Academic literature on the topic 'Soil water;hydraulic properties;water balance'
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Journal articles on the topic "Soil water;hydraulic properties;water balance"
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Cresswell, HP, DE Smiles, and J. Williams. "Soil structure, soil hydraulic properties and the soil water balance." Soil Research 30, no. 3 (1992): 265. http://dx.doi.org/10.1071/sr9920265.
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We review the influence of soil structural change on the fundamental soil hydraulic properties (unsaturated hydraulic conductivity and the soil moisture characteristic) and utilize deterministic modelling to assess subsequent effects on the soil water balance. Soil structure is reflected in the 0 to -100 kPa matric potential section of the soil moisture characteristic with marked changes often occurring in light to medium textured soils' (sands, sandy-loam, loams and clay-loams). The effect of long-term tillage on soil structure may decrease hydraulic conductivity within this matric potential range. The 'SWIM' (Soil Water Infiltration and Movement) simulation model was used to illustrate the effects of long-term conventional tillage and direct drilling systems on the water balance. The effects of plough pans, surface crusts and decreasing surface detention were also investigated. Significant structural deterioration, as evidenced by substantially reduced hydraulic conductivity, is necessary before significant runoff is generated in the low intensity rainfall regime of the Southern Tablelands (6 min rainfall intensity <45 mm h-1). A 10 mm thick plough pan (at a depth of 100 mm) in the A-horizon of a long-term conventionally tilled soil required a saturated hydraulic conductivity (K,) of less than 2.5 mm h-1 before runoff exceeded 10% of incident rainfall in this rainfall regime. Similarly, a crust K, of less than 2.5 mm h-1 was necessary before runoff exceeded 10% of incident rainfall (provided that surface detention was 2 or more). As the crust K, approached the rainfall rate, small decreases in Ks resulted in large increases in runoff. An increase in surface detention of 1 to 3 mm resulted in a large reduction in runoff where crust K, was less than 2-5 mm h-1. Deterministic simulation models incorporating well established physical laws are effective tools in the study of soil structural effects on the field water regime. Their application, however, is constrained by insufficient knowledge of the fundamental hydraulic properties of Australian soils and how they are changing in response to our land management.
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Connolly, R. D., M. Bell, N. Huth, D. M. Freebairn, and G. Thomas. "Simulating infiltration and the water balance in cropping systems with APSIM-SWIM." Soil Research 40, no. 2 (2002): 221. http://dx.doi.org/10.1071/sr01007.
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We test APSIM-SWIM's ability to simulate infiltration and interactions between the soil water balance and grain crop growth using soil hydraulic properties derived from independent, point measurements. APSIMSWIM is a continuous soil-crop model that simulates infiltration, surface crusting, and soil condition in more detail than most other soil-crop models. Runoff, soil water, and crop growth information measured at sites in southern Queensland was used to test the model. Parameter values were derived directly from soil hydraulic properties measured using rainfall simulators, disc permeameters and ponded rings, and pressure plate apparatus. In general, APSIM-SWIM simulated infiltration, runoff, soil water and the water balance, and yield as accurately and reliably as other soil crop models, indicating the model is suitable for evaluating effects of infiltration and soil-water relations on crop growth. Increased model detail did not hinder application, instead improving parameter transferability and utility, but improved methods of characterising crusting, soil hydraulic conductivity, and macroporosity under field conditions would improve ease of application, prediction accuracy, and reliability of the model. Model utility and accuracy would benefit from improved representation of temporal variation in soil condition, including effects of tillage and consolidation on soil condition and bypass flow in cracks. infiltration, crop models, APSIM, water balance, soil structure.
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Oliver, Y. M., and K. R. J. Smettem. "Predicting water balance in a sandy soil: model sensitivity to the variability of measured saturated and near saturated hydraulic properties." Soil Research 43, no. 1 (2005): 87. http://dx.doi.org/10.1071/sr03146.
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Water balance modelling based on Richards’ equation requires accurate description of the soils’ hydraulic parameters. Unfortunately, these parameters vary spatially and temporally as well as between measurement techniques. For most field modelling exercises, the hydraulic parameters are obtained from a small number of measurements or predicted from soil properties using pedo-transfer functions. The effect of different measurement techniques on the description of soil hydraulic parameters has been the subject of many studies but the effect of the variability of the hydraulic parameters on the predicted water balance has not been widely investigated. In this study we compared the hydraulic parameters obtained solely from laboratory measurements with those obtained from a rapid wet end field measurement technique, augmented by dry end laboratory data. The water balance was modelled using the laboratory and field hydraulic parameter sets and compared to field water contents measured by time domain reflectometry (TDR). In a sandy soil, we found the total profile water content to be well modelled by both hydraulic parameter datasets, but the water content at a specific depth was less well predicted using either of the measured parameter sets. The water content at a specific depth was under-predicted prior to the rainfall event and over-predicted after the rainfall, regardless of whether the hydraulic parameters were obtained from laboratory or field measurements. Generally, the hydraulic parameters that were obtained from the field measurements gave a closer fit to the measured TDR water contents. The sensitivity of the modelled water balance to changes in the hydraulic parameters within the observed range of parameter values was also investigated. Parameter percentage coefficient of variation within measurement techniques ranged from 60% for air entry, he; 19% for residual water content, θr; 5% for slope of the water retention curve, n; and 7% for saturated water content, θs. The percentage differences between the parameters obtained from the laboratory and field measurement techniques for the topsoil and subsoil respectively were 47% and 50% for he, 100% for θr, 28% and 40% for n, and –14.4% and 4.0% for θs. Modelling water content changes at a particular depth in the sandy soil was found to be most influenced by variations in θs, and n. Predicted water contents were also affected by the θr but less influenced by the saturated hydraulic conductivity, Ks. The he was the least influential parameter but also the most variable. This suggests that measurement of θs, related to bulk density changes caused by tillage, wheel compaction, and consolidation, is required for water balance studies. Generally, n had small variability between measurements at a particular depth, which is promising for the use of pedo-transfer functions related to soil texture.
