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Characterization of soil infiltration is crucial for designing and assessing hydrological processes. The study aimed to characterize the infiltration across various soil types (ranging from fine to moderately coarse in texture), agricultural land uses (including paddy fields, fallow lands, and upland crops) and major soil groups in India using Kostiakov, Philip, Horton, Holtan, Green and Ampt, and modified Kostiakov models. The mean basic infiltration rate was maximum in medium-texture soil (7.0 cm h− 1), followed by moderately fine (4.6 cm h− 1), fine (3.7 cm h− 1), and moderately coarse (3.2 cm h− 1) soils. Under paddy, fallow land uses and upland crops, the values of basic infiltration rate were 2.5, 4.1 and 5.3 cm h− 1, respectively. Across major soil groups, a significant variations in basic infiltration rates were observed among different soil types. Particularly, the highest infiltration rate was recorded in brown hill soil (8.1 cm h− 1); conversely, the lowest infiltration rate was in black soil (3.2 cm h− 1), attributed to the predominance of montmorillonite clay. By using rank-based multicriteria decision making, the Philip model was found to be the overall best-performing model. The Kostiakov model came in close second phase. Moreover, depending on the kind of land cover, Philip model outperformed other models, while Kostiakov fared better in upland crops and paddy fields. Additionally, Philip's model also performed better than other infiltration models across a range of soil textures. The study emphasized the significane of choosing suitable models to appropriately quantify the infiltration across a range of hydrological and agricultural contexts by highlighting the effects of soil texture, land use, and soil type on infiltration rates. [ABSTRACT FROM AUTHOR]

Changing the soil and underlying surface conditions is a key practice for realizing irrigation on‐site storage and infiltration. However, biochar addition and grass planting effects on soil infiltration and water retention capacity remain unclear. The effects of 0% biochar (C1), 1% biochar (C3), 2% biochar (C4), 3% biochar (C5) under ryegrass and 0% biochar (C2), 1% biochar (C6), 2% biochar (C7) and 3% biochar (C8) under Festuca arundinacea on infiltration behaviours were modelled by using sandy loessial soil columns with 'bare soil + 0% biochar' as the control (CK). (i) There is a linear relationship between cumulative infiltration and CK–C8 treatment wetting fronts (R2 ≥ 0.982), which showed an initial rising trend and then tended to gradual, and the influence of different treatments was primarily reflected in the middle and late infiltration stages. (ii) Both biochar and grass planting decreased the soil infiltration capacity compared with that of the CK treatment. A high biochar addition rate was beneficial for inhibiting soil water infiltration and improving water retention ability in sandy loessial soil, however, ryegrass soil infiltrabilities under 1%, 2% and 3% biochar were all stronger than that of F. arundinacea. (iii) The cumulative infiltration fitting effects in different treatments with the Kostiakov, Kostiakov–Lewis, Philip, USDA–NRCS, Horton and Green–Ampt equations were all good, although there were some differences in the infiltration rate curves under the six different fitting equations. This study is helpful in understanding effective sandy loessial soil storage ability for irrigation and efficient water resource usage. [ABSTRACT FROM AUTHOR]

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Abstract Rainfall serves as a significant factor contributing to slope stability challenges in mountainous areas, and simulating the process of slope rainwater movement is a crucial approach for analyzing the stability of slopes triggered by rainfall. By combining computer numerical simulation technology with traditional hydraulic and hydrological calculation theories, it is possible to create an efficient and precise rainwater movement model that can simulate and analyze the process of rainwater movement on slopes. Utilizing natural slopes as the focal point of our research, the cellular automaton method was applied to simulate rainfall runoff on slopes, and a Cellular Automata (CA) based model for rainwater movement process was developed. This model modified the Green-Ampt (G-A) infiltration model by adopting an elliptical water content curve and introducing a coefficient that quantifies the ratio of saturated to unsaturated depth. Additionally, we refined the rules governing runoff generation and convergence within the slope and on its surface, enabling a comprehensive simulation of the entire rainwater movement process on the slope. Furthermore, the effectiveness of the model was validated through analytical solutions derived from simplified assumptions, laboratory experiments on infiltration and runoff in the flume, and a case study of a natural slope. The results show that the infiltration calculation results of the rainwater movement model are closer to the experimental values, and their overall values are slightly higher than the measured values, which are basically consistent with the model test results; The runoff calculation results show a phenomenon of initially increasing and gradually approaching the measured values compared to the measured values. When applying the model to an actual slope, it was found that the model comprehensively accounts for the influence of slope seepage, infiltration and runoff process, has better performance compared to G-A modified model. The model can be used to describe the spatial distribution and temporal variation of infiltration and runoff processes.

