Human activities, as well as climate variability, have had increasing impacts on natural hydrological systems, particularly streamflow. However, quantitative assessments of these impacts are lacking on large scales. In this study, we use the simulations from six global hydrological models driven by three meteorological forcings to investigate direct human impact (DHI) and climate impact on streamflow in China. Results show that, in the sub-periods of 1971-1990 and 1991-2010, one-fifth to one-third of mean annual streamflow (MAF) was reduced due to DHI in northern basins, and much smaller (< 4 %) MAF was reduced in southern basins. From 1971-1990 to 1991-2010, total MAF changes range from 13% to 10% across basins wherein the relative contributions of DHI change and climate variability show distinct spatial patterns. DHI change caused decreases in MAF in 70% of river segments, but climate variability dominated the total MAF changes in 88% of river segments of China. In most northern basins, climate variability results in changes of -9% to 18% in MAF, while DHI change results in decreases of 2% to 8% in MAF. In contrast with the climate variability that may increase or decrease streamflow, DHI change almost always contributes to decreases in MAF over time, with water withdrawals supposedly being the major impact on streamflow. This quantitative assessment can be a reference for attribution of streamflow changes at large scales, despite remaining uncertainty. We highlight the significant DHI in northern basins and the necessity to modulate DHI through improved water management towards a better adaptation to future climate change.
1.Chinese Acad Sci, Key Lab Water Cycle & Related Land Surface Proc, Inst Geog Sci & Nat Resources Res, A11 Datun Rd, Beijing 100101, Peoples R China 2.Eawag, Swiss Fed Inst Aquat Sci & Technol, Ueberlandstr 133, CH-8600 Dubendorf, Switzerland 3.Univ Paris Saclay, Lab Sci Climat & Environm, IPSL, CEA,CNRS,UVSQ, F-91191 Gif Sur Yvette, France 4.Univ Basel, MGU, Dept Environm Sci, Peterspl 1, CH-4003 Basel, Switzerland 5.Univ Chinese Acad Sci, Coll Resources & Environm, Beijing 100049, Peoples R China 6.Univ Kassel, Ctr Environm Syst Res, Wilhelmshoher Allee 47, D-34109 Kassel, Germany 7.Hirosaki Univ, Grad Sch Sci & Technol, Hirosaki, Aomori, Japan 8.Goethe Univ Frankfurt, Inst Phys Geog, Altenhoferallee 1, D-60438 Frankfurt, Germany 9.Senckenberg Biodivers & Climate Res Ctr SBiK F, Senckenberganlage 25, D-60325 Frankfurt, Germany 10.Potsdam Inst Climate Impact Res PIK, Earth Syst Anal, Telegraphenberg A31, D-14473 Potsdam, Germany 11.Michigan State Univ, Dept Civil & Environm Engn, E Lansing, MI 48824 USA 12.Int Inst Appl Syst Anal, Laxenburg, Austria 13.Natl Inst Environm Studies, 16-2 Onogawa, Tsukuba, Ibaraki, Japan
Recommended Citation:
Liu, Xingcai,Liu, Wenfeng,Yang, Hong,et al. Multimodel assessments of human and climate impacts on mean annual streamflow in China[J]. HYDROLOGY AND EARTH SYSTEM SCIENCES,2019-01-01,23(3):1245-1261