Comparison of Procedures to estimate Steady Flow Rate in Field Measurement of Saturated Hydraulic Conductivity by the Guelph Permeameter Method

1999 ◽  
Vol 74 (1) ◽  
pp. 63-71 ◽  
Author(s):  
V. Bagarello ◽  
G. Giordano
Keyword(s):  
Hydraulic Conductivity ◽  
Steady Flow ◽  
Flow Rate ◽  
Field Measurement ◽  
Saturated Hydraulic Conductivity ◽  
Guelph Permeameter

FIELD MEASUREMENT OF THE SATURATED HYDRAULIC CONDUCTIVITY OF A MACROPOROUS SOIL WITH UNSTABLE SUBSOIL STRUCTURE.

Soil Science ◽  
1998 ◽  
Vol 163 (11) ◽  
pp. 841-852 ◽  
Author(s):  
Lalit M. Arya ◽  
Thomas S Dierolf ◽  
Agus Sofyan ◽  
I. P. G. Widjaja-Adhi ◽  
M. Th. van Genuchten
Keyword(s):  
Hydraulic Conductivity ◽  
Field Measurement ◽  
Saturated Hydraulic Conductivity

AN EVALUATION OF THE GUELPH PERMEAMETER FOR MEASURING SATURATED HYDRAULIC CONDUCTIVITY

1990 ◽  
Vol 33 (4) ◽  
pp. 1179-1184 ◽  
Author(s):  
J. Gallichand ◽  
C. A. Madramootoo ◽  
P. Emight ◽  
S. F. Barrington
Keyword(s):  
Hydraulic Conductivity ◽  
Saturated Hydraulic Conductivity ◽  
Guelph Permeameter

scholarly journals CONDUTIVIDADE HIDRÁULICA DO SOLO SATURADO NA ZONA VADOSA IN SITU E EM LABORATÓRIO

Irriga ◽  
2009 ◽  
Vol 14 (3) ◽  
pp. 413-422
Author(s):  
Rodrigo Trevisan ◽  
Luiz Felipe Salemi ◽  
Jorge Marcus de Moraes ◽  
Julio Cesar Martins de Oliveira
Keyword(s):  
Hydraulic Conductivity ◽  
Sao Paulo ◽  
Laboratory Method ◽  
Saturated Hydraulic Conductivity ◽  
Fundamental Parameter ◽  
São Paulo ◽  
Advantages And Disadvantages ◽  
Constant Head ◽  
Guelph Permeameter

 CONDUTIVIDADE HIDRÁULICA DO SOLO SATURADO NA ZONA VADOSA IN SITU E EM LABORATÓRIO  Rodrigo Trevisan1; Luiz Felippe Salemi1;  Jorge Marcos de Moraes1;  Júlio Cesar Martins de Oliveira(4)(1)Laboratório de Ecologia Isotópica, Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Piracicaba, SP,  e-mail: [email protected] (4)Laboratório de Física de Solos, Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Piracicaba, SP  1 RESUMO A condutividade hidráulica do solo é uma propriedade fundamental na determinação da dinâmica da água e de solutos em solos saturados e não - saturados, sendo útil na resolução de problemas relacionados à preservação do meio ambiente, da agricultura e dos recursos hídricos. Muitos métodos são empregados para a sua determinação em solos saturados, tanto em campo como em laboratório, cada um com suas vantagens e desvantagens. Nesse contexto, o objetivo do presente trabalho foi o de comparar um método de campo, o método do permeâmetro de carga constante (“Permeâmetro Guelph”), e um método de laboratório, também de carga constante usando amostras indeformadas de solo, em um solo classificado como Latossolo Vermelho Escuro, da região de Piracicaba - SP. Conclui-se que o método de campo e o método de laboratório não podem ser considerados diferentes. UNITERMOS: permeabilidade; zona não saturada; latossolo; permeâmetro guelph.  TREVISAN, R.; SALEMI, L. F.; MORAES, J. M.; OLIVEIRA, J. C. M. THE SATURATED HYDRAULIC CONDUCTIVITY IN THE VADOSE ZONE IN SITU AND IN LABORATORY  2 ABSTRACT The saturated hydraulic conductivity of the soil is a fundamental parameter to determine  water and solutes dynamics in the soil, and it is useful  to resolve problems related to environmental, agricultural and water resources preservation. Many methods are used for its determination, in field and in the laboratory, each one with its advantages and disadvantages. The main objective of the present work was to compare a field method, using a constant head permeameter (“Guelph Permeameter”), to a laboratory method also employing a constant head in undisturbed samples in a soil classified as dark red Latosol (Oxisol) in the area ofPiracicaba. The results show, through statistical analysis, that the values obtained by the field and laboratory methods cannot be considered different. KEYWORDS: permeability; unsaturated zone; oxisol;guelph permeameter.

