Seasonality and Drivers of Low Flows Across Europe and the United States. Issue 9 (14th September 2021)

• Record Type: Journal Article
• Authors: Floriancic, Marius G.; Berghuijs, Wouter R.; Molnar, Peter; Kirchner, James W.
• Is Part Of: Water resources research. Volume 57:Issue 9(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-09-14
• Subjects: low flow -- seasonality -- climate -- drought -- precipitation -- evapotranspiration; Hydrology -- Periodicals; 333.91
• DOI: 10.1029/2019WR026928
• Languages: English
• ISSNs: 0043-1397

Abstract

Abstract: Low river flows can negatively impact society and the riverine environment. Thus, it is useful to predict their seasonal timing and reveal their main drivers. The typical timing of low flows varies between regions, yet systematic overviews across Europe and the United States are rare. Here, we identify regional patterns of the seasonal timing of annual minimum flows, and the consistency of that timing, across 1860 European and US catchments. Catchments where low flows typically occur during late summer or winter tend to have more consistent low‐flow timings. We compare the timing of annual low flows with that of potential climatic drivers. Low flows in 89% of the European and 86% of the US catchments exhibit a statistically significant ( p < 0.05) overlap in timing with at least one potential climatic driver. In most catchments, low flows tend to occur during the warm season, reflecting a period of high potential evapotranspiration exceeding precipitation. In the higher elevation European Alps, Scandinavia, the Rocky Mountains, and the Upper Midwest and Plains states, low flows mostly occur during winter as a result of freezing temperatures which inhibit snowmelt. Binomial statistics also enabled us to statistically exclude individual climatic drivers for certain regions. The regional patterns of timings and drivers of low flows across Europe and the contiguous US can inform low‐flow management, provide context for the evolution of low flows under climate change, and point to processes that require attention in future low‐flow research. Key Points: Across Europe and the US, seasonal patterns in low flows and potential low‐flow drivers (precipitation, ET, and freezing) vary regionally For 1860 catchments in Europe and the US we assign (and exclude) dominant drivers of annual low flows using binomial statistics Most low flows occur in late summer driven by ET, but in cold regions low flows often occur in winter driven by freezing