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Zhao Liu
School of Water and Environment, Chang’an University, Xi’an, China

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Original article
Published: 14 August 2021 in Environmental Earth Sciences
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The Yellow River is the mother river of the Chinese nation. The source region of the Yellow River is an important region for water conservation in China. The hydro-ecological environment of the Yellow River source region is very fragile. Therefore, the variation processes of runoff and sediment discharge in the Yellow River source region have become the subject of considerable concern in recent years. However, the source region of the Yellow River has been studied relatively little, and the influence of these two process in the source region of the Yellow River remains unclear. In this paper, precipitation, runoff, sediment discharge, and their interactions in the source region of the Yellow River from 1956 to 2018 were analyzed using several different time-series evaluation methods, such as Spearman’s rank correlation coefficient method, the ordered clustering analysis method, and the double-mass curve method. Furthermore, the impact of Huangheyuan hydropower station on these hydrological elements was analyzed in relation to the few other human activities in Sanjiangyuan National Nature Reserve. The results indicated that the precipitation in the source region of the Yellow River increased significantly, the sediment discharge decreased non-significantly, and there was no significant change in runoff over this time period. The years 1995 and 2011 were probable mutation points of the sediment discharge series, and the mutation point of the precipitation series was likely 2001. The Huangheyuan hydropower station is the main reason for the decrease in annual sediment discharge in the source region of the Yellow River.

ACS Style

LianJing Ma; Zhao Liu; Baofeng Zhao; Jiawei Lyu; Feimin Zheng; Wen Xu; Xuebin Gan. Variations of runoff and sediment and their response to human activities in the source region of the Yellow River, China. Environmental Earth Sciences 2021, 80, 1 -12.

AMA Style

LianJing Ma, Zhao Liu, Baofeng Zhao, Jiawei Lyu, Feimin Zheng, Wen Xu, Xuebin Gan. Variations of runoff and sediment and their response to human activities in the source region of the Yellow River, China. Environmental Earth Sciences. 2021; 80 (17):1-12.

Chicago/Turabian Style

LianJing Ma; Zhao Liu; Baofeng Zhao; Jiawei Lyu; Feimin Zheng; Wen Xu; Xuebin Gan. 2021. "Variations of runoff and sediment and their response to human activities in the source region of the Yellow River, China." Environmental Earth Sciences 80, no. 17: 1-12.

Articles
Published: 20 May 2020 in Human and Ecological Risk Assessment: An International Journal
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To study rainfall forecast error’s influence on flood operation, short-term (24 hours ahead) rainfall forecast accuracy in Qian river basin were analyzed, probabilities of event on flood operation risk were estimated based on Bayesian theory, and the dynamic control scheme was discussed. Results show that, accuracy rate and missing report rate decreased while vacancy rate increased with the increase of rainfall forecast magnitude. For flood operation based on current rainfall forecast information of different magnitudes, level I (“no rain”) error nearly has no impact on it, level II (“light rain”) error has a little impact on small flood operation, and level III (“no less than moderate rain”) error has a great impact on large flood. For the dynamic control scheme in flood season, it is not necessary to discharge flood ahead of schedule so that limited water level can be kept at the upper boundary to provide higher potential energy for power generation when forecasting rainfall shows “no rain” or “light rain”, while it should be discharged ahead of schedule so that limited water level can be kept at a lower value to ensure an adequate flood storage capacity when forecasting rainfall shows “no less than moderate rain”.

ACS Style

Zhifeng Jia; Zilong Guan; Zhao Liu; Dongming Yang. Influence of short-term rainfall forecast error on flood forecast operation: A risk assessment based on Bayesian theory. Human and Ecological Risk Assessment: An International Journal 2020, 26, 2447 -2461.

AMA Style

Zhifeng Jia, Zilong Guan, Zhao Liu, Dongming Yang. Influence of short-term rainfall forecast error on flood forecast operation: A risk assessment based on Bayesian theory. Human and Ecological Risk Assessment: An International Journal. 2020; 26 (9):2447-2461.

Chicago/Turabian Style

Zhifeng Jia; Zilong Guan; Zhao Liu; Dongming Yang. 2020. "Influence of short-term rainfall forecast error on flood forecast operation: A risk assessment based on Bayesian theory." Human and Ecological Risk Assessment: An International Journal 26, no. 9: 2447-2461.

Journal article
Published: 30 May 2019 in Water
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With the improvement of short-term flood forecasting and short-term rainfall forecast accuracy, as well as the advance of hydrological and meteorological information collection and collation methods, the reservoir flood regulation method taking rainfall or inflow forecast into consideration is gaining more and more attention. As the index of Forecast-Based Operation (FBO), the forecasted factor plays an important part in determining success or failure of FBO due to its uncertainty and accuracy. In this study, possible risk sources were analyzed considering the process and the characteristics of reservoir flood regulation firstly, and the uncertainty of the forecast information and the FBO risks were discussed based on hypothesis testing. Then, combined with the case study of applying FBO on Ankang Reservoir, in which the forecasted net rainfall was selected as the index of the FBO rules, the probability distribution of the forecasted net rainfall errors was derived as the basis of risk analysis. Finally, FBO risk analysis was conducted based on Monte Carlo method for several real flood processes, while a simulation was also carried out with the Conventional Operation (CO) for contrast. The results indicate that the maximum risk was reduced more than half when FBO was adopted. Consequently, the possible remedial measures were put forward in the case of invalid forecast happened based on simulation and the analysis of the principle of flood regulation. The conclusions and methods in this research provide ideas for real-time flood regulation and risk management of reservoirs.

