Results 181 to 190 of about 922,701 (227)

In Situ Method for Estimating Subsurface Unsaturated Hydraulic Conductivity

Water Resources Research, 1995
A method for the estimation of subsurface unsaturated hydraulic conductivity in situ was developed and field tested. The new method is based on Philip's (1992) approximation of water flow from a small subsurface cavity. Measurements of water pressure within the cavity (P) and associated discharge (Q) are used to infer the soil's saturated hydraulic ...
Shani, U., Or, D.
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On the hydraulic conductivity of unsaturated soils

Eos, Transactions American Geophysical Union, 1954
Unsaturated steady flow of mixtures of a liquid and a gas through sands and similar porous media at low Reynolds numbers obeys Darcy's law. The relative liquid permeability K is not constant, but a universal function of the degree of liquid saturation. An approximate theory gives its form, which is a cubic parabola.
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Comparison of Six Methods To Determine Unsaturated Soil Hydraulic Conductivity

Soil Science Society of America Journal, 1994
Abstract Knowledge of soil hydraulic properties is required for soil‐water flow models. Although many studies of individual methods exist, comparisons of methods are uncommon. Therefore, we compared application ranges and results for six laboratory methods for determining hydraulic conductivity or diffusivity on eolian sand, eolian ...
Stolte, J., Freijer, J.I., Bouten, W., Dirksen, C., Halbertsma, J.M., van Dam, J.C., van den Berg, J.A., Veerman, G.J., Wösten, J.H.M.   +8 more
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SATURATED AND UNSATURATED HYDRAULIC CONDUCTIVITY OF SWELLING CLAYS

Soil Science, 1986
The theory of water flow in swelling clays may be developed in a space coordinate system at rest, assuming that the flux of clay particles can be defined by the space gradients of potential responsible for the movement of clay particles, which is related to the gradients of water potential.
M. NAKANO, Y. AMEMIYA, K. FUJII
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Calculating the Unsaturated Hydraulic Conductivity and Diffusivity

Soil Science Society of America Journal, 1976
Abstract The methods of R. D. Jackson and R. H. Brooks and A. T. Corey for calculating the unsaturated hydraulic conductivity from water content‐pressure head relationships are compared. The corresponding diffusivity relationships can also be evaluated either by a numerical differentiation of the water content‐pressure head curves ...
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Studies on unsaturated hydraulic conductivities.

1966
The movement of water through partially saturated soils is of continuing interest to engineers and agriculturists. Agriculturists are concerned with the provision of adequate moisture for proper plant growth and have directed their energies towards predicting moisture movement after allowing for gains from the water-table. [...]
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Simple Laboratory Measurement of Unsaturated Hydraulic Conductivity

Journal of Irrigation and Drainage Engineering, 1987
A simple method called “upward infiltration method” is described for using common soil laboratory equipment to measure unsaturated hydraulic conductivity of soil samples in a short time. The method is based on measurement of water absorption rates under controlled tensions, which leads to an estimate of soil hydraulic conductivity during the wetting ...
Zohrab A. Samani, L. S. Willardson
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UNSATURATED HYDRAULIC CONDUCTIVITY DETERMINATION BY A SCALING TECHNIQUE

Soil Science, 1975
ABSTRACT A scaling technique is presented for estimating the hydraulic conductivity based on experiments of horizontal infiltration of water into an air-dry soil. From plots of the distance from the water source to the wetting front as a function of the square root of time, a scaling factor is obtained that permits the estimation of the hydraulic ...
KLAUS REICHARDT, PAULO L. LIBARDI, DONALD R. NIELSEN   +2 more
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Hydraulic Conductivity Assessment of Unsaturated Soils

1994
Predicting the direction and rate of contaminant transport in the vadose zone requires quantification of soil hydraulic properties. For many problems, the most appropriate approach is to assume that the contamination is moving with the water phase. Therefore, the unsaturated hydraulic conductivity is the most important property governing water movement
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Unsaturated Hydraulic Conductivity for Upward Flow in Soil

Unsaturated Soils 2006, 2006
A method for direct measurement of hydraulic conductivity of unsaturated soil is presented. The method is based on a system of capillary flow from a controlled water table up into a soil column in initially air-dry condition. By measurement of change in soil water content at a known vertical position from the water table, together with a prepared soil ...
V. Sriboonlue, K. Srisuk, S. Konyai, N. Khetkratok   +3 more
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