scholarly journals Karst bare slope soil erosion and soil quality: a simulation case study

Solid Earth ◽  
2015 ◽  
Vol 6 (3) ◽  
pp. 985-995 ◽  
Author(s):  
Q. Dai ◽  
Z. Liu ◽  
H. Shao ◽  
Z. Yang
Keyword(s):  
Soil Erosion ◽  
Surface Runoff ◽  
Rainfall Intensity ◽  
Infiltration Rate ◽  
Soil Infiltration ◽  
Seepage Rate ◽  
Rainfall Duration ◽  
Sediment Production ◽  
Correlation Degree ◽  
Slope Runoff

Abstract. The influence on soil erosion by different bedrock bareness ratios, different rainfall intensities, different underground pore fissure degrees and rainfall duration are researched through manual simulation of microrelief characteristics of karst bare slopes and underground karst crack construction in combination with artificial simulation of rainfall experiment. The results show that firstly, when the rainfall intensity is small (30 and 50 mm h−1), no bottom load loss is produced on the surface, and surface runoff, underground runoff and sediment production are increased with the increasing of rainfall intensity. Secondly, surface runoff and sediment production reduced with increased underground pore fissure degree, while underground runoff and sediment production increased. Thirdly, raindrops hit the surface, forming a crust with rainfall duration. The formation of crusts increases surface runoff erosion and reduces soil infiltration rate. This formation also increases surface-runoff-erosion-damaged crust and increased soil seepage rate. Raindrops continued to hit the surface, leading the formation of crust. Soil permeability showed volatility which was from reduction to increases, reduction, and so on. Surface and subsurface runoff were volatile with rainfall duration. Fourthly, when rock bareness ratio is 50 % and rainfall intensities are 30 and 50 mm h−1, runoff is not produced on the surface, and the slope runoff and sediment production present a fluctuating change with increased rock bareness ratio. Fifthly, the correlation degree between the slope runoff and sediment production and all factors are as follows: rainfall intensity-rainfall duration-underground pore fissure degree–bedrock bareness ratio.

scholarly journals Karst bare slope soil erosion and soil quality: a simulation case study

2015 ◽  
Vol 7 (2) ◽  
pp. 1639-1671
Author(s):  
Q. Dai ◽  
Z. Liu ◽  
H. Shao ◽  
Z. Yang
Keyword(s):  
Soil Erosion ◽  
Surface Runoff ◽  
Rainfall Intensity ◽  
Infiltration Rate ◽  
Soil Infiltration ◽  
Seepage Rate ◽  
Rainfall Duration ◽  
Sediment Production ◽  
Correlation Degree ◽  
Slope Runoff

Abstract. The influence on soil erosion by different bedrock bareness ratios, different rainfall intensities, different underground pore fissure degrees and rainfall duration are researched through manual simulation of microrelief characteristics of karst bare slopes and underground karst crack construction in combination with artificial simulation of rainfall experiment. The results show that firstly, when the rainfall intensity is small (30 and 50 mm h−1), no bottom load loss is produced on the surface, and surface and underground runoff and sediment production is increased with the increasing of rainfall intensity; secondly, surface runoff and sediment production reduced with increased underground pore fissure degree, while underground runoff and sediment production increased; thirdly, raindrops hit the surface, forming a crust with rainfall duration. The formation of crusts increases surface runoff erosion and reduces soil infiltration rate. Increasing of surface runoff erosion damaged crust and increased soil seepage rate. Raindrops continued to hit the surface, leading the formation of crust. Soil permeability showed volatility which were from reduction to increases and reduction, and so on. Surface and subsurface runoff were volatility with rainfall duration; fourthly, when rock bareness ratio is 50% and rainfall intensities are 30 and 50 mm h−1, runoff is not produced on the surface, and the slope runoff and sediment production presents a fluctuating change with increased rock bareness ratio; fifthly, the correlation degree between the slope runoff and sediment production and all factors are as follows: rainfall intensity > rainfall duration > underground pore fissure degree > bed rock bareness ratio.

