Project Overview

Since 2004, an interdisciplinary research team at the University of Arizona has worked with the Bureau of Reclamation to enhance predictive capacity in Lower Colorado River by incorporating climate information into river operations modeling. The project team also evaluates economic and management tools capable of mitigating the impacts of water supply variability during prolonged dry-year conditions. Support for the research has been provided by the University of Arizona Water Sustainability Program and the Bureau of Reclamation.

This project involves four disciplines, spanning hydrologic modeling, paleoclimatology, economics, and management. Research tasks share an interdisciplinary methodology driven by active stakeholder engagement. At the project's outset, the UA team solicited feedback from water managers and users to refine the research scope and identify the core research questions.

Principal Investigators: Bonnie Colby, Kathy Jacobs, David Meko, and Peter Troch

General Inquiries: Rosalind Bark

Objectives

1) Assess current Bureau of Reclamation use of climate information in water resources modeling

2) Identify strategies to better utilize paleoclimatology, climate forecasts, and climate change predictions to improve water supply predictive capacity for the lower Colorado River and the Central Arizona Project

3) Evaluate existing management tools to translate improved predictive capacity into enhanced supply reliability for water users

4) Develop practical supply reliability strategies for use by municipalities, irrigation districts and other stakeholders.

The project includes University of Arizona faculty from four departments, including Bonnie Colby of the Department of Agricultural and Resource Economics, Kathy Jacobs of the Arizona Water Institute, David Meko of the Laboratory of Tree-Ring Research, and Peter Troch also of the Department of Hydrology and Water Resources. Please see contact information for further details.

Approach

The modeling component of this project utilized ensemble streamflow prediction methods to evaluate the predictive capacity of meteorological and climate data in mid-term (24-month) river operations modeling in the Lower Colorado River Basin. The paleoclimate element of the project reconstructed historic streamflows for a 508-year period using tree-ring samples near four streamflow gages in the Upper Colorado River Basin. The water economics team updated crop budgets for crops in Yuma and La Paz County, Arizona and used the residual (farm budget) approach to determine net returns over variable costs (NROVC) for select crops. The economics team also conducted econometric analysis of temporary water transfers in the West to determine the impact of drought on water leasing prices. Finally, the water management team analyzed model outputs, policy documents, and transcripts of shortage planning meetings to identify the key sources of uncertainty in long-range operational modeling. The water management study also evaluated decision making processes under climatic and legal uncertainty by synthesizing stakeholder perspectives on river operations modeling.

See contact information.