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Smettem, K. R. J., and K. L. Bristow. "Obtaining soil hydraulic properties for water balance and leaching models from survey data. 2. Hydraulic conductivity." Australian Journal of Agricultural Research 50, no. 7 (1999): 1259. http://dx.doi.org/10.1071/ar97075.
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Regional scale application of water and solute transport models is often limited by the lack of available data describing soil hydraulic properties and their variability. Direct measurement over large areas is expensive and time consuming. Physico-empirical models derived from soil survey data are therefore an attractive alternative. If the Marshall method of estimating the saturated hydraulic conductivity is simplified to depend primarily on the maximum pore radius, given by the bubbling pressure, then it is equivalent to the Campbell model of saturated hydraulic conductivity which relies entirely on an estimate of the bubbling pressure obtained from particle size data. We apply this simplified physico-empirical model to estimate the ‘matrix’, or textural saturated hydraulic conductivity, K m, using estimates of the bubbling pressure derived entirely from clay content data that are readily available in soil surveys. Model estimates are compared with in situ measurements on surface soils obtained using a disc permeameter with a negative pressure head at the supply surface of 40 mm. Results appear to be satisfactory for broad-scale water balance and leaching risk models that require specification of a matching point for the unsaturated hydraulic conductivity function and for modelling applications requiring generalised application of results from experimental sites.
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Smettem, K. R. J., K. L. Bristow, L. K. Heng, Y. M. Oliver, and E. J. Ford. "Obtaining soil hydraulic properties for water balance and leaching models from survey data. 1. Water retention." Australian Journal of Agricultural Research 50, no. 2 (1999): 283. http://dx.doi.org/10.1071/a97074.
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A physico-empirical 2-parameter power law model of the draining water retention curve (WRC) based solely on clay content is described and further developed using 6 datasets obtained from Australian and New Zealand soils. The slope of the WRC, or pore-size distribution index, is well described by the model but the bubbling pressure, or inflection point is poorly described. Without a good estimation of the bubbling pressure it is not possible to scale the physico-empirical model to the WRC. To achieve the scaling, a single measured point on the WRC in the unsaturated range is required. The resulting estimated water contents may be satisfactory for application within broad-scale leaching risk models and for generalised extrapolation of results from detailed experimental sites but caution is still required for quantitative applications of nitrate leaching models at a particular site. It is concluded that soil surveys could usefully include a single WRC measurement in the field at each sampling location to improve their utility for water and chemical transport modelling.
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Mohajerani, Hadis, Sonja Teschemacher, and Markus C. Casper. "A Comparative Investigation of Various Pedotransfer Functions and Their Impact on Hydrological Simulations." Water 13, no. 10 (May 17, 2021): 1401. http://dx.doi.org/10.3390/w13101401.
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Soil hydraulic properties, which are basically saturated and unsaturated hydraulic conductivity and water retention characteristics, remarkably control the main hydrological processes in catchments. Thus, adequate parameterization of soils is one of the most important tasks in physically based catchment modeling. To estimate these properties, the choice of the PTFs in a hydrological model is often made without taking the runoff characteristics of the catchment into consideration. Therefore, this study introduces a methodology to analyze the sensitivity of a catchment water balance model to the choice of the PTF. To do so, we define 11 scenarios including different combinations of PTFs to estimate the van Genuchten parameters and saturated hydraulic conductivity. We use a calibrated/validated hydrological model (WaSiM-ETH) as a baseline scenario. By altering the underlying PTFs, the effects on the hydraulic properties are quantified. Moreover, we analyze the resulting changes in the spatial/temporal variation of the total runoff and in particular, the runoff components at the catchment outlet. Results reveal that the water distribution in the hydrologic system varies considerably amongst different PTFs, and the water balance components are highly sensitive to the spatial structure of soil hydraulic properties. It is recommended that models be tested by careful consideration of PTFs and orienting the soil parameterization more towards representing a plausible hydrological behavior rather than focusing on matching the calibration data.
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Ross, Peter J. "A method of deriving soil hydraulic properties from field water contents for application in water balance studies." Journal of Hydrology 144, no. 1-4 (April 1993): 143–53. http://dx.doi.org/10.1016/0022-1694(93)90169-a.
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Hartmann, Anne, Markus Weiler, and Theresa Blume. "The impact of landscape evolution on soil physics: evolution of soil physical and hydraulic properties along two chronosequences of proglacial moraines." Earth System Science Data 12, no. 4 (December 4, 2020): 3189–204. http://dx.doi.org/10.5194/essd-12-3189-2020.
