scholarly journals A Rainfall Simulator Used for Testing of Hydrological Performances of Micro-Detention Permeable Pavement

2018 ◽  
Vol 7 (3.18) ◽  
pp. 44 ◽  
Author(s):  
Norazlina Bateni ◽  
Sai Hin Lai ◽  
Frederik Josep Putuhena ◽  
Darrien Yau Seng Mah ◽  
Md Abdul Mannan
Keyword(s):  
Rainfall Intensity ◽  
Drainage System ◽  
Rainfall Simulator ◽  
Rainfall Characteristics ◽  
Permeable Pavement ◽  
Natural Rainfall ◽  
Spatial Uniformity ◽  
Free Drainage ◽  
Coefficient Of Uniformity ◽  
Raindrop Size

A rainfall simulator for laboratory experimentation is developed to test hydrological performances of micro-detention pond permeable pavement, MDPP. Rainfall characteristics consisting of rainfall intensity, spatial uniformity, raindrop size, and raindrop velocity show that natural rainfall is simulated with sufficient accuracy. The rainfall simulator used pressure nozzles to spray water for rainfall intensity from 40 to 220mm/hr. Uniformity distribution test gives coefficient of uniformity of 95% over an area of 1m2. The raindrops falling at velocity ranging from 0.5 to 15m/s with drop sizes diameter between 2 to 5mm. Free drainage system below the rainfall simulator is accompanied with outlet tanks attached with ultrasonic sensor devices to record the outflow data. During the experiments, the outflow received is 98% in average. Experiment results in typical runoff hydrograph and percolation rate of the MDPP system. This shows the ability of the rainfall simulator to obtain initial hydrology data to aid in the design of the MDPP prototype.  

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 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 Research on the Fine-Scale Spatial Uniformity of Natural Rainfall and Rainfall from a Rainfall Simulator with a Rotary Platform (RSRP)

Atmosphere ◽  
2017 ◽  
Vol 8 (12) ◽  
pp. 113
Author(s):  
Bo Liu ◽  
Xiaolei Wang ◽  
Lihua Shi ◽  
Xichuan Liu ◽  
Zhaojing Kang ◽  
...  
Keyword(s):  
Fine Scale ◽  
Rainfall Simulator ◽  
Natural Rainfall ◽  
Spatial Uniformity ◽  
Rotary Platform

scholarly journals Analysis of day rainfall characteristics of Zhengzhou

2018 ◽  
Vol 38 ◽  
pp. 01031 ◽  
Author(s):  
Zhenzhou Shen ◽  
Wenyi Yao ◽  
Peiqing Xiao ◽  
Xueqin Yang
Keyword(s):  
River Basin ◽  
Rainfall Intensity ◽  
Yellow River ◽  
Yellow River Basin ◽  
Terminal Velocity ◽  
Rainfall Characteristics ◽  
Loess Slope ◽  
Natural Rainfall ◽  
Peak Value

Raindrop characteristics, including speed and size of raindrops, in Zhengzhou city of Yellow River basin were analyzed through a natural rainfall on the loess slope. Results showed that the process of natural rainfall belonged to a parabola and counts, size and terminal velocity would increase with the rainfall intensity rising. Besides, the size and terminal velocity of natural raindrops were relatively scattered; In the process of individual rainfall, the terminal velocity and its peak value were mainly focused between 0.8~5m/s and 1m/s, respectively. Size of raindrops were mainly consisted of 0.125-0.5mm, among which the terminal velocity of raindrops with a size of 0.125mm, 0.25mm, 0.375mm, 0.5mm were primarily 0.8-3.4m/s, 0.6-3.4m/s, 0.8-1m/s, 1-1.4m/s, respectively.

