Experimental Research about the Influence of Grass Coverage on Loess Slope Runoff Sediment Yield

2012 ◽  
Vol 518-523 ◽  
pp. 4504-4509
Author(s):  
Lu Zhang ◽  
Yuee Chen ◽  
Qing Wu
Keyword(s):  
Sediment Yield ◽  
Erosion Rate ◽  
Sediment Concentration ◽  
The Loess Plateau ◽  
Erosion Rates ◽  
Loess Slope ◽  
Water And Sediment ◽  
Slope Sediment ◽  
Runoff Sediment ◽  
Sediment Reduction

It was important to explore the law of water and sediment reduction of loess slope in different grass coverage for carrying out the grass construction and controlling slope erosion in the Loess Plateau. Using the tests of outside artificially runoff erosion simulation, in the condition of 5L/min of the scouring flows, we conducted a pilot study of sediment yield, erosion rates, and runoff sediment concentration in three different slope conditions of 15°, 20°, 25° and three grass coverage conditions of bare slope, 30%~40% and 70%~80%. The results showed that: the grass coverage has significantly influences on sediment yield, erosion rate and runoff sediment concentration of loess slope. Sediment yield of loess slope with grass coverage of 70 ~ 80% is less than 10% of that of bare slope. Under the same conditions of gradient and grass coverage, the sediment yield and runoff sediment concentration had a direct proportion with the scouring flow. Under the same conditions of gradient and scouring flows, the erosion rate and runoff sediment yield of loess slope are basically the same. Grass has a significant role in enhancing resistance to corrosion of soil and reducing erosion of loess slope.

Water and sediment evolution in areas with high and coarse sediment yield of the Loess Plateau

2013 ◽  
Vol 28 (4) ◽  
pp. 448-457 ◽  
Author(s):  
Jia-hong LIU ◽  
Guang-qian WANG ◽  
Hai-hong LI ◽  
Jia-guo GONG ◽  
Jing-yi HAN
Keyword(s):  
Loess Plateau ◽  
Sediment Yield ◽  
The Loess Plateau ◽  
Coarse Sediment ◽  
Water And Sediment

scholarly journals Assessing the Impact of Terraces and Vegetation on Runoff and Sediment Routing Using the Time-Area Method in the Chinese Loess Plateau

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 803 ◽  
Author(s):  
Juan Bai ◽  
Shengtian Yang ◽  
Yichi Zhang ◽  
Xiaoyan Liu ◽  
Yabing Guan
Keyword(s):  
Sediment Yield ◽  
Reduction Rate ◽  
Chinese Loess Plateau ◽  
Area Method ◽  
Chinese Loess ◽  
Sediment Routing ◽  
Water And Sediment ◽  
Sediment Reduction ◽  
The Impact ◽  
The Chinese Loess Plateau

Terracing and vegetation are an effective practice for soil and water conservation on sloped terrain. They can significantly reduce the sediment yield from the surface area, as well as intercept the sediment yield from upstream. However, most hydrological models mainly simulate the effect of the terraces and vegetation on water and sediment reduction from themselves, without considering their roles in the routing process, and thus likely underestimate their runoff and sediment reduction effect. This study added the impact of terraces and vegetation practice on water and sediment routing using the time-area method. The outflow in each travel time zone was revised in each time step by extracting the watershed of the terrace units and the vegetation units and calculating the water or sediment stored by the terraces or held by the vegetation. The revised time-area method was integrated into the Land change Model-Modified Universal Soil Loss Equation (LCM-MUSLE) model. Pianguanhe Basin, in the Chinese Loess Plateau, was chosen as the study area and eight storms in the 1980s and 2010s were selected to calibrate and verify the original LCM-MUSLE model and its revised version. The results showed that the original model was not applicable in more recent years, since the surface was changed significantly as a result of revegetation and slope terracing, while the accuracy improved significantly when using the revised version. For the three events in the 2010s, the average runoff reduction rate in routing process was 51.02% for vegetation, 26.65% for terraces, and 71.86% for both terraces and vegetation. The average sediment reduction rate in routing process was 32.22% for vegetation, 24.52% for terraces, and 53.85% for both terraces and vegetation. This study provides a generalized method to quantitatively assess the impact of terraces and vegetation practice on runoff and sediment reduction at the catchment scale.

