Located on a map, Tucson is seen as a geographic area with specific boundaries. Those of us who actually live in Tucson know the setting more intimately, beyond the one-dimensional view on the map. We know its mountain ranges, rivers and vegetation, and we experience its distinct sense of distance and space. And there is more. We know Tucson as a human setting or, in other words, a home to 750,000 people. The way we live our lives, our beliefs, activities and interests help explain the values that also make Tucson unique.

The human way of life and the physical setting, whether human- made or natural, are not independent of each other; instead they interact. Nowhere is this more evident than in the need for water to sustain a rich and complex urban life. Water is the beginning of such a life, but water also can be the end of it. If a sustainable source of water is not available, a community obviously is in dire straits.

Tucson now relies predominantly on groundwater, considered old water because of its storage underground for hundreds and even thousands of years. Most people realize the city cannot continue to pump this mostly nonrenewable source of water and that other sources of water must be utilized. This raises the important question: What must Tucson do to ensure a sustainable water supply?

Answering this complex question requires a consideration of the physical or environmental conditions of this desert city. Also to be considered are the social, cultural and economic values that prevail in the area. Science and technology are tools to be used. Not to be overlooked are the different sets of values and beliefs that also guide and motivate human actions. The perspective must consider the past, present and future. Obviously there are no simple solutions.

The following study charts a course among the many issues to be considered when attempting to plan a sustainable water future for Tucson. A guiding premise of the study is that identifying such a course is the responsibility of everyone in the community, not just politicians and those with a professional interest in water. With so much at stake, identifying sustainable water supplies might be thought of as a quest, of concern to literally everyone who uses water.

To do justice to the topic, the study provides a broad focus, examining many and varied issues that relate in some way to ensuring future Tucson water supplies, including historic, hydrologic, political, economic and technological concerns. No direct solutions are recommended, but by offering a wealth of information the study intends to demonstrate the complexity of the situation. By promoting an understanding of the various issues, the study will help Tucsonans make informed decisions about their future water supplies.

No other issue better demonstrates the complexity involved in deciding water policy than the Central Arizona Project. To use its water or not to use it and under what conditions and circumstances are considerations that have divided the community and have launched CAP as todays premier Tucson water issue. The first question is whether CAP, which promises a renewable supply of Colorado River water, should be part of Tucsons sustainable water supplies. In the absence of other viable alternatives, use of CAP water becomes a necessity for Tucsons survival. Other questions about CAP water remain. How should it be treated and how should it be distributed? Is it feasible to continue relying exclusively on groundwater for drinking water, with CAP water used only to recharge the aquifer? Is some combination of CAP water, groundwater and effluent viable for Tucson?

What are the implications of Tucsons water supply to the culture and character of the city, now and in the distant future?

This study addresses all of these questions, but it does not propose definitive answers. Ultimately the people must decide social policy. Our goal is to give everyone an opportunity to make well-informed decisions.

The Water Resources Research Center thanks the Office of the President of the University of Arizona for its generous financial support of this study. This publication is one part of the University of Arizona’s Water Sustainability Project.

Many thanks to the following UA faculty and staff who reviewed all or portions of this report and whose expertise was invaluable: Cornelius Steelink, Chemistry Department; Robert Glennon, College of Law; Marv Waterstone, Department of Geography and Regional Development; Gerald Matlock, International Agriculture; Victor Baker, Nathan Buras, Jim Washburne, Gray Wilson, Hydrology and Water Resources Department; Janick Artiola, Jim Riley, Arthur Warrick, Peter Wierenga, Soil Water and Environmental Science Department; Sol Resnick, Val Little, Water Resources Research Center.

A project of this sort builds an awareness of the incredibly varied talents, interests and abilities of members of the Tucson water community, whether employed by government or the private sector, or whose interest in water is not directly related to job or profession. Gratitude is due to many in the water community who provided advice, encouragement and information.