Rainfall serves as a significant factor contributing to slope stability challenges in mountainous areas, and simulating the process of slope rainwater movement is a crucial approach for analyzing the stability of slopes triggered by rainfall. By combining computer numerical simulation technology with traditional hydraulic and hydrological calculation theories, it is possible to create an efficient and precise rainwater movement model that can simulate and analyze the process of rainwater movement on slopes. Utilizing natural slopes as the focal point of our research, the cellular automaton method was applied to simulate rainfall runoff on slopes, and a Cellular Automata (CA) based model for rainwater movement process was developed. This model modified the Green-Ampt (G-A) infiltration model by adopting an elliptical water content curve and introducing a coefficient that quantifies the ratio of saturated to unsaturated depth. Additionally, we refined the rules governing runoff generation and convergence within the slope and on its surface, enabling a comprehensive simulation of the entire rainwater movement process on the slope. Furthermore, the effectiveness of the model was validated through analytical solutions derived from simplified assumptions, laboratory experiments on infiltration and runoff in the flume, and a case study of a natural slope. The results show that the infiltration calculation results of the rainwater movement model are closer to the experimental values, and their overall values are slightly higher than the measured values, which are basically consistent with the model test results; The runoff calculation results show a phenomenon of initially increasing and gradually approaching the measured values compared to the measured values. When applying the model to an actual slope, it was found that the model comprehensively accounts for the influence of slope seepage, infiltration and runoff process, has better performance compared to G-A modified model. The model can be used to describe the spatial distribution and temporal variation of infiltration and runoff processes. [ABSTRACT FROM AUTHOR]

[Objective] The objective of this study was to determine the impact of the combined application of PAM (polyacrylamide) and humic acid on the vertical infiltration characteristics of purple soil in order to provide theoretical references for water and soil conservation, soil improvement, water regulation, and efficient utilization of agricultural water resources in the purple soil region of western Sichuan. [Methods] An indoor soil column simulation experiment was conducted with one check treatment (CK, no mixing), three PAM application levels (PAM-1: 1%, PAM-3: 3%, PAM-5: 5%), and two humic acid application levels (HA-1: 0.1%, HA-5: 0.5%). Infiltration rate, cumulative infiltration volume, and wetting peak transport distance were measured and the variation characteristics were analyzed. The infiltration process was simulated and analyzed using infiltration models. [Results] Compared with CK, the other treatments effectively reduced water infiltration rate, and the infiltration rate gradually decreased with increasing application rate. Under the same cumulative infiltration amount, the infiltration time of each treatment (except H1P1) was greater than that of CK, among which H1P3 and H2P3 were 14.7 times and six times, respectively, the infiltration time of CK. H1P1 had an infiltration time that was 25% less than CK. Within 220 min, the wetting peak transport distances in all treatments were lower than that of CK, with the lowest wetting peak transport distance (4.98 cm) in H1P3, which was significantly shorter (57.67%) than that of CK. Model applicability followed the order of general empirical formula>Kostiakov formula>Horton formula>Philip formula. However, the steady permeability rate (fs) of the general empirical formula deviated from the measured values. [Conclusion] PAM mixed with humic acid can effectively decrease infiltration rate, reduce cumulative infiltration, and slow down the transport distance of the wetting peak. The infiltration reduction effect became more evident with increasing application amount. The optimal treatment was H1S3 (humic acid 0.1 g/g and PAM 3 g/g. Compared with other formulas, the Kostiakov formula was more suitable for describing the soil water infiltration process in the study area.

[Objective] The mechanism on how bryophytes influence water infiltration in the soil surface layer following a short period of heavy precipitation was studied in order to provide data support for the use of bryophytes to control soil erosion in rocky desert areas. [Methods] We measured soil water infiltration in a laboratory study using a one-dimensional soil column covered with Hypnum plumaeforme, Anomodon viticulosus, Weisia controversa, or Bryum coronatum after a short period of 20 mm of precipitation. We used the classical Horton infiltration model and Singh’s entropy infiltration equation to simulate water infiltration, and compared the differences in soil water infiltration. [Results] ① The initial, stable, and mean infiltration rates and the cumulative infiltration amount for the bryophyte-cover treatments were all greater than observed for the bare soil treatment (p

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]

[Objective] The effects of different long-term vegetation restoration types on differences of soil surface infiltration and water storage in the loess gully region of Western Shanxi Province were studied in order to screen and enhance the ecological benefits of natural vegetation restoration as well as artificial vegetation restoration in Loess Plateau in the future, thereby providing a scientific reference for an in-depth understanding of the ecological benefits of vegetation restoration. [Methods] We measured infiltration in the top 30 cm of soil under four types of restored vegetation (Pinus tabulaeformis pure forest, Robinia pseudoacacia pure forest, Platycladus orientalis pure forest, natural forest). We also measured soil physical and chemical properties such as soil bulk density and mechanical composition, and monitored soil moisture dynamics in the four types of restored vegetation in the loess hilly-gully region. We calculated soil water storage and analyzed differences due to vegetation type, and conducted correlation analysis and principal component analysis. Three soil infiltration models were then fitted to the measured processes in order to compare their suitability for use in vegetation restoration areas of the loess hilly-gully region. Differences in soil infiltration and water storage between different vegetation restoration types were also determined. We also evaluated the ability of the models to supplement and improve the surface soil water infiltration pattern under different vegetation restoration types in the Loess Plateau region. [Results] ① Natural forest was more effective in improving the physical properties of the 0—30 cm surface soil compared with pure planted forests. Natural forest had greater water content and better water retention, and planted forests were more effective in improving the infiltration capacity of the soil in the study area compared with natural forest. ② The stable infiltration rate of soil under different vegetation types from largest to smallest followed the order of natural forest > Robinia pseudoacacia pure forest > Pinus tabulaeformis pure forest > Platycladus orientalis pure forest (for the 0—10 cm layer); Pinus tabulaeformis pure forest > Robinia pseudoacacia pure forest > Platycladus orientalis pure forest > natural forest (for the 10—20 cm layer); Pinus tabulaeformis pure forest > Robinia pseudoacacia pure forest > Platycladus orientalis pure forest > natural forest (for the 20—30 cm layer); ③ The Horton model performed better than the Kostiakov and Philip models in fitting soil infiltration in the study area (R2=0.94), and will be helpful in better understanding the soil infiltration pattern in the study area. ④ The main physical characteristics affecting soil infiltration rate were soil bulk density, soil organic carbon, soil water storage capacity and soil clay particle content. [Conclusion] There were significant differences in soil infiltration properties due to different long-term vegetation restoration types. Compared with long-term replanted forests, the long-term natural forest had greater vegetation restoration benefits, and could effectively improve soil quality and enhance soil water retention capacity for the Loess Plateau.

