Abstract
An obvious decline in runoff of the Weihe River has been detected during the last half-century. Climate change and human activity acted as two major factors inducing the reduction. However, little knowledge is acquired on how and to what extent the decadal climate change and human activity induced runoff variations, which is essential for regional water resources planning and management. In this study, the observed data of 3 hydrological stations and 31 meteorological stations were used to analyze the runoff variability, and Variable Infiltration Capacity (VIC) model (Xu Liang, Seattle, WA, United States of America) coupled with scenario simulation was employed to attribute runoff variation of each period. The results showed that runoff decreased significantly at a rate of −1.01 × 108 m3·year−1 with obvious stage characteristic during 1961–2016. The water yield was highest in the 1960s and varying degrees of decline were detected in the following periods, resulting in a decrease of available freshwater by 20.54%–58.24%. Human activity had a dominant contribution to induce an increasing runoff decline from 2.068 to 5.776 km3, while the effect of climate was relatively small and lead to runoff reduction, except in the 1970s. This study gave a comprehensive understanding of time-varying runoff variability and highlighted the importance of appropriate human intervention with respect to climate change to ensure water resources security.
Highlights
Runoff, as a major component of the water cycle, is one of the most important water sources and plays an important role in ecology, society, and economics to support both the natural ecosystem and human society, especially in inland arid areas [1,2]
1962–1970, when it was considered to be less disturbed by human activity based on the Pettitt test and partial correlation analysis with meteorological variables
It is important to note that the calibrated parameters of WH1 and WH2 were used in calibration at Huanxian station to calibrate the parameters of WH3
Summary
As a major component of the water cycle, is one of the most important water sources and plays an important role in ecology, society, and economics to support both the natural ecosystem and human society, especially in inland arid areas [1,2]. An obvious downward trend was detected in many major rivers in China in recent decades, especially in the arid Loess Plateau [3,4,5,6]. Investigated the runoff time series data of 11 catchments in the Loess Plateau and found that all the 11 rivers had a significant negative trend in annual streamflow of 0.13 to 1.58 mm·year−1. Feng [7] applied a transient analysis to discover the time-varying runoff trend and impact factors; the results showed that the average runoff in the Loess Plateau decreased continuously during the period 1961–2009 at an average rate of −0.9 mm·year−1 and three stages of obvious decrease trend in runoff were detected with transitions in 1970, 1981, and 1996. Runoff reduction of 32 hydrological catchments directly resulted in a decline of water yield from 8% during the period of 1980 to 1999 to 5% from 2000–2010 [8].
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