Arizona Water Resources Research Center (WRRC)

Water, People, and the Future: Water Availability for Agriculture in the United States

With a projected 25% and 50% 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 will 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 Approximately 40% of the water withdrawn from U.S. surface and groundwater sources is used for agricultural irrigation.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 water available, substantial efforts will be required to make irrigated agriculture more productive and water-use 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, agricultural water use—and 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.

Conserve to Enhance: Voluntary municipal conservation to support environmental restoration

Existing water conservation programs may not effectively target water users that are motivated by environmental concerns. An earlier project, which culminated in a report dated July 2006, recognized the ongoing need for supplemental inputs of water in riparian restoration projects, which are increasingly common (Megdal et al, 2006). Also, public concern surrounding the need to protect natural water flows is growing (Katz, 2006).

This paper explores the idea that municipal water conservatiion may be a source of water for the environment. In this paper, the authors propose a mechanism by which municipal water conservation could provide funds to cover the cost of acquiring and delivering water to environmental enhancement projects. This study explores some of the basic elements and some of the challenges involved in implementing this concept.

Agricultural Water to Municipal Use

The development of water markets to facilitate the movement of water rights from agricultural to municipal and industrial use has been slower in Arizona than some expected. Researchers surveyed agricultural water supply organizations about their experiences with and attitude toward sales, leases and exchanges of water. This article presents an analysis of survey results in the context of the institutional incentives for and barriers to voluntary water transfers in Arizona. A description of the current legal and institutional context for transactions in water is provided. Survey results suggest that the impact of these institutions on water transfers can be significant in either promoting or impeding transfers depending on the specific circumstances.

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Securing Water for Environmental Purposes: Establishing Pilot Programs

This paper explores implementation of programs to provide water for
the environment, such as check box donation programs and Conserve to Enhance, a mechanism
using voluntary municipal water conservation.

Contaminant Transport Mechanisms in Karst Terrains and Implications on Remediation

Because successful implementation of ground water remediation cannot be achieved without a full understanding of dissolved and non-aqueous phase transport mechanisms, the hydrogeologist must rely on developing a site conceptual model based on interpretation of field data. Investigative techniques for predicting the probable location of both light- and dense-non-aqueous phase liquid (LNAPL and DNAPL) in the flow continuum of karst aquifers are presented in this paper within the framework of ground water remediation options.