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Copyright of Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation Editorial Office 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.)

Copyright of Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation Editorial Office 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 objective of this paper was to evaluate a recently proposed comprehensive model for three-dimensional single-ring infiltration and its suitability for estimating soil hydraulic properties. Infiltration data from four different soils with contrasting characteristics were inverted to estimate field-saturated soil hydraulic conductivity, Kfs, values using a total of fourteen different scenarios. Those scenarios differed by: i) the way they constrained the macroscopic capillary length, λ, and the initial and saturated soil water contents, θi and θs, ii) the use of transient or steady-state data, and iii) the fitting methods applied to transient data. For comparative purposes, the SSBI method (Steady version of the Simplified method based on a Beerkan Infiltration run) was also applied. For validation purposes Kfs data estimated from the different scenarios were compared with those values obtained by numerical inverse modeling with HYDRUS-2D/3D. This comparison identified Approaches 1 and 3, which respectively estimate Kfs via optimization and using analytical expressions, as the most accurate methods. The steady-state scenario of Approach 4 and the SSBI method, both of which use a λ value of first approximation, appeared preferable for field campaigns aimed to sample remote or large areas, given that they do not need additional data and still provide acceptable estimates. The reliability of Kfs data was also checked through a comparison with unsaturated hydraulic conductivity, Kh, values measured in laboratory on extracted soil cores, in order to discriminate between theoretically possible (Kfs > Kh) and impossible (Kfs ≤ Kh) situations. Physically possible Kfs values were always obtained with the exception of the crusted soil, where Kfs < Kh situations suggested that the crust layer reduced water flow during ponding experiments in the field. The new comprehensive model tested in this study represents a valuable tool for analyzing both transient and steady-state infiltration data, as well as experiments carried out with different depths of ponded water, ring sizes and ring insertion depths.

The objective of this paper was to evaluate a recently proposed comprehensive model for three-dimensional single-ring infiltration and its suitability for estimating soil hydraulic properties. Infiltration data from four different soils with contrasting characteristics were inverted to estimate field-saturated soil hydraulic conductivity, Kfs, values using a total of fourteen different scenarios. Those scenarios differed by: i) the way they constrained the macroscopic capillary length, λ, and the initial and saturated soil water contents, θi and θs, ii) the use of transient or steady-state data, and iii) the fitting methods applied to transient data. For comparative purposes, the SSBI method (Steady version of the Simplified method based on a Beerkan Infiltration run) was also applied. For validation purposes Kfs data estimated from the different scenarios were compared with those values obtained by numerical inverse modeling with HYDRUS-2D/3D. This comparison identified Approaches 1 and 3, which respectively estimate Kfs via optimization and using analytical expressions, as the most accurate methods. The steady-state scenario of Approach 4 and the SSBI method, both of which use a λ value of first approximation, appeared preferable for field campaigns aimed to sample remote or large areas, given that they do not need additional data and still provide acceptable estimates. The reliability of Kfs data was also checked through a comparison with unsaturated hydraulic conductivity, Kh, values measured in laboratory on extracted soil cores, in order to discriminate between theoretically possible (Kfs > Kh) and impossible (Kfs ≤ Kh) situations. Physically possible Kfs values were always obtained with the exception of the crusted soil, where Kfs < Kh situations suggested that the crust layer reduced water flow during ponding experiments in the field. The new comprehensive model tested in this study represents a valuable tool for analyzing both transient and steady-state infiltration data, as well as experiments carried out with different depths of ponded water, ring sizes and ring insertion depths.

