A century of water supply expansion for ten U.S. cities

As population and water demand have grown, U.S. cities have responded by expanding their water supplies. This article traces this process over a century for ten U.S. cities. Most of the cities began by providing inexpensive local ground water. As the renewable supply capacity of local sources was exceeded, cities were forced to look further afield to obtain (or purchase) water (e.g., Marion, IL; Greensboro, NC), to access water from Federal projects (Tucson, AZ) or through international or interstate agreements (Waukesha, WI and Virginia Beach, VA), to combine with other localities in large joint projects (Greensboro, NC), or to use eminent domain to annex land for a new reservoir. This last approach has become increasingly limited by environmental statutes. The purchasing of water from other systems (Greensboro, NC) or water rights ( Tucson, AZ), aquifer storage and recovery systems (Tucson, AZ, Wichita, KS), and reclaiming wastewater for use in non-potable landscaping (Alamogordo, NM; Lubbock, TX; Tucson, AZ) are the more expensive options that cities are increasingly utilizing. Desalination represents the end of this process - expensive, but with a potential for enormous supply expansion that exceeds all likely demands. Demand management measures come into play only when the cost of securing additional water begins to exceed the cost of conservation or is induced by law. Reservoirs, well-fields, desalination plants, aquifer storage and recovery systems, and inter-basin water purchases have been abandoned because of the restrictions imposed by environmental laws or because less expensive demand-side options have been identified. The relationship between city size and its progression through these increasingly expensive water supply options is determined by local water resource endowments as determined by legal considerations and its physical geographic setting.