scholarly journals Set-up and calibration of a portable small scale rainfall simulator for assessing soil erosion processes at interrill scale

2017 ◽  
Vol 43 (1) ◽  
pp. 63 ◽  
Author(s):  
J. J. Zemke
Keyword(s):  
Soil Erosion ◽  
Kinetic Energy ◽  
Rainfall Intensity ◽  
Small Scale ◽  
Rainfall Erosivity ◽  
Fall Velocity ◽  
Rainfall Simulator ◽  
Spatial Homogeneity ◽  
Erosion Processes ◽  
Natural Rainfall

A portable rainfall simulator was built for assessing runoff and soil erosion processes at interrill scale. Within this study, requirements and constraints of the rainfall simulator are identified and discussed. The focus lies on the calibration of the simulator with regard to spatial rainfall homogeneity, rainfall intensity, drop size, drop fall velocity and rainfall kinetic energy. These parameters were obtained using different methods including a Laser Precipitation Monitor. A detailed presentation of the operational characteristics is given. The presented rainfall simulator setup featured a rainfall intensity of 45.4 mm·h-1 with a spatial homogeneity of 80.4% based on a plot area of 0.64 m². Because of the comparatively low drop height (2 m), the diameter-dependent terminal fall velocity (1.87 m·s-1) was lower than benchmark values for natural rainfall. This conditioned also a reduced rainfall kinetic energy (4.6 J·m-2·mm-1) compared to natural rainfall with same intensity. These shortfalls, a common phenomenon concerning portable rainfall simulators, represented the best possible trade-off between all relevant rainfall parameters obtained with the given simulator setup. Field experiments proved that the rainfall erosivity was constant and replicable.

scholarly journals Measurement and computation of kinetic energy of simulated rainfall in comparison with natural rainfall

2018 ◽  
Vol 13 (No. 4) ◽  
pp. 226-233 ◽  
Author(s):  
Petrů Jan ◽  
Kalibová Jana
Keyword(s):  
Kinetic Energy ◽  
Drop Size ◽  
Rainfall Intensity ◽  
Soil Aggregates ◽  
Meteorological Parameter ◽  
Simulated Rainfall ◽  
Fall Velocity ◽  
Rainfall Simulator ◽  
Rainfall Characteristics ◽  
Natural Rainfall

Rainfall characteristics such as total amount and rainfall intensity (I) are important inputs in calculating the kinetic energy (KE) of rainfall. Although KE is a crucial indicator of the raindrop potential to disrupt soil aggregates, it is not a routinely measured meteorological parameter. Therefore, KE is derived from easily accessible variables, such as I, in empirical laws. The present study examines whether the equations which had been derived to calculate KE of natural rainfall are suitable for the calculation of KE of simulated rainfall. During the experiment presented in this paper, the measurement of rainfall characteristics was carried out under laboratory conditions using a rainfall simulator. In total, 90 measurements were performed and evaluated to describe the rainfall intensity, drop size distribution and velocity of rain drops using the Thies laser disdrometer. The duration of each measurement of rainfall event was 5 minutes. Drop size and fall velocity were used to calculate KE and to derive a new equation of time-specific kinetic energy (KE<sub>time</sub> – I). When comparing the newly derived equation for KE of simulated rainfall with the six most commonly used equations for KE<sub>time</sub> – I of natural rainfall, KE of simulated rainfall was discovered to be underestimated. The higher the rainfall intensity, the higher the rate of underestimation. KE of natural rainfall derived from theoretical equations exceeded KE of simulated rainfall by 53–83% for I = 30 mm/h and by 119–275% for I = 60 mm/h. The underestimation of KE of simulated rainfall is probably caused by smaller drops formed by the rainfall simulator at higher intensities (94% of all drops were smaller than 1 mm), which is not typical of natural rainfall.

scholarly journals Measurement and computation of kinetic energy of simulated rainfall in comparison with natural rainfall.