scholarly journals Sediment Yield in Dam-Controlled Watersheds in the Pisha Sandstone Region on the Northern Loess Plateau, China

Land ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1264
Author(s):  
Fabing Xie ◽  
Guangju Zhao ◽  
Xingmin Mu ◽  
Peng Tian ◽  
Peng Gao ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Loess Plateau ◽  
Sediment Yield ◽  
Water Conservation ◽  
The Loess Plateau ◽  
Sediment Yields ◽  
Erosion Rates ◽  
Soil Erosion Rate ◽  
Check Dams ◽  
Loss Control

Soil erosion has become the dominant environmental issue endangering sustainable development in agriculture and the ecosystem on the Loess Plateau. Determination of watershed soil erosion rates and sediment yields is essential for reasonable utilization of water resources and soil loss control. In this study, we employed unmanned aerial vehicles (UAVs) and structure-from-motion (SfM) photogrammetry to determine the sediment yields in 24 dam-controlled watersheds in the Pisha sandstone region of the northern Loess Plateau. High differences in total sediment were trapped before the check dams due to their running periods and sediment yields. The estimated specific sediment yield ranged from 34.32 t/(ha∙a) to 123.80 t/(ha∙a) with an average of 63.55 t/(ha∙a), which indicated that the Pisha sandstone region had an intense soil erosion rate. Furthermore, the modified Sediment Distributed Delivery (SEDD) model was applied to identify the erosion-prone areas in the watersheds, and the sediment retained in the check dams were used for model calibration. The performance of the model was acceptable, and the modeling results indicated that the steep Pisha sandstone was the major sediment source for the watersheds, accounting for approximately 87.37% of the sediment yield. Catchment area, erosive precipitation, and badland proportion were the key factors for sediment yield in the dam-controlled watersheds of the Pisha sandstone region, according to multiple regression analyses. These findings indicated that the modified SEDD model is very efficient in identifying spatial heterogeneities of sediment yield in the watershed but requires comprehensive calibration and validation with long-term observations. The Pisha sandstone region is still the key area of soil erosion control in the Loess Plateau, which needs more attention for soil and water conservation due to high sediment yield.

Spatio-temporal analysis of soil erosion in Tokoro river watershed in eastern Hokkaido, Japan

2021 ◽  
Author(s):  
Kunihito Mihara ◽  
Kanta Kuramochi ◽  
Ryusuke Hatano
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Sediment Yield ◽  
Surface Runoff ◽  
Stream Flow ◽  
Erosion Rate ◽  
Sediment Load ◽  
Agricultural Lands ◽  
Sediment Movement ◽  
Water And Sediment

