Unsaturated Soil Hydraulic Conductivity in the Central Amazon: Field Evaluations

2014 ◽  
pp. 283-305 ◽  
Author(s):  
Wenceslau Geraldes Teixeira ◽  
Götz Schroth ◽  
Jean Dalmo Marques ◽  
Bernd Huwe
Keyword(s):  
Hydraulic Conductivity ◽  
Unsaturated Soil ◽  
Soil Hydraulic Conductivity ◽  
Central Amazon ◽  
Soil Hydraulic

Simplified estimation of unsaturated soil hydraulic conductivity using bulk electrical conductivity and particle size distribution

Soil Research ◽  
2013 ◽  
Vol 51 (1) ◽  
pp. 23 ◽  
Author(s):  
Mohammad Reza Neyshabouri ◽  
Mehdi Rahmati ◽  
Claude Doussan ◽  
Boshra Behroozinezhad
Keyword(s):  
Electrical Conductivity ◽  
Particle Size ◽  
Hydraulic Conductivity ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Unsaturated Soil ◽  
Soil Core ◽  
Soil Hydraulic Conductivity ◽  
Core Samples ◽  
Soil Hydraulic

Unsaturated soil hydraulic conductivity K is a fundamental transfer property of soil but its measurement is costly, difficult, and time-consuming due to its large variations with water content (θ) or matric potential (h). Recently, C. Doussan and S. Ruy proposed a method/model using measurements of the electrical conductivity of soil core samples to predict K(h). This method requires the measurement or the setting of a range of matric potentials h in the core samples—a possible lengthy process requiring specialised devices. To avoid h estimation, we propose to simplify that method by introducing the particle-size distribution (PSD) of the soil as a proxy for soil pore diameters and matric potentials, with the Arya and Paris (AP) model. Tests of this simplified model (SM) with laboratory data on a broad range of soils and using the AP model with available, previously defined parameters showed that the accuracy was lower for the SM than for the original model (DR) in predicting K (RMSE of logK = 1.10 for SM v. 0.30 for DR; K in m s–1). However, accuracy was increased for SM when considering coarse- and medium-textured soils only (RMSE of logK = 0.61 for SM v. 0.26 for DR). Further tests with 51 soils from the UNSODA database and our own measurements, with estimated electrical properties, confirmed good agreement of the SM for coarse–medium-textured soils (<35–40% clay). For these textures, the SM also performed well compared with the van Genuchten–Mualem model. Error analysis of SM results and fitting of the AP parameter showed that most of the error for fine-textured soils came from poorer adequacy of the AP model’s previously defined parameters for defining the water retention curve, whereas this was much less so for coarse-textured soils. The SM, using readily accessible soil data, could be a relatively straightforward way to estimate, in situ or in the laboratory, K(h) for coarse–medium-textured soils. This requires, however, a prior check of the predictive efficacy of the AP model for the specific soil investigated, in particular for fine-textured/structured soils and when using previously defined AP parameters.

scholarly journals Determining in-situ unsaturated soil hydraulic conductivity at a fine depth scale with heat pulse and water potential sensors

2018 ◽  
Vol 564 ◽  
pp. 802-810 ◽  
Author(s):  
Zhengchao Tian ◽  
Dilia Kool ◽  
Tusheng Ren ◽  
Robert Horton ◽  
Joshua L. Heitman
Keyword(s):  
Hydraulic Conductivity ◽  
Water Potential ◽  
Unsaturated Soil ◽  
Heat Pulse ◽  
Soil Hydraulic Conductivity ◽  
Depth Scale ◽  
Soil Hydraulic

Application of a Geotechnical Centrifuge for Estimation of Unsaturated Soil Hydraulic Conductivity

2001 ◽  
Vol 29 (6) ◽  
pp. 556 ◽  
Author(s):  
RE Petersen ◽  
RE Link ◽  
DN Singh ◽  
SJ Kuriyan ◽  
V Madhuri
Keyword(s):  
Hydraulic Conductivity ◽  
Unsaturated Soil ◽  
Soil Hydraulic Conductivity ◽  
Geotechnical Centrifuge ◽  
Soil Hydraulic

