Anticipating future impacts on streamflow using multi-century climate records and applied hydrologic models

Project Start Year

2017
Principal Investigators

Collaborators

  • Stephanie McAfee (University of Nevada, Reno)
  • Stephen Gray (National Climate Change and Wildlife Science Center)
  • Gregory Pederson (Northern Rocky Mountain Science Center)
  • Adam Csank (University of Nevada, Reno)
  • Gregory McCabe (USGS Branch of Regional Research, Central Region)

Description

The Colorado River is a crucial water source for millions of people in the Southwest. Warming temperatures, clearly documented in climate records for the Colorado River basin, are having an impact on the amount of annual streamflow yielded from rain and snow. Recent work has revealed that warming temperatures have played an increasingly important role over the past decades, both exacerbating droughts and dampening the effects of wet winters on high stream flows. Understanding and anticipating how warming temperatures will influence future water supply in the Colorado River basin is increasingly important for resource management, particularly in light of recent drought conditions.
The overarching goals of this project are to better understand the influence of temperature on Colorado River streamflow, particularly during droughts, and assist water managers in planning for future droughts. This work expands on a recently completed study, building on that project in two main ways. First, this project extends collaborative work between scientists and Colorado River basin water managers to investigate the range of potential drought conditions under early 21st century warming, using both recent and historical data. For example, with precipitation reconstructions from tree rings for the past 500 years, the team can use a simple hydrologic model to assess the impacts of the longest and most severe droughts of the past on the Colorado River under today’s warmer temperatures. With this information, the project team will contribute to a set of plausible scenarios of future drought that planners can use to help make resource-management decisions. Second, the project is more explicitly examining the drivers of Colorado River drought, with a focus on factors such as the phase of precipitation (rain vs. snow), the timing and rate of snowmelt, and evaporation rates. The project team will also begin to explore the ways that changing temperatures and streamflow might impact the ecological health of the upper Colorado River basin.

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