2018 ◽  
Author(s):  
Petrů Jan ◽  
Kalibová Jana
Keyword(s):  
Kinetic Energy ◽  
Drop Size ◽  
Rainfall Intensity ◽  
Soil Aggregates ◽  
Meteorological Parameter ◽  
Simulated Rainfall ◽  
Fall Velocity ◽  
Rainfall Simulator ◽  
Rainfall Characteristics ◽  
Natural Rainfall

Rainfall characteristics such as total amount and rainfall intensity (I) are important inputs in calculating the kinetic energy (KE) of rainfall. Although KE is a crucial indicator of the raindrop potential to disrupt soil aggregates, it is not a routinely measured meteorological parameter. Therefore, KE is derived from easily accessible variables, such as I, in empirical laws. The present study examines whether the equations which had been derived to calculate KE of natural rainfall are suitable for the calculation of KE of simulated rainfall. During the experiment presented in this paper, the measurement of rainfall characteristics was carried out under laboratory conditions using a rainfall simulator. In total, 90 measurements were performed and evaluated to describe the rainfall intensity, drop size distribution and velocity of rain drops using the Thies laser disdrometer. The duration of each measurement of rainfall event was 5 minutes. Drop size and fall velocity were used to calculate KE and to derive a new equation of time-specific kinetic energy (KE<sub>time</sub> – I). When comparing the newly derived equation for KE of simulated rainfall with the six most commonly used equations for KE<sub>time</sub> – I of natural rainfall, KE of simulated rainfall was discovered to be underestimated. The higher the rainfall intensity, the higher the rate of underestimation. KE of natural rainfall derived from theoretical equations exceeded KE of simulated rainfall by 53–83% for I = 30 mm/h and by 119–275% for I = 60 mm/h. The underestimation of KE of simulated rainfall is probably caused by smaller drops formed by the rainfall simulator at higher intensities (94% of all drops were smaller than 1 mm), which is not typical of natural rainfall.  

scholarly journals Rainfall Erosivity in Soil Erosion Processes

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 722
Author(s):  
Gianni Bellocchi ◽  
Nazzareno Diodato
Keyword(s):  
Soil Erosion ◽  
Construction Projects ◽  
Water Resource Management ◽  
Large Scale ◽  
Rainfall Erosivity ◽  
Special Issue ◽  
Environmental Consequences ◽  
Erosion Processes ◽  
Natural Rainfall ◽  
Raindrop Energy

Regional studies on the erosive power of rainfall patterns are still limited and the actual impacts that may follow on erosional and sedimentation processes are poorly understood. Given the several interrelated challenges of environmental management, it is also not always unclear what is relevant for the development of adaptive and integrated approaches facilitating sustainable water resource management. This editorial introduces the Special Issue entitled “Rainfall Erosivity in Soil Erosion Processes”, which offers options to fill some of these gaps. Three studies performed in China and Central Asia (by Duulatov et al., Water 2019, 11, 897, Xu et al., 2019, 11, 2429, Gu et al. 2020, 12, 200) show that the erosion potential of rainfall is increasing in this region, driving social, economic, and environmental consequences. In the same region (the Weibei Plateau in China), Fu et al. (Water 2019, 11, 1514) assessed the effect of raindrop energy on the splash distance and particle size distribution of aggregate splash erosion. In the Mediterranean, updated estimates of current and future rainfall erosivity for Greece are provided by Vantas et al. (Water 2020, 12, 687), while Diodato and Bellocchi (Water 2019, 11, 2306) reconstructed and investigated seasonal net erosion in an Italian catchment using parsimonious modelling. Then, this Special Issue includes two technologically oriented articles by Ricks at al. The first (Water 2019, 11, 2386) evaluated a large-scale rainfall simulator design to simulate rainfall with characteristics similar to natural rainfall. The data provided contribute to the information that may be useful for the government’s decision making when considering landscape changes caused by variations in the intensity of a rainfall event. The second article (Water 2020, 12, 515) illustrated a laboratory-scale test of mulching methods to protect against the discharge of sediment-laden stormwater from active construction sites (e.g., highway construction projects).

