scholarly journals Assessing Impacts of Climate Change and Human Activities on Streamflow and Sediment Discharge in the Ganjiang River Basin (1964–2013)

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1679 ◽  
Author(s):  
Guo ◽  
Mu ◽  
Hu ◽  
Gao ◽  
Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Water Conservation ◽  
Human Activities ◽  
Large Scale ◽  
Jiangxi Province ◽  
Sediment Discharge ◽  
Change Environment ◽  
Over Time ◽  
Ganjiang River Basin

National large-scale soil and water conservation controls on the Gangjiang River basin have been documented, but the effect of governance on regional watershed hydrology and how the main driving factors act have not been systematically studied yet. To do this, this study evaluated changing trends and detected transition years for both streamflow and sediment discharge using long-term historical records at seven hydrological stations in the Ganjiang River basin over the past 50 years. The double mass curve (DMC) method was used to quantify the effects of both climate change and human activities on hydrological regime shifts. The results showed that the distributions of precipitation, streamflow, and sediment discharge within a year are extremely uneven and mainly concentrated in the flood season of Jiangxi Province. None of the stations showed significant trends over time for either annual precipitation or streamflow, while the annual sediment discharge at most stations decreased significantly over time. The estimation of sediment discharge via DMC indicated that after the transition years, there were rapid reductions in sediment discharge at all hydrological stations, and the average decline degree of midstream and downstream were much larger than that of upstream. Human activities, especially the increase of vegetation cover and construction of large and medium-sized reservoirs, provided a significantly greater contribution to the reduction of sediment discharge than did precipitation changes. As a case study of river evolution under global change environment, this study could provide scientific basis for the control of soil erosion and the management of water resources in Ganjiang River, as well as for the related research of Poyang Lake and the Yangtze River basin of China.

scholarly journals Attribution Analysis of Hydrological Drought Risk Under Climate Change and Human Activities: A Case Study on Kuye River Basin in China

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1958 ◽  
Author(s):  
Zhang ◽  
Wang ◽  
Zhou
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Human Activities ◽  
Large Scale ◽  
Research Area ◽  
Drought Severity ◽  
Drought Risk ◽  
Drought Duration ◽  
Recurrence Period ◽  
The Impact

This study conducted quantitative diagnosis on the impact of climate change and human activities on drought risk. Taking the Kuye river basin (KRB) in China as the research area, we used variation point diagnosis, simulation of precipitation and runoff, drought risk assessment, and attribution quantification. The results show that: (1) the annual runoff sequence of KRB changed significantly after 1979, which was consistent with the introduction of large-scale coal mining; (2) under the same drought recurrence period, the drought duration and severity in the human activity stage were significantly worse than in the natural and simulation stages, indicating that human activities changed the drought risk in this area; and (3) human activities had little impact on drought severity in the short duration and low recurrence period, but had a greater impact in the long duration and high recurrence period. These results provide scientific guidance for the management, prevention, and resistance of drought; and guarantee sustainable economic and social development in the KRB.

scholarly journals Multi-Temporal Variabilities of Evapotranspiration Rates and Their Associations with Climate Change and Vegetation Greening in the Gan River Basin, China

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2568 ◽  
Author(s):  
Meng Bai ◽  
Bing Shen ◽  
Xiaoyu Song ◽  
Shuhong Mo ◽  
Lingmei Huang ◽  
...  
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Human Activities ◽  
Large Scale ◽  
Temporal Dynamics ◽  
Long Term Evolution ◽  
Interactive Effects ◽  
Positive Effects ◽  
Term Evolution

