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Rainfall erosion can cause environmental and economic damage by decreasing the storage capacity of water reservoirs because of the detachment of soil particles. The purpose of this study was to develop a one-dimensional physicomathematical model that can help predict the effects of rainfall erosion on the banks of water reservoirs. The model was developed using the Mein–Larson model to describe water infiltration, the kinematic wave approximation to represent overland flow generation, and the steady state sediment continuity equation to estimate sediment transport. The model was validated using rainfall simulator tests and lateritic soil samples with a bimodal soil–water retention curve. The results showed conformity with the experimental data, identifying a threshold in the models for discharge per unit area and sediment yield rate, as well as a linear increase in the models for total runoff and sediment load per unit area. However, the model failed to capture the peak in sediment yield rate owing to raindrop impact during the initial minutes of rainfall. Parametric analysis highlighted the impact of increasing the calibration constant of splash erosion, erodibility coefficient, and critical shear stress on the slope of the sediment load per unit area model. Despite its limitations, the model demonstrates satisfactory predictive capability for sediment load per unit area under high-intensity rainfalls, achieving an R2 greater than 0.92 in five of the six cases examined. [ABSTRACT FROM AUTHOR]

Dripping rainfall simulators (DRS) for soil research generate water drops with different types of drippers, but metal tubes are most commonly used, often in the form of hypodermic needles. However, scientific papers using dripping rainfall simulators are often incomplete in terms of data on hypodermic needle characteristics, as well as data on drops produced by hypodermic needles under different water pressures. This study determines which drop sizes and dripping speeds are generated by various hypodermic needles at different water pressures. For the purpose of this study, a dripping rainfall simulator was designed and constructed for laboratory use. Water drops were generated with 11 different needles, ranging in size from 16 G to 32 G (tube gauge number), at different water pressures. Measured water drop sizes ranged from 1.42 to 3.69 mm at a dripping speed between 10 and 360 drops per minute and water head from 14 to over 1970 mm. Measured drop sizes, supplemented with data from previous studies, provided information on the relation between drop sizes and the size of the hypodermic needles. Van Boxel's numerical model provided estimations of the fall velocity for different drop diameters and their kinetic energy for falling heights up to 11.5 m. The results of this research can be used to design dripping rainfall simulators for soil research. [ABSTRACT FROM AUTHOR]

During the normal operation of the Huangdeng Hydropower Station's reservoir, many tensile cracks were observed on the surface of the bank slope below the elevation of 1805 m along the highway, causing significant damage to local residents' production and lives. On-site geological investigation, surface and inclinometer displacement monitoring were carried out, and the deformation characteristics of the Cheyiping landslide were analyzed. A controllable intensity rainfall simulator and a reservoir water level variation simulation system were designed in our laboratory. The lower section of the highway along the river in Cheyiping small village was chosen as the prototype, and a centrifuge model test of the reactivation of the Cheyiping ancient landslide induced by rainfall and reservoir water level fluctuations was performed. The characteristics of landslide deformation, pore water pressure, and earth pressure variation under the influence of rainfall and reservoir water level changes are investigated. The thorough analysis revealed that, even if the sliding surface is not deep, the sudden drop in reservoir water level remains the primary controlling factor of slope sliding. Because the permeability of the deposit is low, rainfall has a minor impact on this ancient landslide. The experimental results can be used to guide slope prevention and reservoir management in the Huangdeng Reservoir area. [ABSTRACT FROM AUTHOR]

Trapezoidal hyetographs are common in both real-world small watersheds and laboratory watersheds because (1) real-world hyetographs are often represented by line charts that can be divided into multiple trapezoidal rainfall pulses, and (2) laboratory rainfalls are usually generated by rainfall simulators uniformly in space and time, but when considering infiltration loss, the excess hyetographs may be approximated to be trapezoidal. Particularly, a trapezoidal hyetograph can be converted to a runoff hydrograph simply, accurately, and theoretically based on the general unit hydrograph model. The objective of this research is thus to test the theoretical trapezoidal hyetograph method with laboratory watershed rainfall-runoff data. The results showed that this theoretical method agrees very well with laboratory watershed data, with determination coefficients r2>0.93 for both constant and variable (incident) rainfall intensities. Therefore, the trapezoidal hyetograph method can be used to convert any line-chart hyetograph to a runoff hydrograph analytically, where rectangular and triangular hyetographs are special cases. Finally, the trapezoidal hyetograph method for a constant excess rainfall intensity (or the general rational method) is comparable to the classic kinematic wave theory for overland flow, but it is much simpler in applications. [ABSTRACT FROM AUTHOR]

The results of the energetic characterization of two drip-type rainfall simulators, differing in the length of their capillary tubes, are presented. The rainfall kinetic power and momentum were measured using a single capillary tube and applying weighing and photographic techniques to determine the raindrop mean equivalent diameter and fall velocity, respectively. The measurements highlighted that the simulated rainfall intensity is the only variable affecting raindrop diameter, and the increase in the capillary tube length produces a reduction in rainfall intensity and raindrop diameter. Finally, an empirical relationship relating fall velocity with raindrop falling height and diameter found in the literature was developed and positively tested using both the experimental data of the velocity measurements from the present research and the literature. Relationships to estimate the rainfall kinetic power and momentum based on the knowledge of mass and raindrop falling height were proposed and positively tested for the two simulators in the present investigation. In conclusion, operative guidelines for a drip-type simulator characterization are proposed in this paper, considering that the knowledge of the geometric characteristics of the capillary tube, pressure head, and falling height values are fundamental to having a complete energetic characterization of the rainfall simulator. [ABSTRACT FROM AUTHOR]

Rainfall properties and drop spectra characterization is essential when designing and using rainfall simulators to properly replicate natural rainfall characteristics. This study considered a small-scale rainfall simulator operating under varying nozzle, pressure and rotating disc scenarios. A dynamic rainfall gauge system developed at the Federal University of Lavras was used to quantify the impact velocity of rainfall droplets and kinetic energy, and to conduct radial uniformity analyses. The results showed that the rainfall intensity, impact velocity of droplets, kinetic energy, and uniformity of distribution of rainfall are influenced by effects of the spray nozzle, operating pressure and the rotating disc opening of the rainfall simulator. Lower values of simulated rainfall kinetic energy were observed compared to the empirical natural rainfall kinetic energy at equivalent rainfall intensities. This paper highlights the influence of rainfall simulator design specifications on resultant rainfall spectra and validates simulated rainfall against empirically based natural rainfall characteristics. [ABSTRACT FROM AUTHOR]

The saturated hydraulic conductivity (Ks) plays a crucial role in understanding water entry, redistribution, and hydrological processes at the soil–atmosphere interface. This study compared head-based [mini disk infiltrometer (MDI), automated SATURO, and laboratory permeameter (PM)] and flux-based [rainfall simulator (RS)] methods for determining near-surface Ks through controlled laboratory measurements. Results showed that Ks from RS aligned well with SATURO and PM estimates. The empirical MDI method (MDI-emp) provided Ks estimates one order of magnitude higher than other methods, while an inverse estimation procedure using MDI measurements (MDI-inv) yielded results consistent with other methods. Statistical tests endorsed these findings. Three key conclusions were derived: (i) SATURO, RS, and MDI-inv were consistent in determining near-surface Ks, (ii) RS was sensitive to the mathematical formulation adopted for Ks determination, and (iii) MDI-emp method was unreliable for Ks estimation. These findings underscore the potential of SATURO and MDI-inv as handy methods for Ks evaluation. [ABSTRACT FROM AUTHOR]

