Observed Trends in Global Indicators of Mean and Extreme Streamflow

This study investigates global changes in indicators of mean and extreme streamflow. The assessment is based on the Global Streamflow Indices and Metadata archive and focuses on time series of the annual minimum, the 10th, 50th, and 90th percentiles, the annual mean, and the annual maximum of daily streamflow. Trends are estimated using the Sen‐Theil slope, and the significance of mean regional trends is established through bootstrapping. Changes in the indices are often regionally consistent, showing that the entire flow distribution is moving either upward or downward. In addition, the analysis confirms the complex nature of hydrological change where drying in some regions (e.g., in the Mediterranean) is contrasted by wetting in other regions (e.g., North Asia). Observed changes are discussed in the context of previous results and with respect to model estimates of the impacts of anthropogenic climate change and human water management. Plain Language Summary Studies of trends in streamflow data from across the globe are essential for understanding patterns and changes in water availability (e.g., regions of deficit and abundance) and evaluating the fidelity of global water availability models. This study evaluates historical trends in streamflow data, using a new data set of observations from over 30,000 sites around the world. The study is comprehensive, looking at changes in low flows (defined as the lowest day of flow in each year), average flows, and high flows (the highest day of flow in each year). An interesting outcome is that where trends are present in a region, the direction of the trend is often consistent across all indices for that region (consistently drier or wetter), as distinct from the possibility of stronger extremes (wetter maximums and drier minimums).

[1]  K. Stahl,et al.  Filling the white space on maps of European runoff trends: estimates from a multi-model ensemble , 2012 .

[2]  Justin Hughes,et al.  Streamflow decline in southwestern Australia, 1950–2008 , 2010 .

[3]  S. Hagemann,et al.  Hydrological droughts in the 21st century, hotspots and uncertainties from a global multimodel ensemble experiment , 2013, Proceedings of the National Academy of Sciences.

[4]  Taotao Qian,et al.  Changes in Continental Freshwater Discharge from 1948 to 2004 , 2009 .

[5]  Richard D. Robarts,et al.  Time for in situ renaissance , 2015, Science.

[6]  F. Piontek,et al.  The Inter-Sectoral Impact Model Intercomparison Project (ISI–MIP): Project framework , 2013, Proceedings of the National Academy of Sciences.

[7]  Karl E. Taylor,et al.  An overview of CMIP5 and the experiment design , 2012 .

[8]  Lukas Gudmundsson,et al.  The Global Streamflow Indices and Metadata Archive (GSIM) – Part 2: Quality Control, Time-series Indices and Homogeneity Assessment , 2017 .

[9]  G. Villarini,et al.  The changing nature of flooding across the central United States , 2015 .

[10]  P. Claps,et al.  Changing climate shifts timing of European floods , 2017, Science.

[11]  Kerstin Stahl,et al.  Have streamflow droughts in Europe become more severe or frequent? , 2001 .

[12]  P. P. Mujumdar,et al.  On the basin‐scale detection and attribution of human‐induced climate change in monsoon precipitation and streamflow , 2012 .

[13]  George Kuczera,et al.  Evaluating the non-stationarity of Australian annual maximum flood , 2013 .

[14]  Jean-Luc Probst,et al.  Evidence for global runoff increase related to climate warming , 2004 .

[15]  Laurence C. Smith,et al.  Climatic and anthropogenic factors affecting river discharge to the global ocean, 1951–2000 , 2008 .

[16]  C. Mechoso,et al.  A Recent Increasing Trend in the Streamflow of Rivers in Southeastern South America , 1998 .

[17]  Yoshihide Wada,et al.  Decadal predictability of river discharge with climate oscillations over the 20th and early 21st century , 2015 .

[18]  Felipe J. Colón-González,et al.  Multimodel assessment of water scarcity under climate change , 2013, Proceedings of the National Academy of Sciences.

[19]  Javier Tomasella,et al.  Trends in streamflow and rainfall in tropical South America : Amazonia, eastern Brazil, and northwestern Peru , 1998 .

[20]  L. Smith,et al.  Recent Eurasian river discharge to the Arctic Ocean in the context of longer‐term dendrohydrological records , 2007 .

[21]  Pedro J. Depetris,et al.  Discharge trends and flow dynamics of South American rivers draining the southern Atlantic seaboard: An overview , 2007 .

[22]  S. Demuth,et al.  Streamflow trends in Europe: evidence from a dataset of near-natural catchments , 2010 .

[23]  P. Sen.  Estimates of the Regression Coefficient Based on Kendall's Tau , 1968 .

[24]  D. Burn,et al.  Detection of hydrologic trends and variability , 2002 .

[25]  D. Hannah,et al.  Large‐scale river flow archives: importance, current status and future needs , 2011 .

[26]  Gregory J. McCabe,et al.  A step increase in streamflow in the conterminous United States , 2002 .

[27]  S. Franks,et al.  Multidecadal variability of rainfall and streamflow: Eastern Australia , 2004 .

[28]  Hong Xuan Do,et al.  The Global Streamflow Indices and Metadata Archive - Part 1: Station catalog and Catchment boundary , 2018 .