scholarly journals Controls of macropore network characteristics on preferential solute transport

2014 ◽  
Vol 11 (8) ◽  
pp. 9551-9588 ◽  
Author(s):  
M. Larsbo ◽  
J. Koestel ◽  
N. Jarvis
Keyword(s):  
Hydraulic Conductivity ◽  
Solute Transport ◽  
Flow Rate ◽  
Saturated Hydraulic Conductivity ◽  
Degree Of Saturation ◽  
State Variables ◽  
Local Connectivity ◽  
Soil Matrix ◽  
Network Characteristics ◽  
Preferential Transport

Abstract. In this study we examined the relationships between macropore network characteristics, hydraulic properties and state variables and measures of preferential transport in undisturbed columns sampled from four agricultural topsoils of contrasting texture and structure. Macropore network characteristics were computed from 3-dimensional X-ray tomography images of the soil pore system. Non-reactive solute transport experiments were carried out at five steady-state water flow rates from 2 to 12 mm h−1. The degree of preferential transport was evaluated by the normalised 5% solute arrival time and the apparent dispersivity calculated from the resulting breakthrough curves. Near-saturated hydraulic conductivities were measured on the same samples using a tension disk infiltrometer placed on top of the columns. Results showed that many of the macropore network characteristics were inter-correlated. For example, large macroporosities were associated with larger specific macropore surface areas and better local connectivity of the macropore network. Generally, an increased flow rate resulted in earlier solute breakthrough and a shifting of the peak concentration towards smaller drained volumes. Columns with smaller macroporosities, poorer local connectivity of the macropore network and smaller near-saturated hydraulic conductivities exhibited a greater degree of preferential transport. This can be explained by the fact that, with only two exceptions, global (i.e. sample-scale) continuity of the macropore network was still preserved at low macroporosities. Thus, for any given flow rate pores of larger diameter were actively conducting solute in soils of smaller near-saturated hydraulic conductivity. With less time for equilibration between the macropores and the surrounding matrix the transport became more preferential. Conversely, the large specific macropore surface area and well-connected macropore networks associated with columns with large macroporosities limit the degree of preferential transport because they increase the diffusive flux between macropores and the soil matrix and they increase the near-saturated hydraulic conductivity. The normalised 5% arrival times were most strongly related with the estimated hydraulic state variables (e.g. with the degree of saturation in the macropores R2 = 0.589), since these combine into one measure the effects of irrigation rate and the near-saturated hydraulic conductivity function, which in turn implicitly depends on the volume, size distribution, global continuity, local connectivity and tortuosity of the macropore network.