Nowadays, when the human impact on the environment becomes prominent daily, specific steps are needed to mitigate or halt those changes. By far, agricultural land is most affected by the degradation process, leading to soil erosion and decreased soil quality. Sustainable measures are needed to find a solution to that problem. This study, located in an agricultural area in northwestern Croatia, gives an insight into how different tillage systems (conventional and conservation) with the addition of manure will affect soil physicochemical properties, hydrology response, and overall yield. To assess hydrological response, a rainfall simulator was used; meanwhile, soil samples were taken to determine bulk density, soil water content, water-stable aggregates, and soil organic matter. Soil water content did not show significant differences, whereas bulk density and penetration resistance yielded significantly higher values at 15–30 cm depth compared to 0–15 cm depth. Also, the conservation manure recorded lower bulk density and penetration resistance values than conventional tilled treatments. Water-stable aggregates and soil organic matter were severely affected by manure addition and yielded an increase after harvest. Hydrological response was delayed for the treatments with manure addition. Crop yield was also significantly higher for the conventional treatment with manure addition, whereas the control plots had lower yields. The results of this study show the positive aspects of conservation tillage, especially with manure addition, where soil quality is preserved or even increased. [ABSTRACT FROM AUTHOR]

To identify the key parameters and develop accurate experimental models of detachment and transport, splash detachment and transport of loess soil were investigated in relation to the rainfall characteristics and slope. The experiment was conducted under 25 combinations of five rainfall intensities (60, 84, 108, 132 and 156 mm h−1) and five slope gradients (0°, 5°, 10°, 15° and 20°), using a custom splash pan. Raindrop characteristics (diameter, velocity and kinetics) and splash mass were measured in downslope and upslope. The results indicated that rainfall intensity and slope contributed 94.77% and 0.46%, respectively, to the detachment rate, and 24.39% and 67.82%, respectively, to the transport rate. From a holistic viewpoint, the positive effect of slope became more visible on the detachment rate when the rainfall intensity exceeded 108 mm h−1, and on the transport rate when the slope exceeded 15°. Based on the rainfall simulator in this study, the rainfall kinetic energy (KE, J), raindrop median particle size (D50, mm) and raindrop terminal velocity (V, m s−1) all increased with increasing rainfall intensity (I) within the 60~108 mm h−1 range but decreased with increasing rainfall intensity within the 132~156 mm h−1 range. The rainfall intensity and raindrop characteristics (D50/V/KE) are the key parameters of splash detachment (Dr, g·m−2 min−1), and three detachment models were developed: (1) Dr = 0.1153 I1.09D500.79 (R2 = 0.99, NSE = 0.98, p < 0.01); (2) Dr = 0.0162 I1.11V1.22 (R2 = 0.99, NSE = 0.99, p < 0.01); and (3) Dr = 0.0813 I1.10KE0.18 (R2 = 0.99, NSE = 0.99, p < 0.01). The rainfall intensity and slope are the key parameters for splash transport (Tr, g·m−2 min−1), and the developed transport models could be expressed as: (1) Tr = 0.00657 I1.343S0.116 (R2 = 0.914, NSE = 0.874, p < 0.01) (slopes of 0°, 5° and 10°) and (2) Tr = 0.00218 I1.165S1.033 (R2 = 0.986, NSE = 0.986, p < 0.01) (slopes of 15° and 20°). The results of this study could enhance the understanding of soil splash detachment and transport on loess slopes. [ABSTRACT FROM AUTHOR]

Flooding associated with Hurricane Maria in 2017 had devastating consequences for lives and livelihoods in Puerto Rico. Yet, an understanding of current and future flood risk on small islands like Puerto Rico is limited. Thus, efforts to build resilience to flooding associated with hurricanes remain constrained. Here, we take an event set of hurricane rainfall estimates from a synthetic hurricane rainfall simulator as the input to an event-based rainfall-driven flood inundation model using the hydrodynamic code LISFLOOD-FP. Validation of our model against high-water-mark data for Hurricane Maria demonstrates the suitability of this model for estimating flood hazard in Puerto Rico. We produce event-based flood hazard and population exposure estimates for the present day and the future under the 1.5 and 2 ∘C Paris Agreement goals. Population exposure to flooding from hurricane rainfall in Puerto Rico for the present-day climate is approximately 8 %–10 % of the current population for a 5-year return period, with an increase in population exposure to flooding by 2 %–15 % and 1 %–20 % under 1.5 and 2 ∘C futures (5-year return period). This research demonstrates the significance of the 1.5 ∘C Paris Agreement goal for Small Island Developing States, providing the first event-based estimates of flooding from hurricane rainfall under climate change for a small island. [ABSTRACT FROM AUTHOR]

Purpose: Soil erosion is a complex global environmental problem as it leads to land degradation, increase in sedimentation, triggering landslides, and pollution of the water bodies. Due to their adaptability, economy, and sustainability, nature-based mitigation strategies for erosion prevention have recently been renewed and developed. However, the effectiveness of the mitigation measure with its effect on the erosion process has not been explored in the earlier studies. Keeping this in view, laboratory erosion experiments were conducted. Materials and methods: Laboratory erosion experiments were conducted on bare soil, soil fiber, and soil-root specimens with different parameters to evaluate the erosion potential through soil loss rate using a sloping flume and rainfall simulator. A non-contact measurement option by images through the camera has been adopted for establishing the temporal erosion processes in soil. Results and discussion: The process has been quantified in terms of erosion potential, defined by quantitative (quantity of sediment) and qualitative (eroded area) changes in the soil surface during the experiment under simulated rainfall conditions. The comparison of the eroded area to the final quantity of sediment was enumerated and found to have a good correlation. Conclusions: The results obtained demonstrated the effectiveness of Indian goose grass depicting the changes from splash-induced rill erosion to effectively "no erosion." The study also highlights the success and limitations of the image processing in quantifying the erosion process. [ABSTRACT FROM AUTHOR]

Numerical models are currently the main tool used to simulate the effects of urban flooding. The validation of these models requires thorough and accurate observed data in order to test their performance. The current study presents a series of laboratory experiments in a large‐scale urban drainage physical facility of approximately 100 m2 that includes roofs, streets, inlets, manholes and sewers. The facility is equipped with a rainfall simulator as well as a surface runoff and pipe inflows generators. The experiments were divided in two sets. In Set 1 the surface runoff was generated exclusively by the rainfall input, while in Set 2 the rainfall simulator was used in combination with the runoff generators. In all the tests the water discharge was measured at points on the inlets, roofs, and outfall. The water depth at different locations of the facility was also measured. The experimental tests were replicated numerically using the urban drainage model Iber‐SWMM. Experimental results show that, even in a relatively small catchment the peaks in the hydrographs generated at each element of the facility during intermittent rainfalls are significantly attenuated at the catchment outlet. The agreement between the experimental and numerical results show that there are some differences in the hydrographs generated at each element, but that these differences compensate each other and disappear at the outfall. The results generated provide the research community with a thorough and high‐resolution dataset obtained under controlled laboratory conditions in a large‐scale urban drainage facility, something which has not previously been available. [ABSTRACT FROM AUTHOR]