Concept of a New Pluviometer for Metering Rainfall Erosivity

2012 ◽  
Vol 452-453 ◽  
pp. 316-320 ◽  
Author(s):  
Andrea Alaimo ◽  
Mauro De Marchis ◽  
Gabriele Freni ◽  
Antonio Messineo ◽  
Dario Ticali
Keyword(s):  
Rainfall Intensity ◽  
Rainfall Erosivity ◽  
Natural Phenomena ◽  
Limited Data ◽  
Empirical Relationships ◽  
Rainfall Characteristics ◽  
Natural Rainfall ◽  
Main Driver ◽  
Raindrop Splash ◽  
The Impact

Rainfall is the main driver of several natural phenomena having a large impact on human activities. Its monitoring is then very important for natural disaster prevention and for the preservation of the environment. One important phenomenon is related to soil displacement due to rainfall impact. The intensity of physical soil degradation, detachment and transport of soil particles by raindrop splash and interrill erosion is largely controlled by rainfall characteristics. There is still a lot of debate as to whichparameter expresses the best rainfall erosivity. Due to the limited data ondrop-size distribution of natural rainfall and the time consuming nature of methods to obtain these data, rain erosivity parameters are commonly obtained from empirical relationships based on rainfall intensity. This paper describes an a new pluviometer able to measure several raindrop variables and assess rainfall kinetic energy at the impact with the ground. It enables one to measure drop size and drop velocity in real time and thus any parameter linked to rainfall erosivity. The pluviometer is based on the combination of optical and electrical sensors and it is based on cheap technologies in order to allow the easy distribution of several monitoring station on the analyzed area. A description of the device and of its sensor is presented in the present paper.

A multi-purpose rainfall simulator for field infiltration and erosion studies

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 599 ◽  
Author(s):  
R. J. Loch ◽  
B. G. Robotham ◽  
L. Zeller ◽  
N. Masterman ◽  
D. N. Orange ◽  
...  
Keyword(s):  
Rainfall Intensity ◽  
The Body ◽  
Effective Rainfall ◽  
Laboratory Studies ◽  
Great Flexibility ◽  
Rainfall Simulator ◽  
Plot Size ◽  
Spatial Uniformity ◽  
Coefficients Of Variation ◽  
Steep Slopes

This paper describes a rainfall simulator developed for field and laboratory studies that gives great flexibility in plot size covered, that is highly portable and able to be used on steep slopes, and that is economical in its water use. The simulator uses Veejet 80100 nozzles mounted on a manifold, with the nozzles controlled to sweep to and from across a plot width of 1.5 m. Effective rainfall intensity is controlled by the frequency with which the nozzles sweep. Spatial uniformity of rainfall on the plots is high, with coefficients of variation (CV) on the body of the plot being 8–10%. Use of the simulator for erosion and infiltration measurements is discussed.

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 Development and Calibration of a New Dripper-Based Rainfall Simulator for Large-Scale Sediment Wash-Off Studies

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 152
Author(s):  
Juan Naves ◽  
Jose Anta ◽  
Joaquín Suárez ◽  
Jerónimo Puertas
Keyword(s):  
Physical Model ◽  
Large Scale ◽  
Terminal Velocity ◽  
Final Solution ◽  
Rainfall Simulator ◽  
Natural Rainfall ◽  
Raindrop Size Distribution ◽  
Wide Range ◽  
The Mean ◽  
Raindrop Size

Rainfall simulators are useful tools for controlling the main variables that govern natural rainfall. In this study, a new drop-forming rainfall simulator, which consists of pressure-compensating dripper grids above a horizontal mesh that breaks and distributes raindrops, was developed to be applied in wash-off experiments in a large-scale physical model of 36 m2. The mesh typology and size, and its distance to drippers, were established through a calibration where rain uniformity and distributions of raindrop sizes and velocities were compared with local natural rainfall. Finally, the rain properties of the final solution were measured for the three rain intensities that the rainfall simulator is able to generate (30, 50 and 80 mm/h), obtaining almost uniform rainfalls with uniformity coefficients of 81%, 89% and 91%, respectively. This, together with the very suitable raindrop size distribution obtained, and the raindrop velocities of around 87.5% of the terminal velocity for the mean raindrop diameter, makes the proposed solution optimal for wash-off studies, where rain properties are key in the detachment of particles. In addition, the flexibility seen in controlling rain characteristics increases the value of the proposed design in that it is adaptable to a wide range of studies.

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

Sign in / Sign up

Export Citation Format

Share Document