The study focuses on the effects of slope on the infiltration process and runoff generation for the soil samples from landfill, agricultural and bare surfaces under similar simulated rainfall. Hillslope experimental setup was designed to conduct the experiments with the slope of 10, 20 and 30°. The results indicate that minimum and maximum infiltrated volumes were presented by landfill soil (at 30°) and agricultural soil (at 10°), respectively. Results also reported that, apart from the slope, the amount of induced runoff was significantly affected by land uses and type of surface erosion. The experimental observations were used to estimate empirical infiltration model parameters using nonlinear least square and Artificial Neural Network (ANN) two-layer back-propagation, describing the variation of infiltration rates with slope and soil samples, which showed a decent agreement with the observed data presenting an average R2 and NSE as 0.88 and 0.92, respectively. The efficiency of ANN performance was also found to be associated with a higher proportion of training data. The findings have extensive implications for evaluating the rainfall-runoff process and infiltration estimation for chosen land uses in the urban area. Research highlights: The infiltration process was significantly affected by urban land uses (agricultural land, bare surface and solid waste landfill) as soil samples from landfill and agricultural soil samples showed the lowest and highest cumulative infiltration, respectively, for selected slope ranges 10, 20, 30°. An increment in slope from 10° to 20° caused the reduction in cumulative infiltration by 10.1% and 17.2% and 3% for bare surface, landfill soil and agricultural soil, respectively. Similarly, an increment in slope from 10° to 30° caused the reduction of infiltrated volume by 23.9, 23.8 and 25.4% landfill soil, bare surface soil and agricultural soil, respectively. An increment in slope from 10° to 20° caused 1.31, 1.13 and 1.27 times increment in the runoff for bare surface, landfill soil and agricultural soil, respectively. Similarly, an increment in slope from 10° to 30° caused a 1.65, 1.25, and 4.65 times rise in runoff volume at the downslope for bare surface, landfill soil and agricultural soil, respectively. Experiments had shown no significant relation of slope variation with initial infiltration rate (fo) and constant infiltration rate (fc), although rates were found dependent on land uses and highly influenced by surface erosion mechanism. The Horton model has demonstrated the most efficient results compared to other models for all focused inclined surfaces of soil samples extracted from targeted land uses. The ANN model can be used for parameter estimation based on the field experimental inputs for different land uses with various slopes. The overall performance of the ANN model was found suitable for estimation of the model parameters by evaluating average R2 and NSE as 0.943 and 0.93, respectively, for all mentioned scenarios. [ABSTRACT FROM AUTHOR]

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• A model of bentonite–sand infiltration behavior is presented. • The model has two components: infiltration and prediction models. • The model explains the bentonite–sand slurry infiltration mechanism. • The model predicts mud-spurt occurrences during shield tunneling in sandy layers. During slurry pressure-balance (SPB) shield tunneling in a sand layer, the excavated sand mixes with bentonite slurry. Herein, the pressure infiltration of the saturated sand by the bentonite–sand slurry is modeled to describe the slurry and companion-water flows during the mud spurt period. A maximum infiltration-depth prediction model is also implemented, based on the principles of particle deep-bed filtration. The model closely matches experimental results for a slurry with a low sand-to-bentonite mass ratio, but tends to overestimate the infiltration distance as the mass ratio increases. Furthermore, the prediction model reflects the continuous infiltration phenomenon associated with elevated sand concentrations in the slurry. When combined with the maximum-depth prediction model, the infiltration model strongly aligns with the experimental findings for the mud spurt period. The combined model effectively explains the bentonite–sand slurry infiltration mechanism and accurately predicts mud-spurt occurrences during SPB shield tunneling in sandy layers. [ABSTRACT FROM AUTHOR]

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【Background】 Seasonal water shortage in southern China has made water supply unable to meet the demand and using unconventional water as a supplementary resource for irrigation can partly relieve this pressure. The widely distributed red soils in southern China are weakly acidic characterized by low porosity, and to what extent irrigating such soils with salt-rich unconventional water affects their transport properties is poorly understood. 【Objective】 This paper is to fill this gap by systematically studying the effect of irrigation water salinity on water flow and solute movement in the red soil aimed to improve unconventional water irrigation management in these regions. 【Method】 The experiment was conducted in repacked columns with distilled-water irrigation taken as control (CK); the concentration of the irrigation water ranged from 1.0 to 10 g/L. In each treatment, we measured spatial distribution of water and salt in the soil profile, as well as pH at the end of infiltration. 【Result】 Compared with CK, saline water irrigation impeded water infiltration, with the impedance increasing with salinity concentration. Water-holding capacity of the soil did not show noticeable change when the salinity was less than 3 g/L, but increased significantly when the salinity was 5 g/L (p0.95 and RMSE

ABSTRACT Soil water infiltration rates are essential for hydrological studies, planning and design of irrigation and drainage systems, among other applications. Various studies have been carried out in plots with and without vegetation cover, aiming to identify the influence of the cover on the water infiltration process in soil. However, a few works have addressed the relationship between infiltration rates of a plot with and without vegetation cover. Here we investigated the ability to iterate between infiltration rates with and without vegetation cover, seeking to identify potential correlations. We propose an innovative and easy-to-use empirical model that allows the conversion of infiltration rates in systems with vegetation cover into infiltration rates without coverage and vice versa. Altogether, we used a dataset comprising 142 rainfall simulation experiments under plots with and without cover, including 6 different types of soil and 18 types of land cover and management. The proposed model was based on the Kostiakov-Lewis model, presenting performance similar to other infiltration models, which is effective in a variety of planting and vegetation cover systems.