Fabrication and study of laboratory scale rainfall simulator for soil erosion assessment

2021 ◽  
Vol 8 (2) ◽  
pp. 139-142
Author(s):  
SRIVALLI CHERAKU ◽  
P SWATHI ◽  
Y SUSHMITHA ◽  
D PRANEETHA ◽  
CH RADHA SRIVALLI
Keyword(s):  
Soil Erosion ◽  
Rainfall Intensity ◽  
Slope Angle ◽  
Laboratory Scale ◽  
Rainfall Simulator ◽  
Research Areas ◽  
Natural Rainfall ◽  
Spatial Uniformity ◽  
Ideal Tool ◽  
Raindrop Size

A rainfall simulator is an ideal tool for infiltration, soil erosion and other related research areas for replicating the process and characteristics of natural rainfall. The present paper describes the design of a comprehensive rainfall simulator. In this study a laboratory scale rainfall simulator is developed, which is particularly meant for the assessment of soil erosion at plot scale by considering various soil grain types, soil slope angles and surface exposures under different rainfall conditions. The Rainfall characteristics including the rainfall intensity and its spatial uniformity raindrop size and kinetic energy confirm that natural rainfall conditions are simulated with sufficient accuracy. The comparative measurement was carried out in a laboratory using rainfall simulator fabricated of 4 feet length and 2.5 feet width, where the applied slope angle is 3% with 39 mm/hr rainfall intensity. The runoff and soil loss for different samples were assessed by conducting number of trials. From the results it was found that the soil tilled and keeping it as a bare plot is more prone to runoff compared to soil without tilled and straw mulching has helped to reduce the runoff by 57% as compared to soil without mulching.  

scholarly journals Rainfall Parameters Affecting Splash Erosion under Natural Conditions

2020 ◽  
Vol 10 (12) ◽  
pp. 4103 ◽  
Author(s):  
Nives Zambon ◽  
Lisbeth Lolk Johannsen ◽  
Peter Strauss ◽  
Tomas Dostal ◽  
David Zumr ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Kinetic Energy ◽  
Linear Function ◽  
Rain Gauge ◽  
Total Kinetic Energy ◽  
Rainfall Erosivity ◽  
Erosion Process ◽  
Good Tool ◽  
Splash Erosion ◽  
Natural Rainfall

The interaction between rainfall erosivity parameters and splash erosion is crucial for describing the soil erosion process; however, it is rarely investigated under natural rainfall conditions. In this study, we conducted splash erosion experiments under natural rainfall on three sites in Central Europe. The main goal was to obtain the relationship between splash erosion of the bare soil in seedbed condition and commonly used rainfall erosivity parameters (kinetic energy, intensity, and rainfall erosivity (EI30)). All sites were equipped with a rain gauge and an optical laser disdrometer where the splash erosion was measured, with modified Morgan splash cups. In order to investigate which parameter best describes the splash erosion process for all sites, a regression analysis was performed. In total, 80 splash erosion events were evaluated. Splash erosion can be described as a linear function of total kinetic energy and a non-linear function of EI30. However, the use of the total kinetic energy led to underestimation of the splash erosion rates for highly intensive rainfalls. Therefore, better results were obtained when using average rainfall intensity as the splash erosion predictor or the kinetic energy divided by the rainfall duration. Minor differences between the replicates during splash erosion measurements indicate that the modified Morgan splash cup provides a good tool for soil erosion assessment.

Estimating storm erosion with a rainfall simulator

1997 ◽  
Vol 77 (4) ◽  
pp. 669-676 ◽  
Author(s):  
S. C. Nolan ◽  
L. J. P. van Vliet ◽  
T. W. Goddard ◽  
T. K. Flesch
Keyword(s):  
Soil Loss ◽  
Conventional Tillage ◽  
Reduced Tillage ◽  
Natural Soil ◽  
Rainfall Erosivity ◽  
Slope Length ◽  
Rainfall Simulator ◽  
Rainfall Events ◽  
Plot Size ◽  
Natural Rainfall

