Long-term variations in runoff of the Syr Darya River Basin under climate change and human activities

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.

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Evaluation of changes in streamflow and the underlying causes: a perspective of an upstream catchment in Haihe River basin, China

Journal of Water and Climate Change ◽

10.2166/wcc.2018.184 ◽

2018 ◽

Vol 11 (1) ◽

pp. 241-257 ◽

Cited By ~ 1

Author(s):

Sicheng Wan ◽

Jianyun Zhang ◽

Guoqing Wang ◽

Lu Zhang ◽

Lei Cheng ◽

...

Keyword(s):

Climate Change ◽

River Basin ◽

Human Activities ◽

Hydrological Cycle ◽

Kendall Test ◽

Haihe River Basin ◽

Changing Environment ◽

Haihe River ◽

Hydrological Simulation

Abstract Investigating long-term streamflow changes pattern and its response to climate and human factors is of crucial significance to understand the hydrological cycle under a changing environment. Caijiazhuang catchment located within Haihe River basin, north China was selected as the study area. To detect the trend and changes in streamflow, Mann–Kendall test was used. Elasticity and hydrological simulation methods were applied to assess the relative contribution of climate change and human activities on streamflow variability under three periods (baseline (1958–1977), impact I (1978–1997), and impact II (1998–2012)). The long-term hydro-climatic variables experienced substantial changes during the whole study period, and 1977 was the breaking year of streamflow change. Attribution analysis using the two methods showed consistent results: for impact I, climate change impacts explained 65% and 68% of streamflow reduction; however for impact II, it only represented 49% and 56% of streamflow reduction. This result indicated that human activities were intensifying over time. Various types of human activities presented significant effects on streamflow regimes including volumes and hydrographs. The findings of this paper could provide better insights of hydrological evolution and would thus assist water managers in sustainably managing and providing water use strategies under a changing environment.

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

Water ◽

10.3390/w10081085 ◽

2018 ◽

Vol 10 (8) ◽

pp. 1085 ◽

Cited By ~ 4

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.

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Changes in run‐off and sediment load in the three parts of the Yellow River basin, in response to climate change and human activities

Hydrological Processes ◽

10.1002/hyp.13345 ◽

2018 ◽

Vol 33 (4) ◽

pp. 585-601 ◽

Cited By ~ 10

Author(s):

Chaojun Gu ◽

Xingmin Mu ◽

Peng Gao ◽

Guangju Zhao ◽

Wenyi Sun

Keyword(s):

Climate Change ◽

River Basin ◽

Human Activities ◽

Sediment Load ◽

Yellow River ◽

Yellow River Basin ◽

The Yellow River ◽

Run Off ◽

The Yellow River Basin

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The «rainfall-runoff» system and its long-term fluctuations in the Siverskyi Donets River Basin (Ukraine)

10.5194/egusphere-egu21-13350 ◽

2021 ◽

Author(s):

Hanna Bolbot ◽

Vasyl Grebin

Keyword(s):

Climate Change ◽

Water Resources ◽

River Basin ◽

Air Temperature ◽

River Runoff ◽

Annual Runoff ◽

Annual Precipitation ◽

Spring Flood ◽

Current Period

The current patterns estimation of the water regime under climate change is one of the most urgent tasks in Ukraine and the world. Such changes are determined by fluctuations in the main climatic characteristics - precipitation and air temperature, which are defined the value of evaporation. These parameters influence on the annual runoff distribution and long-term runoff fluctuations. In particular, the annual precipitation redistribution is reflected in the corresponding changes in the river runoff. The assessment of the current state and nature of changes in precipitation and river runoff of the Siverskyi Donets River Basin was made by comparing the current period (1991-2018) with the period of the climatological normal (1961-1990). In general, for this area, it was defined the close relationship between the amount of precipitation and the annual runoff. Against the background of insignificant (about 1%) increase of annual precipitation in recent decades, it was revealed their redistribution by seasons and separate months. There is a decrease in precipitation in the cold period (November-February). This causes (along with other factors) a decrease in the amount of snow and, accordingly, the spring flood runoff. There are frequent cases of unexpressed spring floods of the Siverskyi Donets River Basin. The runoff during March-April (the period of spring flood within the Ukrainian part of the basin) decreased by almost a third. The increase of precipitation during May-June causes a corresponding (insignificant) increase in runoff in these months. The shift of the maximum monthly amount of precipitation from May (for the period 1961-1990) to June (in the current period) is observed. There is a certain threat to water supply in the region due to the shift in the minimum monthly amount of precipitation in the warm period from October to August. Compared with October, there is a higher air temperature and, accordingly, higher evaporation in August, which reduces the runoff. Such a situation is solved by rational water resources management of the basin. The possibility of replenishing water resources in the basin through the transfer runoff from the Dnieper (Dnieper-Siverskyi Donets channel) and the annual runoff redistribution in the reservoir system causes some increase in the river runoff of summer months in recent decades. This is also contributed by the activities of the river basin management structures, which control the maintenance water users' of minimum ecological flow downstream the water intakes and hydraulic structures in the rivers of the basin. Therefore, in the period of current climate change, the annual runoff distribution of the Siverskyi Donets River Basin has undergone significant changes, which is related to the annual precipitation redistribution and anthropogenic load on the basin.