Understanding the spatial-temporal dynamics of evapotranspiration in relation to climate change and human activities is crucial for the sustainability of water resources and ecosystem security, especially in regions strongly influenced by human impact. In this study, a process-based evapotranspiration (ET) model in conjunction with the Global Land Surface Satellite (GLASS) LAI dataset was used to characterize the spatial-temporal pattern of evapotranspiration from 1982 to 2016 over the Gan River basin (GRB), the largest sub-basin of the Poyang Lake catchment, China. The results showed that the actual annual ET (ETa) weakly increased with an annual trend of 0.88 mm year−2 from 1982 to 2016 over the GRB, along with a slight decline in annual potential ET (ETp). On an ecosystem scale; however, only the evergreen broadleaved forest and cropland presented a positive ETa trend, while the rest of the ecosystems demonstrated negative trends of ETa. Both correlation analysis and sensitivity analysis revealed a close relationship between ETa inter-annual variability and energy availability. Attribution analysis illustrated that contributions of climate change and vegetation greening on the ETa trend were −0.48 mm year−2 and 1.36 mm year−2, respectively. Climate change had a negative impact on the ETa trend over the GRB. However, the negative effects have been offset by the positive effects of vegetation greening, which mainly resulted from the large-scale revegetation in forestland and agricultural practices in cropland. It is concluded that large-scale afforestation and agricultural management were the main drivers of the long-term evolution of water consumption over the GRB. This study can improve our understanding of the interactive effects of climate change and human activities on the long-term evolution of water cycles.

scholarly journals Trend and Change-Point Analysis of Streamflow and Sediment Discharge of the Gongshui River in China during the Last 60 Years

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1273 ◽  
Author(s):  
Li-Ping Guo ◽  
Qiang Yu ◽  
Peng Gao ◽  
Xiao-Fei Nie ◽  
Kai-Tao Liao ◽  
...  
Keyword(s):  
Water Resources ◽  
River Basin ◽  
Water Conservation ◽  
Change Point ◽  
Human Activities ◽  
Anthropogenic Impacts ◽  
Change Point Detection ◽  
Change Point Analysis ◽  
Sediment Discharge ◽  
Concentration Data

The Gongshui River basin exhibits one of the most serious soil erosion areas in southern China, and has always been the key control area of national soil and water conservation programs. This study used daily precipitation, streamflow, and sediment concentration data collected from 1957 to 2015 from the main hydrological stations of the Gongshui River to investigate streamflow and sediment discharge variations and their responses to precipitation and human activities. The Mann-Kendall and Pettitt’s test were used for trend and change-point detection. The double mass curve (DMC) method was employed to quantify the effects of precipitation change and human activities on hydrological regime shifts. The results showed insignificant trends of both annual precipitation and streamflow for all stations, while the sediment discharge of most stations exhibited significant decreasing trends. Change-point analyses revealed that all hydrologic stations except Mazhou had transition years. The estimation via DMC indicated that after the change point years, there was a rapid reduction in sediment discharge at Hanlinqiao, Fengkeng, Julongtan, Xiashan, and Chawu stations, but not at Mazhou, Ruijin, and Yangxinjian stations. Human activity provided a significantly greater contribution to sediment discharge than precipitation. The evidence clearly indicates that the degree and extension of conservation or destruction measures and the construction of large- and medium-sized reservoirs were the major factors significantly decreasing or increasing annual sediment discharge of the Gongshui River. This work could serve as the basis for decision making regarding river basin water resources management to estimate the effects of anthropogenic impacts on water and sediment discharge variations during the last few decades, thereby guiding adaptation and protection of the water resources of the Gongshui River flowing into the Poyang Lake.

scholarly journals Identifying dominant component of runoff yield processes: a case study in a sub-basin of the middle Yellow River

2021 ◽  
Author(s):  
Li Zhang ◽  
Caihong Hu ◽  
Shengqi Jian ◽  
Qiang Wu ◽  
Guang Ran ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Conservation ◽  
Human Activities ◽  
Large Scale ◽  
Overland Flow ◽  
Yellow River ◽  
Potential Evapotranspiration ◽  
Subsurface Flow ◽  
Runoff Generation ◽  
Runoff Reduction