[29]  D. Easterling,et al.  Changes in climate extremes and their impacts on the natural physical environment , 2012 .

[30]  L. Bouwer,et al.  Regional sensitivities of mean and peak river discharge to climate variability in Europe , 2008 .

[31]  Lukas Gudmundsson,et al.  The Global Streamflow Indices and Metadata Archive (GSIM) – Part 1: The production of a daily streamflow archive and metadata , 2017 .

[32]  Lukas Gudmundsson,et al.  Regional scaling of annual mean precipitation and water availability with global temperature change , 2017 .

[33]  Kevin E. Trenberth,et al.  Estimates of Freshwater Discharge from Continents: Latitudinal and Seasonal Variations , 2002 .

[34]  T. Stocker,et al.  Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. A Special Report of Working Groups I and II of IPCC Intergovernmental Panel on Climate Change , 2012 .

[35]  Climatic influences on streamflow variability: A comparison between southeastern Australia and southeastern United States of America , 1990 .

[36]  Jeroen C. J. H. Aerts,et al.  Sensitivity of river discharge to ENSO , 2010 .

[37]  K. Stahl,et al.  The influence of decadal-scale variability on trends in long European streamflow records , 2013 .

[38]  Zbigniew W. Kundzewicz,et al.  Trend detection in river flow series: 2. Flood and low-flow index series / Détection de tendance dans des séries de débit fluvial: 2. Séries d'indices de crue et d'étiage , 2005 .

[39]  Jean-Daniel Saphores,et al.  Fighting drought with innovation: Melbourne's response to the Millennium Drought in Southeast Australia , 2015 .

[40]  A. V. Vecchia,et al.  Global pattern of trends in streamflow and water availability in a changing climate , 2005, Nature.

[41]  D. Hannah,et al.  Ocean-atmosphere forcing of summer streamflow drought in Great Britain , 2013 .

[42]  W. Briggs.  Statistical Methods in the Atmospheric Sciences , 2007 .

[43]  Harry F. Lins,et al.  Streamflow trends in the United States , 1999 .

[44]  Ashutosh Kumar Singh,et al.  Coupled oceanic‐atmospheric variability and U.S. streamflow , 2005 .

[45]  Alain Pietroniro,et al.  Rationale for Monitoring Discharge on the Ground , 2012 .

[46]  T. Piechota,et al.  Relationships between Pacific and Atlantic ocean sea surface temperatures and U.S. streamflow variability , 2006 .

[47]  G. Destouni,et al.  Local flow regulation and irrigation raise global human water consumption and footprint , 2015, Science.

[48]  H. Madsen,et al.  Climate-driven variability in the occurrence of major floods across North America and Europe , 2017 .

[49]  Eric F. Wood,et al.  A pan‐arctic evaluation of changes in river discharge during the latter half of the 20th century , 2005 .

[50]  D. Lettenmaier,et al.  Application of New Precipitation and Reconstructed Streamflow Products to Streamflow Trend Attribution in Northern Eurasia , 2008 .

[51]  S. Kanae,et al.  Global flood risk under climate change , 2013 .

[52]  Maciej Radziejewski,et al.  Trend detection in river flow series: 1. Annual maximum flow / Détection de tendance dans des séries de débit fluvial: 1. Débit maximum annuel , 2005 .

[53]  G. Hegerl,et al.  Detection and attribution of climate change: from global to regional , 2013 .

[54]  D. Helsel,et al.  Regional Kendall test for trend. , 2006, Environmental science & technology.

[55]  J. R. Wallis,et al.  Hydro-Climatological Trends in the Continental United States, 1948-88 , 1994 .

[56]  Michael Leonard,et al.  A global-scale investigation of trends in annual maximum streamflow , 2017 .

[57]  Aurélien Ribes,et al.  Trends in Global and Basin-Scale Runoff over the Late Twentieth Century: Methodological Issues and Sources of Uncertainty , 2011 .

[58]  Donald H. Burn,et al.  Climatic influences on streamflow timing in the headwaters of the Mackenzie River Basin , 2008 .

[59]  Nikita Tananaev,et al.  Trends in annual and extreme flows in the Lena River basin, Northern Eurasia , 2016 .

[60]  Ross Woods,et al.  Recent changes in extreme floods across multiple continents , 2017 .

[61]  R. Laugesen,et al.  How streamflow has changed across Australia since the 1950s: evidence from the network of hydrologic reference stations , 2016 .

[62]  Bellie Sivakumar,et al.  Natural hazards in Australia: droughts , 2016, Climatic Change.

[63]  Richard M. Vogel,et al.  Trends in floods and low flows in the United States: impact of spatial correlation , 2000 .

[64]  S. Seneviratne,et al.  Anthropogenic climate change detected in European renewable freshwater resources , 2017 .

[65]  B. Zaake,et al.  A study of variability of annual river flow of the southern African region , 2001 .

[66]  Jeroen C. J. H. Aerts,et al.  Winter atmospheric circulation and river discharge in northwest Europe , 2006 .

[67]  F. Ludwig,et al.  Global water resources affected by human interventions and climate change , 2013, Proceedings of the National Academy of Sciences.