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Examining the Influence of Temperature and Precipitation on Colorado River Water Resources: Reconstructing the Past to Understand the Future

Disentangling the Influence of Cool Season Temperature and Precipitation on Colorado River Water Resources Using Paleo Data
Principal Investigator
Connie Woodhouse


Start Date
End Date
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Streamflow in the Colorado River is heavily influenced by high-elevation snowpack. Warming temperatures in spring can reduce snow-fed flows, with serious implications for the water supplies that support communities and wildlife. While it is already well-known that precipitation has a significant influence on river flow, recent observations suggest that temperature and the amount of water in soil may also influence streamflow. In the face of a changing climate, it is important that resource managers understand how factors such as changing temperatures and precipitation will affect this vital water source. To address this need, researchers are examining records of streamflow, temperature, soil moisture, and precipitation in the upper [...]

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Principal Investigator :
Connie Woodhouse
Co-Investigator :
Gregory Pederson, Adam Csank
Funding Agency :
Southwest CSC
CMS Group :
Climate Adaptation Science Centers (CASC) Program

Attached Files

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“Colorado River in Marble Canyon. Credit: Stewart Tomlinson, USGS”
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“Colorado River in Grand County, UT - Credit: Alan Cressler”
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“Colorado River in Grand County, UT - Credit: Alan Cressler”
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Snow-fed rivers of the western US are becoming especially vulnerable to warm springs which hasten the melting of snow. Research indicates that spring temperatures are increasingly contributing to low flows, along with dry winters, as temperatures have warmed over the past few decades. While winter precipitation (rain and snow) is very important to the water supplies that result from melting snow, we now know that temperatures in spring can also have an important impact on river flow and water supplies. Our records of river flow, temperatures, and winter precipitation are only about 100 years in length - too short to assess the range of temperature and moisture conditions that can impact river flow - so we turn to tree rings which can be used to reconstruct past climate conditions. Reconstructions of past climate allow us to assess the range of climate events, such as drought, that have occurred in the past, and that could occur in the future. These extended records also enable us to compare recent climate and projections of future climate in the context of the past to determine when conditions exceed the range of natural climate variability. In this study, we will use existing Colorado River streamflow and winter precipitation reconstructions for the past 1000 years, along with a new spring temperature record, developed under this study, to evaluate past droughts, many of which have far exceed the length and severity of droughts recorded in the gage record. These long records allow us to investigate the different combinations of temperatures and winter precipitation that have contributed to past droughts. Were major droughts just devastatingly dry or did warmer spring temperatures play a role? How do warm conditions that influenced past drought compare to the warming that is projected in the future? We will collaborate with water managers to help them determine how warming temperatures may influence river flow in the future.

Project Extension

typeTechnical Summary
valueUnderstanding and anticipating the joint impacts of cool-season precipitation and increasing spring temperatures on snowpack and runoff is critical for water resource management and planning in the 21st century. Recent research indicates that spring temperatures are becoming an increasingly important driver of post-1980s snowpack declines in the Southern Rockies. This research shows the combined influence of cool-season temperature and precipitation anomalies of the 20th century served to ameliorate or exacerbate decadal-scale drought/pluvial events in a way that presents substantial, and different, water management challenges. Until now, disentangling the relative roles of temperature and precipitation in driving major decadal-scale departures in upper Colorado River Basin (UCRB) water resources over past centuries has not been possible due a lack of a cool season temperature proxy. New results from NSF-funded work by the PIs shows it is now possible to obtain a record of winter/spring temperatures in the UCRB using d18O derived from tree-ring cellulose in cool-season, moisture-sensitive trees. Independent precipitation reconstructions are also available. This project will build on these research results to develop a winter/spring temperature record for the UCRB to assess periods of extreme, decadal-scale drought and pluvial events over the past 1000 years). The main goals of the study are as follows: 1) Examine the relative importance of spring temperatures and cool season precipitation on past drought and pluvial periods documented in the existing Colorado River reconstruction. 2) Evaluate how the magnitude of projected cool-season warming in CMIP-5 models compares to reconstructed spring warming during the most notable UCRB droughts. 3) Collaborate with water managers to determine key research questions concerning winter/spring temperatures and Colorado River flow, and the best ways to incorporate this information into planning for a future. This proposal directly addresses the Southwest CSC scientific priority #3 Hydrological effects of climate change in the Southwest; and produces baseline data for priority#2, Linking climatic, hydrological and ecological changes at intermediate timescales. It also addresses cross-cutting CSC program priorities including climate impacts on natural resources and engagement with decision makers. Though this project is designed for the UCRB, a similar approach could be used to develop temperature reconstructions where water supplies are dependent on snowpack (e.g. Rio Grande, Sacramento River).
typeFY 14 Grant ($118,024)

Budget Extension


Additional Information


Type Scheme Key
RegistrationUUID NCCWSC 0c38422a-b587-466e-b9c5-9f0b1ded77ef
StampID NCCWSC SW13-WC18034

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