<p>Introduction</p><p>Accelerated erosion by human activities leads to degradation of soil ecosystem services and aquatic environment. It is unavoidable issue in Japan because it holds many sloped agricultural lands. Tokoro river watershed, TRW, in eastern Hokkaido, Japan has unique climate characterized with the least precipitation in Japan and cold winter with little snow which induces soil freezing. Frozen subsoil forms impermeable layers to increase surface runoff in early spring. The objectives of this study were i) to understand the spatial and seasonal variation of water and sediment movement in TRW using Soil and Water Assessment Tool, SWAT which is a process-based hydrological model and ii) to evaluate the impact of agricultural activities, topography of agricultural lands, and runoff characteristics on soil erosion through identification of highly erosive areas and seasons based on the simulation output.</p><p>Materials and methods</p><p>Water and sediment movement in TRW was simulated from 2011/1/1 to 2015/12/31. SWAT calculates water and sediment movement processes using spatial and temporal information of topography, land use, soil, weather, and land management in watershed. TRW was delineated into 17 subbasins based on topographic information and further divided into 764 HRUs which had homogenous combination of slope class, soil type, and land use in each subbasin. On-land processes were calculated in each HRU. After water and sediment yield from HRUs were summed in each subbasin, stream routing processes were calculated. Model parameters were calibrated so that the estimated stream flow and sediment load at the outlet would fit the measurements. From the simulation by the calibrated model, outputs were extracted as follows: 1) Contribution to the gross sediment yield and erosion rate of each land use; 2) Erosion rate of each subbasin; 3) Erosion rate of whole watershed on each month; and 4) Surface runoff and percentage of surface runoff in water yield in each month.</p><p>Results and Discussions</p><p>Calibrated SWAT reproduced well the fluctuation of stream flow and sediment load at the outlet of TRW. Although the model underestimated sediment load during large flood events with the average estimation error of -16.1±5.4% on peak-discharge months, it showed satisfactory performance with coefficient of determination: R<sup>2</sup>=0.88, Nash-Sutcliffe efficiency coefficient: Ens=0.86, and percentage of bias: PBIAS=0.34% for monthly sediment load estimation. Agricultural lands which covered 17.6% of the watershed were considered as the primary sediment sources contributing to 68.5% of estimated gross sediment yield of the watershed. Spatial variation of estimated erosion rate showed high sediment yield in the middle- and down-stream area of TRW where agricultural activities were intensive, and higher sediment yield particularly in the area where more agricultural lands had steep slopes (more than 51 t km<sup>-2</sup> yr<sup>-1</sup>). Monthly erosion rate estimation indicated that the most severe erosion occurred on March and April (6.9±1.4 and 7.3±1.9 t km<sup>-2</sup> mon<sup>-1</sup> respectively). On March, average percentage of surface runoff was estimated as 90.5±6.5%. Therefore, surface runoff in early snowmelt season when the frozen subsoil prevented infiltration was considered as an important driver of soil erosion.</p>

scholarly journals Influences of conservation measures on runoff and sediment yield in different intra-event-based flood regimes in the Chabagou watershed

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shan-Shan Wang ◽  
Zhan-Bin Li ◽  
Le-Tao Zhang ◽  
Bo Ma
Keyword(s):  
Soil Erosion ◽  
Loess Plateau ◽  
Sediment Yield ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
The Loess Plateau ◽  
Flood Duration ◽  
Conservation Measures ◽  
Event Based ◽  
Measurement Period

AbstractThe Loess Plateau in China has suffered severe soil erosion. To control soil erosion, extensive conservation measures aimed at redistributing rainfall, hindering flow velocity and intercepting sediment were implemented on the Loess Plateau. To accurately evaluate the combined effect of conservation measures in the Chabagou watershed, this study classified intra-event-based floods into four regimes via cluster and discriminant analyses. Regime A was characterized by short flood duration and low erosive energy, regime B was characterized by short flood duration and high erosive energy, regime C was characterized by long flood duration and low erosive energy, and regime D was characterized by long flood duration and high erosive energy. The results indicated that peak discharge (qp), runoff depth (H), mean discharge (qm), and runoff erosion power (E) decreased by 75.2%, 56.0%, 68.0% and 89.2%, respectively, in response to conservation measures. Moreover, area-specific sediment yield (SSY), average suspended sediment concentration (SCE), and maximum suspended sediment concentration (MSCE) decreased by 69.2%, 33.3% and 11.9%, respectively, due to conservation measures. The nonlinear regression analysis revealed a power function relationship between SSY and E in both the baseline (1961–1969) and measurement period (1971–1990) in all regimes. Conservation measures reduced sediment yield by not only reducing the runoff amount and soil erosion energy but also transforming the flood regime, for example, transforming a high-sediment-yield regime into a low-sediment-yield regime. Moreover, conservation measures altered the SSY-E relationship in regime A, whereas no obvious difference in regime B or C/D was observed between the measurement period and the baseline period. This study provides a better understanding of the mechanism of runoff regulation and the sediment yield reduction under comprehensive conservation measures in a small watershed on the Chinese Loess Plateau.

