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Wang Z.,Chinese Ministry of Water Resources | Wang W.,Chinese Ministry of Water Resources | Wang W.,Northwest Agriculture and Forestry University | Luo T.,Northwest Agriculture and Forestry University | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2010

A field scouring experiment on soil erosion and sediment yield on unpaved roads was conducted to provide scientific date for predicting and controlling soil and water loss on unpaved roads. Results indicated that the variation of sediment yield appeared in three types, which were smooth, multimodal, and unmoral distribution on the condition of combination of same slope with different runoff discharges, or same discharge with different slopes. Spatial variation of sediment yield with slope profile could be showed reduction in three types, wave, gradual reduction and reduction after increase on the same road surface. The variations of average sediment concentration with supplied runoff discharge were accorded with logarithmic correlations. But, variations of sediment yield rate with supplied runoff discharges, average sediment concentration with slope, sediment yield rate with slope were accorded with linear correlation. The result was prospected to provide theoretical foundation for research and predication in the soil erosion of unpaved roads. Source


Shi Q.-H.,Northwest Agriculture and Forestry University | Wang W.-L.,Northwest Agriculture and Forestry University | Wang W.-L.,Chinese Ministry of Water Resources | Guo M.-M.,Northwest Agriculture and Forestry University | And 5 more authors.
Chinese Journal of Applied Ecology | Year: 2015

Engineering accumulation formed in production and construction projects is characterized by unique structure and complex material composition. Characteristics of soil erosion on the engineering accumulation significantly differ from those on farmland. An artificially simulated rainfall experiment was carried out to investigate the effects of rainfall intensity on the processes of runoff and sediment yielding on the engineering accumulation of different gravel contents (0%, 10%, 20% and 30%) in red soil regions. Results showed that the initial time of runoff generation decreased with increases in rainfall intensity and gravel content, the decreased amplitudes being about 48.5%-77.9% and 4.2%-34.2%, respectively. The initial time was found to be a power function of rainfall intensity. Both runoff velocity and runoff rate manifested a trend of first rising and then in a steady state with runoff duration. Rainfall intensity was found to be the main factor influencing runoff velocity and runoff rate, whereas the influence of gravel content was not significant. About 10% of gravel content was determined to be a critical value in the influence of gravel content on runoff volume. For the underlying surface of 10% gravel content, the runoff volume was least at rainfall intensity of 1.0 mm·min-1 and maximum at rainfall intensity of greater than 1.0 mm·min-1. The runoff volume increased 10%-60% with increase in rainfall intensity. Sediment concentration showed a sharp decline in first 6 min and then in a stable state in rest of time. Influence of rainfall intensity on sediment concentration decreased as gravel content increased. Gravels could reduce sediment yield significantly at rainfall intensity of greater than 1.0 mm·min-1. Sediment yield was found to be a linear function of rainfall intensity and gravel content. ©, 2015, Editorial Board of Chinese Journal of Applied Ecology. All right reserved. Source


Ran D.,Yellow River Institute of Hydraulic Research | Yao W.,Yellow River Institute of Hydraulic Research | Li Z.,Xian University of Technology | Luo Q.,Xifeng Soil and Water Conservation Experimental Station
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

This paper analyzed the effect of warping dams of different configuration ratios on reducing sediment and major factors contribution rate by mathematical statistics method and the investigation data in Dali River basin in middle of Yellow River. The investigation data showed land area of different type dams increased with time in Dali River basin, but presented obviously slow increasing in the near future. Warping dams reduced mean flood amount with 18.4 million m3 and sediment 12.9 million t during 1960-2002 annually, and the ratio of different type dams was 80.1%, 14.6%, 5.3%, respectively. The period of biggest reduction of sediment with 30.2% was 1990 s, and the responding ratio of different type warping dams was 1.84:2.37:5.79.The sediment decrement of large-scale soil-retaining dam was 5.5 times than that of medium dam, and was 15 times than that of small dams. The optimized proportion of distributions of warping dams for achieving continuous sediment reduction in the future in drainage basin was 1:3.0:7.0. The maximum amount of sediment reduction by different types of soil retaining dams correlated closely with flood season rainfall and 1-day maximum rainfall. Within the sediment reduction capability of warping dams, the amount of sediment reduction increased with rainfall intensity, presenting the characteristics of "the more sediment reduction with the more incoming sediment". Reducing sediment of the warping dams had a proportionality relationship with observed flood in different periods. Since 1990s, sediment reduction was about 0.23 t/m3 of unit cubic meter of flood discharge. Sediment reduction amount was about 0.19t/m3 per unit cubic meter of flood discharge during 1970s and 1980s, and the amount was about 0.23 t/m3 since 1990s. The warping dams reduced sediment increased with the value of 3 major factors. The contribution ratio of the factors was in the order: the flood amount ≤ rain season rainfall ≤ 1-day maximum rainfall. Source


