Multiple Indicators of Extreme Changes in Snow-Dominated Streamflow Regimes, Yakima River Basin Region, USA

Journal Article · Wed Sep 22 00:00:00 EDT 2021 · Water (Basel)

DOI:https://doi.org/10.3390/w13192608· OSTI ID:1827598

Wagner, Anna M.  ^[1]; Bennett, Katrina E.  ^[2]; Liston, Glen E. ^[3]; Hiemstra, Christopher A. ^[4]; Cooley, Dan  ^[3]

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1. Army Cold Regions Research and Engineering Laboratory, Fort Wainwright, AK (United States)
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
3. Colorado State Univ., Fort Collins, CO (United States)
4. USDA Forest Service, Salt Lake City, UT (United States)

Snow plays a major role in the hydrological cycle. Variations in snow duration and timing can have a negative impact on water resources. Excluding predicted changes in snowmelt rates and amounts could result in deleterious infrastructure, military mission, and asset impacts at military bases across the US. A change in snowpack can also lead to water shortages, which in turn can affect the availability of irrigation water. We performed trend analyses of air temperature, snow water equivalent (SWE) at 22 SNOTEL stations, and streamflow extremes for selected rivers in the snow-dependent and heavily irrigated Yakima River Basin (YRB) located in the Pacific Northwest US. There was a clear trend of increasing air temperature in this study area over a 30 year period (water years 1991–2020). All stations indicated an increase in average air temperatures for December (0.97 °C/decade) and January (1.12 °C/decade). There was also an upward trend at most stations in February (0.28 °C/decade). In December–February, the average air temperatures were 0.82 °C/decade. From these trends, we estimate that, by 2060, the average air temperatures for December–February at most (82%) stations will be above freezing. Furthermore, analysis of SWE from selected SNOTEL stations indicated a decreasing trend in historical SWE, and a shift to an earlier peak SWE was also assumed to be occurring due of the shorter snow duration. Decreasing trends in snow duration, rain-on-snow, and snowmelt runoff also resulted from snow modeling simulations of the YRB and the nearby area. We also observed a shift in the timing of snowmelt-driven peak streamflow, as well as a statistically significant increase in winter maximum streamflow and decrease in summer maximum and minimum streamflow trends by 2099. From the streamflow trends and complementary GEV analysis, we show that the YRB basin is a system in transition with earlier peak flows, lower snow-driven maximum streamflow, and higher rainfall-driven summer streamflow. This study highlights the importance of looking at changes in snow across multiple indicators to develop future infrastructure and planning tools to better adapt and mitigate changes in extreme events.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE; USDOD
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 1827598
• Report Number(s): LA-UR-21-29336
• Journal Information: Water (Basel), Vol. 13, Issue 19; ISSN 2073-4441
• Publisher: MDPI
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
Earth Sciences
climate change
extreme events
hydrology
snow
trends
snow water equivalent
Yakima River basin