Recent developments regarding the influence of soil surface characteristics on overland flow and erosion

Soil Research ◽  
1992 ◽  
Vol 30 (3) ◽  
pp. 249 ◽  
Author(s):  
PB Hairsine ◽  
CJ Moran ◽  
CW Rose

Recent developments in modelling overland flow and soil erosion, which permit the consilidation of soil surface characteristics, are reviewed. The models of overland flow are found to be sensitive to soil surface micro-topography and surface pore structure. The former affects depressional storage and hydraulic routing and the latter soil hydraulic properties, notably infiltration rate. The models of soil erosion by water are found to be sensitive to surface roughness, strength and the aggregate size distribution, and the deposition characteristics, of the eroded sediment. Methods for describing the roughness of a soil surface are described and the links to the above processes discussed. The implications of new techniques of roughness measurement for this area of research are briefly examined. It is concluded that the new models of erosion and overland flow provide a more realistic description of the influence of soil surface characteristics than previous semi-empirical models. The review identified the case of large form roughness and shallow flow as a poorly described regime. It was also concluded that the relationship between structural degradation and surface roughness warranted investigation.

2021 ◽  
Vol 58 (03) ◽  
pp. 286-299
Author(s):  
Mahesh Chand Singh ◽  
Rohit Singh ◽  
Abrar Yousuf ◽  
Vishnu Prasad

The present study examined 35 morphometric parameters related to stream/drainage network, catchment geometry, and relief aspects for hydrological characterization of the Thana Dam catchment using geospatial tools and techniques. The dam catchment was delineated using the high-resolution Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR) Digital Elevation Model (DEM) data in ArcGIS 10.4.1 software using the Arc Hydro tools. The catchment is comprised of 4th order stream, obtained using a stream threshold value of 100 m length. The lower values of elongation ratio (0.61), circularity ratio (0.22), and form factor (0.29) indicated higher soil erosion potential, mainly due to their inverse relationship with land erodibility. Moreover, the higher values of stream frequency (15.7), drainage density (>5.0), drainage texture (7.48 km-1), and mean bifurcation ratio (4.08-6.33) indicated higher runoff potential, which would intensify the soil erosion, mainly due to their direct relationship with erodibility. Bifurcation ratio, elongation ratio, circulatory ratio, form factor, altogether indicated an elongated shape of the catchment with a fine drainage texture. The higher values of bifurcation ratio and texture ratio of the catchment also indicated severe overland flow (low infiltration rate) with a limited scope for groundwater recharge in the area, which in turn might significantly encourage the soil erosion. Overall, it was concluded that the catchment has a huge runoff potential resulting in high soil erosion due to its fine texture, impermeable subsurface material, steep slope, low infiltration rate, limited vegetation, longer duration of overland flow, and higher surface runoff. The morphometric analysis was found to be suitable for identifying catchment shape and the factors affecting hydrologic conditions and erodibility of the catchment. Thus, Geo-informatics based morphometric analysis of a reservoir catchment can be useful to study the erosion potential in relation to hydrologic (rainfall-runoff relationship) and other related land characteristics (e.g., relief, slope, infiltration rate, etc.).


2014 ◽  
Vol 78 (2) ◽  
pp. 589-597 ◽  
Author(s):  
Bing Wang ◽  
Guang-Hui Zhang ◽  
X.C. Zhang ◽  
Zhen-Wei Li ◽  
Zi-Long Su ◽  
...  

2020 ◽  
Author(s):  
Annie Ockelford ◽  
Joanna Bulalrd ◽  
Cheryl McKenna-Neuman ◽  
Patrick O'Brien

