Quantifying the effects of climate variability and human activities on runoff from the Laohahe basin in northern China using three different methods (pages 2492–2505)

摘要

Much attention has recently been focused on the effects that climate variability and human activities have had on runoff.nIn this study, these effects are quantified using three methods, namely, multi-regression, hydrologic sensitivity analysis, andnhydrologic model simulation. A conceptual framework is defined to separate the effects. As an example, the change in annualnrunoff from the semiarid Laohahe basin (18 112 km2) in northern China was investigated. Non-parametric Mann-Kendall test,nPettitt test, and precipitation-runoff double cumulative curve method were adopted to identify the trends and change-pointsnin the annual runoff from 1964 to 2008 by first dividing the long-term runoff series into a natural period (1964–1979) and anhuman-induced period (1980–2008). Then the three quantifying methods were calibrated and calculated, and they providednconsistent estimates of the percentage change in mean annual runoff for the human-induced period. In 1980–2008, humannactivities were the main factors that reduced runoff with contributions of 89–93%, while the reduction percentages duento changes in precipitation and potential evapotranspiration only ranged from 7 to 11%. For the various effects at differentndurations, human activities were the main reasons runoff decreased during the two drier periods of 1980–1989 and 2000–2008.nIncreased runoff during the wetter period of 1990–1999 is mainly attributed to climate variability. This study quantitativelynseparates the effects of climate variability and human activities on runoff, which can serve as a reference for regional waternresources assessment and management. Copyright  2011 John Wiley & Sons, Ltd.