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Analysis of Long-Term Trends of Annual and Seasonal Rainfall in the Awash River Basin, Ethiopia

Water ◽

10.3390/w11071498 ◽

2019 ◽

Vol 11 (7) ◽

pp. 1498 ◽

Cited By ~ 2

Author(s):

Solomon Mulugeta ◽

Clifford Fedler ◽

Mekonen Ayana

Keyword(s):

Climate Change ◽

River Basin ◽

Summer Rainfall ◽

Seasonal Rainfall ◽

Winter Rainfall ◽

Adaptation Measures ◽

Awash River Basin ◽

Long Term Trends ◽

Increasing Trends

With climate change prevailing around the world, understanding the changes in long-term annual and seasonal rainfall at local scales is very important in planning for required adaptation measures. This is especially true for areas such as the Awash River basin where there is very high dependence on rain- fed agriculture characterized by frequent droughts and subsequent famines. The aim of the study is to analyze long-term trends of annual and seasonal rainfall in the Awash River Basin, Ethiopia. Monthly rainfall data extracted from Climatic Research Unit (CRU 4.01) dataset for 54 grid points representing the entire basin were aggregated to find the respective areal annual and seasonal rainfall time series for the entire basin and its seven sub-basins. The Mann-Kendall (MK) test and Sen Slope estimator were applied to the time series for detecting the trends and for estimating the rate of change, respectively. The Statistical software package R version 3.5.2 was used for data extraction, data analyses, and plotting. Geographic information system (GIS) package was also used for grid making, site selection, and mapping. The results showed that no significant trend (at α = 0.05) was identified in annual rainfall in all sub-basins and over the entire basin in the period (1902 to 2016). However, the results for seasonal rainfall are mixed across the study areas. The summer rainfall (June through September) showed significant decreasing trend (at α ≤ 0.1) over five of the seven sub-basins at a rate varying from 4 to 7.4 mm per decade but it showed no trend over the two sub-basins. The autumn rainfall (October through January) showed no significant trends over four of the seven sub-basins but showed increasing trends over three sub-basins at a rate varying from 2 to 5 mm per decade. The winter rainfall (February through May) showed no significant trends over four sub-basins but showed significant increasing trends (at α ≤ 0.1) over three sub-basins at a rate varying from 0.6 to 2.7 mm per decade. At the basin level, the summer rainfall showed a significant decreasing trend (at α = 0.05) while the autumn and winter rainfall showed no significant trends. In addition, shift in some amount of summer rainfall to winter and autumn season was noticed. It is evident that climate change has shown pronounced effects on the trends and patterns of seasonal rainfall. Thus, the study contribute to better understanding of climate change in the basin and the information from the study can be used in planning for adaptation measures against a changing climate.

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

Sustainability ◽

10.3390/su12166644 ◽

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.

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Influence of Climatic Conditions on Western Siberian Forest Fires

Predicting, Monitoring, and Assessing Forest Fire Dangers and Risks - Advances in Environmental Engineering and Green Technologies ◽

10.4018/978-1-7998-1867-0.ch012 ◽

2020 ◽

pp. 269-293

Author(s):

Valentina Petrovna Gorbatenko ◽

Marina Alexandrovna Volkova ◽

Olga Vladimirovna Nosyreva ◽

George Georgievich Zhuravlev ◽

Irina Valerievna Kuzhevskaia

Keyword(s):

Climate Change ◽

Air Temperature ◽

Forest Fires ◽

Western Siberia ◽

Climatic Conditions ◽

Fire Season ◽

General Regularity ◽

Weather Events ◽

Long Term Variations

Current climate changes in Russia are attended by the increase in frequency of dangerous weather events. This chapter researches long-term variations of the dangerous weather's events on Western Siberia and to reveal general regularity, which can be associated with forest fires. The researches have been carried out for the territories of southeast of Western Siberia. The duration of the fire season increases due to climate change. This is due both to the earlier snowfall and the onset of the phenological spring, and to the increase in the duration of the thunderstorm period. Thunderstorms in Siberia are a much more frequent cause of forest fires (28%) than in other territories. Wildfire frequency is correlated with air temperature and drought anomalies.

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

Water ◽

10.3390/w11101958 ◽

2019 ◽

Vol 11 (10) ◽

pp. 1958 ◽

Cited By ~ 1

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.

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