<p>Recent studies of soils in the Alps and Middle East indicate airborne transport of microplastics following wind erosion may be significant.  Where microplastics have been entrained by wind they show substantial enrichment ratios compared to mineral particle erosion.  Further, microplastic shape affects enrichment ratios with those for fibres greater than for microbeads which may reflect the lower density and asymmetric shape of microplastics compared to soil particles. This suggests that terrestrial to atmospheric transfer of microplastics could be a significant environmental transport pathway. However, currently we have very little understanding of how the properties, in particular the surface characteristics, of the sediment which they are being eroded from affects their entrainment potential.</p><p>This paper reports wind tunnel studies run to explore the impacts of soil surface characteristics on microplastic flux by wind erosion.  Experiments were performed in a boundary layer simulation wind tunnel with an open-loop suction design.  The tunnel has a working section of 12.5m x 0.7m x 0.76m and is housed in an environmental chamber which, for this study, was held constant at 20 <sup>o</sup>C and 20% RH. In experiments two types of low density microplastic (microbeads and fibres) were mixed into a poorly-sorted soil containing 13% organics.  The polyethylene microbeads had a size range of 212-250 microns and density of 1.2 g cm<sup>3</sup> and the polyester fibres were 5000 microns long and 500-1000 microns in width with a density of 1.38 g cm<sup>3</sup>.  Microplastics were mixed into the sediment in concentrations ranging from 40-1040 mg kg<sup>-1</sup>. For each experiment, test surfaces were prepared by filling a 1.0m x 0.35m x  0.025m metal tray with the given mixture of test material which was lowered into the wind tunnel such that it was flush with the tunnel floor and levelled. The wind tunnel was then switched on and run with increasing wind speeds using 0.25 m s<sup>-1</sup> increments until continuous saltation occurred.  Soil surface roughness was scanned prior to and after each experiment using a high resolution laser scanner (0.5mm resolution over the entire test section).  Transported soil and microplastic particles were captured in bulk using a 2 cm wide by 40 cm tall Guelph-Trent wedge trap that was positioned 2 m downwind of the test bed. </p><p>Discussion concentrates on linking the changes in soil surface topography to the magnitude of microplastic flux where data shows that there is a correlation between the development of the soil surfaces and overall microplastic flux.  Specifically, soil surface roughness is seen as a significant control on microplastic flux where it has a greater overall effect on microplastic fibre flux as compared to the microplastic beads.  The outcome of this research is pertinent to developing understanding surrounding the likely controls and hence propensity of microplastics to be entrained from soil by wind erosion.  </p>


2021 ◽  
Author(s):  
Annie Ockelford ◽  
Joanna Bullard ◽  
Cheryl McKenna Neuman ◽  
Patrick O'Brien

<p>Recent studies of soils in the Alps and Middle East indicate airborne transport of microplastics following wind erosion may be significant.  Where microplastics have been entrained by wind they show substantial enrichment ratios compared to mineral particle erosion.  Further, microplastic shape affects enrichment ratios with those for fibres greater than for microbeads which may reflect the lower density and asymmetric shape of microplastics compared to soil particles. This suggests that terrestrial to atmospheric transfer of microplastics could be a significant environmental transport pathway. However, currently we have very little understanding of how the properties, in particular the surface characteristics, of the sediment which they are being eroded from affects their entrainment potential.</p><p>This paper reports wind tunnel studies run to explore the impacts of soil surface characteristics on microplastic flux by wind erosion.  Experiments were performed in a boundary layer simulation wind tunnel with an open-loop suction design.  The tunnel has a working section of 12.5m x 0.7m x 0.76m and is housed in an environmental chamber which, for this study, was held constant at 20 <sup>o</sup>C and 20% RH. In experiments two types of low density microplastic (microbeads and fibres) were mixed into a poorly-sorted soil containing 13% organics.  The polyethylene microbeads had a size range of 212-250 microns and density of 1.2 g cm<sup>3</sup> and the polyester fibres were 5000 microns long and 500-1000 microns in width with a density of 1.38 g cm<sup>3</sup>.  Microplastics were mixed into the sediment in concentrations ranging from 40-1040 mg kg<sup>-1</sup>. For each experiment, test surfaces were prepared by filling a 1.0m x 0.35m x  0.025m metal tray with the given mixture of test material which was lowered into the wind tunnel such that it was flush with the tunnel floor and levelled. The wind tunnel was then switched on and run with increasing wind speeds using 0.25 m s<sup>-1</sup> increments until continuous saltation occurred.  Soil surface roughness was scanned prior to and after each experiment using a high resolution laser scanner (0.5mm resolution over the entire test section).  Transported soil and microplastic particles were captured in bulk using a 2 cm wide by 40 cm tall Guelph-Trent wedge trap that was positioned 2 m downwind of the test bed. </p><p>Discussion concentrates on linking the changes in soil surface topography to the magnitude of microplastic flux where data shows that there is a correlation between the development of the soil surfaces and overall microplastic flux.  Specifically, soil surface roughness is seen as a significant control on microplastic flux where it has a greater overall effect on microplastic fibre flux as compared to the microplastic beads.  The outcome of this research is pertinent to developing understanding surrounding the likely controls and hence propensity of microplastics to be entrained from soil by wind erosion. </p>


