scholarly journals Spatiotemporal response of the water cycle to land use conversions in a typical hilly-gully basin on the Loess Plateau, China

2017 ◽  
Author(s):  
Linjing Qiu ◽  
Yiping Wu ◽  
Lijing Wang ◽  
Xiaohui Lei ◽  
Weihong Liao ◽  
...  

Abstract. The hydrological effects of the ‘Grain for Green’ project (GFGP) on the Loess Plateau have been largely debated due to the complexity of the water system and its multiple driving factors. The aim of this study was to investigate the response of the hydrological cycle to the GFGP measures based on a case study of the Yanhe basin, a typical hilly-gully area on the Loess Plateau of China. First, we analyzed the land use and land cover (LULC) changes from 1990 to 2010. Then, we evaluated the effects of LULC changes and sloping land conversion on the main hydrological components in the basin considering the land surface characteristics and climate impacts. The Soil and Water Assessment Tool (SWAT) was used for this analysis. The results indicated that farmland exhibited a decreasing trend declining from 40.2 % of the basin area in 1990 to 17.6 % in 2010, and the woodland and grassland areas correspondingly increased due to the implementation of the GFGP in the basin. Due to land use changes from 1990 to 2010, surface runoff and the water yield exhibited decreasing trends, whereas evapotranspiration (ET) increased, resulting in a persistent decrease in soil water. Additionally, converting cropland areas with slopes ≥ 15° or > 25° to grassland and woodland had negative effects on surface runoff, the water yield and soil water and a positive effect on ET. The magnitudes of the hydrological effects generated by sloping cropland to woodland conversion were greater than those for sloping cropland to grassland conversion. These results suggest that the expansive revegetation of sloping land could reduce runoff generation, particularly in woodland areas, but these effects could reduce the soil water volume in the region. Overall, this study can be used to improve sustainable land use planning and water resource management on the Loess Plateau in China.

2017 ◽  
Vol 21 (12) ◽  
pp. 6485-6499 ◽  
Author(s):  
Linjing Qiu ◽  
Yiping Wu ◽  
Lijing Wang ◽  
Xiaohui Lei ◽  
Weihong Liao ◽  
...  

Abstract. The hydrological effects of the Grain for Green project (GFGP) on the Loess Plateau have been extensively debated due to the complexity of the water system and its multiple driving factors. The aim of this study was to investigate the response of the hydrological cycle to the GFGP measures based in a case study of the Yanhe Basin, a typical hilly–gully area on the Loess Plateau of China. First, we analyzed the land use and land cover (LULC) changes from 1990 to 2010. Then, we evaluated the effects of LULC changes and sloping land conversion on the main hydrological components in the basin using the Soil and Water Assessment Tool (SWAT). The results indicated that cropland exhibited a decreasing trend, declining from 40.2 % of the basin area in 1990 to 17.6 % in 2010, and that the woodland and grassland areas correspondingly increased. With the land use changes from 1990 to 2010, the water yield showed a decreasing trend which was mainly due to decrease in surface runoff. In contrast, evapotranspiration (ET) showed an increasing trend over the same period, resulting in a persistent decrease in soil water. The conversion of sloping cropland to grassland or woodland exerted negative effects on water yield and soil water. Compared with the land use condition in 2010, the negative effects were most evident where cropland with a slope  ≥  15° was converted to woodland, with decreases in surface runoff and soil water of 17.1 and 6.4 %, respectively. These results suggest that the expansive reforestation on sloping land in the loess hilly–gully region decreased water yield and increased ET, resulting in reduced soil water. The results of this study can be used to support sustainable land use planning and water resource management on the Loess Plateau in China.


Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 82 ◽  
Author(s):  
Youcai Kang ◽  
Jianen Gao ◽  
Hui Shao ◽  
Yuanyuan Zhang

Climate and land-use change are the two main driving forces that affect watershed hydrological processes. Separately assessing their impacts on hydrology is important for land-use planning and water resource management. In this research, the SWAT (Soil and Water Assessment Tool) and statistical methods were applied to evaluate the effects of climate and land-use change on surface hydrology in the hilly-gully region of the Loess Plateau. The results showed that surface runoff and soil water presented a downward tendency, while evapotranspiration (ET) presented an upward tendency in the Yanhe watershed from 1982 to 2012. Climate is one the dominant factors that influence surface runoff, especially in flooding periods. The average contribution rate of surface runoff on stream flow accounted for 55%, of which the flooding period accounted for 40%. The runoff coefficient declined by 0.21 after 2002 with the land-use change of cropland transformed to grassland and forestland. The soil water exhibited great fluctuation along the Yanhe watershed. In the upstream region, the land-use was the driving force to decline soil water, which reduced the soil water by 51%. Along the spatial distribution, it converted from land-use change to climate variability from northwest to southeast. The ET was more sensitive to land-use change than climate variability in all sub-basins, and increased by 209% with vegetation restoration. To prevent the ecosystem degradation and maintain the inherent ecological functions of rivers, quantitative assessment the influence of climate variability and land-use change on hydrology is of great importance. Such evaluations can provide insight into the extent of land use/cover change on regional water balance and develop appropriate watershed management strategies on the Loess Plateau.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Zhixiang Lu ◽  
Songbing Zou ◽  
Zuodong Qin ◽  
Yonggang Yang ◽  
Honglang Xiao ◽  
...  