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Abstract. Soil physical properties highly influence soil hydraulic properties, which define the soil hydraulic behavior. Thus, changes within these properties affect water flow paths and the soil water and matter balance. Most often these soil physical properties are assumed to be constant in time, and little is known about their natural evolution. Therefore, we studied the evolution of physical and hydraulic soil properties along two soil chronosequences in proglacial forefields in the Central Alps, Switzerland: one soil chronosequence developed on silicate and the other on calcareous parent material. Each soil chronosequence consisted of four moraines with the ages of 30, 160, 3000, and 10 000 years at the silicate forefield and 110, 160, 4900, and 13 500 years at the calcareous forefield. We investigated bulk density, porosity, loss on ignition, and hydraulic properties in the form of retention curves and hydraulic conductivity curves as well as the content of clay, silt, sand, and gravel. Samples were taken at three depths (10, 30, 50 cm) at six sampling sites at each moraine. Soil physical and hydraulic properties changed considerably over the chronosequence. Particle size distribution showed a pronounced reduction in sand content and an increase in silt and clay content over time at both sites. Bulk density decreased, and porosity increased during the first 10 millennia of soil development. The trend was equally present at both parent materials, but the reduction in sand and increase in silt content were more pronounced at the calcareous site. The organic matter content increased, which was especially pronounced in the topsoil at the silicate site. With the change in physical soil properties and organic matter content, the hydraulic soil properties changed from fast-draining coarse-textured soils to slow-draining soils with high water-holding capacity, which was also more pronounced in the topsoil at the silicate site. The data set presented in this paper is available at the online repository of the German Research Center for Geosciences (GFZ; Hartmann et al., 2020b). The data set can be accessed via the DOI https://doi.org/10.5880/GFZ.4.4.2020.004.
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Filipović, Vilim, Thomas Weninger, Lana Filipović, Andreas Schwen, Keith L. Bristow, Sophie Zechmeister-Boltenstern, and Sonja Leitner. "Inverse estimation of soil hydraulic properties and water repellency following artificially induced drought stress." Journal of Hydrology and Hydromechanics 66, no. 2 (June 1, 2018): 170–80. http://dx.doi.org/10.2478/johh-2018-0002.
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AbstractGlobal climate change is projected to continue and result in prolonged and more intense droughts, which can increase soil water repellency (SWR). To be able to estimate the consequences of SWR on vadose zone hydrology, it is important to determine soil hydraulic properties (SHP). Sequential modeling using HYDRUS (2D/3D) was performed on an experimental field site with artificially imposed drought scenarios (moderately M and severely S stressed) and a control plot. First, inverse modeling was performed for SHP estimation based on water and ethanol infiltration experimental data, followed by model validation on one selected irrigation event. Finally, hillslope modeling was performed to assess water balance for 2014. Results suggest that prolonged dry periods can increase soil water repellency. Inverse modeling was successfully performed for infiltrating liquids, water and ethanol, withR2and model efficiency (E) values both > 0.9. SHP derived from the ethanol measurements showed large differences in van Genuchten-Mualem (VGM) parameters for the M and S plots compared to water infiltration experiments. SWR resulted in large saturated hydraulic conductivity (Ks) decrease on the M and S scenarios. After validation of SHP on water content measurements during a selected irrigation event, one year simulations (2014) showed that water repellency increases surface runoff in non-structured soils at hillslopes.
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Alam, M. Shahabul, S. Lee Barbour, and Mingbin Huang. "Characterizing uncertainty in the hydraulic parameters of oil sands mine reclamation covers and its influence on water balance predictions." Hydrology and Earth System Sciences 24, no. 2 (February 18, 2020): 735–59. http://dx.doi.org/10.5194/hess-24-735-2020.
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Abstract. One technique to evaluate the performance of oil sands reclamation covers is through the simulation of long-term water balance using calibrated soil–vegetation–atmosphere transfer models. Conventional practice has been to derive a single set of optimized hydraulic parameters through inverse modelling (IM) based on short-term (<5–10 years) monitoring datasets. This approach is unable to characterize the impact of variability in the cover properties. This study utilizes IM to optimize the hydraulic properties for 12 soil cover designs, replicated in triplicate, at Syncrude's Aurora North mine site. The hydraulic parameters for three soil types (peat cover soil, coarse-textured subsoil, and lean oil sand substrate) were optimized at each monitoring site from 2013 to 2016. The resulting 155 optimized parameter values were used to define distributions for each parameter/soil type, while the progressive Latin hypercube sampling (PLHS) method was used to sample parameter values randomly from the optimized parameter distributions. Water balance models with the sampled parameter sets were used to evaluate variations in the maximum sustainable leaf area index (LAI) for five illustrative covers and quantify uncertainty associated with long-term water balance components and LAI values. Overall, the PLHS method was able to better capture broader variability in the water balance components than a discrete interval sampling method. The results also highlight that climate variability dominates the simulated variability in actual evapotranspiration and that climate and parameter uncertainty have a similar influence on the variability in net percolation.
Dissertations / Theses on the topic "Soil water;hydraulic properties;water balance"
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Zhang, Shulan. "Soil hydraulic properties and water balance under various soil management regimes on the Loess Plateau, China /." Umeå : Dept. of Forest Ecology, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/2005126.pdf.
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Minasny, Budiman. "Efficient Methods for Predicting Soil Hydraulic Properties." University of Sydney. Land, Water & Crop Sciences, 2000. http://hdl.handle.net/2123/853.