The influence of aspect and vegetation on seasonal changes in erosion under rainfall simulation on a clay soil in Spain

1998 ◽  
Vol 78 (2) ◽  
pp. 321-330 ◽  
Author(s):  
A. Cerdà
Keyword(s):  
Soil Loss ◽  
Sediment Concentration ◽  
Rainfall Simulation ◽  
Vegetation Growth ◽  
Erosion Rates ◽  
The North ◽  
Runoff Sediment ◽  
High Runoff ◽  
Runoff And Soil Loss ◽  
Over Time

The seasonal and spatial variability of soil erosion under contrasting slope aspects in southeastern Spain was studied by performing and interpreting 84 rainfall simulation experiments conducted at an intensity of 55 mm h−1 during 1 h. The vegetated soils on the north-facing slope and the upper afforested parts had negligible sediment yield, runoff and erosion, while the bare soils on the south-facing slope had very high runoff rates. Runoff sediment concentration decreased over time during simulated rainfall events on the vegetated areas while it increased on the bare ones. Solute release decreased over time on both surface types. Seasonally, runoff sediment concentration was highest in autumn, decreasing in winter and spring, due to the exhaustion of erodible soil and the vegetation growth. Sediment concentrations increased slightly in summer when runoff and erosion rates where very low. Increasing seasonal variability corresponded with increasing runoff and soil loss rates. Key words: Runoff, soil loss, Mediterranean, erodibility

scholarly journals Soil erosion by snow gliding – a first quantification attempt in a subalpine area in Switzerland

2014 ◽  
Vol 18 (9) ◽  
pp. 3763-3775 ◽  
Author(s):  
K. Meusburger ◽  
G. Leitinger ◽  
L. Mabit ◽  
M. H. Mueller ◽  
A. Walter ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Land Cover ◽  
Sediment Yield ◽  
Soil Loss ◽  
Water Erosion ◽  
Erosion Rates ◽  
The Difference ◽  
Snow Gliding

Abstract. Snow processes might be one important driver of soil erosion in Alpine grasslands and thus the unknown variable when erosion modelling is attempted. The aim of this study is to assess the importance of snow gliding as a soil erosion agent for four different land use/land cover types in a subalpine area in Switzerland. We used three different approaches to estimate soil erosion rates: sediment yield measurements in snow glide depositions, the fallout radionuclide 137Cs and modelling with the Revised Universal Soil Loss Equation (RUSLE). RUSLE permits the evaluation of soil loss by water erosion, the 137Cs method integrates soil loss due to all erosion agents involved, and the measurement of snow glide deposition sediment yield can be directly related to snow-glide-induced erosion. Further, cumulative snow glide distance was measured for the sites in the winter of 2009/2010 and modelled for the surrounding area and long-term average winter precipitation (1959–2010) with the spatial snow glide model (SSGM). Measured snow glide distance confirmed the presence of snow gliding and ranged from 2 to 189 cm, with lower values on the north-facing slopes. We observed a reduction of snow glide distance with increasing surface roughness of the vegetation, which is an important information with respect to conservation planning and expected and ongoing land use changes in the Alps. Snow glide erosion estimated from the snow glide depositions was highly variable with values ranging from 0.03 to 22.9 t ha−1 yr−1 in the winter of 2012/2013. For sites affected by snow glide deposition, a mean erosion rate of 8.4 t ha−1 yr−1 was found. The difference in long-term erosion rates determined with RUSLE and 137Cs confirms the constant influence of snow-glide-induced erosion, since a large difference (lower proportion of water erosion compared to total net erosion) was observed for sites with high snow glide rates and vice versa. Moreover, the difference between RUSLE and 137Cs erosion rates was related to the measured snow glide distance (R2 = 0.64; p < 0.005) and to the snow deposition sediment yields (R2 = 0.39; p = 0.13). The SSGM reproduced the relative difference of the measured snow glide values under different land uses and land cover types. The resulting map highlighted the relevance of snow gliding for large parts of the investigated area. Based on these results, we conclude that snow gliding appears to be a crucial and non-negligible process impacting soil erosion patterns and magnitude in subalpine areas with similar topographic and climatic conditions.

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