Some Swedish school buildings built in the 1960s and 1970s experience indoor air quality problems, where the contaminants are suspected to come from the crawl space underneath the building. The poor indoor air quality causes discomfort among pupils and teachers. Installing an exhaust fan to maintain a negative pressure difference in the crawl space relative to indoors or increasing the ventilation in the classroom are two examples of common measures taken to improve the indoor air quality. However, these measures are not always effective, and sometimes the school building has to be demolished. The relation between pressure distribution, contaminant concentration in the classroom, outdoor temperature, wind, mechanical ventilation, and air leakage distribution is complex. A better understanding of these relations is crucial for making decisions on the most efficient measure to improve the indoor air quality. In this paper, a model for contaminant infiltration from the crawl space is used together with the Monte Carlo method to study these relations. Simulations are performed for several cases where different building shapes, building orientations, shielding conditions, and geographical locations are simulated. Results show, for example, that for a building with an imbalanced ventilation system, air is leaking from the crawl space to the classroom for the majority of cases and that concentration levels in the classroom are usually the highest during mild and calm days. [ABSTRACT FROM AUTHOR]

Soil infiltration is important for urban open space to exert sponge benefits, and its permeability characteristics are influenced by physical and chemical properties. To determine the characteristics and differences of soil permeability in different open spaces, we used the cutting-ring method to measure the soil infiltration process in four types of open space. The effects of physicochemical properties on soil infiltration were analyzed through comparison. The infiltration process of the four types of green spaces was fitted on the basis of Kostiakov and Philip infiltration models, and the suitability of the models was discussed. The water infiltration process shows that the law of initial infiltration rate > average infiltration rate > stable infiltration rate. The stable infiltration rate of each green space ranges from 2.46 mm/min to 3.60 mm/min, and the ranking is as follows: park > square > block > other shared space. The determination coefficient of the Kostiakov model for the soil infiltration process of the four types of green space is higher than 0.94, which is suitable to describe the soil infiltration characteristics of green space in the study area. The soil infiltration performance of green space shows a negative correlation with soil bulk density and moisture content but a positive correlation with non-capillary porosity. This study provides a reference for the construction of sponge cities and ecological hydrological observation.

Loess is a kind of Quaternary loose deposits. There are many primary and secondary pores and cracks in the loess, which provide preferential channels for water to enter the soil and form preferential infiltration phenomenon. This water movement mode is called preferential flow. The existence of preferential infiltration and preferential flow is one of the main causes of landslide and other loess geological disasters, so it is necessary to study the phenomenon of preferential infiltration. Based on the discussion of the classification of loess dominant structural planes by previous scholars, this paper puts forward the classification method of loess preferential channels, then discusses the preferential flow classification of domestic and foreign scholars and the main research methods, and analyzes their advantages and disadvantages. This paper summarizes the main infiltration models of the current preferential flow and the characteristics of the governing equations representing the models, analyzes and discusses the deficiency of present research and the development direction in the future at the end. [ABSTRACT FROM AUTHOR]

The in-situ liquid injection leaching process of ionized rare earth is a typical process of effusion infiltration, and the infiltration efficiency directly determines the mining efficiency. Assuming that the infiltrated (NH4)2SO4 solution is uniformly distributed in the homogeneous orebody, the relationships between the following groups are derived and studied: (1) The position and time of the infiltration front; (2) The infiltration intensity and the infiltration time; (3) The advancing speed and time of the infiltration front.A wireless network sensor detection system for parameter detection is established based on 4G network,air pressure sensor and water sensor are embedded in the ore body.The sensors are connected to the terminal via the 4G network,the data collection and wireless transmission of water content change and air pressure change of one-imensional fluid infiltration test in the homogeneous ore body with different compaction density were completed by the proposed wireless network sensor detection system. The results show that the influence of residual air pressure can be ignored during the infiltration;the advancing speed of the infiltration front is the fastest at the beginning, and then gradually decreased and stabilized; the change process of infiltration volume corresponds to the process of infiltration front advancing speed; the higher the density, the slower the advancing speed of the infiltration front, the lower the infiltration intensity, and the more difficult the infiltration; the deduced theory can be in good agreement with the actual infiltration situation with high accuracy, which can effectively simulate the infiltration process of ionized rare earth in-situ liquid injection mining. [ABSTRACT FROM AUTHOR]

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Abstract The movement of water into soil is the primary driving force in nutrient transport for crops, and the laws governing this movement can be affected by crop roots and plough pans. The main objectives of this study were to monitor the movement of water during rain along a soil profile influenced by soybean roots and a plough pan and to assess whether these factors influenced the efficacy of using the Richards equation to simulate the transport of soil water along a profile associated with a single rain. Experiments and model simulations were carried out. Our results suggested that the soybean field soil may have had preferential flow paths. Soybean stems and leaves transferred rainwater that otherwise would have fallen farther from the central stalk. The transmission of rainwater by the branches and leaves had a larger effect than the interception of rainwater by the branches and leaves. The effect of the root system on the soil particles may increase soil capillary action and ultimately increase saturated hydraulic conductivity. Saturated hydraulic conductivity was higher near the surface than at depth, because the transmission of water by the root system and the effect of large gaps were greater in the soil near the surface. Saturated hydraulic conductivity for both bare land and land covered with soybean plants decreased linearly from depths of 0–15 cm along the soil profile, particularly in the presence of a plough pan. We developed a linear equation to represent the variation in saturated hydraulic conductivity in the 0–15-cm layer in the black soil area of northeastern China. Using our linear model for saturated hydraulic conductivity as a parameter, the Richards equation more accurately simulated soil water transport along a profile influenced by soybean roots and a plough pan in rainy conditions.