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Both empirical and process-simulation models are useful for evaluating the effects of management practices on environmental quality and crop yield. The use of these models is limited, however, because they need many soil property values as input. The first step towards modelling is the collection of input data. Soil properties can be highly variable spatially and temporally, and measuring them is time-consuming and expensive. Efficient methods, which consider the uncertainty and cost of measurements, for estimating soil hydraulic properties form the main thrust of this study. Hydraulic properties are affected by other soil physical, and chemical properties, therefore it is possible to develop empirical relations to predict them. This idea quantified is called a pedotransfer function. Such functions may be global or restricted to a country or region. The different classification of particle-size fractions used in Australia compared with other countries presents a problem for the immediate adoption of exotic pedotransfer functions. A database of Australian soil hydraulic properties has been compiled. Pedotransfer functions for estimating water-retention and saturated hydraulic conductivity from particle size and bulk density for Australian soil are presented. Different approaches for deriving hydraulic transfer functions have been presented and compared. Published pedotransfer functions were also evaluated, generally they provide a satisfactory estimation of water retention and saturated hydraulic conductivity depending on the spatial scale and accuracy of prediction. Several pedotransfer functions were developed in this study to predict water retention and hydraulic conductivity. The pedotransfer functions developed here may predict adequately in large areas but for site-specific applications local calibration is needed. There is much uncertainty in the input data, and consequently the transfer functions can produce varied outputs. Uncertainty analysis is therefore needed. A general approach to quantifying uncertainty is to use Monte Carlo methods. By sampling repeatedly from the assumed probability distributions of the input variables and evaluating the response of the model the statistical distribution of the outputs can be estimated. A modified Latin hypercube method is presented for sampling joint multivariate probability distributions. This method is applied to quantify the uncertainties in pedotransfer functions of soil hydraulic properties. Hydraulic properties predicted using pedotransfer functions developed in this study are also used in a field soil-water model to analyze the uncertainties in the prediction of dynamic soil-water regimes. The use of the disc permeameter in the field conventionally requires the placement of a layer of sand in order to provide good contact between the soil surface and disc supply membrane. The effect of sand on water infiltration into the soil and on the estimate of sorptivity was investigated. A numerical study and a field experiment on heavy clay were conducted. Placement of sand significantly increased the cumulative infiltration but showed small differences in the infiltration rate. Estimation of sorptivity based on the Philip's two term algebraic model using different methods was also examined. The field experiment revealed that the error in infiltration measurement was proportional to the cumulative infiltration curve. Infiltration without placement of sand was considerably smaller because of the poor contact between the disc and soil surface. An inverse method for predicting soil hydraulic parameters from disc permeameter data has been developed. A numerical study showed that the inverse method is quite robust in identifying the hydraulic parameters. However application to field data showed that the estimated water retention curve is generally smaller than the one obtained in laboratory measurements. Nevertheless the estimated near-saturated hydraulic conductivity matched the analytical solution quite well. Th author believes that the inverse method can give a reasonable estimate of soil hydraulic parameters. Some experimental and theoretical problems were identified and discussed. A formal analysis was carried out to evaluate the efficiency of the different methods in predicting water retention and hydraulic conductivity. The analysis identified the contribution of individual source of measurement errors to the overall uncertainty. For single measurements, the inverse disc-permeameter analysis is economically more efficient than using pedotransfer functions or measuring hydraulic properties in the laboratory. However, given the large amount of spatial variation of soil hydraulic properties it is perhaps not surprising that lots of cheap and imprecise measurements, e.g. by hand texturing, are more efficient than a few expensive precise ones.
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George, Brendan Hugh. "Comparison of techniques for measuring the water content of soil and other porous media." University of Sydney, 1999. http://hdl.handle.net/2123/491.
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The measurement of water in soil on a potential, gravimetric or volumetric basis is considered, with studies concentrating on the measurement of water by dielectric and neutron moderation methods. The ability of the time-domain reflectometry technique to measure water content simultaneously at different spatial locations is an important advantage of the technique. The reported apparent dielectric by the TRASE� time-domain reflectometer and Pyelab time-domain reflectometry systems is sensitive to change in extension cable length. In some soil, e.g. a commercial sand, the response to increasing extension length of extension cable is linear. For other soil a linear response occurs for certain lengths of cable at different moisture contents. A single model accounting for clay content, extension cable length, time-domain reflectometry system, probe type and inherent moisture conditions explained 62.2 % of variation from the control (0 m extension) cable. The extension cable causes a decrease in the returning electromagnetic-wave energy; leading to a decline in the slope used in automatic end-point determination. Calibration for each probe installation when the soil is saturated, and at small water contents is recommended. The ability of time-domain reflectometry, frequency-domain and neutron moderation techniques in measuring soil water content in a Brown Chromosol is examined. An in situ calibration, across a limited range of water contents, for the neutron moderation method is more sensitive to changing soil water content than the factory supplied 'universal' calibration. Comparison of the EnviroSCAN� frequency-domain system and the NMM count ratio indicates the frequency-domain technique is more sensitive to change in soil water conditions. The EnviroSCAN� system is well suited to continuous profile-based measurement of soil water content. Results with the time-domain reflectometry technique were disappointing, indicating the limited applicability of time-domain reflectometry in profile based soil water content measurement in heavy-textured soil, or soil with a large electrical conductivity. The method of auguring to a known depth and placement of the time-domain reflectometry probe into undisturbed soil is not recommended. A time-domain reflectometry system is adapted for in situ measurement of water in an iron ore stockpile. The laboratory calibration for water content of the processed iron ore compares favourably to a field calibration. In the field study, the 28 m extension cable used to connect the probes to the time-domain reflectometry affected the end-point determination of the time-domain reflectometry system. To account for this, 0.197 should be subtracted from the reported apparent dielectric before calculation of volumetric moisture content.
