Effects of vegetation cover of natural grassland on runoff and sediment yield in loess hilly region of China

2013 ◽  
Vol 94 (3) ◽  
pp. 497-503 ◽  
Author(s):  
Xining Zhao ◽  
Xiaoli Chen ◽  
Jun Huang ◽  
Pute Wu ◽  
Matthew J Helmers
2021 ◽  
Author(s):  
María Rosario Vidal-Abarca Gutiérrez ◽  
Alberto Martínez-Salvador ◽  
Carmelo Conesa-García ◽  
María Luisa Suárez-Alonso ◽  
Francisco Alonso-Sarria ◽  
...  

<p>Semiarid basins contribute significantly to sediment loads, as they are often characterized by torrential flows, source areas with high sediment-producing rates, great availability of erodible material subjected to intense weathering processes, and poor vegetation cover. Vegetation, despite its scarce presence, is a dynamic component of this environment, which provides a range of important ecosystem services such as biodiversity, flood retention, nutrient sink, erosion control and groundwater recharge. This study examines the vegetation responses to the magnitude of peak flows and its contribution to the changes in runoff and sediment yield during the period 1997-2020 in a catchment Mediterranean semiarid basin: The Rambla de la Azohía (southeastern Spain).Vegetation type, density, preferred location and degree of permanence in each sub-basin were analyzed in order to determine their degree of influence on surface runoff and erosion control. Changes in riparian vegetation cover was quantified at large scale for the analysis period (1997-2020), using remotely sensed spatial information, such as satellite images and aerial photographs separated by two years on average (at scales from 1:15000 to 1:30000, and resolution between 0.22 and 0.50 m/pixel). A geo-spatial erosion prediction model was applied to estimate the runoff and sediment load generated at the event scale, taking into account the variability of the vegetation cover in each sub-basin. The simulated outputs of this model were previously calibrated with water levels measured by pressure sensors and suspended sediment records.The results showed both a poor response of vegetation (low incidence in the runoff coefficient) in steep metamorphic watersheds, capable of supplying large sediment loads, and functioned as an efficient ecosystem service (stabilization of slopes and decrease in peak flow) in less steep sub-basins with slopes in the shadow, composed of limestone formations and alluvial fans. This suggests important spatial differences in the vegetation impact, according to other environmental conditions intrinsic to each sub-basin, but also a low overall influence on the temporal variability of sediment fluxes at the event scale. This research was funded by FEDER/Spanish Ministry of Science, Innovation and Universities—State Research Agency (AEI)/Projects CGL2017-84625-C2-1-R and CGL2017-84625-C2-2-R; State Program for Research, Development and Innovation Focused on the Challenges of Society.</p>


Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1373 ◽  
Author(s):  
Shanghong Zhang ◽  
Zehao Li ◽  
Xiaonan Lin ◽  
Cheng Zhang

Climate change has an important impact on water balance and material circulation in watersheds. Quantifying the influence of climate and climate-driven vegetation cover changes on watershed-scale runoff and sediment yield will help to deepen our understanding of the environmental effects of climate change. Taking the Zhenjiangguan Watershed in Sichuan Province, China as a case study, three downscaled general circulation models with two emission scenarios were used to generate possible climatic conditions for three future periods of P1 (2020–2039), P2 (2050–2069) and P3 (2080–2099). Differences in scenarios were compared with the base period 1980–1999. Then, a Normalized Difference Vegetation Index climate factor regression model was established to analyze changes to vegetation cover under the climate change scenarios. Finally, a Soil and Water Assessment Tool model was built to simulate the response of runoff and sediment yield in the three future periods under two different scenarios: only changes in climate and synergistic changes in climate and vegetation cover. The temperature and precipitation projections showed a significant increasing trend compared to the baseline condition for both emission scenarios. Climate change is expected to increase the average annual runoff by 15%–38% compared with the base period, and the average annual sediment yield will increase by 4%–32%. The response of runoff and sediment yield varies in different periods, scenarios, and sub-watersheds. Climate-driven vegetation cover changes have an impact on runoff and sediment yield in the watershed, resulting in a difference of 5.8%–12.9% to the total changes. To some extent, the changes in vegetation cover will inhibit the hydrological impact of climate changes. The study helps to clarify the effects of climate and vegetation cover factors on hydrological variations in watersheds and provides further support for understanding future hydrological scenarios and implementing effective protection and use of water and soil resources.