Debris flow disasters were caused by surface erosion with high rainfall, especially in mountain villages on the island of Bali. This research aims to understand the stability behavior of volcanic soil due to physical and mechanical conditions based on numerical analysis with Plaxis 3D software. The experiment was used by planting in a test box in the form of a steel frame and equipped with a rainfall simulator to determine slope stability due to planting a combination of elephant grass and vetiver. Numerical results for volcanic soil conditions without vegetation show a soil tension of 0.6854 kN/m2. Model results after four days, there was a decrease of 0.0001m, and after 33 days there was a decrease of 0.0000064 m for the slope 45°. The safety factor of slopes without vegetation is 0.8, so this condition has the threat of landslides and surface erosion. Experimental results show that adding elephant grass combined with vetiver grass can reduce erosion by 94.6% on slope 45o and 92.67% on slope 60o. The effectiveness of the resulting runoff reaches 55.48% on slope 45o and 53.89% on slope 60o. This increase in effectiveness was caused by the development of elephant grassroots, which spread horizontally, thereby increasing the bond with the top layer of soil. [ABSTRACT FROM AUTHOR]

Nature-based solutions (NBSs) always provide optimal opportunities for researchers and policymakers to develop sustainable and long-term solutions for mitigating the impacts of flooding. Computing the hydrological process in hilly areas is complex compared to plain areas. This study used a laboratory-scaled hillslope model to study rainfall-runoff responses considering the natural hillslope conditions prevailing in hill torrents creating flash floods. The objective of this study was to estimate the impact of nature-based solutions on time-to-peak for flash flooding events on hilly terrains under different scenarios. Many factors decide the peak of runoff generation due to rainfall, like land use conditions, e.g., soil porosity, vegetation cover, rainfall intensity, and terrain slope. To reduce these complexities, the model was designed with thermopore sheets made of impermeable material. A hillslope model using NBS was designed to evaluate flood hydrograph attenuation to minimize the peak discharge (Qp) and increase time-to-peak (Tp) under varying rainfall, land cover, and drainage channel slope conditions. A rainfall simulator was used to analyze the formation of hydrographs for different conditions, e.g., from barren to vegetation under three different slopes (S0, S1, S2) and three rainfall intensities (P1, P2, P3). Vegetation conditions used were no vegetation, rigid vegetation, flexible vegetation, and the combination of both rigid and flexible vegetation. The purpose of using all these conditions was to determine their mitigation effects on flash flooding. This experimental analysis shows that the most suitable case to attenuate a flood hydrograph was the mixed vegetation condition, which can reduce the peak discharge by 27% to 39% under different channel slopes. The mixed vegetation condition showed an increase of 49% in time-to-peak (Tp) compared to the no vegetation condition. Additionally, under P1 rainfall and a bed slope of 0°, it reduced the peak discharge by up to 35% in the simulated flood and effectively minimized its potentially destructive impacts. [ABSTRACT FROM AUTHOR]

This document serves as a closure to a previous article on infiltration model parameters for sandy soils. It addresses points raised by discussers and compares the data to previous work. The writers agree with the discussers' assessment that soil placed in test plots may not directly apply to natural soils, and they acknowledge the importance of ground cover in infiltration and runoff. Additional tests on stone-covered soils are included to illustrate the impact of ground cover. The document also compares findings to previous studies, showing close agreement. The document provides data on the effective hydraulic conductivity of different soil types, categorized as "Bare (scraped)" or "Low," along with corresponding values. The authors acknowledge the study's limitations and the importance of soil data in hydrologic modeling, emphasizing the need for improved methods of model parameterization. [Extracted from the article]

This study investigated the behaviour of permeable interlocking concrete pavement (PICP) in terms of water infiltration volume, surface runoff volume, and load resistance, using a specific lab apparatus, designed and manufactured as a rainfall simulator. The connecting pattern of the surface blocks is a stretcher bond pattern with a joint spacing of (5 and 10 mm) between the block pavers to be filled with a small-sized open-graded aggregate to finalise the permeable surface of joints. The adopted pattern has been examined under three rainfall intensities of (20, 40, and 60 l/min), four longitudinal slopes (0, 2, 4, and 6%), and three transverse slopes (0, 2, and 4%). The results showed that at high rainfall intensities (60 l/min), high longitudinal slopes (6%), and high transverse slopes (4%), the stretcher-bonded PICP with 5 mm spacing between the blocks infiltrates less water than the one with 10 mm. Furthermore, PICP with 5 mm spacing has higher surface runoff than PICP with 10 mm spacing at high rainfall intensities (60 l/min), high longitudinal slopes (6%), and all transverse slope percentages (0, 2, and 4%). In addition, the load resistance of stretcher-bonded PICP with 5 mm spacing between the blocks is higher than that of 10 mm at all the subjected loads in the load-deflection test. Despite the shown differences between both types of PICP, they are strongly recommended as an alternative choice for ordinary dense-graded pavement. [ABSTRACT FROM AUTHOR]

Rainfall simulators are important pieces of equipment to investigate hydrological processes and soil erosion. Here, we investigated the operational characteristics, the rainfall characteristics, and the soil erosion process under collecting plots and rainfall patterns using the InfiAsper simulator. We evaluated the standard plot of the simulator in a rectangular shape (1.0 × 0.7 m), as well as a circular plot (0.8 m diameter), and four precipitation patterns, characterized as advanced (AV), intermediate (IN), delayed (DL), and constant (CT). In the laboratory, uniformity and water consumption tests were carried out for shutter-disk rotations from 138 to 804 rpm, and in the field, simulated rains were applied on a Dystric Acrisol. Rains with different patterns were simulated and presented a uniformity coefficient above 83% for the circular plot and 78.2% for the rectangular plot. The soil erosion varied as a function of the precipitation patterns and, to a lesser extent, according to the shape of the experimental plot. However, runoff and soil loss in AV were 2.1 and 3.5 times greater when using a circular plot. Concerning IN and DL, the length of the rectangular plot may have influenced the formation of small furrows throughout most of the simulated rainfall event, providing greater runoff (13.1 mm) and soil loss (13.6 g m−2). The results obtained are promising, but plots with different shapes associated with rainfall patterns simulated by InfiAsper must be evaluated in other classes and soil use and cover conditions. [ABSTRACT FROM AUTHOR]

During rainfall, plant litter interception regulates overland flow with an impact on water runoff generation and sediment displacement. Besides the rainfall characteristics, the effects of litter mass, thickness, storage and drainage properties on rainfall interception are reasonably well understood. In contrast, less is known about the influence of leaf traits, which we hypothesized to affect interception, soil hydrology and conservation via litter structure assembly.We measured the runoff and soil loss generation as determined by litter layer structural and hydraulic properties of 16 coexisting tropical woody species with wide‐range morphological leaf traits in a rainfall simulator experiment.Our results show that litter produced by coexisting species can differ in precipitation interception, thereby influencing runoff and soil loss. This is because there is important interspecific variation in litter water storage and drainage, which are negatively affected by leaf area (LA). Leaf water repellency positively affected litter water storage. Moreover, LA also negatively affected litter layer density. Litter density, in turn, increased runoff, but decreased soil loss, possibly due to protection against splash erosion.These results can be used to predict the effects of plant traits on the soil water balance and soil integrity protection through ecohydrological interception by the litter layer. The next research steps will be to extend our model to multiple‐species litter layers, and to validate and calibrate our model in different field situations in different ecosystems.Synthesis: We revealed the direct and indirect effects of species leaf size and hydraulic traits on litter rainfall interception, runoff and soil loss. We propose a new litter‐soil ecohydrological model, by using structural equation models, which can be used as a tool to predict ecosystem functioning, and guide management and restoration actions with water and soil conservation targets. [ABSTRACT FROM AUTHOR]

