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March 2000
Science
Kathy Miller. (Photo by Carlye Calvin.)

How are changing values and increasing demands affecting the policy environment for water resource management in the United States? What are the implications of these changes for our ability to make effective use of improved hydrometeorological information? Kathy Miller (ESIG) addressed these and related questions in a talk at the recent annual meeting of the American Association for the Advancement of Science in Washington, D.C. "Human Water and Land Uses: Vulnerabilities, Values, and Management Options" was part of a session on hydrometeorological frontiers on Saturday, 19 February.

Kathy noted that current vulnerabilities have been shaped by past investments in water-control infrastructure and by past decisions regarding water resource use. While the United States has perhaps the most highly developed water control infrastructure in the world, we are not immune to droughts, floods, and conflicts between competing water users. In the western U.S., irrigated agriculture accounts for 90% of total water consumption. New values and demands are increasingly competing with established agricultural water uses. Efforts to provide water for growing cities, hydropower, stream-based recreation, and aquatic ecosystem restoration have been hampered by overlapping and conflicting government mandates.

According to Kathy, "The resulting muddle of confused lines of communication, fuzzy jurisdictional boundaries, and multiple decisions being made or influenced by parties with strongly divergent interests has become the policy equivalent of a Gordian knot." However, she added, "All across the West, people are looking for alternatives."

Water solutions can yield unexpected outcomes, as Kathy pointed out with her recent case study of California's highly irrigated San Joaquin Valley. After ten years of litigation by environmental groups, farmers in the valley agreed to release 35,000 acre-feet of water last summer from the Friant Dam on the San Joaquin River. The release was part of an experiment to test the feasibility of restoring a frequently dry part of the river between the reservoir and Mendota Pool. While many observers predicted that the released water would simply be sucked up by the dry riverbed, most of it flowed through that section directly to Mendota Pool, where it became available for use by irrigators in the lower San Joaquin Valley.

The success of the $2.5 million experiment was a surprise, said Kathy. "Was it simply a fortuitous result of high groundwater levels, thanks to several years of normal or above-normal precipitation, or can such success be sustained under California's frequent excursions into drought conditions? Without a better understanding of the fluxes of water between the valley's surface and groundwater systems, we can only guess at the answer." She noted that workable, affordable solutions to water-resource conflicts will increasingly require better understanding and prediction of integrated hydrological-ecological systems, as well as policy tools that respond to changes in both natural systems and society.


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