Interpreting soil loss from rainfall simulators is complicated by the uncertain relationship between simulated and natural rainstorms. Our objective was to develop and test a method for estimating soil loss from natural rainfall using a portable rainfall simulator (1 m2 plot size). Soil loss from 12 rainstorms was measured on 144-m2 plots with barley residue in conventional tillage (CT), reduced tillage (RT) and zero tillage (ZT) conditions. A corresponding "simulated" soil loss was calculated by matching the simulator erosivity to each storm's erosivity. High (140 mm h−1) and low (60 mm h−1) simulation intensities were examined. The best agreement between simulated and natural soil loss occurred using the low intensity, after making three adjustments. The first was to compensate for the 38% lower kinetic energy of the simulator compared with natural rain. The second was for the smaller slope length of the simulator plot. The third was to begin calculating simulator erosivity only after runoff began. After these adjustments, the simulated soil loss over all storms was 99% of the natural soil loss for CT, 112% for RT and 95% for ZT. Our results show that rainfall simulators can successfully estimate soil loss from natural rainfall events. Key words: Natural rainfall events, simulated rainfall, erosivity, tillage

scholarly journals Modelling Effects of Rainfall Patterns on Runoff Generation and Soil Erosion Processes on Slopes

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2221
Author(s):  
Qihua Ran ◽  
Feng Wang ◽  
Jihui Gao
Keyword(s):  
Soil Erosion ◽  
Rainfall Intensity ◽  
Temporal Patterns ◽  
Runoff Generation ◽  
Slope Length ◽  
Erosion Processes ◽  
Total Runoff ◽  
Wide Range ◽  
Critical Slope ◽  
Rainfall Patterns

Rainfall patterns and landform characteristics are controlling factors in runoff and soil erosion processes. At a hillslope scale, there is still a lack of understanding of how rainfall temporal patterns affect these processes, especially on slopes with a wide range of gradients and length scales. Using a physically-based distributed hydrological model (InHM), these processes under different rainfall temporal patterns were simulated to illustrate this issue. Five rainfall patterns (constant, increasing, decreasing, rising-falling and falling-rising) were applied to slopes, whose gradients range from 5° to 40° and projective slope lengths range from 25 m to 200 m. The rising-falling rainfall generally had the largest total runoff and soil erosion amount; while the constant rainfall had the lowest ones when the projective slope length was less than 100 m. The critical slope of total runoff was 15°, which was independent of rainfall pattern and slope length. However, the critical slope of soil erosion amount decreased from 35° to 25° with increasing projective slope length. The increasing rainfall had the highest peak discharge and erosion rate just at the end of the peak rainfall intensity. The peak value discharges and erosion rates of decreasing and rising-falling rainfalls were several minutes later than the peak rainfall intensity.

scholarly journals Estimation of rainfall erosivity based on WRF-derived raindrop size distributions

2020 ◽  
Vol 24 (11) ◽  
pp. 5407-5422
Author(s):  
Qiang Dai ◽  
Jingxuan Zhu ◽  
Shuliang Zhang ◽  
Shaonan Zhu ◽  
Dawei Han ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Kinetic Energy ◽  
Water Conservation ◽  
Large Scale ◽  
Weather Prediction ◽  
Wrf Model ◽  
Analysis Data ◽  
Rainfall Erosivity ◽  
Size Distributions ◽  
Raindrop Size

Abstract. Soil erosion can cause various ecological problems, such as land degradation, soil fertility loss, and river siltation. Rainfall is the primary water-driven force for soil erosion, and its potential effect on soil erosion is reflected by rainfall erosivity that relates to the raindrop kinetic energy. As it is difficult to observe large-scale dynamic characteristics of raindrops, all the current rainfall erosivity models use the function based on rainfall amount to represent the raindrops' kinetic energy. With the development of global atmospheric re-analysis data, numerical weather prediction techniques become a promising way to estimate rainfall kinetic energy directly at regional and global scales with high spatial and temporal resolutions. This study proposed a novel method for large-scale and long-term rainfall erosivity investigations based on the Weather Research and Forecasting (WRF) model, avoiding errors caused by inappropriate rainfall–energy relationships and large-scale interpolation. We adopted three microphysical parameterizations schemes (Morrison, WDM6, and Thompson aerosol-aware) to obtain raindrop size distributions, rainfall kinetic energy, and rainfall erosivity, with validation by two disdrometers and 304 rain gauges around the United Kingdom. Among the three WRF schemes, Thompson aerosol-aware had the best performance compared with the disdrometers at a monthly scale. The results revealed that high rainfall erosivity occurred in the west coast area at the whole country scale during 2013–2017. The proposed methodology makes a significant contribution to improving large-scale soil erosion estimation and for better understanding microphysical rainfall–soil interactions to support the rational formulation of soil and water conservation planning.

