WATER AVAILABILITY AND QUALITY ISSUES IN THE UNITED STATES: THE ROLE OF SCIENCE IN MEETING NEW CHALLENGES

Within the United States, it is not at all clear that the fundamental issues of water availability and quality are driven simply by population growth or that there is an impending disaster. Rather, the issues are more a function of social and technological choices that have been made in recent years. The historical trends that dominate our water issues today include: increasing competition among urban, industrial, agricultural and ecological uses of water; lack of new surface-water storage facilities to increase reliable yields; increasing reliance on ground water resulting in gradual decreases in ground-water storage and depletion of base flow in rivers; and the need to move from point-source control of pollution to nonpoint-source controls to further enhance water quality. The resolution of these issues is centered on social and technological choices about the best uses of the water resource. Ultimately, wise resolution of these issues depends greatly on sound data, improved technology, and scientific understanding. Some of the issues that are in need of improved understanding are: long-term impacts of ground-water development, land use, and climate change on surface-water flow; the consequences for aquatic ecosystems of changes in rivers, including flow, temperature, geomorphology, riparian vegetation, and water chemistry; the effectiveness of “best management practices” on water quality and quantity; and the consequences of low (non-lethal) concentrations of mixtures of man-made compounds on human and aquatic life. Improved understanding, new hydrologic models, long-term data sets, and real-time data can all provide major contributions to avoiding what some would consider to be “impending disasters.”