The purpose of this study is to experimentally estimate the criteria for shallow landslide occurrence using hydrological indicators such as matric suction and volumetric water content for representative soils with the different geological conditions in which landslides frequently occur in South Korea. To investigate the detection criteria for shallow landslides, a series of landslide model tests are conducted using weathered soils obtained from regions of granite, gneiss, and mudstone where landslides occur. A landslide model test device, which includes a rainfall simulator, a slope model flume, and a measurement system with sensors, is developed to simulate shallow landslides that generally occur on natural slopes during rainfall. Based on the results of the model test, an infinite slope stability analysis considering the suction stress of unsaturated soil is applied to analyze changes in the safety factor of the slopes according to rainfall. Using the domestic standard of slope design used in South Korea, landslide detection criteria based on the safety factor of slopes are recommended as 1.3 for attention-level alerts and 1.0 for warning-level alerts. The matric suction corresponding to the attention and warning levels is defined as the critical matric suction, and the volumetric water content corresponding to the critical matric suction on the soil‒water characteristic curve (SWCC) is defined as the critical volumetric water content. The proposed critical matric suctions and critical volumetric water contents can potentially be used as basic data to detect the time of shallow landslide occurrence and issue a landslide early warning. [ABSTRACT FROM AUTHOR]

Because of the benefits of solar energy, solar photovoltaic (PV) technology is being deployed at an unprecedented rate and the number of photovoltaic panels is sharply increasing. Agrophotovoltaic systems (solar farms) seem to be the most sustainable tools to create renewable energy without compromising agricultural production. However, utility‐scale solar energy development is land intensive and its large‐scale installation can have negative impacts on the environment. Moreover, its impacts on soil and on relative hydrological processes have been poorly studied. This article aims to evaluate the impact of solar panels on the runoff generation process, which is directly linked to the soil erosion process. Using a rainfall simulator, runoff measurements for a rainfall intensity equal to 56 mm/h were carried out by assuming different panel arrangements with respect to the maximum slope direction of the field (cross slope and aligned slope). Results were compared to a control reference of the same plot, with no panels (bare soil). Physical models found in the literature were then applied and calibrated, to upscale the models to a much higher hillslope length. Results showed that solar panels increase the peak discharge by about 11 times compared to the reference hillslope. A moderate effect of PV panel arrangement was observed on the peak discharges (11.7 and 11.5 times higher, for cross slope and aligned slope panels, respectively), whereas the time to runoff was the lowest for aligned slope panels (0.3 h), higher for cross slope panels (0.62 h), and the highest (1.2 h), for the bare soil hillslope. As it would be expected, upscaling the models to longer hillslopes resulted in increases in outlet discharges, and in the time to runoff, with an exception for aligned slope panels. [ABSTRACT FROM AUTHOR]

Urban flooding, soil erosion, and water pollution are common issues nowadays. The hydrological cycle is being disrupted due to improper planning of development that necessitates extensive studies conducted globally to study ways to address these issues. Significant and accurate data are required to rectify and amend the current situation. Rainfall simulators (RSs) are widely applied in research as they replicate the natural rainfall under controlled conditions and are repeatable. However, based on the published research, it is found that there are significant gaps. The RS has no standardization to cater different environmental conditions, yet vital rainfall characteristics and aspects have to be carried out wisely for better accuracy and data analysis. This review article discusses the gaps and parameters required in RS experiments. Core Ideas: Types of rainfall simulators (RSs) and formulas for the calculation of vital parameters have been highlighted.Crucial parameters to be considered when studying hydrological properties using RS have been highlighted.Contradictions in the correlation between drop size and kinetic energy have been analyzed and discussed by researchers.The preferred RS type and the advantages of utilizing RS over natural rainfall for research purposes have been pointed out.The optimum height required to achieve the terminal velocity for pressurized RS from the ground and non‐pressurized RS have been highlighted. [ABSTRACT FROM AUTHOR]

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study of soil erosion is one of the necessities of watershed management, and erosion control requires understanding the behavior of runoff and sediment production in different conditions. This study aims to evaluate the effect of soil particle percentage, soil organic carbon (OC) content, slope, and initial moisture on runoff components and the amount of sediment at the plot scale. In this study, a rainfall simulator has been used to generate rainfall in the Shamsabad area, Ardabil province, Iran, and was performed at 58 points through synthetic rainfall with 20-min duration. Also, soil samples were taken and their properties were determined through laboratory analysis. The GIS was used to produce slope layers and Topographic Wetness Index. The average percentage of soil OC was 0.90, and the average of clay, sand, and silt was 24.39%, 50.26%, and 24.35%, respectively. Taylor diagram and triple diagram models were used to determine the dependence of runoff and sediment behavior on independent variables. The average percentage of soil OC was 0.90, and the average of clay, sand, and silt was 24.39%, 50.26%, and 24.35%, respectively. The results showed that runoff termination time is directly related to soil clay content and inversely related to soil sand content; in other words, with increasing sand to more than 35%, runoff production time became longer. The amount of sediment or soil clay has shown a positive relationship with the percentage of sand, and the amount of slope is negatively related. By increasing the amount of soil clay to above 40%, the amount of sediment has reached its highest level in gentle slope values (< 10 degrees). Considering the complexity of sediment production behavior and the role of various factors on runoff and sediment production in interaction with all influential factors should be considered. [ABSTRACT FROM AUTHOR]

Flooding associated with Hurricane Maria in 2017 had devastating consequences for lives and livelihoods in Puerto Rico. Yet, an understanding of current and future flood risk in small islands like Puerto Rico is limited. Thus, efforts to build resilience to flooding associated with hurricanes remain constrained. Here, we take an event set of hurricane rainfall estimates from a synthetic hurricane rainfall simulator as the input to an event-based rainfall-driven flood inundation model using hydrodynamic code LISFLOOD-FP. Validation of our model against High Water Mark data for Hurricane Maria demonstrates the suitability of this model for estimating flood hazard in Puerto Rico. We produce event-based flood hazard and population exposure estimates for the present day, and the future under the 1.5 °C and 2 °C Paris Agreement goals. Population exposure to flooding from hurricane rainfall in Puerto Rico for the present day climate is approximately 8–10 % of the current population for 5-year return period, with an increase in population exposure to flooding by 2–15 % and 1–20 % under 1.5 °C and 2 °C futures (5-year return period). This research demonstrates the significance of the 1.5 °C Paris Agreement goal for Small Island Developing States, providing the first event-based estimates of flooding from hurricane rainfall under climate change in a small island. [ABSTRACT FROM AUTHOR]

Hydrological evaluation of soil-water relationships for infiltration and drainage is a complex issue. Within the scope of this study, the significance of the experimental studies for the drainage design of sports fields is emphasized. In addition, a standard technique was tried to develop due to the lack of absence of certain specifications and inaccurate designs mostly based on the traditional experience regarding sports field drainage. The essential circumstances for the success of the experimental studies were presented and a sample drainage section was compared. As a result of the experimental studies, it was understood that the pattern of the hyetograph applied to the system and the layer thicknesses of the drainage section were highly effective on the parameters of the output flow hydrograph. Due to the lack of studies for sports field drainage that their mechanisms were not clearly revealed, the presented study is significant in term of developing a new perspective and procedure to the relevant field. [ABSTRACT FROM AUTHOR]

