Quantitative contribution of climate change and human activities to runoff changes in the Wei River basin, China

Hydrol. Earth Syst. Sci.

Wang

et al. 2016

Abstract. Water resources in river systems have been changing under the impact of both climate variability and human activities. Assessing the respective impact on decadal streamflow variation is important for water resource management. By using an elasticity-based method and calibrated TOP-MODEL and VIC hydrological models, we quantitatively isolated the relative contributions that human activities and climate variability made to decadal streamflow changes in the Jinghe basin, located in the northwest of China. This is an important watershed of the Shaanxi province that supplies drinking water for a population of over 6 million people. The results showed that the maximum value of the moisture index (E 0 /P ) was 1.91 and appeared in 1991-2000, and the decreased speed of streamflow was higher since 1990 compared with . The average annual streamflow from 1990 to 2010 was reduced by 26.96 % compared with the multiyear average value (from 1960 to 2010). The estimates of the impacts of climate variability and human activities on streamflow decreases from the hydrological models were similar to those from the elasticity-based method. The maximum contribution value of human activities was 99 % when averaged over the three methods, and appeared in [1981][1982][1983][1984][1985][1986][1987][1988][1989][1990] due to the effects of soil and water conservation measures and irrigation water withdrawal. Climate variability made the greatest contribution to streamflow reduction in 1991-2000, the values of which was 40.4 %. We emphasized various source of errors and uncertainties that may occur in the hydrological model (parameter and structural uncertainty) and elasticity-based method (model parameter) in climate change impact studies.

Section: Hydrological Model Simulation Resultssupporting

confidence: 82%

Assessing the impact of climate variability and human activities on streamflow variation

Chang

Hydrol. Earth Syst. Sci.

Wang

et al. 2016

“…In recent years, hydrologists have put great efforts into attribution analysis of changes in runoff [16][17][18][19][20][21][22][23][24][25][26]. Broadly, the attribution analysis methods can be mainly divided into five categories: (1) Paired catchment studies.…”

Section: Introductionmentioning

confidence: 99%

Attribution of Runoff Change for the Xinshui River Catchment on the Loess Plateau of China in a Changing Environment

Wang

Yang

2016

Water

Abstract:Stream flow plays a crucial role in the environment, society, and the economy, and identifying the causes of changes in runoff is important to understanding the impact of climate change and human activity. This study examines the variation trends in recorded runoff for the Xinshui River, a tributary of the Yellow River on the Loess Plateau, and uses hydrological simulations to investigate how climate change and human activity have contributed to those trends. Results show that the recorded runoff at the Daning station on the Xinshui River declined significantly from 1955-2008 with an abrupt change occurring in 1973. The Simplified Water Balance Model (SWBM) simulates monthly discharge well with a Nash-Sutcliffe efficiency (NSE) coefficient of 78% and a relative error of volumetric fit (RE) of 0.32%. Runoff depth over the catchment in 1973-2008 fell by 25.5 mm relative to the previous period, with human activity and climate change contributing 60.6% and 39.4% of the total runoff reduction, respectively. However, the impacts induced by climate change and human activities are both tending to increase. Therefore, efforts to improve the ecology of the Loess Plateau should give sufficient attention to the impacts of climate change and human activity.

“…A number of studies have been conducted to separate the impact of climate variation and human activities on river discharge [7][8][9]. Using regression techniques Ye et al [10] and Tian et al [11] investigated the effects of climate variability and human activities on the long-term change in runoff of the Lena River Basin and Hutuo River Basin in China; however, a clear conclusion on the magnitude of each of the two factors could not be drawn due to the limitation of the analytical method.…”

Section: Introductionmentioning

confidence: 99%

Separating the Impacts of Climate Variation and Human Activities on Runoff in the Songhua River Basin, Northeast China

2014

Water

Climate variation and human activities are commonly recognized as two major factors affecting basin hydrology. However, quantifying their individual effect on runoff is challenging. In this study, long-term (1960-2009) river discharge and weather data in the Songhua River Basin (SRB, 556,800 km 2 ), Northeast China, were gathered to separate the impacts of climate variation and human activities on runoff in five sub basins of the SRB. Mann-Kendall test, moving t-test and precipitation-runoff double cumulative curve were utilized to identify trends and change points of the hydrometeorlogical variables. Based on the change point, the 50-year study period was divided into two time series : 1960-1974 where minimal human activities took place and 1975-2009 where extensive land use change occurred and river engineering projects were undertaken. Subsequently, individual contributions of climate and human factors were assessed through a hydrologic sensitivity analysis. Our study found a significant decline in runoff of the SRB over the past 50 years. Contribution of climate variation and human activities to the change varied temporally and spatially. For the 1975-2009 period, human activities made a greater contribution (62%-82%) to the total runoff decline of the SRB. However, climate variation played a bigger role in runoff reduction in two sub river basins (63%-65%) between 1975 and 1989, OPEN ACCESSWater 2014, 6 3321 as well as in runoff increase in other two sub river basins (85%-86%) between 1990 and 1999. Spatially, the effect of human activities on runoff decline was relatively stronger in the lower basin areas in the 1960s and 1970s while showing an increasing role in the upper basin areas in the past two decades.