Regulation and Critical Threshold of Grass Cover on Slope Runoff in LoessHilly Gully Region under Artificial

2021 ◽  
Author(s):  
Qiufen Zhang ◽  
Xizhi Lv ◽  
Rongxin Chen ◽  
Yongxin Ni ◽  
Li Ma
Keyword(s):  
Soil Erosion ◽  
Rainfall Intensity ◽  
Climatic Conditions ◽  
Vegetation Coverage ◽  
Critical Threshold ◽  
Runoff Generation ◽  
Grassland Vegetation ◽  
Slope Flow ◽  
The Impact ◽  
Slope Runoff

<p>The slope runoff caused by rainstorm is the main cause of serious soil and water loss in the loess hilly area, the grassland vegetation has a good inhibitory effect on the slope runoff, it is of great significance to reveal the role of grassland vegetation in the process of runoff generation and control mechanism for controlling soil erosion in this area. In this study, typical grassland slopes in hilly and gully regions of the loess plateau were taken as research objects. Through artificial rainfall in the field, the response rules of slope rainfall-runoff process to different grass coverage were explored. The results show that: (1) The time for the slope flow to stabilize is prolonged with the increase of vegetation coverage, and shortened with the increase of rainfall intensity; (2) At 60 mm·h <sup>−1</sup> rainfall intensity, the threshold of grassland vegetation coverage is 75.38%; at 90 mm·h<sup> −1</sup> rainfall intensity, the threshold of grassland vegetation coverage is 90.54%; at 120 mm·h <sup>−1</sup> rainfall intensity, the impact of grassland vegetation coverage on runoff is not significant; (3) the Reynolds number and Froude number of slope flow are 40.07‒695.22 and 0.33‒1.56 respectively, the drag coefficient is 1.42‒43.53. Under conditions of heavy rainfall, the ability of grassland to regulate slope runoff is limited. If only turf protection is considered, about 90% of grassland coverage can effectively cope with soil erosion caused by climatic conditions in loess hilly and gully regions. Therefore, in loess hilly areas where heavy rains frequently occur, grassland's protective effect on soil erosion is obviously insufficient, and investment in vegetation measures for trees and shrubs should be strengthened.</p>

scholarly journals Study on Variation of Surface Runoff and Soil Moisture Content in the Subgrade of Permeable Pavement Structure

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Lijun Hou ◽  
Yuan Wang ◽  
Fengchun Shen ◽  
Ming Lei ◽  
Xiang Wang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Water ◽  
Surface Runoff ◽  
Rainfall Intensity ◽  
Soil Moisture Content ◽  
Asphalt Pavement ◽  
Infiltration Rate ◽  
Runoff Coefficient ◽  
Flood Peak

The self-designed indoor simulated rainfall device was used to rain on five types of pavement structures with 4 types of rainfall intensity (2.5 mm/min, 3.4 mm/min, 4.6 mm/min, and 5.5 mm/min). The effect of rainfall intensity on the surface runoff, the relation between the subgrade soil moisture content changes, and the influence of initial soil water content on rain infiltration rate are studied. The test results show that the surface runoff coefficient of densely asphalted pavement is greater than 90% in drainage pavements and it has little influence on the reducing and hysteresis of the flood peak. The surface runoff coefficient of large-void asphalt pavement (permeable) is less than 40%. Although the large-void asphalt pavement (permeable) can reduce a small amount of surface runoff, it has no obvious effect on the reduction and hysteresis of the flood peak. In semipermeable pavement, with the increasing of the thickness of base (graded gravel), the surface runoff coefficient decreases at different rainfall intensities, parts of the surface runoff are reduced, and the arrival of flood peaks is delayed. In permeable roads, almost no surface runoff occurred. As time continued, the soil moisture content quickly reached a saturated state and presented a stable infiltration situation under the action of gravity and the gradient of soil water suction. As the initial moisture content increases, the initial infiltration rate decreases and the time to reach a stable infiltration rate becomes shorter. The drier the soil, the greater the initial infiltration rate and the higher the soil moisture content after infiltration stabilization. Permeable roads can greatly alleviate the pressure of urban drainage and reduce the risk of storms and floods.

scholarly journals Investigating rainfall duration effects on transport of chemicals from soil to surface runoff on a loess slope under artificial rainfall conditions