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Geogrid reinforced soil walls (GRSWs) constructed using low-permeable backfills often experience failures when subjected to rainfall. The objective of this paper is to employ centrifuge modelling to investigate the effect of geogrid types on the performance of GRSW models constructed with low-permeable backfill, when subjected to rainfall intensity of 10 mm/h. A 4.5 m radius large beam centrifuge facility was used, and rainfall was simulated using a custom-designed rainfall simulator at 40 gravities. Digital Image Analysis (DIA) was employed to understand the deformation behaviour of GRSWs with low stiffness geogrid layers with and without drainage provision subjected to rainfall. Additionally, the effect of varying stiffness of geogrid reinforcement layers across the height of GRSW was also investigated. The interpretation of DIA helped to quantify displacement vector fields, face movements, surface settlement profiles and geogrid strain distribution with depth. Irrespective of drainage provision, GRSWs reinforced with low stiffness geogrid layers experienced a catastrophic failure at the onset of rainfall. However, GRSW reinforced with geogrid layers of varying stiffness was observed to perform well. This study demonstrates the effective use of DIA of GRSWs subjected to rainfall along with centrifuge-based physical model testing. • This study highlights the performance of GRSWs subjected to rainfall in a geotechnical centrifuge at 40 gravities. • The use of DIA is explored for understanding the deformation behaviour of GRSWs and geogrid strain distribution at the onset of rainfall. • DIA facilitates in analysing the behaviour of GRSWs at the onset of climatic events (like rainfall) in a geotechnical centrifuge. [ABSTRACT FROM AUTHOR]

This study used a large-scale ASTM International D6459 rainfall simulator to evaluate performance of various types of erosion control products used in construction. Rolled erosion control products (RECPs), hydraulic erosion control products (HECPs), and soil amendments were tested and compared based on Cover factor (C factor), a parameter between 0 and 1 where 0 represents perfect erosion protection and 1 represents bare soil. All products behaved statistically similarly at the lowest rainfall intensity [ 5.1 cm/h (2 in./h)] with an average C factor of 0.03. At the next intensity of 10.2 cm/h (4 in./h), RECPs had significantly lower C factors than HECPs (0.11 and 0.41, respectively). Among the HECPs, Type 2 had worse C factors than other products, but all deteriorated at the highest 15.2 cm/h (6 in./h) intensity, reaching an average C factor of 0.48. Most (88%) products met their industry minimum specifications at the lowest rainfall intensity, but only 25% met them by the highest intensity. The soil amendments did not have published C factors, so their performance was compared to traditional products. Gypsum statistically matched the RECPs while Polyacrylamide (PAM) statistically matched the HECPs. Preliminary testing was performed on thee straw applications, but due to sampling differences only a soil loss ratio, or simple ratio of soil lost on the bare plot to soil lost on the treated plots, was calculated. A cost estimate obtained though local professionals revealed that the straw treatments appeared to be the most economical in terms of total dollars spent per reduction in sediment loss, and that the cost of premium hydraulic mulches did not appear to translate into improved performance. This study is useful because large-scale simulations more accurately reflect field erosion performance, but they are seldom performed due to time and cost considerations. In addition, varying intensities revealed performance differentiations, many product types were compared, and using an industry standard allows for confident comparison to other results. This study used a large-scale ASTM D6459 rainfall simulator to evaluate sediment loss performance of four types of erosion control products used on construction sites: rolled erosion control products (RECPs), hydraulic erosion control products (HECPs), straw mulch, and soil amendments. Under a 5.1 cm/h intensity, all products tested behaved statistically identically. As rainfall intensity increased to 10.2 and 15.2 cm/h , gypsum and RECPs performed better than polyacrylamide (PAM) and HECPs. Of the seven products that had available manufacturer specifications, all fell short of advertised performance. Preliminary results suggest that straw may be the most cost-effective erosion control measure of the methods tested. This study suggests that more adherence to nationally and internationally recognized testing standards is needed in the field of rainfall simulation. It also suggests that erosion performance data from large-scale simulators is more reliable than data obtained from small-scale simulators. [ABSTRACT FROM AUTHOR]

Soil loss due to surface water erosion is one of the degradation processes that most affects the physical quality of the soil and produces the largest area of degradation worldwide. This study compared soil loss in two methods of harvesting sugarcane for panela production, considering factors such as rainfall intensity, slope of the land, and time of plant growth. It was observed that the moment just after harvesting is when the greatest differences between cutting methods occur, the loss of soil being greater when harvesting by "parejo" than when harvesting by "entresaque". As the crop develops, this difference decreases, and soil loss is more influenced by the intensity of precipitation. Finally, the measurements made after cutting were compared with a soil condition without vegetation cover, where it was observed that soil losses in crops already established with sugarcane were notably lower concerning this condition. This study establishes the importance of leaf mulch as a soil protection factor in sugarcane crops for panela. [ABSTRACT FROM AUTHOR]

Riverscape aggradation due to the deposition of fine particles above natural forest litter can change the soil, sediment, and water properties, damage riparian vegetation, and reduce environmental integrity, especially in headwater streams. Litter addition techniques that enhance surface roughness and permeability can decrease the interference of fine particles on the ecosystem, representing a low‐tech alternative to recover disturbed riparian areas. We aimed to evaluate run‐off, percolation, storage coefficients, run‐off volume, and sediment yield using a rainfall simulator and the mitigation potential provided by the addition of forest litter to limnological variables—turbidity, total suspended solids (TSS), electrical conductivity, pH, nitrogen—which are indicators of integrity that can reflect streams' aggradation. Fifteen soil samples from a disturbed area (silt and clay deposits aboveground), five from an undisturbed area (sandy soil), and superficial forest litter were obtained from riparian areas adjacent to two small streams in Carajás National Forest, Brazil. The addition of litter showed great potential to mitigate erosive processes and to reestablish hydrological processes in the disturbed soil. The run‐off volume and sediment yield were 2–4 times lower in litter addition treatments compared to non‐litter addition. Litter addition also improved run‐off water quality, especially turbidity and TSS, which were 12–16 times and 3–13 times lower, respectively. The experimental addition of litter has shown encouraging results to be applied in situ as a sustainable, low‐cost, and simplified nature‐based solution to contribute to the restoration of degraded riparian forests and reduce in‐stream silt and clay aggradation. [ABSTRACT FROM AUTHOR]

This study was performed in major habitats of Gundelia tournefortii L. in the Central Zagros region, Iran, to pursue the two following objectives: (a) analyzing the percentage of canopy cover and density per unit area (m2) of the plant in controlling runoff and reducing the soil loss amount and (b) investigating some soil physicochemical properties and their impact on reducing the amount of runoff generation and sediment yield. The vegetation parameters of G. tournefortii L. were measured by completely randomized design using transect quadrat sampling method. It used a portable rainfall simulator apparatus. The highest amount of efficacy of the vegetation parameters of G. tournefortii L. in controlling runoff generation and sediment yield occurred during the first fifteen minutes of the rainfall continuity times in comparison to the second fifteen minutes of ones. As a result, in relation to runoff generation, the study sites No. 5 (1.73), No. 4 (1.85), No. 8 (1.90), and No. 1 (1.96) mm were allocated the largest contribution, respectively. Meanwhile, in relation to sediment yield, the following results were obtained. The study sites No. 5 (10.87), No. 4 (10.55), No. 8 (11.23), and No. 1 (11.35) g had the largest contribution, respectively. The findings showed that G. tournefortii L. has a prominent role in controlling runoff generation and sediment yield, and because of its high compatibility and deployment, it can be introduced as a suitable cover plant for soil conservation in natural fields. [ABSTRACT FROM AUTHOR]

Rainfall simulators are versatile research tools that facilitate studying rain events and the many related physical phenomena. This work describes the development and validation of an indoor, large-scale rainfall simulator comprising a rain module installed 10.4 m from ground level, a redistribution screen at an adjustable distance below the rain module, and an ultra-filtered-water recirculation system. The droplet formers installed in the rain module were selected to achieve a wide range of rain intensities. The simulator was calibrated and validated using local natural rainfall data collected with a disdrometer over 30 months. The height of the rain module allows terminal velocity to be reached at ground level. At the same time, the redistribution screen and the droplet formers guarantee the wide variability of simulated rainfall in terms of intensity and the size of the drops. As a result, we show that the rain simulator, with proper calibration of the screen's position, can reproduce measured natural rainfall over a broad range of intensities with high spatial and temporal uniformity and kinetic energy. [ABSTRACT FROM AUTHOR]