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Jiang, Pingping. "Variability of soil hydraulic properties and estimation of plant-available water on claypan-soil landscapes." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4783.
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Thesis (Ph. D.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 25, 2007) Vita. Includes bibliographical references.
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Shahadha, Saadi Sattar. "Measured Soil Hydraulic Properties as RZWQM2 Input to Simulate Soil Water Dynamics and Crop Evapotranspiration." UKnowledge, 2018. https://uknowledge.uky.edu/pss_etds/110.
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Agricultural system models integrate many different processes that cannot all be measured in field experiments and help quantify soil water dynamics, crop evapotranspiration, and crop growth with high temporal resolution. Understanding soil water dynamics and crop evapotranspiration is essential to improve agricultural management of field crops. For example, the interaction between nitrogen application rate and water dynamics is not sufficiently understood. In most cases, model simulations deviate from field measurements, especially when model input parameters are indirectly and unspecifically derived. The extent to which measured soil hydraulic property inputs decrease the discrepancy between measured and simulated soil water status is not well understood. Consequently, this study: (i) investigated thr use of measured soil hydraulic properties as Root Zone Water Quality Model (RZWQM2) inputs compared to indirectly derived inputs; (ii) explored the capability of calibrating measured soil hydraulic property input parameters for one crop and using them for other crops without further calibration; (iii) studied the effect of the nitrogen application rate on the behavior of soil water dynamics and crop evapotranspiration using RZWQM2 under different rainfall amounts. To evaluate the model in different field management conditions, a field experiment with soybean, corn, wheat, and fallow soil was conducted from 2015 – 2017 to collect field data to calibrate and validate the RZWQM2 model. The model presented a satisfactory response to using measured soil hydraulic property inputs and a satisfactory capability to quantify the effect of nitrogen rates on daily crop evapotranspiration, soil water dynamics, and crop growth. With sufficient measurements of soil hydraulic parameters, it was possible to build a RZWQM2 model that produced reasonable results even without calibration.
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Zhang, Zhuanfang. "Measuring soil hydraulic properties and stochastic analysis of water movement using line sources." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ40393.pdf.
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Scanlan, Craig Anthony. "Processes and effects of root-induced changes to soil hydraulic properties." University of Western Australia. School of Earth and Environment, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0188.
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[Truncated abstract] Root-induced changes to soil hydraulic properties (SHP) are an essential component in understanding the hydrology of an ecosystem, and the resilience of these to climate change. However, at present our capacity to predict how roots will modify SHP and the consequences of this is limited because our knowledge of the processes and effects are highly fragmented. Also, current models used to investigate the relationship between plants and root-induced changes to SHP are based on empirical relationships which have limited applicability to the various and often contrasting ecosystems that occur. This thesis focuses specifically on the quantifying the processes by which roots modify SHP and developing models that can predict changes to these and the water balance. Both increase and decreases in saturated hydraulic conductivity have been attributed to the presence of roots. In general, decreases occur when the root system is relatively young, and increases occur when the roots senesce and begin to decay, creating voids for water flow. The evidence available suggests that the change in pore geometry created by roots is the dominant process by which roots modify SHP because they are more permanent and of a greater magnitude than changes to fluid properties or soil structure. We first quantified the effects of wheat roots on SHP of a coarse sand with a laboratory experiment where we measured changes in both SHP and the root system at 3, 5, 7 and 9 weeks after sowing (weeks). ... The main message that can be drawn from this thesis is that root-induced changes to SHP are dynamic, and dependent upon the combination of soil texture, connectivity of root-modified pores and the ratio of root radius to pore radius. Consequently, root-induced changes to the water balance have the same dependencies. The work in this thesis provides a significant first step towards improving our capacity to predict how roots modify soil hydraulic properties. By defining the range for the parameters used to predict how the soil is modified by roots, we are able to make quantitative assessments of how a property such as hydraulic conductivity will change for a realistic circumstance. Also , for the first time we have measured changes in soil hydraulic properties and roots and have been able to establish why a rapid change from a root-induced decrease to increase in Ks occurred. The link between physiological stage of the root system, and the changes that are likely to occur has implications for understanding how roots modify SHP: it may provide an effective tool for predicting when the switch from a decrease to increase occurs. Further work is required to test the validity of the assumptions we have made in our models that predict changes to SHP. While we have endeavoured to define the parameter space for those parameters that we have introduced, there is still some uncertainty about the connectivity of root-modified pores. Also, the parameterisation of the soil domain with roots is based upon work that measures 'fine' roots only which may not provide a true representation of the effect trees and perennial shrubs have on SHP. It is inevitable that root-induced changes to SHP will affect the fate of solutes in the soil, and temporal dynamics of root-induced changes to these may be particularly important for the timing of nutrient and pesticide leaching.
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Salazar, Osvaldo. "Modelling water discharge and nitrogen loads from drained agricultural land at field and watershed scale /." Uppsala : Department of Soil and Environment, Swedish University of Agricultural Sciences, 2009. http://epsilon.slu.se/200932.pdf.
