U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights


Water Management Influences Long-Term Changes in River Flows
Published: March 01, 2018
Posted: July 30, 2018

Changes in water volume tend to be smaller in managed watersheds but occur earlier.

The Science
Water management activities, such as irrigation withdrawals and dam operations, strongly influence the flow of water through a watershed. Researchers from the U.S. Department of Energy’s Pacific Northwest National Laboratory conducted the first regional modeling study to explore how these activities might modulate the effects of long-term changes in temperature and precipitation on regulated river flows. They found that close to half of the watersheds in the western United States could experience noticeable flow changes earlier in the century than they would in the absence of water management. While results vary substantially across different watershed regions and seasons, the overall magnitude of change tends to be smaller in highly managed watersheds.

The Impact
This work is the first large-scale investigation of the “emergence of change” in highly regulated versus unregulated rivers—that is, it accounts for the influence of water management as well as for changing environmental conditions. Water management activities are generally thought to reduce flow variations, which was confirmed. However, the work revealed that water management can accelerate the emergence of these smaller changes. The findings highlight significant regional and seasonal differences in how long-term Earth system changes will affect water availability. These results can be used to help understand and prepare for possible shifts in the timing and magnitude of future flows in the western United States. The research also highlights the need to account for human influences when constructing models of energy systems and other sectors that are strongly affected by changes in water availability.

Summary
This study focused on seasonal and regional variations in the emergence (the “when”) of flow volume changes. Using a large-scale hydrologic model driven by three different Earth system models, researchers used statistical techniques to identify when noticeable shifts in flow volume occurred in each water basin across the western United States. They examined two different scenarios of projected temperature and precipitation changes over the 21st century. They then compared hydrological simulations that included water management with those that did not consider the influence of dams, irrigation, and other human influences on water flow. The research team also analyzed historical conditions for context and comparison. The results showed that in 40 percent of river basins, water management activities accelerate the emergence of noticeable changes in annual flow volume (that is, the changes appear earlier in the century than in simulations that did not consider water management activities). In 10 percent of basins, however, water management delays the onset of noticeable changes. Even though water management generally accelerates the emergence of changes in flow, the magnitude of those changes over the 21st century is smaller in heavily managed basins. The picture gets more complex when looking at individual seasons, but in general, compared to unregulated conditions, the overall sensitivity of flow changes to water management tends to decrease in the spring and increase in the winter and summer.

Contacts
(BER PM)

Bob Vallario
Multi-Sector Dynamics
bob.vallario@science.doe.gov

(PI Contact)
Ian Kraucunas
Pacific Northwest National Laboratory
Ian.Kraucunas@pnnl.gov

Funding
The regional analysis and writing of the paper were supported by the U.S. Department of Energy, Office of Science, as part of the Multi-Sector Dynamics, Earth and Environmental System Modeling Program. The integrated hydrologic simulations were conducted under the Laboratory Directed Research and Development Program at Pacific Northwest National Laboratory, a multiprogram national laboratory operated by Battelle for the U.S. Department of Energy.

Publications
Zhou, T., N. Voisin, G. Leng, M. Huang, and I. Kraucunas. “Sensitivity of Regulated Flow Regimes to Climate Change in the Western United States.” Journal of Hydrometeorology 19, 3 (2018). [DOI: 10.1175/JHM-D-17-0095.1]

Related Links
Journal Article

Topic Areas:

  • Research Area: Earth and Environmental Systems Modeling
  • Research Area: Multisector Dynamics (formerly Integrated Assessment)

Division: SC-23.1 Climate and Environmental Sciences Division, BER

 

BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

May 10, 2019
Quantifying Decision Uncertainty in Water Management via a Coupled Agent-Based Model
Considering risk perception can improve the representation of human decision-making processes in age [more...]

May 09, 2019
Projecting Global Urban Area Growth Through 2100 Based on Historical Time Series Data and Future Scenarios
Study provides country-specific urban area growth models and the first dataset on country-level urba [more...]

May 05, 2019
Calibrating Building Energy Demand Models to Refine Long-Term Energy Planning
A new, flexible calibration approach improved model accuracy in capturing year-to-year changes in bu [more...]

May 03, 2019
Calibration and Uncertainty Analysis of Demeter for Better Downscaling of Global Land Use and Land Cover Projections
Researchers improved the Demeter model’s performance by calibrating key parameters and establi [more...]

Apr 22, 2019
Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles
Representation of warm temperature events varies considerably among global climate models, which has [more...]

List all highlights (possible long download time)