A constant-head well permeameter method for measuring field-saturated hydraulic conductivity above an impermeable layer

2004 ◽  
Vol 84 (3) ◽  
pp. 255-264 ◽  
Author(s):  
Masaki Hayashi ◽  
William L. Quinton
Keyword(s):  
Hydraulic Conductivity ◽  
Weighted Average ◽  
Saturated Hydraulic Conductivity ◽  
Shape Factors ◽  
Promising Tool ◽  
Northern Regions ◽  
Measuring Field ◽  
Impermeable Layer ◽  
Constant Head ◽  
Guelph Permeameter

Hydrologic understanding of mountainous and northern regions of Canada is poor owing to the lack of critical field data such as hydraulic conductivity. A portable field instrument, the Guelph permeameter (GP), is a promising tool for measuring field-saturated hydraulic conductivity in remote watersheds inaccessible by motorized vehicles. In order to extend the applicability of the GP method to relatively thin soils underlain by impermeable bedrock or permafrost, a new set of shape factors was determined by numerical simulation. The new shape factors gave accurate values of field-saturated hydraulic conductivity when tested in the laboratory. The impermeable layer causes flow around the auger hole to be primarily horizontal. Therefore, the GP method measures a predominantly horizontal field-saturated hydraulic conductivity in these thin soils. The measured conductivity represents a weighted average of the soil surrounding the submerged surface of the auger hole. In layered soil, the weight is greater for the layers close to the bottom of the hole than for those close to the top. Key words: Guelph permeameter, hydraulic conductivity, forest hydrology, permafrost, peat

scholarly journals Relations between macropore network characteristics and the degree of preferential solute transport

2014 ◽  
Vol 18 (12) ◽  
pp. 5255-5269 ◽  
Author(s):  
M. Larsbo ◽  
J. Koestel ◽  
N. Jarvis
Keyword(s):  
Hydraulic Conductivity ◽  
Solute Transport ◽  
Flow Rate ◽  
Saturated Hydraulic Conductivity ◽  
Degree Of Saturation ◽  
State Variables ◽  
Local Connectivity ◽  
Soil Matrix ◽  
Network Characteristics ◽  
Preferential Transport

Abstract. The characteristics of the soil macropore network determine the potential for fast transport of agrochemicals and contaminants through the soil. The objective of this study was to examine the relationships between macropore network characteristics, hydraulic properties and state variables and measures of preferential transport. Experiments were carried out under near-saturated conditions on undisturbed columns sampled from four agricultural topsoils of contrasting texture and structure. Macropore network characteristics were computed from 3-D X-ray tomography images of the soil pore system. Non-reactive solute transport experiments were carried out at five steady-state water flow rates from 2 to 12 mm h−1. The degree of preferential transport was evaluated by the normalised 5% solute arrival time and the apparent dispersivity calculated from the resulting breakthrough curves. Near-saturated hydraulic conductivities were measured on the same samples using a tension disc infiltrometer placed on top of the columns. Results showed that many of the macropore network characteristics were inter-correlated. For example, large macroporosities were associated with larger specific macropore surface areas and better local connectivity of the macropore network. Generally, an increased flow rate resulted in earlier solute breakthrough and a shifting of the arrival of peak concentration towards smaller drained volumes. Columns with smaller macroporosities, poorer local connectivity of the macropore network and smaller near-saturated hydraulic conductivities exhibited a greater degree of preferential transport. This can be explained by the fact that, with only two exceptions, global (i.e. sample scale) continuity of the macropore network was still preserved at low macroporosities. Thus, for any given flow rate, pores of larger diameter were actively conducting solute in soils of smaller near-saturated hydraulic conductivity. This was associated with larger local transport velocities and, hence, less time for equilibration between the macropores and the surrounding matrix which made the transport more preferential. Conversely, the large specific macropore surface area and well-connected macropore networks associated with columns with large macroporosities limit the degree of preferential transport because they increase the diffusive flux between macropores and the soil matrix and they increase the near-saturated hydraulic conductivity. The normalised 5% arrival times were most strongly correlated with the estimated hydraulic state variables (e.g. with the degree of saturation in the macropores R2 = 0.589), since these combine into one measure the effects of irrigation rate and the near-saturated hydraulic conductivity function, which in turn implicitly depends on the volume, size distribution, global continuity, local connectivity and tortuosity of the macropore network.

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