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Almeida, Eurileny Lucas de. "Measurement of hydraulic conductivity and water retention curves for different methods and prediction of soil physical properties by kriging." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13855.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoKnowledge of the physical and hydraulic properties of the soil and its spatial dependence is important because it allows you to perform the zoning of the area in plots that receive differentiated management. This work was divided into three chapters whose general objective is to measure the hydraulic conductivity and water retention curve in soil by different methods and by using the Kriging, draw maps of soil physical attributes of the Irrigation Perimeter Baixo AcaraÃ. To obtain the water retention in soil curve method was used filter paper compared to the traditional method in five different soils Perimeter. To measure the hydraulic conductivity were used capacitive sensors to replace the tensiometer in the instantaneous profile installed method on a Argissolo Vermelho Amarelo eutrÃfico , as well as the calibration of these sensors in the field and laboratory. The maps were obtained by kriging of soil properties: sand, silt, clay, soil and particle density, porosity and saturated hydraulic conductivity. To obtain this last the tension infiltrometer and the constant load permeameter were used.
O conhecimento dos atributos fÃsico-hÃdricos do solo e de sua dependÃncia espacial à importante, pois permite realizar o zoneamento da Ãrea em glebas que receberÃo prÃticas de manejo diferenciadas. Este trabalho foi dividido em trÃs capÃtulos cujo objetivo geral à medir a condutividade hidrÃulica e a curva de retenÃÃo de Ãgua no solo por diferentes mÃtodos e, utilizando a Krigagem, elaborar mapas de atributos fÃsicos dos solos do PerÃmetro Irrigado Baixo AcaraÃ. Para obtenÃÃo da curva de retenÃÃo de Ãgua no solo foi utilizado o mÃtodo do papel filtro em comparaÃÃo ao mÃtodo tradicional em cinco diferentes solos do PerÃmetro. Para medida da condutividade hidrÃulica foram utilizados sensores capacitivos em substituiÃÃo aos tensiÃmetro no mÃtodo do perfil instantÃneo instalado em um Argissolo Vermelho Amarelo eutrÃfico, como tambÃm a calibraÃÃo desses sensores em campo e laboratÃrio. Os mapas obtidos atravÃs da Krigagem foram dos atributos do solo: areia, silte, argila, densidade do solo e partÃculas, porosidade e condutividade hidrÃulica saturada. Para obtenÃÃo deste ultimo foram utilizados o infiltrÃmetro de tensÃo e o permeÃmetro de carga constante.
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Benard, Pascal [Verfasser], and Andrea [Akademischer Betreuer] Carminati. "Microhydrological niches in soils : how mucilage and EPS alter soil hydraulic properties and water dynamics / Pascal Benard ; Betreuer: Andrea Carminati." Bayreuth : Universität Bayreuth, 2020. http://d-nb.info/1209196573/34.
Full textBooks on the topic "Soil water;hydraulic properties;water balance"
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McKenzie, Neil, Keppel Coughlan, and Hamish Cresswell. Soil Physical Measurement and Interpretation for Land Evaluation. CSIRO Publishing, 2002. http://dx.doi.org/10.1071/9780643069879.
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Soil physical measurements are essential for solving many natural resource management problems. This operational laboratory and field handbook provides, for the first time, a standard set of methods that are cost-effective and well suited to land resource survey. It provides:
practical guidelines on the soil physical measurements across a range of soils, climates and land uses;
straightforward descriptions for each method (including common pitfalls) that can be applied by people with a rudimentary knowledge of soil physics, and
guidelines on the interpretation of results and integration with land resource assessment.
Soil Physical Measurement And Interpretation for Land Evaluation begins with an introduction to land evaluation and then outlines procedures for field sampling. Twenty detailed chapters cover pore space relations, water retention, hydraulic conductivity, water table depth, dispersion, aggregation, particle size, shrinkage, Atterburg limits and strength. The book includes procedures for estimating soil physical properties from more readily available data and shows how soil physical data can be integrated into land planning and management decisions.
Book chapters on the topic "Soil water;hydraulic properties;water balance"
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Krounbi, Leilah, and Naftali Lazarovitch. "Soil Hydraulic Properties Affecting Root Water Uptake." In Encyclopedia of Agrophysics, 748–54. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-90-481-3585-1_149.
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Rawls, W. J., and D. L. Brakensiek. "Estimation of Soil Water Retention and Hydraulic Properties." In Unsaturated Flow in Hydrologic Modeling, 275–300. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2352-2_10.
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Durner, Wolfgang, Efstathios Diamantopoulos, Sascha C. Iden, and Benedikt Scharnagl. "Hydraulic Properties and Non-equilibrium Water Flow in Soils." In Application of Soil Physics in Environmental Analyses, 403–34. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06013-2_17.
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Nützmann, G., H. Moser, and H. Handke. "Inverse Parameter Identification of Soil Hydraulic Properties Results of a New Soil Column Experiment." In Computational Methods in Water Resources X, 785–92. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-010-9204-3_95.
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Horton, R., R. R. Allmaras, and R. M. Cruse. "Tillage and Compactive Effects on Soil Hydraulic Properties and Water Flow." In Mechanics and Related Processes in Structured Agricultural Soils, 187–203. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2421-5_15.
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Jedidi, Asma, Sana Dardouri, and Jalila Sghaier. "Numerical Study of Soil Water Content to Estimate the Hydraulic Properties of Soil in Tunisia." In Recent Advances in Environmental Science from the Euro-Mediterranean and Surrounding Regions, 1031–33. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-70548-4_297.
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Kanzari, Sabri. "Spatio-Temporal Variability of the Soil Hydraulic Properties—Effect on Modelling of Water Flow and Solute Transport at Field-Scale." In Recent Advances in Environmental Science from the Euro-Mediterranean and Surrounding Regions, 1279–81. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-70548-4_375.