Abstract The effects of long-term natural climate change and human activities on runoff generation mechanism in the middle Yellow River Basin are long-standing concerns. This study analyzed the characteristics of hydro-climatic variables in the meso-scale Tuweihe catchment based on the observed data for the period 1956–2016 and a climate elastic method. The spatial distribution of dominant runoff processes (DRP) following land use changes in case of rainfall was identified. The results show significant decreasing trends in annual runoff, whereas slightly downward trends are identified for annual precipitation and potential evapotranspiration, 1984 is detected as the mutation year of the study period. The average contributions of climate change and human activities to the runoff reduction in the Tuweihe catchment were 33.2% and 66.8%, respectively. In general, the influences of human activities on runoff are applied mostly through the alteration of the catchment characteristics. The dominant runoff processes changes between 1980 and 2015 show significant effects of large-scale soil and water conservation measures in the Tuweihe catchment. We found that Hortonian overland flow (HOF) and fast subsurface flow (SSF1) were the two main processes in 1980 (30.3% and 34.4% respectively), but the proportion of HOF decreased by 9.6% in 2015. The proportions of saturation overland flow (SOF) and SSF have increased to varying degrees, which means that the catchment is more prone to generate subsurface flow processes. Consequently, under similar rainfall conditions, the runoff yield of flood events decreases in the second period.

Decline of sediment transport due to damming and eco-engineering is approaching its limits

2021 ◽  
Author(s):  
Boyan Li ◽  
Yunchen Wang ◽  
Chao Wang ◽  
Wei Wang ◽  
Aiwen Lin ◽  
...  
Keyword(s):  
Climate Change ◽  
Sediment Transport ◽  
Soil Erosion ◽  
River Basin ◽  
Water Conservation ◽  
Human Activities ◽  
Sediment Load ◽  
Yangtze River Basin ◽  
Sensitivity Index ◽  
The Impact

Abstract Sediment transport from rivers to ocean is increasingly influenced by climate change and intensive human activities1, constituting a research priority of global relevance2. However, little attention has been paid to quantify and predict the contribution of driving factors to the sediment load. By integrating local-scale hydrologic modeling with soil erosion estimation model, and the soil erosion and sediment yield balance equation, we quantify watershed-scale changes in sediment load under forecasted climate change and human activities in the Yangtze River Basin (YRB), China. We also develop a new metric, the sediment load sensitivity index, that identifies sensitive to anthropogenic variability over the past 30 years. It was found that the reservoirs deposition was the primary factor (81.37 %) among human activities contributing to the decline in sediment load, followed by the soil and water conservation measures (SWCM) (18.63 %). The sediment load shows a slight increasing trend for the 1.5 °C and 2.0 °C global warming at 2020–2039 and 2040–2059, respectively. Climate change dominates the sediment load trend in the future due to the effectiveness of dams and reservoirs decreases and the saturation of the capacity of the SWCM to capture sediment. Although these findings indicate the importance of the impact of climate change on changes in sediment load, it is necessary to apply them to appropriate management to adapt to climate changes in future river basin management policies.

scholarly journals Effects of Climate Change and Human Activities on Soil Erosion in the Xihe River Basin, China

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1085 ◽  
Author(s):  
Shanshan Guo ◽  
Zhengru Zhu ◽  
Leting Lyu
Keyword(s):  
Climate Change ◽  
Soil Erosion ◽  
River Basin ◽  
Air Temperature ◽  
Human Activities ◽  
Sediment Load ◽  
Sudden Increase ◽  
Validation Period ◽  
Total Change ◽  
Calibration Period

Climate change and human activities are the major factors affecting runoff and sediment load. We analyzed the inter-annual variation trend of the average rainfall, air temperature, runoff and sediment load in the Xihe River Basin from 1969–2015. Pettitt’s test and the Soil and Water Assessment Tool (SWAT) model were used to detect sudden change in hydro-meteorological variables and simulate the basin hydrological cycle, respectively. According to the simulation results, we explored spatial distribution of soil erosion in the watershed by utilizing ArcGIS10.0, analyzed the average erosion modulus by different type of land use, and quantified the contributions of climate change and human activities to runoff and sediment load in changes. The results showed that: (1) From 1969–2015, both rainfall and air temperature increased, and air temperature increased significantly (p < 0.01) at 0.326 °C/10 a (annual). Runoff and sediment load decreased, and sediment load decreased significantly (p < 0.01) at 1.63 × 105 t/10 a. In 1988, air temperature experienced a sudden increase and sediment load decreased. (2) For runoff, R2 and Nash and Sutcliffe efficiency coefficient (Ens) were 0.92 and 0.91 during the calibration period and 0.90 and 0.87 during the validation period, for sediment load, R2 and Ens were 0.60 and 0.55 during the calibration period and 0.70 and 0.69 during the validation period, meeting the model’s applicability requirements. (3) Soil erosion was worse in the upper basin than other regions, and highest in cultivated land. Climate change exacerbates runoff and sediment load with overall contribution to the total change of −26.54% and −8.8%, respectively. Human activities decreased runoff and sediment load with overall contribution to the total change of 126.54% and 108.8% respectively. Runoff and sediment load change in the Xihe River Basin are largely caused by human activities.

