Search

Abstract: This paper is to highlight the threatening of climate change on the water shortage problem in North China, a semi-arid and arid area. Observations show that the runoff of the major rivers is decreasing dramatically especially in the lower reaches where water ishighly demanded. Most noticeable are the dry-outs of the Yellow River, the so-called ‘mother river of China’.Water scarcity would be the most front challenge for the society and economy in China, especially the urban area with extremely high population density. The government already paid attention to the deepening of the underground water level at Beijing. Sustainable water resource management should the top priority for the local community to adapt to climate change. Studies show that human activities heavily impact on the local climate and environment in China and a dramatics amount of clean water is wasted or polluted. [Copyright &y& Elsevier]

Under the impacts of climate variability and human activities, there are statistically significant decreasing trends for streamflow in the Yellow River basin, China. Therefore, it is crucial to separate the impacts of climate variability and human activities on streamflow decrease for better water resources planning and management. In this study, the Qinhe River basin (QRB), a typical sub-basin in the middle reach of the Yellow River, was chosen as the study area to assess the impacts of climate variability and human activities on streamflow decrease. The trend and breakpoint of observed annual streamflow from 1956 to 2010 were identified by the nonparametric Mann-Kendall test. The results showed that the observed annual streamflow decreased significantly ( P < 0.05) and a breakpoint around 1973 was detected. Therefore, the time series was divided into two periods: 'natural period' (before the breakpoint) and 'impacted period' (after the breakpoint). The observed annual streamflow decreased by 68.1 mm from 102.3 to 34.2 mm in the two periods. The climate elasticity method and hydrological model were employed to separate the impacts of climate variability and human activities on streamflow decrease. The results indicated that climate variability was responsible for 54.1 % of the streamflow decrease estimated by the climate elasticity method and 59.3 % estimated by the hydrological modeling method. Therefore, the climate variability was the main driving factor for streamflow decrease in the QRB. Among these driving factors of natural and anthropogenic, decrease in precipitation and increase in water diversion were the two major contributions of streamflow reduction. The finding in this study can serve as a reference for regional water resources management and planning. [ABSTRACT FROM AUTHOR]

The eco-hydrological requirements of a river are related to the health of the river. In recent years, changing climate and intensifying human activities have further aggravated water problems in the Yellow River. Considering hydrological changes, this study addressed the ecological water requirements of the Yellow River basin, wherein the threshold ecological water requirement corresponded to the streamflow with the largest occurrence probability determined by the Pearson Type III distribution. Instream flow ± one standard deviation was adopted as the water resource management target and abrupt changes in streamflow were detected by using the Mann-Whitney test. The results of the analysis indicated that: (1) the annual flow of the Yellow River substantially decreased after abrupt changes and the probability significantly dropped that the amount of annual streamflow satisfied the ecological instream flow requirement; and (2) the water resource management target was satisfied well after th echange point only at the Tangnaihai station, located in the upper Yellow River basin. From the upper to the lower Yellow River basins, the probability has dramatically decreased that the ecological water requirement target is satisfied. Therefore, the Yellow River basin will likely face increasingly serious water problems, particularly in the middle and lower parts. [ABSTRACT FROM AUTHOR]