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Wang, Chi-Yuen, and Michael Manga. "Groundwater Level." In Lecture Notes in Earth System Sciences, 155–200. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-64308-9_6.
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AbstractGroundwater level has long been known to respond to earthquakes; several types of response have been documented. Advances in the last decade were made largely through the studies of water-level response to Earth tides and barometric pressure. These studies have demonstrated that the hydraulic properties of groundwater systems are dynamic and change with time in response to disturbances such as earthquakes. This approach has been applied to estimate the permeability of several drilled active fault zones, to identify leakage from deep aquifers used for the storage of hazardous wastewater, and to reveal the potential importance of soil water and capillary tension in the unsaturated zone. Enhanced permeability is the most cited mechanism for the sustained changes of groundwater level in the intermediate and far fields, while undrained consolidation remains the most cited mechanism for the step-like coseismic changes in the near field. A new mechanism has emerged that suggests that coseismic release of pore water from unsaturated soils may also cause step-like increases of water level. Laboratory experiments show that both the undrained consolidation and the release of water from unsaturated zone may occur to explain the step-like water-level changes in the near field.
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"Measurement and Characterization of Soil Hydraulic Properties." In Soil-Water-Solute Process Characterization, 233–88. CRC Press, 2004. http://dx.doi.org/10.1201/9781420032086-10.
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Reynolds, W., and D. Elrick. "Measurement and Characterization of Soil Hydraulic Properties." In Soil-Water-Solute Process Characterization, 197–252. CRC Press, 2004. http://dx.doi.org/10.1201/9781420032086.ch6.
Full textConference papers on the topic "Soil water;hydraulic properties;water balance"
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Waugh, William J., Craig H. Benson, and William H. Albright. "Sustainable Covers for Uranium Mill Tailings, USA: Alternative Design, Performance, and Renovation." In ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2009. http://dx.doi.org/10.1115/icem2009-16369.
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The U.S. Department of Energy Office of Legacy Management is investigating alternatives to conventional cover designs for uranium mill tailings. A cover constructed in 2000 near Monticello, Utah, USA, was a redundant design with a conventional low-conductivity composite cover overlain with an alternative cover designed to mimic the natural soil water balance as measured in nearby undisturbed native soils and vegetation. To limit percolation, the alternative cover design relies on a 160-cm layer of sandy clay loam soil overlying a 40-cm sand capillary barrier for water storage, and a planting of native sagebrush steppe vegetation to seasonally release soil water through evapotranspiration (ET). Water balance monitoring within a 3.0-ha drainage lysimeter, embedded in the cover during construction, provided convincing evidence that the cover has performed well over a 9-year period (2000–2009). The total cumulative percolation, 4.8 mm (approximately 0.5 mm yr−1), satisfied a regulatory goal of <3.0 mm yr−1. Most percolation can be attributed to the very wet winter and spring of 2004–2005, when soil water content exceeded the storage capacity of the cover. Diversity, percent cover, and leaf area of vegetation increased over the monitoring period. Field and laboratory evaluations several years after construction show that soil structural development, changes in soil hydraulic properties, and development of vegetation patterns have not adversely impacted cover performance. A new test facility was constructed in 2008 near Grand Junction, Colorado, USA, to evaluate low-cost methods for renovating or transforming conventional covers into more sustainable ET covers.
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Jalut, Qassem H., and Anmar S. Saleh. "Evaluation of conjunctive water use impacts on soil hydraulic properties and root water uptake using HYDRUS-3D model." In 2018 1st- International Scientific Conference of Engineering Sciences - 3rd Scientific Conference of Engineering Science (ISCES). IEEE, 2018. http://dx.doi.org/10.1109/isces.2018.8340564.
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Chan, T. P., and R. S. Govindaraju. "A Stochastic Model for Determining Soil Hydraulic Properties from Particle Size Distribution." In Probabilistic Approaches to Groundwater Modeling Symposium at World Environmental and Water Resources Congress 2003. Reston, VA: American Society of Civil Engineers, 2003. http://dx.doi.org/10.1061/40696(2003)26.
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Stamm, Christian, Katrin Schneeberger, Hannes Fluehler, and Christian Maetzler. "Estimating soil hydraulic properties from time series of remotely sensed and in-situ measured topsoil water contents." In International Symposium on Remote Sensing, edited by Manfred Owe, Guido D'Urso, and Leonidas Toulios. SPIE, 2003. http://dx.doi.org/10.1117/12.462382.
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Mallants, Dirk, Doncho Karastanev, Dimitar Antonov, and Janez Perko. "Innovative In-Situ Determination of Unsaturated Hydraulic Properties in Deep Loess Sediments in North-West Bulgaria." In The 11th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2007. http://dx.doi.org/10.1115/icem2007-7202.
