The runoff of the Fenhe River flowed into the Yellow River (RRY) is reducing significantly due to the influence of climate change and human activities. It is generating bad situation of shortage of water resources and led to the deterioration of ecological environment of Shanxi Province. At the same time, the reduction in RRY causes the runoff reduction in Yellow River and exacerbated the water resources shortage of the middle area of the Yellow River. Therefore, it is important to alleviate water shortage and develop the soil and water conservation measurements and regional water policy by analyzing the influence of human activities and climate change on the RRY.
The existing study quantified the reduction in amount of RRY which caused by
human activities and climate change using statistical methods and watershed
hydrological model. The main results of the study were as follow: Using hydrological variation diagnosis system, the variation
characteristics of long time series of measured annual runoff were analyzed
in Hejin station that is the Fenhe River control station. The results showed
that the runoff of Fenhe River run into Yellow River declined year by year,
in 1971, fell the most obviously. The impact of LUCC on runoff was calculated using the method of area
ratio in the Fenhe River basin. Human activities were major factor in the
reduction of RRY than the climate change, contributed 83.09 % of the
total reduction in RRY, Groundwater exploitation gave the greatest
contribution to the decrease in RRY in the scope of several kinds of human
activity (30.09 %), followed by coal mining (26.03 %), climate
changed contributed 19.17 % of the total reduction of RRY, and the
decrease of precipitation contributed 20.81 %. But the variation of air
temperature and wind speed would result in the increase of the amount of RRY.
The Yellow River Basin is the origin of Chinese civilization, is the second
largest river after the Yangtze River, but the Yellow River Basin water
shortage is extremely short, accounting for about 2 % of China's runoff
is about 12 % of China's population production and living water, The
basin's gross domestic product (GDP) accounts for 9 % of the country (He
et al., 2013). Zhang Xuecheng and other pointed out that the trend of runoff
from Fen River Basin to the yellow river was significantly reduced, is one of
the major causes of runoff reduction in the Yellow River (Zhang and Wang,
2001). However, after entering the 1970s, the measured flow of the Yellow
River and its main tributaries showed a significant reduction, while the main
stream and the main tributaries were repeatedly broken up (Zhang et al.,
2000; Mu et al., 2007; Jia et al., 2007; Xu et al., 2012). Fenhe River is the
second largest tributary of the Weihe River in the middle reaches of the
Yellow River. It has an important influence on the process of water and
sediment evolution in the middle and lower reaches of the Yellow River. At
the same time, the Fen River is the largest river in Shanxi Province. Its
basin area is 39 826 km
There are four methods to evaluate the hydrological effects of environmental changes: similar watershed comparative test, hydrological model simulation, sensitivity analysis based on hydrothermal coupled equilibrium equation and statistical regression analysis (Li et al., 2009). Similar watershed comparison test method is to select two experimental conditions with similar climatic conditions, topography, area and other characteristics. Under the same gradient and climatic conditions, change the climatic conditions of another experimental basin or the watershed characteristics, the differences between hydrological variables in these two experimental watersheds analyze the impact of human activities on hydrological processes in the basin. However, this method has limitations in the watershed scale for high cost and difficult to find similar watershed (Zhao et al., 2010). Statistical regression analysis is based on the analysis of hydrological and meteorological data using statistical principles. Through the analysis of the factors influencing the process of runoff formation, the main influencing factors of runoff variation are established, and the regression equation of runoff and main influencing factors is established. The advantages of the method are relatively easy to implement, but do not reflect the nonlinear relationship between rainfall and runoff (Ahn and Merwade, 2014), and the accuracy of the results is not high (Jiang et al., 2011). Sensitivity analysis is mainly used to quantitatively analyze the impact of climate change on runoff, which evaluates the impact of climate change on runoff by determining the degree of change in the runoff of the basin due to changes in the climate factors of the unit, and is widely used in quantitative analysis of environmental change Runoff effects, and achieved satisfactory results (Wang et al., 2013; Elfert and Bornmann, 2010; Awan and Ismaeel, 2014; Ahn and Merwade, 2014; Zeng et al., 2014). Based on the understanding of hydrological phenomena, the hydrological model of watershed through establishes a hydrological model by mathematical method to analyzes its causes and the relationship between hydrological elements, and. With the development of computer and GIS technology, hydrological model method has become a powerful tool to study hydrological problems (Awan and Ismaeel, 2014; Ahn and Merwade, 2014; Li et al., 2009). Although the impact of climate change and human activities on runoff, domestic and foreign scholars have done a lot of research and determine the very rich results, there are still some problems: Most research of the impact of the quantitative analysis of climate change and human activities on runoff research, only take the factors that impact runoff changes as climate factors and human factors, and on this basis, quantitative analysis the impact of both changes in runoff, the impact of human activities to the next level, a detailed division of the various climate and human activities on runoff is not included.
