نتایج جستجو برای: equivalent hydraulic conductivity

تعداد نتایج: 212988  

Journal: :Ground water 2004
Shaw-Yang Yang Hund-Der Yeh

Slug test data obtained from tests performed in an unconfined aquifer are commonly analyzed by graphical or numerical approaches to determine the aquifer parameters. This paper derives three fourth-degree polynomials to represent the relationship between Bouwer and Rice's coefficients and the ratio of the screen length to the radius of the gravel envelope. A numerical approach using the nonline...

2010
Andrew S. Gregory Nigel R.A. Bird W. Richard Whalley Peter Matthews

To understand the hydraulic properties of soils, accurate prediction of unsaturated hydraulic conductivity is needed which is commonly derived from the soil water release characteristic. In fine-textured soils the modified Mualem-van Genuchten (MMVG) function has been used extensively to predict the change in relative conductivity with changes in matric potential, but this assumes that the soil...

1999
Anthony T. Cahill Fabrizio Ungaro Marc B. Parlange Michael Mata Donald R. Nielsen

A method for determining optimal parameters for a field-scale hydraulic conductivity function is presented and tested on soil moisture and matric potential data measured at several locations in a field drainage experiment. The change in moisture content over time at the individual locations is modeled using Richards’ equation, and an optimization for the hydraulic conductivity parameters is per...

2017
Song-Hun Chong

Soil consolidation as the dissipation of excess pore water pressure is mainly affected by the relative hydraulic conductivity among the layers. Geostatistical parameters such as the mean, the standard deviation, and the correlation length are physical indicators for each sedimentation and formation history. The effects of spatial variability on the excessive pore water pressure dissipation duri...

2002
Greg A. Oldenborger Robert A. Schincariol Lalu Mansinha

[1] Spatial variability of hydraulic conductivity exerts a predominant control on groundwater flow by influencing advective pathways, hydrodynamic dispersion, and density-dependent instabilities. Space-local spectral texture segmentation aids in the macroscale characterization of the spatial heterogeneity of natural porous media via an outcrop analogue approach. Detailed photographic data sets ...

2005
Scott Purdy

Accurately measuring the in situ hydraulic conductivity (permeability) of a clay liner is a major factor in the construction of landfill containment systems. Laboratory and large-scale field test methods are often utilized on test pads constructed prior to placement of the production liner to determine the hydraulic conductivity of the clay. While these test methods provide reliable results, th...

Journal: :Plant physiology 1992
H S Neufeld D A Grantz F C Meinzer G Goldstein G M Crisosto C Crisosto

Genotypic variability in vulnerability of leaf xylem to water-stress-induced cavitation was determined in four sugarcane (Saccharum sp.) clones using detached leaf segments in a hydraulic conductivity apparatus. Vulnerability curves were constructed by plotting the percentage of maximum conductivity versus leaf water potential (psi(I)) and fitting curves using a Weibull function. The psi(I) at ...

Journal: :Tree physiology 2003
Jarmila Pittermann John Sperry

We tested the hypotheses that freezing-induced embolism is related to conduit diameter, and that conifers and angiosperms with conduits of equivalent diameter will exhibit similar losses of hydraulic conductivity in response to freezing. We surveyed the freeze-thaw response of conifers with a broad range of tracheid diameters by subjecting wood segments (root, stem and trunk wood) to a freeze-t...

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: :Computers & Geosciences 2010
Haiyan Zhou Liangping Li J. Jaime Gómez-Hernández

The main point of this paper is to propose a non-local three-dimensional hydraulic conductivity full tensor upscaling algorithm and code. The algorithm is capable of transforming very refined cell conductivity models into coarse block conductivity models for quick and accurate solution of the groundwater flow equation. Flow rate and hydraulic head gradient are the variables used to relate the o...

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