2019 ◽  
Vol 14 (No. 4) ◽  
pp. 183-194
Author(s):  
Yali Zhang ◽  
Xiaoyang Li ◽  
Xingchang Zhang ◽  
Huaien Li
Keyword(s):  
Soil Erosion ◽  
Power Function ◽  
Surface Runoff ◽  
Concentration Curve ◽  
Desorption Kinetics ◽  
Concentration Change ◽  
Rainfall Duration ◽  
Loess Slope ◽  
Artificial Rainfall ◽  
Sheet Erosion

The release and transport of soil chemicals in water erosion conditions are important for the local environment, soil and water resources conservation. According to the artificial rainfall experiments with a constant rainfall intensity of 90 mm/h and different rainfall duration (30, 60, 90, 120 and 150 min), the traits of soil PO<sub>4</sub><sup>3–</sup>, K<sup>+</sup>, and Br<sup>–</sup> release and transport from soil to surface runoff on the loess slope were analysed, and a model describing the chemical concentration change in surface runoff under soil erosion conditions was developed. The runoff coefficient quickly increased in 15 min or so, and then it was stable in the range of 0.60–0.85. The sediment intensity decreased in 30 min and soon increased after severe sheet erosion occurred on the slope. The concentration curve of Br<sup>–</sup> in surface runoff can be divided into two stages, quickly decreasing in the initial 30 min after the surface runoff occurred, and then stable. The concentration curve of PO<sub>4</sub><sup>3–</sup> and K<sup>+</sup> in surface runoff can be divided into three stages, quickly decreasing like Br<sup>– </sup>was decreasing, then stable, and increasing after severe sheet erosion began. Compared with the exponential function, the power function was found more suitable for fitting the change in chemicals in runoff with unsaturated soil; while neither of them could well fit the PO<sub>4</sub><sup>3–</sup> and K<sup>+</sup> concentration change after severe erosion occurred. The transport of chemicals under complex soil erosion conditions seems to be a dynamic release process between surface runoff and sediment. Based on the convection-dispersion mechanism and desorption kinetics, the polynomial model under soil erosion conditions was created. For adsorbed PO<sub>4</sub><sup>3–</sup> and K<sup>+</sup>, it is more suitable to simulate that process than the power function, while it is not so good for mobile Br<sup>–</sup>.  

Soil Erosion Process in Sloped Shrub Plots under Simulated Rainfall

2011 ◽  
Vol 347-353 ◽  
pp. 2094-2097 ◽  
Author(s):  
Pei Qing Xiao ◽  
Wen Yi Yao ◽  
Chang Gao Wang
Keyword(s):  
Soil Erosion ◽  
Sediment Yield ◽  
Rainfall Intensity ◽  
Infiltration Rate ◽  
Simulated Rainfall ◽  
Slope Gradient ◽  
Erosion Process ◽  
Infiltration Process ◽  
Negative Relation ◽  
Runoff And Sediment Yield

Runoff, sediment yield and infiltration process of shrub plots were studied under rainfall intensities of 45, 87 and 127 mm/h with 20° slope gradient using simulated rainfall experiment. The results showed that cumulative runoff and cumulative sediment yield of shrub plot had an obvious positive correlation with rainfall time. Under rainfall intensity of 45 mm/h, runoff and sediment yield of shrub plot kept a constant level. Under rainfall intensity of 87 mm/h, runoff kept a fluctuant increase, whereas sediment yield basically kept steady. Under rainfall intensity of 127 mm/h, runoff and sediment yield of shrub plot increased evidently due to the formation of erosion pits. Infiltration rate of shrub plot had a negative relation with runoff as well as sediment yield.

scholarly journals THE ROLE OF EARTHWORMS IN PASTURE PRODUCTION AND MOISTURE CONSERVATION

1966 ◽  
pp. 168-183 ◽  
Author(s):  
S.M.J. Stockdill ◽  
G.G. Cossens
Keyword(s):  
Soil Erosion ◽  
Chemical Properties ◽  
Infiltration Rate ◽  
Physical And Chemical Properties ◽  
Soil Infiltration ◽  
Pasture Production ◽  
Physical And Chemical ◽  
Soil Infiltration Rate ◽  
And Chemical Properties