According to the available data, the main factors influencing the runoff in
the Fenhe River Basin are: the annual rainfall of the Fenhe River Basin is
reduced by 38 800 m
Fenhe River Basin is located at 110.5–113.5
Fenhe River Basin belongs to mid latitude continental monsoon climate, the
climate is characterized by four distinctive seasons: short day and little
rain and more sand wind in spring (Liang et al., 2010), high temperature and
more rainstorm in summer, the difference in start time is more, mild and
sunny in autumn, scarce precipitation and cold and dry in winter. The basin
is rich in light and heat resources, lack of water resources. The average
temperature of Fenhe River Basin changed from 13 to 4
The nine hydrological stations on Fenhe River, from upstream to downstream be: Jingle, Fenhe Reservoir, Zhaishang, Lanchun, Erba, Yitang, Zhaocheng, Chaizhuang and Hejin. Among them, the Hejin Station is the Fenhe entering Yellow River control station, whose control basin area is 38 728 square kilometers, accounting for 98 % of the total area of Fenhe River basin.
The average precipitation in the Fenhe River Basin (1956–2012 series) is 503 mm, and the distribution of precipitation is decreasing from the southeast to the northwest, but it is closely related to the terrain elevation. The warm and humid airflow brought by the summer monsoon is the main source of water vapor for precipitation. Precipitation from June to September accounts for more than 70 % of the total annual precipitation.
Fenhe River Basin.
This study collected the annual runoff from 1956 to 2012 in the Fen River Basin into the Yellow Control Station (Hejin station), and the rainfall data from 1956 to 2012 in the Fenhe River Basin. The meteorological data of the 10 major weather stations in the basin (Hejin, Jiexiu, Lok, Linfen, Qixian, Qingxu, Taigu, Taiyuan and Yicheng) from 1956 to 2012 including mean daily wind speed, daily average temperature, daily maximum temperature, daily minimum temperature, sunshine hours, relative humidity and daily mean vapor pressure. At the same time, the data of surface water consumption, the results of soil and water conservation measures in Fenhe River Basin, the data of human water consumption, the data of water conservancy construction and the data of coal mining were collected. Runoff data and rainfall data were collected from the Hydrological Bureau of the Ministry of water resources compiled by the hydrological data series of the Yellow River. Meteorological data from China Meteorological Data network.
In addition, this study also collected the Fenhe River Basin groundwater depth data in Fenhe River Basin in 2001–2012, which include a total of 199 groundwater depth monitoring station (Fig. 2), It can be seen from the figure that the Fenhe River Basin groundwater depth monitoring stations in this study are concentrated in Taiyuan and Linfen basins. The soil data of the Fen River basin in this paper are derived from the HSWD soil database (Fig. 3) constructed by the International Food and Agriculture Organization (FAO), and the soil classification is FAO-90. And the obtain data is correct by the reference to “Shanxi Soil” edited by Liu Yaosong.
Distribution of Groundwater Level and Buried Survey in Fenhe River Basin.
Distribution of Soil Types in Fenhe River Basin.
Based on the analysis of the characteristics of measured annual runoff of
Hejin River in Hejin River Basin, the main climatic and human influencing
factors of Fenhe River entering the Yellow River runoff were determined.
Based on the annual variation of annual runoff of Hejin River. The measured
annual runoff of Hejin station is divided into two periods: “basis period”
and “change period”, the difference between the mean measured annual runoff
of “base period” and “change period” is the total reduction, The total
reduction in the Fen River into the Yellow River runoff includes the
reductions caused by climate change and the reductions caused by major human
activities. On the basis of estimating the total reduction of the Yellow
River runoff from the Fen River, a unified framework for the reduction of the
diameter of the Fenhe River into the Yellow River is established. In this
framework, the separation and evaluation of the effects of climate change and
main human activities on runoff are as follows (Wang et al., 2008):
The hydrological variation diagnostic system takes into account both the trend and the jumping of two variants (Xie et al., 2010). The basic idea is to use a variety of mutation test methods to diagnose the hydrological sequence in detail on the basis of the possibility of preliminary test, and to obtain the efficiency coefficient of the trend and jump diagnosis conclusion, then the degree of fitting of the hydrological sequence to the jumping component or trend component is evaluated according to the efficiency coefficient. According to the actual hydrological investigation and analysis, the variant forms and conclusions were verified, and the final diagnosis results were obtained. The system can solve the problem that the test result of the single method is not reasonable and the results of various methods are inconsistent.
Trend of annual average runoff in Hejin station.
The results of runoff diagnosis in Hejin station.