IMPROVED SIMULATION OF UNSATURATED SOIL HYDRAULIC CONDUCTIVITY BY THE MOVING MEAN SLOPE APPROACH

Soil Science ◽  
1993 ◽  
Vol 155 (1) ◽  
pp. 8-14 ◽  
Author(s):  
P. MOLDRUP ◽  
J. Aa. HANSEN ◽  
D. E. ROLSTON ◽  
T. YAMAGUCHI
Keyword(s):  
Hydraulic Conductivity ◽  
Unsaturated Soil ◽  
Soil Hydraulic Conductivity ◽  
Soil Hydraulic

scholarly journals A software to calculate soil hydraulic conductivity in internal drainage experiments (SHC, Version 2.00)

2007 ◽  
Vol 31 (5) ◽  
pp. 1219-1222 ◽  
Author(s):  
Durval Dourado Neto ◽  
Klaus Reichardt ◽  
Adriana Lúcia da Silva ◽  
Osny Oliveira Santos Bacchi ◽  
Luis Carlos Timm ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Unsaturated Soil ◽  
Soil Profile ◽  
Field Experiments ◽  
Water Infiltration ◽  
Internal Drainage ◽  
Soil Hydraulic Conductivity ◽  
Soil Hydraulic

A software for the calculation of unsaturated soil hydraulic conductivity K(theta) is presented for commonly used methods found in the literature, based on field experiments in which a soil profile is submitted to water infiltration followed by internal drainage. The software is available at: [email protected].

scholarly journals Assessing the Effects of Rainfall Intensity and Hydraulic Conductivity on Riverbank Stability

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 741
Author(s):  
Toan Thi Duong ◽  
Duc Minh Do ◽  
Kazuya Yasuhara
Keyword(s):  
Hydraulic Conductivity ◽  
Unsaturated Soil ◽  
Rainfall Intensity ◽  
Groundwater Table ◽  
Wetting Front ◽  
Soil Hydraulic Conductivity ◽  
Rainwater Infiltration ◽  
Soil Hydraulic ◽  
Transient Seepage ◽  
Riverbank Stability

Riverbank failure often occurs in the rainy season, with effects from some main processes such as rainfall infiltration, the fluctuation of the river water level and groundwater table, and the deformation of transient seepage. This paper has the objective of clarifying the effects of soil hydraulic conductivity and rainfall intensity on riverbank stability using numerical analysis with the GeoSlope program. The initial saturation condition is first indicated as the main factor affecting riverbank stability. Analyzing high-saturation conditions, the obtained result can be used to build an understanding of the mechanics of riverbank stability and the effect of both the rainfall intensity and soil hydraulic conductivity. Firstly, the rainfall intensity is lower than the soil hydraulic conductivity; the factor of safety (FOS) reduces with changes in the groundwater table, which is a result of rainwater infiltration and unsteady state flow through the unsaturated soil. Secondly, the rainfall intensity is slightly higher than the soil hydraulic conductivity, the groundwater table rises slowly, and the FOS decreases with both changes in the wetting front and groundwater table. Thirdly, the rainfall intensity is much higher than the soil hydraulic conductivity, and the FOS decreases dominantly by the wetting front and pond loading area. Finally, in cases with no pond, the FOS reduces when the rainfall intensity is lower than hydraulic conductivity. With low hydraulic conductivity, the wetting front is on a shallow surface and descends very slowly. The decreasing of FOS is only due to transient seepage changes of the unsaturated soil properties by losing soil suction and shear strength. These obtained results not only build a clearer understanding of the filtration mechanics but also provide a helpful reference for riverbank protection.

Comparison of Six Methods To Determine Unsaturated Soil Hydraulic Conductivity

1994 ◽  
Vol 58 (6) ◽  
pp. 1596 ◽  
Author(s):  
J. Stolte ◽  
J. M. Halbertsma ◽  
G. J. Veerman ◽  
J. H. M. Wösten ◽  
J. I. Freijer ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Unsaturated Soil ◽  
Soil Hydraulic Conductivity ◽  
Soil Hydraulic

scholarly journals On simple methods for unsaturated soil hydraulic conductivity determination

1993 ◽  
Vol 50 (2) ◽  
pp. 326-328 ◽  
Author(s):  
O.O.S. Bacchi ◽  
K. Reichardt
Keyword(s):  
Hydraulic Conductivity ◽  
Unsaturated Soil ◽  
Theoretical Basis ◽  
Soil Hydraulic Conductivity ◽  
Conductivity Model ◽  
Soil Hydraulic

The simple methods of LIBARDI et al. (1980) and SISSON et al. (1980) for K(theta) estimation, although developed on completely different theoretical basis, are rigorously identical for the exponential hydraulic conductivity model. The unit gradient approximation used in these methods seems valid for practical purposes but is theoretically in valid.

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