Water, People, and the Future: Water Availability for Agriculture in the United States
University of Arizona
With a projected 25 percent and 50 percent increase in U.S. and world population, respectively, by the year 2050, substantial increases in freshwater use for food, fiber, and fuel production, as well as municipal and residential consumption, are inevitable. This increased water use does not come without consequences. Already, the United States has experienced the mining of groundwater, resulting in declining water tables, increased costs of water withdrawal, and the deterioration of water quality. Long-term drought conditions have greatly decreased surface water flows. Climate change predictions include higher temperatures, decreases in snowpack, shifts in precipitation patterns, increases in evapotranspiration, and more frequent droughts. Not surprisingly, conflicts over water use are continually emerging. As one of the largest users of water in the United States, agriculture will be impacted significantly by changes in water availability and cost. Approximately 40 percent of the water withdrawn from U.S. surface and groundwater sources is used for agricultural irrigation. Although the proportion of available freshwater used in agriculture varies widely among geographical areas, it is a major proportion of total water use in every area. Increasing responsibilities are being placed on agricultural water users at a time when available water resources are decreasing. Additionally, increasing industrial and residential water use will continue to limit the water available to agriculture. Since agriculture faces a future with less available water supply, substantial efforts will be required to make irrigated agriculture more efficient. It is important to the economic vitality of the United States including agriculture that policymakers, water managers, and water users work collaboratively to achieve sustainable water resource management. Multiple issues require attention: water quality, environmental water needs, municipal demands for water, water resource availability, and agricultural water use. No issue can be addressed individually. This paper discusses the diverse demands for water resources past, current, and future using the impacts, regulations, challenges, and policies of specific U.S. states as examples. The authors indicate that the reliability of water quantity and quality deserves the attention of all levels of government and that private and public sector leadership will be critical.