2016 ◽  
Vol 37 (3) ◽  
pp. 1155 ◽  
Author(s):  
Wander Cardoso Valim ◽  
Elói Panachuki ◽  
Dorly Scariot Pavei ◽  
Teodorico Alves Sobrinho ◽  
Wilk Sampaio Almeida

The cultivation of sugarcane uses different cropping systems that result in varying quantities of crop waste, this may influence soil erosion. The objective of this study was to evaluate the loss of soil and water, the infiltration rate, and soil surface roughness in an area cultivated with sugarcane (Saccharum spp.). Six treatments with different levels of plant waste were evaluated: sugarcane without plant waste; sugarcane with 4.0 Mg ha-1 of waste; sugarcane with 8.0 Mg ha-1 of waste; sugarcane with 12.0 Mg ha-1 of waste; sugarcane with 16.0 Mg ha-1 of waste; and burned sugarcane. The treatments were arranged in a randomized block design with four replications, totalling 24 experimental plots. As soil depth increased, there is reduction in macroporosity, total soil porosity, organic carbon content, mean geometric diameter and weighted mean diameter of the soil aggregates, whereas the bulk density of the soil displays the opposite trend. The presence of sugarcane waste on the soil surface increases the time required for the initiation of surface runoff. Sugarcane waste does not alter soil surface roughness, and at the minimum amount of waste administered (4 Mg ha-1) reduces losses of soil and water and increases the infiltration rate. The lack of soil surface coverage after harvesting the sugarcane contributes to soil and water loss, and reduces the rate of stable infiltration of water into the soil.


2013 ◽  
Vol 409-410 ◽  
pp. 339-343 ◽  
Author(s):  
Su Fang Cui ◽  
Ying Hua Pan ◽  
Quan Yuan Wu ◽  
Zhen Hua Zhang ◽  
Bao Xiang Zhang

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.


2005 ◽  
Vol 9 (5) ◽  
pp. 1-30 ◽  
Author(s):  
A. L. Presbitero ◽  
C. W. Rose ◽  
B. Yu ◽  
C. A. A. Ciesiolka ◽  
K. J. Coughlan ◽  
...  

Abstract At the Visayas State College of Agriculture (ViSCA) on the island of Leyte in the Philippines, hydrologic and soil-loss measurements were recorded for 32 erosion events over 3 yr on three 12-m-long bare soil plots with slopes of approximately 50%, 60%, and 70%. Measurements included rainfall and runoff rates at 1-min intervals, total soil lost per event from the plot, rill details when observed after an erosion event, and soil settling-velocity characteristics. Storm events are characterized by high rainfall rates but quite low rates of runoff, because of the consistently high infiltration rate of the stable clay soil (an Oxic Dystropept). Both observation and modeling indicated that overland flow is commonly so shallow that much of the soil surface is likely to be unsubmerged. For the 70% slope plot, half the events recorded mean sediment concentrations from 100 to 570 kg m−3. A somewhat constant hydrologic lag between rainfall and runoff is used to estimate a Manning’s roughness coefficient n of about 0.1 m−1/3 s, a value used to estimate velocity of overland flow. Possible effects of shallow flows and high sediment concentrations on existing erosion theory are investigated theoretically but are found to have only minor effects for the ViSCA dataset. A soil erodibility parameter β was evaluated for the data whenever rilling was recorded following an erosion event. The values of β indicate that, except for events with higher stream powers, other erosion processes in addition to overland flow could have contributed to soil loss from erosion plots in a significant number of events.


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