Soil Research ◽  
2013 ◽  
Vol 51 (1) ◽  
pp. 50 ◽  
Author(s):  
Xining Zhao ◽  
Pute Wu ◽  
Xiaoli Chen ◽  
Matthew J. Helmers ◽  
Xiaobo Zhou

Runoff volume, sediment yield and infiltration on hillslope in the hilly region of Loess Plateau were studied using a rainfall simulator. Two land cover (natural grassland, NG, and bare hillslope, BS) and three different rainfall intensities (2.0, 1.5, 0.75 mm min–1) were implemented. The runoff time of the NG2.0 treatment was 4.8 min earlier, the average infiltration rate was 5.60% lower, the runoff rate was 1.12 times higher and the sediment production rate was 3.28 times lower than those in the BS2.0 treatment. The runoff time for the NG1.5 and the NG0.75 treatments were 6 and 27 min slower, respectively, the average infiltration rate were 10.78 and 23.52% higher, respectively, the runoff rate were 1.67 and 4.25 times lower, respectively, and the sediment production rate were 5.21 and 16.75 times lower, respectively, than those for the BS1.5 and BS0.75 treatments. The effects of slope on sediment reduction were significantly greater than the effects of its runoff reduction, and there occurred more significant sediment-reducing effects with the decrease of rainfall intensity. Efficient use of rainfall runoff in the natural grassland at high intensity should be taken into considerations especially under current conditions of the co-existing drought-caused water shortage and soil erosion in the loess hilly regions.


2018 ◽  
Vol 38 ◽  
pp. 01032
Author(s):  
Chun Xia Yang ◽  
PeiQing Xiao ◽  
Li Li ◽  
Peng Jiao

Land consolidation measures affected the underlying surface erosion environment during the early stage of vegetation construction, and then had an impact on rainfall infiltration, erosion and sediment yield. This paper adopted the field simulated rainfall experiments to analyze the function that pockets site preparation measures affected on rainfall infiltration, runoff sediment yield and runoff erosion ability. The results showed that,the measures can delay the rainfall runoff formation time of the slope by 3'17" and 1'04" respectively,Compared with the same condition of the bare land and natural grassland,The rainfall infiltration coefficient each increased by 76.47% and 14.49%, and infiltration rate increased by 0.26 mm/min and 0.11mm/min respectively; The amount of runoff and sediment yield were reduced because of the pockets site preparation ,The amount of runoff reducing rate were 33.51% and 30.49%, and sediment reduction rate were 81.35% and 65.66%, The sediment concentration was decreased by 71.99% and 50.58%; Runoff velocity of bare slope and natural grassland slope decreased by 38.12% and 34.59% respectively after pockets site preparation . The runoff erosion rate decreased by 67.92% and 79.68% respectively. The results will have a great significance for recognizing the effect of water and sediment reduction about vegetation and the existence of its plowing measures at the early period of restoration.


1998 ◽  
Vol 78 (4) ◽  
pp. 699-706 ◽  
Author(s):  
S. I. Gill ◽  
M. A. Naeth ◽  
D. S. Chanasyk ◽  
V. S. Baron

Currently, there is interest in Western Canada in extending the grazing season using perennial and annual forages. Of greatest concern is the environmental sustainability of these grazing systems, with emphasis on their ability to withstand erosion. A study to examine the runoff and sediment yields of annual and perennial forages in central Alberta was initiated in 1994. Runoff and sediment yield were quantified under snowmelt and rainfall events for two seasons. Rainfall simulation was used to further examine runoff under growing season conditions. Four forage treatments (two annuals: triticale and a barley/triticale mixture and two perennials: smooth bromegrass and meadow bromegrass) and three grazing intensities (light, medium and heavy) were studied, each replicated four times. Total annual runoff was dominated by snowmelt. Generally runoff volumes, sediment yields, sediment ratios and runoff coefficients were all low. Bare ground increased with increasing grazing intensity and was significantly greater in annuals than perennials for all grazing intensities. Litter biomass decreased with increasing grazing intensity and was generally similar in all species for both years at heavy and medium grazing intensities. Results from the rainfall simulation corroborated those under natural rainfall conditions and generally indicated the sustainability of these grazing systems at this site. Key words: Forages, soil erosion, sustainability, rainfall simulation


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