We applied an integrated approach to investigate the impacts of land use and land cover (LULC) changes on hydrology at different scales in the Loess Plateau of China. Hydrological modeling was conducted for the LULC maps from remote sensing images at two times in the Upper Fenhe River watershed using the SWAT model. The main LULC changes in this watershed from 1995 to 2010 were the transformation of farmland into forests, grassland, and built-up land. The simulation results showed that forested land contributed more than any other LULC class to water yield, but built-up land had most impact due to small initial loss and infiltration. At basin scale, a comparison of the simulated hydrological components of two LULC maps showed that there were slight increases in average annual potential evapotranspiration, actual evapotranspiration, and water yield, but soil water decreased, between the two intervals. In subbasins, obvious LULC changes did not have clear impacts on hydrology, and the impacts may be affected by precipitation conditions. By linking a hydrological model to remote sensing image analysis, our approach of quantifying the impacts of LULC changes on hydrology at different scales provide quantitative information for stakeholders in making decisions for land and water resource management.


2019 ◽  
Vol 11 (5) ◽  
pp. 1443 ◽  
Author(s):  
Rui Yan ◽  
Yanpeng Cai ◽  
Chunhui Li ◽  
Xuan Wang ◽  
Qiang Liu

This study researched the individual and combined impacts of future LULC and climate changes on water balance in the upper reaches of the Beiluo River basin on the Loess Plateau of China, using the scenarios of RCP4.5 and 8.5 of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). The climate data indicated that both precipitation and temperature increased at seasonal and annual scales from 2020 to 2050 under RCP4.5 and 8.5 scenarios. The future land use changes were predicted through the CA-Markov model. The land use predictions of 2025, 2035, and 2045 indicated rising forest areas with decreased agricultural land and grassland. In this study, three scenarios including only LULC change, only climate change, and combined climate and LULC change were established. The SWAT model was calibrated, validated, and used to simulate the water balance under the three scenarios. The results showed that increased rainfall and temperature may lead to increased runoff, water yield, and ET in spring, summer, and autumn and to decreased runoff, water yield, and ET in winter from 2020 to 2050. However, LULC change, compared with climate change, may have a smaller impact on the water balance. On an annual scale, runoff and water yield may gradually decrease, but ET may increase. The combined effects of both LULC and climate changes on water balance in the future were similar to the variation trend of climate changes alone at both annual and seasonal scales. The results obtained in this study provide further insight into the availability of future streamflow and can aid in water resource management planning in the study area.


2010 ◽  
Vol 60 (4) ◽  
pp. 369-380 ◽  
Author(s):  
D.L. She ◽  
M.A. Shao ◽  
L.C. Timm ◽  
I. Pla Sentís ◽  
K. Reichardt ◽  
...  

2009 ◽  
Vol 23 (21) ◽  
pp. 3083-3092 ◽  
Author(s):  
Shengping Wang ◽  
Zhiqiang Zhang ◽  
Ge Sun ◽  
Steven G. McNulty ◽  
Manliang Zhang

2020 ◽  
Vol 34 (6) ◽  
pp. 1446-1459 ◽  
Author(s):  
Zhongwu Li ◽  
Hao Peng ◽  
Binggeng Xie ◽  
Chun Liu ◽  
Xiaodong Nie ◽  
...  

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Aman Srivastava ◽  
Pennan Chinnasamy

AbstractThe present study, for the first time, examined land-use land cover (LULC), changes using GIS, between 2000 and 2018 for the IIT Bombay campus, India. Objective was to evaluate hydro-ecological balance inside campus by determining spatio-temporal disparity between hydrological parameters (rainfall-runoff processes), ecological components (forest, vegetation, lake, barren land), and anthropogenic stressors (urbanization and encroachments). High-resolution satellite imageries were generated for the campus using Google Earth Pro, by manual supervised classification method. Rainfall patterns were studied using secondary data sources, and surface runoff was estimated using SCS-CN method. Additionally, reconnaissance surveys, ground-truthing, and qualitative investigations were conducted to validate LULC changes and hydro-ecological stability. LULC of 2018 showed forest, having an area cover of 52%, as the most dominating land use followed by built-up (43%). Results indicated that the area under built-up increased by 40% and playground by 7%. Despite rapid construction activities, forest cover and Powai lake remained unaffected. This anomaly was attributed to the drastically declining barren land area (up to ~ 98%) encompassing additional construction activities. Sustainability of the campus was demonstrated with appropriate measures undertaken to mitigate negative consequences of unwarranted floods owing to the rise of 6% in the forest cover and a decline of 21% in water hyacinth cover over Powai lake. Due to this, surface runoff (~ 61% of the rainfall) was observed approximately consistent and being managed appropriately despite major alterations in the LULC. Study concluded that systematic campus design with effective implementation of green initiatives can maintain a hydro-ecological balance without distressing the environmental services.


2021 ◽  
Vol 312 ◽  
pp. 107354 ◽  
Author(s):  
Ai-Tian Ren ◽  
Rui Zhou ◽  
Fei Mo ◽  
Shu-Tong Liu ◽  
Ji-Yuan Li ◽  
...  

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