Granite residual soil is vulnerable to collapse under rainfall-induced erosion. This may in turn lead to the occurrence of landslides or debris flows on slopes. Previous studies on use of microbial-induced carbonate precipitation (MICP) technique for soil stabilization are often conducted on sandy soils and also with rainfall-induced erosion are rarely assessed for a slope treated with MICP. This study investigated the feasibility of using the MICP technique for surface protection of granite residual soil slopes against erosion. The MICP technique was applied to soil samples using the spraying method. Hydraulic conductivity and rainfall erosion tests (using flume) were conducted to assess the coating effects of MICP on granite residual soils. In addition, crust thickness, calcite content and near-surface strength were measured to interpret the results. Tests were repeated to assess any variability in results. Scanning electron microscopy, energy-dispersive spectrometer and X-ray diffraction (XRD) were conducted on treated and untreated samples to interpret the formation of calcite due to MICP. After 7 days of curing, the calcite content increases to 4.3%, whereas mean coating thickness is 4.2 mm. Unconfined compressive strength is increased by 20.3% as compared with the bare soil. MICP treatment reduced the soil hydraulic conductivity and erosion rate by 90.9% and 95.2%, respectively. This was attributed to the bio-cementation process generating a surface coating on granite residual soils, leading to a reduction in pore throats, as observed in the obtained micrographs. Compared to the bare soil, the runoff rate in the MICP-treated soil was increased by 39.4% on average. However, the erosion is found to reduce significantly in MICP-treated soil. Based on ANOVA analysis, it could be concluded that the rainfall intensity found to be a significant factor affecting the erosion rate of granite residual soil slopes. [ABSTRACT FROM AUTHOR]

Rainfall is a key abiotic factor of ecosystems that can both provide benefits and contribute to negative environmental impacts. Due to spring precipitation levels increasing in the Midwest, there has been increased interest in developing and evaluating practices that can mitigate the effects of heavy rainfall. As this is an area of interest for both agriculture and environmental sciences, demonstrating the actions of severe rainfall can be a powerful tool in the natural sciences classroom as well as in the field. Rainfall simulators are ideal for this demonstration as they can create repeated, uniform rainfall events while introducing limited variability between events. Building on previous literature, we constructed a cost‐effective, easily transportable design that can be utilized in the classroom, the lab, and the field. Here, tests were conducted to measure flow rate, rain droplet size, and uniformity of water dispersion on the cost‐effective and easily obtained solid cone‐style herbicide nozzle. We found no statistically significant differences among rainfall dispersion metrics or in raindrop uniformity analyses. This demonstrates the capability of constructing this type of teaching and research equipment at little cost while producing highly consistent and size‐relevant artificial rainfall. Core Ideas: Rainfall simulators are useful for experiential learning activities related to environmental impacts of rainfall.The Christianson coefficient and flour pan test can be used to evaluate rainfall produced by a simulator.The simulator design proved to be cost‐effective and adaptable for both educational activities and field research. [ABSTRACT FROM AUTHOR]

Water repellent soils represent some of the most responsive natural surfaces from the point of view of overland flow generation. Measurement of the runoff response of such soils can therefore provide characteristics that can help constrain hydrological models or improve the conceptual models of hillslope runoff generation. We have analysed the overland flow characteristics of water repellent sandy soils at three sites with different dominant vegetation (hereafter denoted as the lichen, moss and herb sites) and following vegetation removal (scalping) during extreme rainfall events created by a rainfall simulator (three consecutive sprinklings at 2.1 mm min−1 for 15 min each with a 5 min hiatus between the sprinklings). Despite the extreme water repellency (WR) and rainfall intensity, on average just up to a half of the rainfall left the plots as an overland flow. Whilst the overland flow mostly generated quickly (on average within 50–120 s), the vegetation substantially delayed its appearance (by approximately 100% compared to scalped plots). The median values of the runoff coefficients were 6% and 49% on the soil with and without vegetation, respectively. Good relationships between the overland flow characteristics and soil moisture were found only for the scalped plots. Although the time to runoff and runoff coefficients after each of the three consecutive sprinklings were not substantially different, the differences between the soil with and without vegetation remained substantial. The results indicated: (a) high variability within each of the sites, including the lichen site that appeared homogenous; (b) all vegetated plots retained a higher amount of water than the scalped plots; (c) although all sites exhibited high WR, the combined influence of preferential flow, higher hydraulic conductivity and specific vegetation (soapwort, black locust) mitigated its effects at the herb site; (d) the relatively lower overland flow at that site may point to subsurface flow. [ABSTRACT FROM AUTHOR]

Pavement deterioration is mainly caused by high traffic loading and by increased levels of runoff water resulting from storms, floods, or other reasons. Consequently, this issue can be efficiently solved by employing permeable pavement, such as permeable interlocking concrete pavement (PICP) to control water runoff and endure increased traffic loads. This study investigates the performance of PICP, in both 45° and 90° herringboned surface patterns, in terms of the infiltration of volumes of water, runoff water volumes, and the ability of pavement to withstand static loading. All the related tests in this study were implemented using a lab apparatus that was fabricated as a simulator for rainfall. Various conditions were adopted during the performance tests, including the application of longitudinal slopes (0, 2.5, 5, and 7.5%), side slopes (0, 2.5, and 5%), and different rainfall intensities (25, 50, 75, and 100 L/min). The results indicated that at high rainfall intensities (75 and 100 L/min), PICP with the 45° herringboned surface pattern had the highest volume of infiltrated water and the lowest runoff water at all the adopted longitudinal and side slopes. In addition, PICP with the 45° herringboned surface pattern showed higher resistance to deflection under a static loading test than the 90° herringboned pattern under the same conditions. Therefore, PICP with a 45° herringboned surface pattern showed supremacy in terms of runoff reduction and load resistance in comparison to PICP with a 90° herringboned pattern. Even though there are differences between the two types of PICP, they are both strongly recommended as alternatives to regular pavement. [ABSTRACT FROM AUTHOR]

Soil erosion by water is a major global environmental concern due to its devastating effect on agricultural sustainability and food security. The aim of the current study was to investigate the effectiveness of agri-mats on water erosion control using a laboratory rainfall simulator. Six agri-mat samples were subjected to a runoff and infiltration rate test for this study: three agri-mats were made with 100% dry sugarcane bagasse and the other three agri-mats were made with 10% dry algae +90% dry sugarcane bagasse. The 100% dry sugarcane bagasse agri-mat treatment had higher runoff rate of 16.8 millimeters per hour (mm.hr−1) compared to a mere 1.7 mm.hr−1 recorded under the BA agri-mat during the first 10 min. In addition, the 100% dry sugarcane bagasse agri-mats released magnesium at a rate of 105.7 mg.hr−1 (milligrams per hour) compared to 6.6 mg.hr−1 lost from the 10% dry algae +90% dry sugarcane bagasse agri-mat treatment. Results shows that when algae was used as an additional organic material during the fabrication process, agri-mat delayed runoff by absorbing more moisture than it loses. Algae has the capacity to increase water-holding capacity while improving nutrient status and electrical conductivity of the agri-mats, making them more beneficial not only as the runoff combating technology but as a soil conditioner. [ABSTRACT FROM AUTHOR]

