scholarly journals Effects of climate change and human activities on runoff in the Nenjiang River Basin, Northeast China

2012 ◽  
Vol 9 (10) ◽  
pp. 11521-11549 ◽  
Author(s):  
L. Q. Dong ◽  
G. X. Zhang ◽  
Y. J. Xu

Abstract. The Nenjiang River Basin (NRB) is an important grain-production region with abundant wetlands in Northeast China. Climate change and anthropogenic activities have dramatically altered the spatial and temporal distribution of regional stream discharge and water resources, which poses a serious threat to wetland ecosystems and sustainable agriculture. In this study, we analyzed 55-yr (1956–2010) rainfall and runoff patterns in the river basin to quantitatively evaluate the impact of human activities on regional hydrology. The long-term hydrologic series were divided into two periods: period I (1956–1974), during which minimum land use change occurred, and period II (1975–2010), during which land use change intensified. Kendall's rank correlation test, non-parametric Pettitt test and precipitation-runoff double cumulative curve (DCC) methods were utilized to identify the trends and thresholds of the annual runoff in the upstream, midstream, and downstream basin areas. Our results showed that the runoff in the NRB has continuously declined in the past 55 yr, and that the effects of climate change and human activities on the runoff reduction varied in the upstream, midstream and downstream area over different time scales. For the entire study period, climate change has been the dominant factor, accounting for 69.6–80.3% of the reduction in the total basin runoff. However, the impact of human activities has been increasing from 19.7% during the 1950s–1970s to 30.4% in the present time. Spatially, the runoff reduction became higher from the upstream to the downstream areas, revealing an increasing threat of water availability to the large wetland ecosystem in the lower river basin. Furthermore, the sustainable development of irrigated agriculture in the NRB will be a threat to the survival of the wetlands.

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1775 ◽  
Author(s):  
Jingyi Bu ◽  
Chunxia Lu ◽  
Jun Niu ◽  
Yanchun Gao

Juma River, located in the Midwest of the Haihe River basin, is an important source of water supply to Beijing and Hebei. Over the past decades, the region has been seriously threatened by water shortages owing to complex climate conditions and intensive human activities. This study investigated the runoff characteristics of the Juma River by employing the Soil and Water Assessment Tool (SWAT) and stochastic methods for the period of 1961–2013. Accordingly, the runoff changes attributed to the climate variation and different types of anthropogenic activities (land use change and direct human intervention) were estimated, respectively, in conjunction with the improved quantitative response analysis. The results indicated that the annual runoff of both Zijingguan station and Zhangfang station has decreased significantly at the 0.001 significance level, and reduction rates were −0.054 billion m3 and −0.10 billion m3, respectively. Moreover, the persistency of this trend has been shown for decades (Hurst coefficient > 0.50). The SWAT model was calibrated and validated during the baseline period of 1961–1978. Significant rising temperatures and declining precipitation were the main reasons for runoff reduction, especially during the two periods of 1998–2002 and 2003–2008. Additionally, water withdrawal of Wuyi canal aggravated the runoff reduction and water scarcity conditions in the region. After 2009, the effects of direct human intervention exceeded those of climate change. However, the impact of land use change can be seen as negligible during the study period. Climate change had a greater effect on runoff reduction in winter, while the impact of human activities was more dramatic in summer.


2020 ◽  
Vol 12 (16) ◽  
pp. 6423
Author(s):  
Lanhua Luo ◽  
Qing Zhou ◽  
Hong S. He ◽  
Liangxia Duan ◽  
Gaoling Zhang ◽  
...  

Quantitative assessment of the impact of land use and climate change on hydrological processes is of great importance to water resources planning and management. The main objective of this study was to quantitatively assess the response of runoff to land use and climate change in the Zhengshui River Basin of Southern China, a heavily used agricultural basin. The Soil and Water Assessment Tool (SWAT) was used to simulate the river runoff for the Zhengshui River Basin. Specifically, a soil database was constructed based on field work and laboratory experiments as input data for the SWAT model. Following SWAT calibration, simulated results were compared with observed runoff data for the period 2006 to 2013. The Nash-Sutcliffe Efficiency Coefficient (NSE) and the correlation coefficient (R2) for the comparisons were greater than 0.80, indicating close agreement. The calibrated models were applied to simulate monthly runoff in 1990 and 2010 for four scenarios with different land use and climate conditions. Climate change played a dominant role affecting runoff of this basin, with climate change decreasing simulated runoff by −100.22% in 2010 compared to that of 1990, land use change increasing runoff in this basin by 0.20% and the combination of climate change and land use change decreasing runoff by 60.8m3/s. The decrease of forestland area and the corresponding increase of developed land and cultivated land area led to the small increase in runoff associated with land use change. The influence of precipitation on runoff was greater than temperature. The soil database used to model runoff with the SWAT model for the basin was constructed using a combination of field investigation and laboratory experiments, and simulations of runoff based on that new soil database more closely matched observations of runoff than simulations based on the generic Harmonized World Soil Database (HWSD). This study may provide an important reference to guide management decisions for this and similar watersheds.


2019 ◽  
Vol 2 (2) ◽  
pp. 125-131
Author(s):  
Loi Thi Pham ◽  
Khoi Nguyen Dao

Assessing water resources under the influence of environmental change have gained attentions of scientists. The objective of this study was to analyze the impacts of land use change and climate change on water resources in terms quantity and quality in the 3S basin in the period 1981–2008 by using hydrological modeling (SWAT model). The results showed that streamflow and water quality (TSS, T-N, and T-P) tend to increase under individual and combined effects of climate change and land use change. In addition, the impact of land use change on the flow was smaller than the climate change impact. However, water balance components and water quality were equally affected by two factors of climate change and land use change. In general, the results of this study could serve as a reference for water resource management and planning in the river basin.