RESEARCH has shown that pasture production on soils without earthworms is limited to considerably less than the true potential. Increased production with beneficial earthworms is associated with pronounced changes in the physical and chemical properties of the soil. Infiltration rate is increased, moisture is conserved and the risk of soil erosion is reduced

scholarly journals Soil infiltration based on bp neural network and grey relational analysis

2013 ◽  
Vol 37 (1) ◽  
pp. 97-105 ◽  
Author(s):  
Wang Juan ◽  
Wu Pute ◽  
Zhao Xining
Keyword(s):  
Neural Network ◽  
Rainfall Intensity ◽  
Vegetation Type ◽  
Slope Gradient ◽  
Soil Infiltration ◽  
Antecedent Soil Moisture ◽  
Rainfall Duration ◽  
Relational Analysis ◽  
Cumulative Infiltration ◽  
Grey Relational

Soil infiltration is a key link of the natural water cycle process. Studies on soil permeability are conducive for water resources assessment and estimation, runoff regulation and management, soil erosion modeling, nonpoint and point source pollution of farmland, among other aspects. The unequal influence of rainfall duration, rainfall intensity, antecedent soil moisture, vegetation cover, vegetation type, and slope gradient on soil cumulative infiltration was studied under simulated rainfall and different underlying surfaces. We established a six factor-model of soil cumulative infiltration by the improved back propagation (BP)-based artificial neural network algorithm with a momentum term and self-adjusting learning rate. Compared to the multiple nonlinear regression method, the stability and accuracy of the improved BP algorithm was better. Based on the improved BP model, the sensitive index of these six factors on soil cumulative infiltration was investigated. Secondly, the grey relational analysis method was used to individually study grey correlations among these six factors and soil cumulative infiltration. The results of the two methods were very similar. Rainfall duration was the most influential factor, followed by vegetation cover, vegetation type, rainfall intensity and antecedent soil moisture. The effect of slope gradient on soil cumulative infiltration was not significant.

Simulation of Runoff for Varying Mulch Coverage on a Sloped Surface

2013 ◽  
Vol 409-410 ◽  
pp. 339-343 ◽  
Author(s):  
Su Fang Cui ◽  
Ying Hua Pan ◽  
Quan Yuan Wu ◽  
Zhen Hua Zhang ◽  
Bao Xiang Zhang
Keyword(s):  
Soil Erosion ◽  
Rainfall Intensity ◽  
Overland Flow ◽  
Soil Surface ◽  
Northwest China ◽  
Slope Gradient ◽  
Soil Infiltration ◽  
Infiltration Capacity ◽  
Coverage Ratio ◽  
Runoff Volume

The use of thin plastic film to cover slope surfaces can lead to slope runoff and soil erosion in Loess hilly areas in northwest China. Three main factors (slope, rainfall intensity, and coverage ratio) were selected to analyze variations in runoff dynamics for a Lou soil surface and to obtain a theoretical foundation for practical application. The results indicate that for a fixed rainfall intensity and coverage ratio, a critical slope gradient close to 26.8% was observed. For a fixed coverage ratio and slope gradient, the cumulative runoff volume increased with the rainfall intensity. Overland flow varied with the coverage ratio and this can be attributed to increases in the cumulative runoff volume and runoff velocity with increasing coverage ratio. The experimental results show that for double-ridge cultivation with film mulching, the best coverage ratio is 50:150. This ratio not only reduces moisture evaporation and promotes soil conservation, but also effectively improves rainwater utilization and reduces soil erosion. In addition, for slope gradients exceeding 26.8%, runoff decreases and the soil infiltration capacity increases, so a slope gradient of 26.836.4% is optimal for the local cultivation model.

scholarly journals Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips – Part 1: nonuniform infiltration and soil water redistribution

2018 ◽  
Vol 22 (1) ◽  
pp. 53-70 ◽  
Author(s):  
Rafael Muñoz-Carpena ◽  
Claire Lauvernet ◽  
Nadia Carluer
Keyword(s):  
Shallow Water ◽  
Water Table ◽  
Surface Runoff ◽  
Rainfall Intensity ◽  
Initial Conditions ◽  
Companion Paper ◽  
Soil Infiltration ◽  
Shallow Water Table ◽  
Vegetative Filter Strips ◽  
Filter Strips