Notes: 1971(
Calculation results of impacts of climate change on inlet runoff in Fenhe River Basin.
The relative contribution of the factors affecting the natural runoff in the Fenhe River Basin from 1980 to 2012.
Based on the 10 weather station data, the basin's potential
evapotranspiration from 1956 to 2012 was calculated using the Penman-Monteith
formula recommended by the International Food and Agriculture Organization
(FAO) (Pereira et al., 2015), as shown in the following equation. At the same
time collected and compiled from 1956 to 2012 reservoir, water supply, land
use and coal mine data.
Variation of Precipitation Runoff and Departure from Hejin Station.
The change of annual rainfall and potential evaporation will lead to the
change of water balance, Koster (Koster et al., 1999) and Milly (Milly and
Dunne, 2002) give the calculation formula of the change of runoff caused by
the change of annual rainfall and potential evaporation in the basin:
The exploitation of surface water affects the runoff of the surface water by the increasing or decreasing of surface water consumption. The groundwater exploitation affects the runoff through the groundwater consumption and the amount of submerged water. The water conservancy project affects the regional runoff and the soil and water conservation measures through the increase or decrease in the regional evaporation Change the land use type area to affect runoff. Therefore, this paper uses the sub-calculation method to calculate the impact of various human activities on the Fen River runoff.
Showing in Fig. 4 is the Hejin station 1956–2012 runoff
trends and 5-year sliding map. It can be seen that the annual runoff from
1956 to 2012 is 994 million m
On the basis of preliminary diagnosis, three flow diagnosis methods of three
trend diagnosis methods and 11 jump diagnosis methods were used to determine
the flow rate of Hejin station. The first significant
Figure 5 shows the relationship between rainfall runoff and anomaly in Hejin station. It can be seen from Fig. 5a that the rainfall-runoff relationship in the basin has changed significantly before and after 1971, and the rainfall-runoff curve after 1971 shows that the runoff generated by 1971 Before 1971. It can be seen from Fig. 5b that the change of rainfall sequence is relatively stable, which is basically positive and negative alternately, and the runoff is basically positive anomaly before the 1970s, and it is basically negative anomaly after the 1970s, The At the same time, before and after the mutation, the precipitation is mainly between 306 mm and 652 mm, and the change trend of the precipitation sequence is not obvious. According to the runoff forming mechanism, we judge that the underlying land surface condition in the basin must change. This result is confirmed by some factual data collected in the introduction.
Table 2 shows the results of climate change on the impact of Fenhe into the
Yellow River runoff calculation, Compared with the base period, the reduction
of rainfall in the Fenhe River Basin from 1980 to 2012 resulted in an average
annual reduction of 6.89 mm, Which is 267 million m
Based on the quantitative analysis of the main influencing factors of Fenhe
runoff sharply decrease, the contribution rate of the main influencing
factors of Fenhe River runoff to the sharp drop in runoff is quantitatively
described in the attribution segmentation frame of Fenhe River runoff. Table 3
shows the contribution rate of the main influencing factors of the runoff
sharply decrease in the Fenhe River Basin from 1980 to 2012. The climate
change causes the Fenhe runoff to decrease by an average of 246 million m
In this paper, based on the determination of the main influencing factors of
the runoff of the Fenhe River flows into the Yellow River, the variation of
the runoff series trend of the Hejin River in the Hejin River is analyzed by
the hydrological variation diagnosis system. The annual runoff of the main
site of the Fenhe River is significantly reduced, The runoff reduce by the
rate of 0.158 million m
Based on the principle of water balance, this paper calculates the change of rainfall and potential evaporation and the contribution rate of human surface, groundwater exploitation, land use, water conservancy project and coal mining to Fenhe River runoff decrease, and quantitative evaluate the influence of various factors on runoff from Fenhe River into Yellow River.
However, it is assumed that various factors are independent of each other, But in reality, various factors affect each other, and it is difficult to segment the various factors precisely. Therefore, the influence of the various factors calculated in this paper on the sharp drop in the yellow runoff is only estimated, Moreover, the calculation of the impact of various factors, there must be a repeated calculation part The accurate segmentation and calculation of the influence of various factors on the decrease of the runoff of Fenhe River into the Yellow River need further study.
The data are not publicly accessible, because it comes from the the Yellow River Water Conservancy Commission, the state functional organ.
The authors declare that they have no conflict of interest.
This article is part of the special issue “Innovative water resources management – understanding and balancing interactions between humankind and nature”. It is a result of the 8th International Water Resources Management Conference of ICWRS, Beijing, China, 13–15 June 2018.
This paper is supported by the key special special project “the mechanism and trend prediction of water and sediment change in the the Yellow River basin” (2016YFC040240203). Edited by: Bo Pang Reviewed by: two anonymous referees