نتایج جستجو برای: environment unsaturated and hydraulic conductivity then

تعداد نتایج: 16901497  

2006
K. Schwärzel

As compared with mineral soils, there are few in situ measurements of the unsaturated hydraulic properties of peat soils available. We used parameter estimation (inverse) methods to estimate the water retention and hydraulic conductivity functions of drained peat soils from both laboratory and field data. The laboratory data were obtained on small cores using the traditional evaporation method,...

2001
Michael Raviv J. Heinrich Lieth Rony Wallach

Rose plants (Rosa x hybrida L. CV. Kardinal, grafted on Natal Brier) were grown in UC mix and in coconut coir. Water release curves and hydraulic conductivity of the media were measured. Water tensions in the media were maintained within a predetermined narrow range by tension-actuated irrigation, using high-flow electronic tensiometers. Transpiration rate of plants sitting on load cells was me...

2012
Zilong Wang Qiuxiang Jiang Qiang Fu Tianxiao Li

The identification of freezing-thawing soil hydraulic properties is the basis and key problem of studying soil water movement. Current identifying methods of the properties have many limitations, such as big error, high uncertainty and low operability. Thus, the identifying method of freezingthawing soil hydraulic properties was researched in the research. The estimating parameters of soil free...

2005
M. M. VILLAGRA P. MICHIELS R. HARTMANN

Experimentally determined values of unsaturated soil hydraulic conductivity are presented for an Alfisol of the county of Piracicaba, S.P., Brazil. Simultaneous measurements of soil water content and pressure head are made along a 125 m transect within an irrigated field during the internal drainage process. Calculations of the soil hydraulic conductivity were made using the instantaneous profi...

Journal: :Journal of the Japanese Society of Snow and Ice 2000

Journal: :Applied sciences 2022

Determining the constitutive properties that describe incipient hydraulic behavior of materials, including matrix domains and distribution macro micropores, is crucial to analyzing preferential water flow in saturated soils, ks, unsaturated, ku. This study focused on determining conductivity porous media under total partial saturation conditions. The infiltration characteristics three reconstit...

Journal: :Water research 2006
C D Beal E A Gardner G Kirchhof N W Menzies

Soil absorption systems (SAS) are used commonly to treat and disperse septic tank effluent (STE). SAS can hydraulically fail as a result of the low permeable biomat zone that develops on the infiltrative surface. The objectives of this experiment were to compare the hydraulic properties of biomats grown in soils of different textures, to investigate the long-term acceptance rates (LTAR) from pr...

1999
Stefan Finsterle Boris Faybishenko

Modeling flow and solute transport in the unsaturated zone on the basis of the Richards equation requires specifying values for unsaturated hydraulic conductivity and water potential as a function of saturation. The objectives of the paper are to evaluate the design of a transient, radial, multi-step outflow experiment, and to determine unsaturated hydraulic parameters using inverse modeling. W...

2005
Marcel G. Schaap

The unsaturated soil hydraulic properties are often described using Mualem–van Genuchten (MVG) type analytical functions. Recent studies suggest several shortcomings of these functions near saturation, notably the lack of second-order continuity of the soil water retention function at saturation and the inability of the hydraulic conductivity function to account for macroporosity. We present a ...

2009
Jiu Jimmy Jiao Haipeng Guo

[1] Most analytical and numerical models developed to analyze pumping test data focus on saturated flow below the water table. Traditionally the soil above the initial water table prior to pumping has been thought to have little influence on the test results and has usually been ignored. It is hypothesized that, if the unsaturated zone is capped by low-permeability soil, airflow in the unsatura...

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