cities, exacerbated by wars and famine. In one medieval epidemic, during a prolonged continental war in the 17th century, 25% of the entire European population vanished.The situation of urban water resources during the 19th century and in the first half of the 20th century worsened. As cities became industrialized, pollution from industries and loads from reinvented flushing toilets in households (communal flushing toilets were known and used by ancient civilizations of Greece and Rome millennia ago) discharged without treatment into streams resulted in bodies of water devoid of oxygen and smelly due to hydrogen sulfide emanating from decomposing anoxic sediments and water. The response of city engineers and planners was to put the streams out of sight-that is, cover them and/or turn them into combined sewers. In general, until the 20th century, the water environment was not a major interest of architects, builders, or rulers/governments of cities. The people living in the ancient and medieval cities were obviously afraid of epidemics, but...