Sustainable Water for the Upper Santa Cruz Valley

On October 31, 2007, a Sustainability Forum was held at the University of Arizona. Sponsored by the University, the City of Tucson, Pima County, and PAG, the event provided an opportunity for approximately 125 people to participate in a series of discussions to help craft perspectives on the value and meaning of sustainability in the greater Tucson community. Participants met in small groups to consider specific topics including: Water Resources, Urban Green Assets, Landfill Waste Reduction, Reducing Green House Gas Emissions, People Resources, Community Attributes, and Working Together. The Forum was open to the public and while participation reflected a wide range of interests most participants were strongly committed to the need to achieve a more sustainable approach in the community.

This report provides a detailed summary of the discussions that took place in the group that considered the topic of Sustainable Use of Local Water Resources. The group held three distinct discussion sessions allowing a substantial portion of those attending to participate. The group was led by Dr. Sharon Megdal.

A consortium of Arizona’s three universities focused on water sustainability through research, technical assistance, education, and technology; building collaborative, multidisciplinary solutions to water management challenges

The aquifer that supplies Sahuarita and Green Valley is experiencing long-term groundwater decline, caused primarily by heavy pumping from agriculture and mining, with municipal use also contributing. Recharge remains far below total withdrawals, and water quality concerns—including increasing hardness, sulfate plumes, and land subsidence—highlight the need for coordinated regional management.

Central Arizona Project (CAP) water and strategically located recharge facilities are essential to balancing future supply and demand. While there is no immediate crisis, the region faces a serious long-term water challenge that will require sustained planning, investment, and collaboration. USCPUG’s role is to bring together water providers, industry, agriculture, and government agencies to guide solutions and support a sustainable water future for the Upper Santa Cruz Valley.

The CAP Water Allocation Model is a draft table estimating how Central Arizona Project (CAP) water could be distributed among major user groups—residential, golf courses, Pima County, mines, and agriculture—for the years 2010, 2020, and 2030, including projected overdraft for each period. It serves as a planning tool to visualize how renewable CAP water might offset groundwater pumping under different future scenarios.

An outline of projected aquifer overdraft and water source allocations from 2010 to 2030.

A map of regional subsidence with the proposed recharge site.