scholarly journals Comparison between sprinkler irrigation and natural rainfall based on droplet diameter

2016 ◽  
Vol 14 (1) ◽  
pp. e1201 ◽  
Author(s):  
MaoSheng Ge ◽  
Pute Wu ◽  
Delan Zhu ◽  
Daniel P. Ames
Keyword(s):  
Soil Erosion ◽  
Kinetic Energy ◽  
Droplet Diameter ◽  
Vertical Component ◽  
Radial Distance ◽  
Sprinkler Irrigation ◽  
Application Rate ◽  
Horizontal Component ◽  
Natural Rainfall ◽  
Actual Field

<p>An indoor experiment was conducted to analyze the movement characteristics of different sized droplets and their influence on water application rate distribution and kinetic energy distribution. Radial droplets emitted from a Nelson D3000 sprinkler nozzle under 66.3, 84.8, and 103.3 kPa were measured in terms of droplet velocity, landing angle, and droplet kinetic energy and results were compared to natural rainfall characteristics. Results indicate that sprinkler irrigation droplet landing velocity for all sizes of droplets is not related to nozzle pressure and the values of landing velocity are very close to that of natural rainfall. The velocity horizontal component increases with radial distance while the velocity vertical component decreases with radial distance. Additionally, landing angle of all droplet sizes decreases with radial distance. The kinetic energy is decomposed into vertical component and horizontal component due to the oblique angles of droplet impact on the surface soil, and this may aggravate soil erosion. Therefore the actual oblique angle of impact should be considered in actual field conditions and measures should be taken for remediation of soil erosion if necessary.</p>

scholarly journals Impact of Wheat Residue on Soil Erosion Processes

2018 ◽  
Vol 46 (2) ◽  
pp. 553-562 ◽  
Author(s):  
Ataollah KAVIAN ◽  
Leila GHOLAMI ◽  
Maziar MOHAMMADI ◽  
Velibor SPALEVIC ◽  
Moghadeseh FALAH SORAKI
Keyword(s):  
Soil Erosion ◽  
Water Conservation ◽  
Soil Conservation ◽  
Rainfall Intensity ◽  
Sandy Loam ◽  
Sediment Concentration ◽  
Runoff Coefficient ◽  
Northern Iran ◽  
Erosion Processes ◽  
Loam Soil

Soil erosion is one of the key challenges in soil and water conservation. Vegetation that covers soil and organic and inorganic mulch is very useful for the control of erosion processes. This study examined treatment with wheat residual (as agriculture mulch) on infiltration, time to runoff, runoff coefficient, sediment concentration and soil erosion processes. The study has been conducted for sandy-loam soil taken from summer rangeland (Northern Iran) with simulated rainfall intensities of 50 and 100 mm h-1. The experiment was conducted in slopes of 30% in three replications with two amounts of wheat residual of 50 and 90 %. The results showed that conservation percent of soil erosion for wheat residual 50 and 90% was 61.68 and 73.25%, respectively (in rainfall intensity of 50 mm h-1). Also, the conservation percent of soil erosion for wheat residual of 50 and 90% cover was 70.68 and 90.55, respectively (in rainfall intensity of 100 mm h-1). It was concluded that the conservation treatments could reduce runoff coefficient, sediment concentration and soil erosion and increase the time to runoff and infiltration coefficient. This effect was significant on time for infiltration, sediment concentration and soil erosion variables (R2=0.99), time to runoff and runoff coefficient variables (R2=0.95). The interaction effects of rainfall intensity and soil conservation was significant for sediment concentration and soil erosion variables (R2=0.99).

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