THE CHOICE OF WATER SUPPLY SOURCES FOR U.S. CITIES

Municipal governments consider the provision of water supply as an essential service for public health and safety, economic growth, and community well-being. As the demand for water increases with population growth, municipal water sources are approaching their limits and water source expansion is often constrained by the physical and seasonal availability of fresh water, environmental protection policies and other factors. As systems strive to balance supply and demand, it is important to know what choices U. S. cities are making in developing new sources of supply and, in particular, how U.S. environmental policies are influencing the range of water supply alternatives. This research inquiry was constructed based on four hypotheses: 1) development of large surface water impoundments is no longer a preferred choice of a new source, 2) water utilities increasingly are relying on non-conventional sources for augmenting their supplies. 3) environmental statutes act as constraints in developing water sources, and 4) water needs and planning choices vary by geographic region and water system size. Evidence to explore these hypotheses was collected from detailed case studies of the history of source development of ten municipal water systems and an email survey of 189 drinking water systems throughout the U.S. The historical record of these systems was used to identify a pattern of three distinct periods of water source development: i) groundwater regime, ii) surface water regime, and iii) non-conventional regime. Source development before the Great Depression (1930s) was identified as the groundwater regime. The surface water regime began with the addition of large number of reservoirs that were added as part of the public works programs instituted after the Great Depression. Surface water source development slowed after the 1970s due to the enactment of environmental statutes and the non-conventional regime began. The nationwide water utility survey showed that about 88 percent of respondents reduced their per capita water use since the institution of national plumbing standards in the 1990s. The research also found that development of large surface water impoundments is no longer a preferred choice for cities or municipalities and that non-conventional water sources, such as water reclamation and desalination and reclamation began to be employed as alternative sources in 1980s. Environmental statutes such as, National Environmental Policy Act, Clean Water Act (CWA), Safe Drinking Water Act (SDWA), Endangered Species Act (ESA), Rivers and Harbors Act (RHA), and Wild and Scenic Rivers Act (WRSA) have been criticized as constraints to the development of new water sources. However, this research shows that water utilities in general perceive that these statutes are not a constraint. Only 24 percent of respondents perceived them as a constraint and some respondents actually perceived these statutes as an enabler to sustainable water source development. In general, the ESA, CWA 404 permit and NPDES permits were reported to be barriers to water source development, while the SDWA was most reported as an enabler. The research also found that water supply needs and planning choices vary by geographic region. Water systems in the West were more likely to be in need of water source expansion than systems in the East. When considering supply expansions, eastern cities are more likely to pursue conventional sources whereas western cities more likely to pursue a combination of conventional and non-conventional. The water utility survey and case studies showed that while U.S. water systems have employed water demand management techniques to make dramatic reductions in their per capita water use, they nonetheless continue to pursue new water supply sources to meet anticipated future water demands. In spite of this trend toward capacity expansion, virtually all the ten case study water systems currently have surplus water with their current supply exceeding their water demand