In this study, negative head height tests were performed on loess samples from Weibei, Shaanxi, China, to investigate capillary ascent in unsaturated compacted loess. The results of tests performed under different compaction intensities were used to determine the change relationships between the negative head height and blow count and between the pore diameter and blow count. The curve relating the capillary height to the compacted loess pore diameter was approximately parabolic, with the critical pore diameter corresponding to the peak capillary height. The conditions of applicability of Jurin's law were analyzed. A capillary resistance to capillary water, in addition to surface tension and gravity, was identified during capillary migration. A stress analysis of capillary pore water was used to propose a method for determining the critical infiltration surface depth of an unsaturated loess. [ABSTRACT FROM AUTHOR]

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Field-scale estimation of a soil infiltration function is important for the design, simulation, and/or evaluation of surface irrigation systems. Semi-empirical and empirical infiltration models are used to estimate the infiltration function. Semi-empirical infiltration models have substantial computational and parameterization complexities, e.g., soil hydraulic parameters are needed to estimate the infiltration function. In contrast, empirical infiltration models are generally not considered to have specific initial and boundary conditions. The objectives of this study were to compare a semi-empirical infiltration model and an empirical infiltration model. The Green-Ampt model (GA) and the Kostiakov model (KE) were used as semi-empirical and empirical infiltration models, respectively. The soil hydraulic parameters for the GA model were estimated using various pedotransfer functions (PTFs), and in an additional assessment, the measured water content data were used to calibrate and validate the soil hydraulic parameters using the HYDRUS-1D model. The results show that the hydraulic performance computed with the KE or GA model is nearly the same, as long as they are calibrated using the same observation data. Additionally, the results indicate that the GA model with the soil hydraulic parameters obtained from the PTFs adequately represented the soil infiltration function in the borders. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering 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.)

To determine the influence of different bulk densities and texture on soil water infiltration after remediation in gravel-mulched areas, we subjected two different soil types were to a battery of tests to determine their soil infiltration characteristics. The results show that the soil infiltration capacity decreases with increasing soil bulk density. A logarithmic negative correlation was identified between stable infiltration rate and the bulk density of the two soils (R2 > 95%). Moreover, the larger the bulk density, the smaller the cumulative infiltration, and there is a significant linear negative correlation between density and infiltration. The Kostiakov infiltration model better describes the infiltration process of the Lou soil at all stages and the infiltration of Yellow-brown soil before 40 min. Finally, as soil water is redistributed, and its content increases with soil depth, and the greater the bulk density, the greater the water storage capacity of the soil from 0 to 30 cm. Overall, the soil bulk density should be no less than 1.5 g/cm3 when Lou soil is chosen to cover on gravel-mulched land, and not less than 1.4 g/cm3 for Yellow-brown soil. [ABSTRACT FROM AUTHOR]

Field-saturated hydraulic conductivity (Kfs) is an important parameter used to estimate field water requirements in irrigation systems, although it is widely considered to be difficult to determine. In this study, we conducted 27 field infiltration tests with a double-ring infiltrometer to determine Kfs in agricultural fields during the dry season in Myanmar. However, Kfs values estimated by fitting the Philip model (Soil Sci 84(3):257–264, 1957. 10.1097/00010694-195709000-00010) to the measured data produced negative values for many fields. The aims of this study were the following: (1) to select an infiltration model applicable to irrigable fields for which parameter Kfs of the Philip model obtained negative values, (2) to identify factors causing erroneous Kfs values, and (3) to present a method of obtaining valid Kfs values in a case study conducted in Myanmar. Using the data obtained, the performance of five models, Philip, Swartzendruber (Water Resour Res 23(5):809–817, 1987. 10.1029/WR023i005p00809), Brutsaert (Water Resour Res 13(2):363–368, 1977. 10.1029/WR013i002p00363), Mezencev (Meteorol Hidrol 3:33–40, 1948), and Horton (Proc Soil Sci Soc Am 5:339–417, 1940), were assessed by examining fitting quality and estimates of Kfs values. The results showed the following: (1) The Horton model was the most useful, as it showed the better fitting of parameters; (2) factors that produced negative Kfs values were deformation of the infiltration curve due to the magnitude of initial infiltration caused by drying of the soil; and (3) nonnegative Kfs values were obtained by rejecting an initial infiltration period, determined by improving the cumulative linearization approach of the Philip model. The revised Kfs was overestimated in comparison with reference values, so a formula for applying revised Kfs was presented. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering 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.)