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In the framework of selecting a suitable site for final disposal of low- and intermediate level short-lived radioactive waste (LILW-SL) in Bulgaria, site characterization is ongoing at the Marichin Valog site, North-West Bulgaria. The site is characterized by a complex sequence of loess, clayey gravel, and clay layers, of which the first 30–40 m are unsaturated. Proper knowledge about unsaturated water flow and concomittant radionuclide transport is key input to safety assessment calculations. Constant-head infiltrometer tests were carried out at several meters below ground surface to determine the unsaturated hydraulic properties of silty loess, clayey loess, and clayey gravel layers. Individual infiltrometers were equipped with 0.5-m-long filter sections; the shallowest filter was from 2 to 2.5 m depth, whereas the deepest was from 9.5 to 10 m depth. Infiltration tests provided data on cumulative infiltration and progression of the wetting front in the initially unsaturated sediments surrounding the infiltrometer. A cylindrical time-domain reflectometry TRIME probe was used to measure water content variations with time during progression of the wetting front. Access tubes for the TRIME probe were installed at 0.3 to 0.5 m from the infiltrometer tubes. By means of an inverse optimization routine implemented in the finite element code HYDRUS-2D, field-scale soil hydraulic parameters were derived for all layers. Results show a great consistency in the optimized parameter values, although the test sites were several meters apart. Apparently the size of the affected volume of soil was large enough to reduce the effect of spatial variability and to produce average field-scale hydraulic parameters that are relevant for large-scale predictions of flow patterns and radionuclide migration pathways.
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Neelamani, S., and K. Al-Banaa. "Inline and Vertical Wave Force Variation due to Burial of Submarine Pipeline in Random Wave Fields." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-49431.
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Marine pipelines encounter significant dynamic forces due to the action of waves. In order to reduce such forces, they are buried below the seabed. The wave force on the pipeline at any depth of burial for the given hydrodynamic condition depends on the properties of the sea bed soil. Physical model is used for assessing the hydrodynamic force on the pipeline for a wide range of random wave conditions, for different burial depths and in four types of soils. It is found that for all the four soil types, the horizontal force reduces with increase in depth of burial, whereas the vertical force generally increases up to certain depth of burial, mainly due to the significant change in the magnitude as well as the phase lag between the pore water pressures in the vertical direction. Among the soils, well graded soil is good for half burial of pipeline, since the least vertical force occurs for this soil. On the other hand, uniformly graded and low hydraulic conductivity soil attracts the maximum vertical force for half burial. On the other hand, such soil is good for full burial or further increase of burial, since it attracts less vertical force when compared to the other soils. The results of this study will help the submarine pipeline design engineers to select the minimum safe burial depth in a range of cohesion-less soil.
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Kostka, Pal, Zsolt Techy, and James J. Sienicki. "Hydrogen Mixing Analyses for a VVER Containment." In 10th International Conference on Nuclear Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/icone10-22206.
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Hydrogen combustion may represent a threat to containment integrity in a VVER-440/213 plant owing to the combination of high pressure and high temperature. A study has been carried out using the GASFLOW 2.1 three-dimensional CFD code to evaluate the hydrogen distribution in the containment during a beyond design basis accident. The VVER-440/213 containment input model consists of two 3D blocks connected via one-dimensional (1D) ducts. One 3D block contains the reactor building and the accident localization tower with the suppression pools. Another 3D block models the air traps. 1D ducts represent the check valves connecting the accident localization tower with the air traps. The VVER pressure suppression system, called “bubbler condenser,” was modeled as a distributed heat sink with water thermodynamic properties. This model accounts for the energy balance. However, it is not currently possible to model dynamic phenomena associated with the water pools (e.g., vent clearing, level change). The GASFLOW 2.1 calculation gave detailed results for the spatial distribution of thermal-hydraulic parameters and gas concentrations. The range and trend of the parameters are reasonable and valuable. There are particularly interesting circulation patterns around the steam generators, in the bubbler tower and other primary system compartments. In case of the bubbler tower, concentration and temperature contour plots show an inhomogeneous distribution along the height and width, changing during the accident. Hydrogen concentrations also vary within primary system compartments displaying lower as well as higher (up to 13–20% and higher) values in some nodes. Prediction of such concentration distributions was not previously possible with lumped parameter codes. GASFLOW 2.1 calculations were compared with CONTAIN 1.2 (lumped parameter code) results. Apart from the qualitatively similar trends, there are, for the time being, quantitative differences between the results concerning, for example, pressure histories, or the total amount of steam available in the containment. The results confirm the importance of detailed modeling of the containment, as well as of the bubbler condenser and sump water pools. The study showed that modeling of hydrogen distribution in the VVER-440/213 containment was possible using the GASFLOW 2.1 code with reasonable results and remarkable physical insights.
Reports on the topic "Soil water;hydraulic properties;water balance"
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Shillito, Rose, Markus Berli, and Teamrat Ghezzehei. Quantifying the effect of subcritical water repellency on sorptivity : a physically based model. Engineer Research and Development Center (U.S.), July 2021. http://dx.doi.org/10.21079/11681/41054.
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Soil water wettability or water repellency is a phenomenon that can affect infiltration and, ultimately, runoff. Thus, there is a need to develop a model that can quantitatively capture the influence of water repellency on infiltration in a physically meaningful way and within the framework of existing infiltration theory. The analytical model developed in this study relates soil sorptivity (an infiltration parameter) with contact angle (a direct measure of water repellency) for variably saturated media. The model was validated with laboratory experiments using a silica sand of known properties treated to produce controlled degrees of water repellency. The measured contact angle and sorptivity values closely matched the model‐predicted values. Further, the relationship between the frequently used water drop penetration time test (used to assess water repellency) and sorptivity was illustrated. Finally, the direct impact of water repellency on saturated hydraulic conductivity was investigated due to its role in infiltration equations and to shed light on inconsistent field observations. It was found that water repellency had minimal effect on the saturated hydraulic conductivity of structureless sand. A quantitative model for infiltration incorporating the effect of water repellency is particularly important for post‐fire hydrologic modeling of burned areas exhibiting water repellent soils.