The temporal heterogeneity of rainfall is substantial in urban catchments, and it often has huge impacts on stormwater simulation and management. Using a design storm with a fixed pattern may cause uncertainties in hydrological modeling. Here, we propose an event-based stochastic parametric rainfall simulator (ESPRS) for stormwater simulation in a sponge city with green roofs, permeable pavements, and bioretention cells. In the ESPRS, we used five distributions to fit the measured rainfall events and evaluated their performance using Akaike's Information Criterion, Anderson—Darling goodness-of-fit test, and p-values. The vast rainfall time series data generated using the ESPRS were used to run the storm water management model for outflow simulations in the catchment, thus revealing the influence of temporal rainfall characteristics on the hydrological responses. The results showed the following: (1) The ESPRS outperforms the Chicago method in predicting extreme precipitation events, and its control factors are the rainfall peak period, rainfall peak fraction, and cumulative rainfall fraction at the peak period. (2) The best-fit functions for the rainfall depth in each period have different distributions, mostly being in lognormal, gamma, and generalized extreme value distributions. (3) Rear-type precipitation events with high peak fractions are the most negative pattern for outflow control. The developed ESPRS can suitably reproduce rainfall time series for urban stormwater management. [ABSTRACT FROM AUTHOR]

Knowledge of the issue of water movement in the soil is the basis for agricultural activity, but also for many other sectors. One of the basic indicators that is evaluated in soil science is the rate of water infiltration into the soil. The article specifically states how soil texture and soil moisture affect the rate of water infiltration. The results show that changes in water infiltration can be significant and certain trends can be traced. The rate of water infiltration into the soil is most affected by the sand fraction (soil particles 0.05-2 mm). The higher the percentage of these soil particles in the soil, the lower the changes in infiltration rate depending on the degree of saturation. The article further evaluates soil moisture in relation to texture. The results were obtained at several research locations within the period 2014-2021 in the territory of the Czech Republic. The above findings are primarily applicable to the region of Central Europe or can be used as comparative values for regions in the rest of the world. [ABSTRACT FROM AUTHOR]

The process of converting rainfall into runoff in a region is complex and is affected by many different factors. There is a close relation between land use and erosion. Soil erosion involves the separation and transport of soil particles by runoff. Therefore, runoff production is an important process that is related to soil loss and environmental effects of agricultural operations due to its involvement in nutrient loss. As a result, it is necessary to study the amount of runoff produced as one of the main processes of soil erosion. Rainfall simulator allow repeated measurements in different fields to determine the factors affecting runoff and erosion. Despite the challenges, the use of simulators is common worldwide due to its many benefits in various fields of soil erosion and sediment production. In Iran this method was used in many researches with different targets. Kavian et al (2019) simulated the effect of herbaceous residues on runoff production, Golshan et al (2018) using the rainfall simulator compared the SWAT model and Regression model. In other countries other research can be mentioned the researches of Biddoccu et al (2016), Zhang et al (2018a) and Wang et al (2018). For this purpose, in the present study, which was carried out in one of the forest areas in the east of Ardabil province, called Fandoghlu forest area, the amount of runoff and sediment from the rainfall was measured and compared in different land uses using a rainfall simulator machine. In this study, the relationship between land use and runoff and sediment production was investigated in the Fandoghlu forest with 4378 ha area, using a rainfall simulator machine. The used rainfall simulator has 1 m2 area with the ability to adjust the intensity and duration of rainfall. The rainfall simulator machine was installed at 104 points with 21.867 mm / hr. rainfall intensity during the 15 mints in the three different land use consisting of forest, rang and agriculture. Soil sampling was performed from each land use from a depth of 0-20 cm. 34 samples were taken for forest use and 35 samples of intact and untouched soil were collected for each of the agricultural and rangeland uses, and a total of 104 soil samples were collected. The location of the points was recorded via the Global Positioning System (GPS). Using laboratory soil samples, parameters of initial soil moisture, bulk density, organic carbon, soil particle size distribution, true bulk density, total porosity, saturated hydraulic conductivity, saturated moisture, field capacity, permanent and susceptible wilting point usage and weight average of aggregate diameter were measured. The mean values of soil bulk density in forest, rangeland and agricultural uses were 0.881, 1.067 and 1.355 g / cm3, respectively. In rangeland use, the increase in specific gravity of the soil relative to the forest can be attributed to the kicking of livestock due to uncontrolled grazing (Ferreras et al., 2006). The mean values of true specific gravity and total soil porosity in forest were obtained. The rangeland and agricultural uses are equal to 1.905, 2.018 and 2.162, and 53.60, 46.46, 37.09 respectively. The reason for the reduction of true specific gravity in forest use is because the organic part of the soil inherently has a small true specific gravity. As by increasing the share of soil organic matter, the actual specific gravity decreases (Zhang et al., 2018b). In forest, rangeland and agricultural uses, the amount of runoff was equal to 868.5, 925 and 1425 ml/m2. Also, the amount of sediment concentration in each of the land uses was 1.937, 8.889 and 44.222, respectively. The results showed that vegetation, slope, soil characteristics and land use change have a significant effect on runoff and sediment components in the study area. Field studies and direct statistics of harvesting are very important in watershed management and estimating runoff and sediment production. The rainfall simulator used in this research can be transported to difficult areas that can provide integrated information from the watershed. The distribution of soil particle size on runoff and sediment components showed that there is a significant difference between different amounts of silt, clay and sand in each of the land uses and runoff volume. So that the amount of clay and silt from the forest to the pasture and arable land is reduced and the amount of sand is increased. Silty soils have low permeability due to low adhesion and porosity and as a result, more runoff volume. Therefore, land use management in this area can play a very important role in reducing runoff and fertile soil. [ABSTRACT FROM AUTHOR]

Acid rain is a problem that despite efforts to reduce atmospheric pollution, continues to impact not only countries where there is a high production of pollutants, but also transboundary areas to which the pollutants are transported. In addition to its effects on human health, there are also the effects on infrastructure and the consequences that this entails. This study on the effect of rain and acid rain on calcareous materials highlights the need for protection of buildings constructed from these materials, many of which are part of the cultural heritage. The effects caused by rain and acid rain were studied using a rain simulator whose features allow the simulation of natural conditions as realistically as possible. In the same way, the effect of a coating synthesized from nanomaterials, which has been shown to serve as protection against the degradation caused by rain, was analyzed. In addition to a long-lasting protection of the stone material, this type of coating avoids the need for the replacement of elements and the recurrent cleaning of degraded parts. It also avoids the accumulation of parts on the ground, the transport of personnel, work materials and raw materials, thereby contributing to the reduction of the carbon footprint and water savings, which in turn reduces the production of pollutants that cause acid rain. [ABSTRACT FROM AUTHOR]