Highlights • Impacts of cultivation practices on the infiltration process of lateritic soils are investigated. • Infiltration models are assessed for simulating infiltration behavior at plot and field scales. • Swartzendruber model gives best estimates of saturated hydraulic conductivity. • Swartzendruber, Brutsaert and Kostiakov-Lewis models show best fitting ability. • Infiltration characteristics of lateritic soils are greatly affected by cultivation practices. Abstract Lateritic vadose zone, mostly found in tropical humid regions, is very complex and hence behaves in a different way than other vadose zones. Until now, little is known about the impact of agricultural practices on the infiltration dynamics of such vadose zones. To this end, the present study was conceived to explore infiltration characteristics of lateritic soil-water zones by conducting 72 double-ring infiltration experiments at multiple sites considering both plot and field scales having paddy-wheat cultivation practices. Furthermore, five infiltration models, two empirical (Kostiakov and Kostiakov-Lewis) and three process-based (Philip Two-Term, Swartzendruber and Brutsaert) were fitted to the site-specific infiltration data and their performance was critically evaluated for modeling infiltration behavior of the lateritic vadose zone. Results indicated that the mean 'quasi-steady infiltration rate' of the Experimental Plot measured before paddy cultivation was about 0.23 ± 0.2 mm/min, which decreased by around 80% after paddy cultivation and then increases by more than 200% after wheat cultivation. Similarly, at the field scale, the 'quasi-steady infiltration rate' decreases by about 60% after paddy cultivation. The Swartzendruber model followed by the Brutsaert model provided the most reliable estimates of saturated hydraulic conductivity. The Swartzendruber, Brutsaert and Kostiakov-Lewis models showed a greater fitting ability in predicting 'cumulative infiltration' under all cultivation practices at both plot and field scales. In contrast, all the five infiltration models predicted infiltration rate with a lower accuracy than the cumulative infiltration. It is concluded that the infiltration characteristics of lateritic vadose zones are greatly influenced by cultivation practices as well as by macro-pores and low-permeability layers present in the soil profile. Given the significant field heterogeneity, future studies should explore the efficacy of other process-based infiltration models [e.g., the Smith and Parlange (1978) model, the Kutílek and Krejča model (1987), and the modified Green-Ampt models] in predicting the infiltration characteristics of lateritic terrains. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a new procedure to perform geological and geotechnical land zoning at the 1:50,000 scale for potential Hortonian overland flow (R pot values). The procedure was applied to the Ribeirão do Feijão Basin, São Paulo State, Brazil. The zoning was conducted using a procedure that combines rainfall data, engineering geological mapping, infiltration modelling, and anthropogenic and geomorphic aspects. The association between the geological-geotechnical units defined by the engineering geological mapping and the land use types generated 29 different infiltration condition categories, which were used to divide the basin into 94 territorial units. The in situ infiltration test and geotechnical data for each infiltration condition category combined with several rainfall event types were used as inputs to the Philip model to obtain the values of the R pot and infiltration values. The R pot and infiltration values estimated by the proposed procedure agreed well with the values estimated by the Chu model. The 94 territorial units were grouped into 4 classes based on the variability and magnitude of the potential Hortonian overland flow. The first class represents the areas where infiltration predominates (59 km2) for all selected rainfall events, and the second class represents areas of infiltration and flooding (11 km2). Infiltration is predominant in the third class; however, overland flow can be generated (133 km2) depending on the intensity and duration of the rainfall event. The fourth class represents the main source areas of overland flow generation and runoff (40 km2). The areas considered in the third and fourth classes are affected by erosion processes due to the potential generation of Hortonian overland flow. The results indicated that the proposed procedure is adequate for identifying, characterizing, classifying and dividing a region into units with distinct geological and geotechnical zones that are associated with potential Hortonian overland flow. Therefore, the procedure is an appropriate tool for regional planning and water management at the 1:50,000 scale because the results define land units with specific environmental characteristics. The application of the procedure is not expensive and uses common equipment but requires experienced or trained professionals to perform the field and laboratory work. Highlights • In situ infiltration tests are important for characterizing geotechnical variability. • Philip infiltration model was used to estimate potential Hortonian overland flow. • Appropriate geotechnical characterization is essential to overland flow estimation. • 94 territorial units were classified in four geological and geotechnical zones. • The proposed procedure is suitable for regional planning and water management. [ABSTRACT FROM AUTHOR]

This study explores the infiltration law for water-repellent soil and identifies the most suitable mathematical model. A laboratory experiment was conducted using a one-dimensional vertical soil column,and the water infiltration into this column was measured for both hydrophilic and hydrophobic soils from the Guishui River basin. The experimental data were then fitted using a Kostiakov piecewise function,Fourier series,first-order Gaussian function,and Gaussian piecewise function. The results indicate that the cumulative infiltration increases to a plateau,whereas,for hydrophobic soil,the infiltration rate is a single-peak curve that increases and then decreases with time. Model graphical analysis shows that the Kostiakov piecewise function model has a maximum and a minimum value appear simultaneously at inflection point of infiltration rate. The produces multiple peaks that do not reflect the monotone increase and decrease of the infiltration rate either side of the peak for Fourier series model. The first-order Gaussian function model cannot replicate the test phenomenon whereby the infiltration rate after the maximum is greater than before. If we ignore the rapid infiltration process at the beginning of the experiment,the Gaussian piecewise function model not only reflects the monotone increase and decrease either side of the peak infiltration rate,but also produces the experimental phenomenon whereby the infiltration rate after the maximum is greater than before. [ABSTRACT FROM AUTHOR]