2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Susanne Rolinski ◽  
Alexander V. Prishchepov ◽  
Georg Guggenberger ◽  
Norbert Bischoff ◽  
Irina Kurganova ◽  
...  

AbstractChanges in land use and climate are the main drivers of change in soil organic matter contents. We investigated the impact of the largest policy-induced land conversion to arable land, the Virgin Lands Campaign (VLC), from 1954 to 1963, of the massive cropland abandonment after 1990 and of climate change on soil organic carbon (SOC) stocks in steppes of Russia and Kazakhstan. We simulated carbon budgets from the pre-VLC period (1900) until 2100 using a dynamic vegetation model to assess the impacts of observed land-use change as well as future climate and land-use change scenarios. The simulations suggest for the entire VLC region (266 million hectares) that the historic cropland expansion resulted in emissions of 1.6⋅ 1015 g (= 1.6 Pg) carbon between 1950 and 1965 compared to 0.6 Pg in a scenario without the expansion. From 1990 to 2100, climate change alone is projected to cause emissions of about 1.8 (± 1.1) Pg carbon. Hypothetical recultivation of the cropland that has been abandoned after the fall of the Soviet Union until 2050 may cause emissions of 3.5 (± 0.9) Pg carbon until 2100, whereas the abandonment of all cropland until 2050 would lead to sequestration of 1.8 (± 1.2) Pg carbon. For the climate scenarios based on SRES (Special Report on Emission Scenarios) emission pathways, SOC declined only moderately for constant land use but substantially with further cropland expansion. The variation of SOC in response to the climate scenarios was smaller than that in response to the land-use scenarios. This suggests that the effects of land-use change on SOC dynamics may become as relevant as those of future climate change in the Eurasian steppes.


Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2658
Author(s):  
Rui Luo ◽  
Shiliang Yang ◽  
Yang Zhou ◽  
Pengqun Gao ◽  
Tianming Zhang

A key challenge to the sustainability and security of grassland capacity is the protection of water-related ecosystem services (WESs). With the change of land use, the supply of aquatic ecosystem services has changed, and the grassland-carrying capacity has been affected. However, the correlation mechanism between WESs and the grassland-carrying capacity is not clear. In this study, we used the InVEST(Integrated Valuation of Ecosystem Services and Tradeoffs) model to evaluate the impact of land-use change on WESs, and made a tradeoff analysis between WESs and grassland-carrying capacity. Considering that the Heihe River Basin (HRB) was an important grassland vegetation zone, which was a milestone for the development of animal husbandry in China, HRB was taken as a case. The main findings are as follows: (1) the spatial distribution of WESs shows the dissimilation rule, the upper reaches are the main water yield area, the soil retention is weakening in the middle and lower reaches, and the pollution has further increased in the middle and upper reaches. (2) The carrying capacity of animal husbandry decreased in the upper reaches, increased in Shandan County and Zhangye City in the middle reaches, and decreased sharply in other regions. (3) There was a positive correlation between the livestock-carrying capacity and nitrogen export in 2018, which was increasing. As the change of land use has changed the evapotranspiration structure, WESs have undergone irreversible changes. Meanwhile, the development of large-scale irrigated farmland and human activities would be the source of a further intensification of regional soil erosion and water pollution. Therefore, it is necessary to trade off the WESs and animal husbandry under land-use change. This paper revealed how WESs changed from 2000 to 2018, the characteristics of the changes in the spatial and temporal distribution, and the carrying capacity. It aims to provide a scientific basis for coordinating the contradiction between grassland and livestock resources, improving the regional ecological security situation, and carrying out ecosystem management.


2021 ◽  
Author(s):  
Morteza Akbari ◽  
Ehsan Neamatollahi ◽  
Hadi Memarian ◽  
Mohammad Alizadeh Noughani

Abstract Floods cause great damage to ecosystems and are among the main agents of soil erosion. Given the importance of soils for the functioning of ecosystems and development and improvement of bio-economic conditions, the risk and rate of soil erosion was assessed using the RUSLE model in Iran’s Lorestan province before and after a period of major floods in late 2018 and early 2019. Furthermore, soil erosion was calculated for current and future conditions based on the Global Soil Erosion Modeling Database (GloSEM). The results showed that agricultural development and land use change are the main causes of land degradation in the southern and central parts of the study area. The impact of floods was also significant since our evaluations showed that soil erosion increased from 4.12 t ha-1 yr-1 before the floods to 10.93 t ha-1 yr-1 afterwards. Field surveying using 64 ground control points determined that erodibility varies from 0.17 to 0.49% in the study area. Orchards, farms, rangelands and forests with moderate or low vegetation cover were the most vulnerable land uses to soil erosion. The GloSEM modeling results revealed that climate change is the main cause of change in the rate of soil erosion. Combined land use change-climate change simulation showed that soil erosion will increase considerably in the future under SSP1-RCP2.6, SSP2-RCP4.5, and SSP5-RCP8.5 scenarios. In the study area, both natural factors, i.e. climate change and human factors such as agricultural development, population growth, and overgrazing are the main drivers of soil erosion.


2018 ◽  
Vol 135 (3-4) ◽  
pp. 1031-1044 ◽  
Author(s):  
Thomas Gries ◽  
Margarete Redlin ◽  
Juliette Espinosa Ugarte

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