Abstract. Vegetation buffers like vegetative filter strips (VFSs) are often used to protect water bodies from surface runoff pollution from disturbed areas. Their typical placement in floodplains often results in the presence of a seasonal shallow water table (WT) that can decrease soil infiltration and increase surface pollutant transport during a rainfall-runoff event. Simple and robust components of hydrological models are needed to analyze the impacts of WT in the landscape. To simulate VFS infiltration under realistic rainfall conditions with WT, we propose a generic infiltration solution (Shallow Water table INfiltration algorithm: SWINGO) based on a combination of approaches by Salvucci and Entekhabi (1995) and Chu (1997) with new integral formulae to calculate singular times (time of ponding, shift time, and time to soil profile saturation). The algorithm was tested successfully on five distinct soils, both against Richards's numerical solution and experimental data in terms of infiltration and soil moisture redistribution predictions, and applied to study the combined effects of varying WT depth, soil type, and rainfall intensity and duration. The results show the robustness of the algorithm and its ability to handle various soil hydraulic functions and initial nonponding conditions under unsteady rainfall. The effect of a WT on infiltration under ponded conditions was found to be effectively decoupled from surface infiltration and excess runoff processes for depths larger than 1.2 to 2 m, being shallower for fine soils and shorter events. For nonponded initial conditions, the influence of WT depth also varies with rainfall intensity. Also, we observed that soils with a marked air entry (bubbling pressure) exhibit a distinct behavior with WT near the surface. The good performance, robustness, and flexibility of SWINGO supports its broader use to study WT effects on surface runoff, infiltration, flooding, transport, ecological, and land use processes. SWINGO is coupled with an existing VFS model in the companion paper (Lauvernet and Muñoz-Carpena, 2018), where the potential effects of seasonal or permanent WTs on VFS sediment and pesticide trapping are studied.

scholarly journals Sediment production and soil water infiltration under different simulated rainfall characteristics

2019 ◽  
Vol 23 (8) ◽  
pp. 572-578
Author(s):  
Wilk S. de Almeida ◽  
Daniel F. de Carvalho ◽  
Fernandes A. C. Pereira ◽  
Janaína R. C. Rouws
Keyword(s):  
Surface Runoff ◽  
Infiltration Rate ◽  
Water Infiltration ◽  
Soil Tillage ◽  
Rainfall Characteristics ◽  
Sediment Production ◽  
Randomized Design ◽  
Production Water ◽  
Soil Water Infiltration ◽  
Completely Randomized Design

ABSTRACT The study was carried out to evaluate sediment production, water infiltration and surface runoff in an Ultisol under simulated rainfalls with similar erosivity, but different combinations of intensity (Int) and duration (Dur). The rainfalls were applied after soil tillage in the period from August to September 2017, in Seropédica, RJ State, Brazil. Using a computer program, the treatments were defined from the erosivity calculated for a rainfall with intensity of 60 mm h-1 and duration of 60 min, resulting in the other combinations of Int and Dur: 44.5 mm h-1 and 106 min; 53.5 mm h-1 and 78 min; 66.9 mm h-1 and 48 min; and 76.5 mm h-1 and 38 min, in a completely randomized design with five repetitions. Sediment production varied from 2.17 to 6.11 g m-2, respectively, in the treatments with Int 53.5 mm h-1 and Dur 78 min and Int 44.5 mm h-1 and Dur 106 min. Stable infiltration rate (mm h-1) were 21.6, 37.7, 31.4, 29.5, and 22.4, respectively, in the treatments Int 44.5 mm h-1 and Dur 106 min; Int 53.5 mm h-1 and Dur 78 min; Int 60.4 mm h-1 and Dur 60 min; Int 66.9 mm h-1 and Dur 48 min; and Int 76.5 mm h-1 and Dur 38 min. The different combinations of intensity and duration of rainfalls with similar erosivity change sediment production, but do not significantly influence surface runoff and water infiltration in the soil.

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