Guo M.,Northwest Agriculture and Forestry University | Wang W.,Northwest Agriculture and Forestry University | Wang W.,Chinese Ministry of Water Resources | Li J.,Yangtze River Scientific Research Institute | And 6 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2015

In the hill-gully area of the Loess Plateau, serious man-made soil and water loss occurs in disturbed soils of sloping farmlands formed in the process of tillage operation. Frequent farming activities cause ephemeral gullies to develop continuously on sloping farmlands. Although an ephemeral gully may be refilled and rehabilitated, new ephemeral gully may develop in the original position in next rainy season. An indoor flow scouring experiment under artificially simulated rainfall was carried out in the State Key Laboratory of Soil Erosion and Dryland Agriculture on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, China in July 2014. The effects of tillage treatments on runoff and sediment yielding in ephemeral gully and its morphology were investigated at different rainfall intensities and slope degrees under the condition of upslope concentrated flow. Based on preliminary field investigations, 3 slope degrees of 15°, 20° and 25° were selected. Rainfall intensity was designed at 1.0, 1.5, and 2.0 mm/min. Flow discharges were 7.53 to 23.45 L/min. Plots of 8 m×1m were laid out for experiments and 3 flow sections were set up for runoff and sediment measurements. Before each test, rainfall intensity was calibrated repeatedly until the rainfall uniformity coefficient reached 85% or above. During each test, flow velocity was measured with dye tracing method and flow width and depth were measured with point gauge system. Runoff sample was taken once a minute within 3 minutes before runoff generation, and once 3 minutes after runoff generation. The results showed that: 1) Flow regimes for non-tilled and tilled ephemeral gullies were characterized by turbulent flow; Tillage could decrease Reynolds number and Froude number by 0.95%-30.77% and 3.41%-35.66%, and increase Darcy-Weisbach coefficient and Manning roughness coefficient by 4.01%-58.82% and 0.88%-27.87%, respectively; and 2) Compared to non-tilled ephemeral gully, the soil detachment rate for tilled ephemeral gully increased by 9.48%-37.87% under the experimental condition; The soil detachment rates for non-tillage and tillage ephemeral gullies were in a very significantly linear relationship with the interaction of slope and flow discharge, and the interaction of rainfall intensity and slope; It was also significantly linearly correlated with flow shear stress, stream power and unit stream power; Critical shear stress, stream power and unit stream power was 17.576 N/m2, 5.036 W/(m2·s) and 0.0381 m/s, respectively for non-tillage ephemeral gully, and 10.585 N/m2, 3.544 W/(m2·s) and 0.0277 m/s, respectively for tillage ephemeral gully; 3) Compared to non-tillage ephemeral gully, the eroded width and area of tilled ephemeral gully increased by 1.98%-31.79% and 0.84%-32.03%, respectively, but the incised depth was reduced by 2.82%-26.67%; 4) The soil erosion mass for ephemeral gully increased from 0.91% to 22.80% due to tillage treatment; The ratios of soil erosion mass for tillage and non-tillage ephemeral gullies to the total soil erosion mass were 35.95%-57.72% and 42.68%-69.03%, respectively. The erosion masses for non-tillage and tillage ephemeral gullies were a significantly linear function of the interaction of rainfall intensity and flow discharge. This study may provide valuble information for the construction of an ephemeral gully erosion model and the security and protection of agricultural eco-environment. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved. Source


Ran D.-C.,Yellow River Institute of Hydraulic Research | Ran D.-C.,CAS Institute of Soil and Water Conservation | Zhao L.-Y.,Tianshui Soil and Water Conservation Experimental Station | Zhang Z.-P.,Xifeng Soil and Water Conservation Experimental Station | Luo Q.-H.,Xifeng Soil and Water Conservation Experimental Station
Shuili Xuebao/Journal of Hydraulic Engineering | Year: 2010

The effect of soil and water conservation measures on the slope on rill erosion with different scale in the Loess Plateau in the Middle Yellow River is quantatively analyzed. The results show that the action of rill erosion reduction due to soil and water conservation measures is more than that of reducing soil with infiltration and interception. In the small scale, the effect of soil and water conservation measures on slope can reduce rill erosion up to about 55%. In bigger scale, the soil and water conservation can reduce the rill erosion higher than the erosion reduction on slope by 1.1 to 1.25 times. The erosion reduction is about 29% of the total reduction by soil and water conservation in the valley. So, to reduce rill erosion by soil and water conservation on slope should be considered in calculating the reduced erosion by soil and water conservation measures in Loess Plateau around the Middle Yellow River. Source

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