Gas service stations are one of the major sources of volatile organic compounds in urban environments. Their emissions are expected not only to affect the ambient air quality but also that in any nearby buildings. This is particularly the case in Malta where most service stations have been built within residential zones. For this reason, it is important to understand the dispersion of volatile organic compounds (VOCs) from service stations and their infiltration into nearby residences. Two models were considered; one to predict the dispersion of VOCs in the outdoor environment in the vicinity of the service station and another one to predict the filtration of the compounds indoors. The two models can be used in tandem to predict the concentration of indoor VOCs that originate from a service station in the vicinity. Outdoor and indoor concentrations of VOCs around a service station located in a street canyon were measured, and the results used to validate the models. Predictions made using the models were found to be in general agreement with the measured concentrations of the pollutants. [ABSTRACT FROM AUTHOR]

• A thorough theoretical analysis of three new hydrological infiltration models. • A thorough evaluation against Hydrus outputs and experimental infiltration data. • Best model based on GA approach with parametrization of initial pressure head. Infiltration is a crucial process in various fields such as hydrology, agriculture, urban soils, and particularly for Sustainable Urban Drainage Systems (SUDS) operation. Over the past century, the physics of infiltration has been extensively studied by developing models that estimate the dynamics of infiltration. In this study, three physically-based infiltration models (CH 1, CH 2, and CH 3) have been developed as part of the Canoe Hydrobox (CH) platform, designed to simulate and evaluate the performance of SUDS. The three models rely on similar approaches to the Green-Ampt (GA) model by describing the water flux as the product of the equivalent hydraulic gradient and the equivalent hydraulic conductivity. The models differ in their ways of defining the hydraulic gradient and conductivity from the hydric conditions, soil parameters, and geometric features. The two first models (CH 1 and CH 2) consider an increase in the hydraulic conductivity with infiltrated water amount, whereas the last model (CH 3) considers only the saturated hydraulic conductivity. For the hydraulic gradient, the first model considers the difference between the surface water pressure head and the height of infiltrated water. The other two models consider the difference between the surface water pressure head and the isostatic water pressure head at the surface in equilibrium with the height of infiltrated water. These models were applied to simulate water infiltration processes into dry, wet, and intermediate-wet soils. We compared these results with the numerical solution of the Richards equation using HYDRUS software. The comparison allowed the assessment of the capability of CH models to satisfy the critical principles of soil water infiltration. Subsequently we used the three models to invert six real experimental infiltration data to test their capability to work in inverse mode. The two models (CH 1 and CH 2) produced specific time-evolution of infiltration rates in disagreement with the physics of water infiltration under regular conditions (e.g., no water repellence). The third model (CH 3) performed the best for both direct and indirect modes and is therefore considered as the best candidate. The CH 3 model will be implemented in the new version of Canoe Hydrobox (CH) platform. This study provides a basis for further research into hydrological models for SUDS and their hydraulic performance. [ABSTRACT FROM AUTHOR]

The impact of the infiltration and airflow pattern of the building envelope and structure on thermal load is significant. Building energy simulation tools take this feature into account when calculating the heating and cooling load and evaluating the indoor hygrothermal environment. However, in many cases, the infiltration and airflow modeling is performed without appropriate assumption and understanding in research and the industrial field of building energy simulations. This is due to not only the lack of understanding or ignorance of their significance but also the complex nature of the infiltration and airflow pattern in buildings. In this study, the history and theoretical background of the infiltration and airflow models, which have been developed for several decades by various researchers with different types of tools, are investigated. The historical evolution of the models and their adoption in different building energy simulation tools are discussed to facilitate the proper use and implementation of infiltration and airflow models. Finally, the guidelines and practical insight for selecting the appropriate infiltration and airflow models in building energy simulation are presented with different scenarios of modeling along with actual examples from previous studies. • Discussed history and theoretical background of infiltration and airflow models. • Illustrated adoption of infiltration and airflow models into building energy simulation tools. • Presented guidelines for selecting appropriate models for building energy modelers. [ABSTRACT FROM AUTHOR]

The partitioning of crop canopy water may affect soil water distribution and this may in turn affect sprinkler irrigation application efficiency. The aim of this work was to develop a methodology to evaluate spatial and temporal soil water content distribution in the case of sprinkler irrigation application efficiency considering stemflow. Time domain reflectometry (TDR) soil moisture monitoring was carried out on eight soil water sensor locations for both center pivot and traveling big gun irrigation in different phenological and tillage cases. The two case studies were chosen because they show the two opposite limits of the methodology's application. Two water distribution estimation methods were employed: raw measured soil moisture and model simulation of the infiltration process. The infiltration process was modeled by means of the two-dimensional (2D) Richard's equation. The simulations were calibrated on the data measured at eight soil water sensor locations. The stemflow and surface runoff conveyed in the interrow by hilling were obtained as additional model-fitting parameters. During center pivot irrigation, 34% of the water delivered in the interrow was conveyed in the row. During traveling big gun irrigation. 88% of the water delivered in the row was conveyed in the interrow. Soil water distributions calculated from measured data overestimated irrigation application efficiency by approximately 15%. The spatial and temporal soil water content distribution obtained from simulation of the water infiltration process allowed mass balance closure in both case studies. The proposed simulation method evaluated stemflow effects on the water distribution profile, leading to accurate application efficiency calculations. [ABSTRACT FROM AUTHOR]