Rainfall simulators represent often-used equipment for soil research. Depending on their performance, they could be appropriate for some soil research or not. The aim of this research is to provide insight into the capabilities of existing dripping rainfall simulators (DRS) to mimic natural rainfall and the frequency of simulated rainfalls of certain characteristics, facilitate the selection of rain simulators that would best meet the needs of soil research and to reach a step closer to the standardization of rainfall simulators. DRS performance was analyzed integrally, for simulators with more than one dripper (DRS>1) and with one dripper (DRS=1). A statistical analysis was performed for the performance of the DRS, wetted area, drop size, rainfall intensity, duration and kinetic energy. The analysis showed that DRS can provide rainfall that corresponds to natural rainfall, except in terms of the drop size distribution and wetted area. However, usually there are more factors that do not correspond to natural rainfall, such as the median drop size, volume and kinetic energy. Metal and plastic tubes (MT and PT) as the most present dripper types showed a strong relation between the outer diameter (OD) and drop size, while the inner diameter (ID) relation was moderate-to-weak. However, when increasing the range of MT drippers, for diameter size, the relation significance becomes very strong for bouts ID and OD. With the increase in the ID of PT, the relation deviates from the logarithmic curve that represents all drippers together. The sizes of the drops generated by the drippers are mostly in the range between 2 and 6 mm, while the number of drops smaller than 2 mm is relatively small. The intensity and duration of the simulated rain can be successfully produced to match natural values, with the most frequently simulated short-term rainfall of a high intensity. Most simulations were conducted at a fall height of up to 2 m, and then their number gradually decreases as the height gets closer to 5 m. Most simulations (58.6%) occur in the range between 20-90% KE, then 33.0% in a range of 90-100%, with only 8.4% lower than 20% KE. [ABSTRACT FROM AUTHOR]

This document is a discussion of a research paper titled "Infiltration Model Parameters from Rainfall Simulation for Sandy Soils." The authors express gratitude to the original authors for their contribution to arid-land hydrology and emphasize the importance of considering soil conditions when applying rainfall simulation results. They reference previous rainfall simulation work in Albuquerque, highlighting the impact of ground cover on rainfall loss. The document provides information on the relationship between soil properties and infiltration rates, presenting a table with data on different soil types and their parameters. The authors note the variability among results and suggest further investigation into certain parameters. They hope that the historical information provided will be useful to other researchers in the field of Southwest rainfall-runoff hydrology. [Extracted from the article]

To avoid flooding and erosion hazards, post-fire management actions are essential in Mediterranean forests after severe wildfires. In this regard, mulching is the most common action but some mulch materials, such as straw, may lead to adverse impacts in burned forests. The use of yellow mistletoe fruits (Loranthus europaeus Jacq., hereafter "LE") for the production of biodegradable mulch and its effectiveness in post-fire hydrology have never been studied. To fill this gap, this study has evaluated surface runoff and rainsplash erosion in a pine forest in Central Eastern Spain burned by a wildfire and mulched by a mixture of LE fruits and straw (with or without adding clay particles) using a portable rainfall simulator. Compared to untreated sites, runoff increased in burned and mulched soils (by 13.6% for the mixture without clay and by 17.2% when clay was added, in the latter case significantly). This increase was mainly due to the compact layer created by mulch application on the soil surface. However, the peak flow and the time to peak were lower in mulched soils (on average by 32.7% and 60.5%, significantly only for the mulch mixture without clay), thus indicating that, in these soils, peak runoff takes longer and its maximum value is lower compared to untreated sites. Soil erosion noticeably and significantly decreased (up to 97%) in mulched areas in comparison to untreated sites without significant differences between the two mixtures. Overall, this study indicates to land managers that soil mulching with a mixture of Loranthus europaeus Jacq. and straw is an effective post-fire management action to reduce the soil erosion risk after a wildfire. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of biodiesel as a co-solvent with the wood preservative creosote to reduce the amount of hydrocarbon-based carrier utilized. Small blocks of wood were treated at a pilot scale using three different creosote concentrations. The diluent used was a blend of 80% soybean biodiesel and 20% petroleum diesel. The efficacy of creosote was tested against brown rot and white rot fungi. The results of the wood-block test and agar test suggested that there was no significant effect of biodiesel on the efficacy of creosote as a wood preservative. As creosote-treated wood is commonly used for railway ties, its potential impact on the surrounding environment was also assessed by studying the leaching behavior of creosote–biodiesel–diesel blend treated railway ties. Rainfall simulators were used to imitate an exposure of treated wood to a significant amount of rainfall. Wood core drilled from the exposed railway ties and leaching water samples were analyzed for the levels of polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPHs). Overall, this study demonstrated that the diluent containing biodiesel had no negative effect on the performance of creosote as a wood preservative and towards the natural environment. [ABSTRACT FROM AUTHOR]

In the Czech Republic, the Universal Soil Loss Equation provides the basis for defining the soil protection strategy. Field rainfall simulators were used to define the actual cover-management factor values of the most extensively seeded crops in the Czech Republic. The second purpose was to assess rainfall-runoff ratio for different crops and management to contribute to the debate of water retention effectiveness during approaching climate change. The methodology focused on multi-seasonal measurements to cover the most important phenological phases. The rainfall intensity was 60 mm·h−1 for 30 min and a plot size of 16 m2. More than 380 rainfall simulation experiments provided data. Soil conservation techniques proved to have a significant effect on runoff reduction. Conventionally seeded maize can reduce the runoff ratio to around 50%. However, cover crops combined with reduced tillage or direct seeding can reduce the runoff ratio to 10–20% for 'dry' conditions and to 12–40% for 'saturated' conditions. Conventionally seeded maize on average loses 4.3 Mg·ha−1 per 30 min experiment. However, reduced tillage and direct seeding reduce soil loss to 0.6 and 0.16 Mg·ha−1, respectively. A comparison with the original USDA values for maize showed that it is desirable to redefine the crop cover factor. [ABSTRACT FROM AUTHOR]

Extreme climate events are expected to occur very frequently and intensively with climate change, and such extreme events can induce irreversible damage to plants and soils, as well as ecosystems. Accordingly, there is a need to understand the effects of extreme climate events on ecosystems. Here, we designed a temperature and precipitation manipulation system to simulate extreme climate events of heat, drought, and heavy rainfall. We constructed three soil surface temperature manipulation levels (control, 3 °C, and 6 °C increases) and three precipitation manipulation levels (control, drought, and heavy rainfall) with six replicates, and operated these from day of year (DOY) 195 to 233 in 2020. Infrared heaters increased the soil surface temperature during the extreme heat treatments. For precipitation manipulation, the automatic rainout shelter excluded ambient rainfall to produce drought conditions and an artificial rainfall simulator with spray nozzles produced heavy rainfall conditions. As a result, the soil surface temperature (°C ± one standard deviation) was higher in the 3 °C and 6 °C heated treatments than in the control by 2.7 ± 0.2 and 5.7 ± 0.5, respectively. The mean soil water content (vol. %) was 12.9 ± 8.6 in the drought treatment, 14.1 ± 7.8 in the control, and 16.1 ± 8.3 in the heavy rainfall treatment during the precipitation manipulation period. The results showed that the system design and operation were as expected. The designed system can be effectively utilized to investigate the responses of plants and soils to extreme climate events. [ABSTRACT FROM AUTHOR]

Controlled traffic farming (CTF) is used to confine soil compaction to the least possible area of the field, thereby achieving economic and environmental benefits. In the context of climate change, soil erosion is one of the most discussed topics, and there is a research gap in understanding the effects of CTF on soil erosion in Central Europe. The aim of this work was to show the potential of CTF to reduce water erosion, in terms of water runoff and soil loss on steep land. A 16 ha experimental field with a CTF technology implemented since 2009 at the Slovak University of Agriculture was used in this research. Three traffic intensity locations were selected and watered using a rainfall simulator. The results showed that the soil which had not been wheeled for 12 years had the lowest water runoff: its intensity after 20 min of simulated rain was 10 times lower compared to the multiple traffic treatment. The soil loss, expressed as the total soil sediments collected after 35 min, in the no traffic area was lower by 70%, compared to the soil with one-pass treatment and only 25% of the loss in the multiple traffic areas. These results show that CTF can significantly reduce soil loss through water runoff on steep land. [ABSTRACT FROM AUTHOR]