The Moderating Influence of Spring Climate on the Rio Grande Headwaters: A Paleo Perspective
While snowpack is the main influence on Rio Grande water year streamflow, spring hydroclimate can play a role in moderating this influence in a subset of years. Through an investigation of the relationship between winter snowpack and spring hydroclimate conditions and Rio Grande streamflow, we find...
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| Published in: | Water resources research Vol. 60; no. 8 |
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| Main Authors: | , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Washington
John Wiley & Sons, Inc
01-08-2024
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| Subjects: | |
| Online Access: | Get full text |
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| Summary: | While snowpack is the main influence on Rio Grande water year streamflow, spring hydroclimate can play a role in moderating this influence in a subset of years. Through an investigation of the relationship between winter snowpack and spring hydroclimate conditions and Rio Grande streamflow, we find low snowpack years with relatively cool, wet springs coincide with slightly above median streamflow in 18% of the years in the instrumental record (1936–2018), while the opposite conditions occur during 24% of years. Over this period, an increase in years with low snowpack/cool wet springs is evident, likely due to a significant decreasing trend in snowpack. We analyze two 15‐century tree‐ring reconstructions to provide long‐term context for the variable relationship between snowpack and spring hydroclimate. Results suggests irregular but quasi‐multidecadal periods when spring conditions may have moderated the effect of a relatively dry winter or reduced the effect of a relatively wet winter. The reconstructions also provide context for the observed trend in the increasing importance of spring conditions over the instrumental period, which appears to be related to both natural climate variability and climate change. In the Rio Grande basin, as mountain snowpack declines due to warming temperatures, spring conditions may be playing an increasingly important role for water resources, at least in the near term.
Plain Language Summary
Winter snowpack is the dominant source of water for Rio Grande streamflow. Spring moisture is typically a minor contributor, but in a subset of years, spring conditions can make a difference, ameliorating the impact of a low snowpack or moderating the influence of a high snowpack on water year (October–September) streamflow. Instrumental climate data suggest that spring conditions have become increasingly important with regard to streamflow, concurrent with declining snowpack. Tree‐ring reconstructions of snowpack and spring hydroclimate that extend 1,500 years into the past suggest that both natural climate variability and the influence of warming temperatures on snowpack are likely to be responsible for recent increasing influence of spring conditions on Rio Grande streamflow. Streamflow declines are not yet evident in the headwaters of this river, and the contribution of spring moisture may be part of the reason. However as temperatures continue to warm, spring moisture will be less of a mitigating factor in low snowpack years.
Key Points
Snowpack is the main influence on Rio Grande streamflow, but spring can play an important conditioning factor in a subset of years
Springs are not becoming cooler and wetter but are increasingly more influential to streamflow due to snowpack decline
Paleo data reflect the increasing importance of spring and suggest the trend is due to both natural variability and climate warming |
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| ISSN: | 0043-1397 1944-7973 |
| DOI: | 10.1029/2023WR036909 |