The University of Arizona

Disentangling the Influence of Antecedent Temperature and Soil Moisture on Colorado River Water Resources | CLIMAS

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Disentangling the Influence of Antecedent Temperature and Soil Moisture on Colorado River Water Resources

Disentangling the Influence of Antecedent Temperature and Soil Moisture on Colorado River Water Resources

Lead Investigator:  

This is a DOI Southwest Climate Science Center project, with leverage from CLIMAS. The main goal of this project is to better understand how the set of hydroclimatic factors - prior summer/fall soil moisture, cool season precipitation/snowpack, and late winter/spring temperatures - contribute to low annual flows on the Colorado River. We will use a combination of instrumental data, tree-ring reconstructions, and downscaled CMIP5 projections to investigate the differing roles of these factors in both instrumental period droughts and droughts that have occurred over past centuries, including conditions in major sub-basins. We will test the sensitivity of annual low flows to different CMIP5 scenarios of changes in soil moisture, winter precipitation, and winter/spring temperatures, and compare climate conditions associated with historic/paleo low flows to those associated with low flows derived from downscaled projections. 

This understanding is critically important to resource managers who are currently anticipating the impacts of climate variability and change on limited water supplies in the upper Colorado River basin. To develop the proposal, we engaged with a group of Colorado River basin water managers who assisted in directing research questions and ensuring the project’s relevance to resource management. This group of water managers will form an advisory board to guide the analysis and generation of research products through interaction with the science team, an interdisciplinary group with expertise in climatology, paleoclimatology, hydrologic modeling, and climate projection analysis, with extensive experience working with resource managers. Additional partnerships with Western Water Assessment (WWA) and CLIMAS will promote a broader exposure to and use of project results by water resource management through a workshop for resource managers and articles featured in WWA and CLIMAS online publications for stakeholders.