scholarly journals Vegetation Changes and Their Response to Global Change Based on NDVI in the Koshi River Basin of Central Himalayas Since 2000

2020 ◽  
Vol 12 (16) ◽  
pp. 6644
Author(s):  
Xue Wu ◽  
Xiaomin Sun ◽  
Zhaofeng Wang ◽  
Yili Zhang ◽  
Qionghuan Liu ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
River Basin ◽  
Human Activities ◽  
Vegetation Change ◽  
Precipitation Trend ◽  
Central Himalayas ◽  
Annual Minimum Temperature ◽  
Vegetation Activity ◽  
Koshi River Basin

Vegetation forms a main component of the terrestrial biosphere owing to its crucial role in land cover and climate change, which has been of wide concern for experts and scholars. In this study, we used MODIS (moderate-resolution imaging spectroradiometer) NDVI (Normalized Difference Vegetation Index) data, land cover data, meteorological data, and DEM (Digital Elevation Model) data to do vegetation change and its relationship with climate change. First, we investigated the spatio-temporal patterns and variations of vegetation activity in the Koshi River Basin (KRB) in the central Himalayas from 2000 to 2018. Then, we combined NDVI change with climate factors using the linear method to examine their relationship, after that we used the literature review method to explore the influence of human activities to vegetation change. At the regional scale, the NDVIGS (Growth season NDVI) significantly increased in the KRB in 2000–2018, with significant greening over croplands in KRB in India. Further, the croplands and forest in the KRB in Nepal were mainly influenced by human interference. For example, improvements in agricultural fertilization and irrigation facilities as well as the success of the community forestry program in the KRB in Nepal increased the NDVIGS of the local forest. Climate also had a certain impact on the increase in NDVIGS. A significant negative correlation was observed between NDVIGS trend and the annual minimum temperature trend (TMN) in the KRB in India, but an insignificant positive correlation was noted between it and the total annual precipitation trend (PRE). NDVIGS significantly decreased over a small area, mainly around Kathmandu, due to urbanization. Increases in NDVIGS in the KRB have thus been mainly affected by human activities, and climate change has helped increase it to a certain extent.

scholarly journals Causes of Variations in Sediment Yield in the Jinghe River Basin, China

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jinliang Zhang ◽  
Yizi Shang ◽  
Jinyong Liu ◽  
Jian Fu ◽  
Shitao Wei ◽  
...  
Keyword(s):  
River Basin ◽  
Sediment Yield ◽  
Water Conservation ◽  
Yellow River ◽  
Soil And Water Conservation ◽  
Water Diversion ◽  
Sediment Discharge ◽  
Jinghe River Basin ◽  
Jinghe River ◽  
Soil And Water

Abstract The Jinghe River remains the major sediment source of the Yellow River in China; however, sediment discharge in the Jinghe River has reduced significantly since the 1950s. The objective of this study is to identify the causes of sediment yield variations in the Jinghe River Basin based on soil and water conservation methods and rainfall analyses. The results revealed that soil and water conservation projects were responsible for half of the total sediment reduction; sediment retention due to reservoirs and water diversion projects was responsible for 1.3% of the total reduction. Moreover, the Jinghe River Basin has negligible opportunity to improve its vegetation cover (currently 55% of the basin is covered with lawns and trees), and silt-arrester dams play a smaller role in reducing sediment significantly before they are entirely full. Therefore, new large-scale sediment trapping projects must be implemented across the Jinghe River Basin, where heavy rainfall events are likely to substantially increase in the future, leading to higher sediment discharge.

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