ACS Style

Zhao Liu; Jiawei Lyu; Zhifeng Jia; Lixia Wang; Bin Xu. Risks Analysis and Response of Forecast-Based Operation for Ankang Reservoir Flood Control. Water 2019, 11, 1134 .

AMA Style

Zhao Liu, Jiawei Lyu, Zhifeng Jia, Lixia Wang, Bin Xu. Risks Analysis and Response of Forecast-Based Operation for Ankang Reservoir Flood Control. Water. 2019; 11 (6):1134.

Chicago/Turabian Style

Zhao Liu; Jiawei Lyu; Zhifeng Jia; Lixia Wang; Bin Xu. 2019. "Risks Analysis and Response of Forecast-Based Operation for Ankang Reservoir Flood Control." Water 11, no. 6: 1134.

Journal article
Published: 12 March 2019 in Water
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Analyzing the encounter frequency of high–low runoff and sediment yield is important for the appropriate dispatching of runoff–sediment resources, as well as river regulation. However, there have been no reports on the utilization of the pair-copula function in analyzing the runoff–sediment characteristics from a probabilistic perspective and conducting probability control on the runoff–sediment yields of different hydrologic stations. This paper builds marginal distribution functions on the basis of kernel distribution theory. In addition, this paper builds the joint distribution functions through pair-copula functions in order to analyze the encounter probability and the compensation characteristics of high–low runoff and sediment at different stations on the Weihe River in China, as well as the origins of runoff–sediment, to conduct probability control of river runoff–sediment resource allocation. The results show that, in different periods, the synchronous probability of high–low runoff of the Weihe River’s Xianyang and Huaxian Stations, and the Jinghe River’s Zhangjiashan Station differ, while that of high–low sediment at the three stations changes little—remaining at around 54%. Therefore, the sediment and runoff of the Weihe River apparently have different origins. In years of high and low runoff, if the runoffs of the Xianyang and Zhangjiashan Stations can be kept within a certain range, then the runoff of the Huaxian Station will be in a particular range, at a certain probability. Sediment at the Huaxian Station can be controlled, in a similar way. These results are of great significance for the water and sediment management department of the Weihe river, in order to reasonably allocate water and sediment resources.

ACS Style

Qiying You; Hao Jiang; Yan Liu; Zhao Liu; Zilong Guan. Probability Analysis and Control of River Runoff–sediment Characteristics based on Pair-Copula Functions: The Case of the Weihe River and Jinghe River. Water 2019, 11, 510 .

AMA Style

Qiying You, Hao Jiang, Yan Liu, Zhao Liu, Zilong Guan. Probability Analysis and Control of River Runoff–sediment Characteristics based on Pair-Copula Functions: The Case of the Weihe River and Jinghe River. Water. 2019; 11 (3):510.

Chicago/Turabian Style

Qiying You; Hao Jiang; Yan Liu; Zhao Liu; Zilong Guan. 2019. "Probability Analysis and Control of River Runoff–sediment Characteristics based on Pair-Copula Functions: The Case of the Weihe River and Jinghe River." Water 11, no. 3: 510.

Thematic issue
Published: 22 August 2017 in Environmental Earth Sciences
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Due to deficient water resources in the Loess Plateau, watershed management plays a very important role, not only for ecological and environmental protection but also for the social development of the region. To better understand the hydrological and water resource variations in the typical watershed of the Loess Plateau and the Qinghe River Basin, the influences of land cover and climate change were analysed, and a SWAT model was built to simulate the response of the hydrological situation to land cover changes that have occurred over the past 30 years. The results demonstrated that the main land cover change occurring in the Qinghe River Basin was the conversion of land cover from grassland to woodland and farmland from the late 1980s to 2010. Woodland and farmland took 87.36 and 10.55%, respectively, from the overall area transferred over 20 years and more than 18% of the total watershed area. Hydrological simulation results indicated that land cover played a predominant role in the hydrological variation of the Qinghe River Basin, although the effects of climate change should not be discounted. The significant changes in land cover could be superimposed by policy orientation and economic requirements. Although it is hard to evaluate the land cover changes and the corresponding hydrological responses in a simple language, related analyses have demonstrated an increasing trend of runoff in the dry season, while there is a somewhat decreasing trend during the flood season in the river basin. There results could be significant and provide a positive influence on both future flood control and the conservation of water and soil.

ACS Style

Zhao Liu; Lulu Li; Lixia Wang; Qing Wang; Qiang Li. Hydrological situation of a typical watershed in the Loess Tableland Area of China over the past 30 years. Environmental Earth Sciences 2017, 76, 577 .

AMA Style

Zhao Liu, Lulu Li, Lixia Wang, Qing Wang, Qiang Li. Hydrological situation of a typical watershed in the Loess Tableland Area of China over the past 30 years. Environmental Earth Sciences. 2017; 76 (16):577.

Chicago/Turabian Style

Zhao Liu; Lulu Li; Lixia Wang; Qing Wang; Qiang Li. 2017. "Hydrological situation of a typical watershed in the Loess Tableland Area of China over the past 30 years." Environmental Earth Sciences 76, no. 16: 577.