A drive point application of the Guelph Permeameter method for coarse-textured soils

Reynolds, W. D.; Lewis, Jeffrey

doi:10.1016/j.geoderma.2012.04.004

Cited by 28 publications

(17 citation statements)

References 22 publications

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“…A three dimensional flow domain ( Fig. 1) was adopted for all simulations by using the HYDRUS-2D/3D software package (Šimůnek et al, 2007), which is widely employed for simulating water, heat, and/or solute movement in two or three dimensions (Shan and Wang, 2012;Reynolds and Lewis, 2012). The side length of the square flow domain in the X-Y plane was 140 cm and the depth in the Z direction was 180 cm.…”

Section: Soils and Numerical Simulationsmentioning

confidence: 99%

Testing steady-state analysis of single-ring and square pressure infiltrometer data

2016

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Testing reliability of the saturated soil hydraulic conductivity, K s , estimated by applying the steady-state singlering (SR) model to the quasi steady-state infiltration rates obtained with a single-ring pressure infiltrometer (PI) increases confidence in the estimated K s values. Determining a means to estimate K s from infiltration data collected with a square infiltrometer allows the use of sources of different shapes. Using numerically simulated infiltration rates for six homogeneous soils ranging in texture from sand to silty clay loam, this investigation suggested an overall good performance of the SR model, with estimated K s values differing by not more than 25% from the true values for the 90% of the 96 considered runs. Larger errors were generally obtained for the silty clay loam soil. Even in this case, however, a small ring radius (0.038 m), a relatively high initial soil water content (initial effective saturation = 0.4) and a relatively high depth of ponding (0.10 m) allowed the obtainment of accurate predictions of K s (error = 13%) with a run of practically sustainable duration (4 h). The SR model was also usable to analyze quasi steady-state infiltration data collected with a square infiltrometer when infiltration was assumed to occur through a circular source having the same area of the square infiltrometer. With this assumption, the estimates of K s differed from the true values by not more than a practically negligible 16%. The results of this investigation should help better interpret K s values obtained with the PI and also improve the experimental methodology, depending on the soil. Moreover, a wider applicability of the infiltrometer techniques, i.e. not limited to a circular source, can be expected. Soil heterogeneity should be taken into account in the future since heterogeneity is common in the field.

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Section: Soils and Numerical Simulationsmentioning

confidence: 99%

Testing steady-state analysis of single-ring and square pressure infiltrometer data

2016

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“…Recently, constant-head, radial steady flow was further considered by Reynolds and Lewis (2012) on the premise that, with the classical Guelph permeameter (GP) technique, practical difficulties can arise in gravelly materials, where augering can be problematic, and in uncohesive materials, where the well may collapse during the augering process or upon wetting. One convenient and rapid way designed to get around these problems was to form the well using a "drive point" casing rather than an auger.…”

Section: Drive Point Guelph Permeametermentioning

confidence: 99%

“…For m ¼ 2, the regression approach is equivalent to the simultaneous equations approach. An alternative multiple-head calculation involves an iterative curvefitting procedure (Reynolds and Lewis 2012). In a method comparison carried out on a medium-coarse glacial outwash sand, the drive point GP method yielded two-three times higher α* and K fs values as compared to the original GP method (Reynolds and Lewis 2012).…”

Section: Drive Point Guelph Permeametermentioning

confidence: 99%

“…An alternative multiple-head calculation involves an iterative curvefitting procedure (Reynolds and Lewis 2012). In a method comparison carried out on a medium-coarse glacial outwash sand, the drive point GP method yielded two-three times higher α* and K fs values as compared to the original GP method (Reynolds and Lewis 2012). The detected differences were thought to be a consequence of flow impedance in the original GP wells, due to progressive collapse of the unlined well wall during the flow measurements, and/or gradual sinking of the GP outflow tip into the unprotected base of the well due to the weight of the GP apparatus.…”

Section: Drive Point Guelph Permeametermentioning

confidence: 99%

“…(2.116) also requires the measurement of Δθ and the estimation of α*, which can be carried out on the basis of the textural/structural soil characteristics (Table 2.1) (Elrick and Reynolds 1992a;Reynolds and Lewis 2012). Taking into account that Eq.…”

Section: Principles and Application Of The Techniquementioning

confidence: 99%

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