A multistep constant-head borehole test to determine field saturated hydraulic conductivity of layered soils

Xiang, Jiannan; Scanlon, Bridget R.; Mullican, William F.; Chen, L.; Goldsmith, Richard S.

doi:10.1016/s0309-1708(96)00017-6

Cited by 10 publications

(8 citation statements)

References 15 publications

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“…How-ever, investigations examining the heterogeneity of the vadose zone are limited relative to the saturated zone by the fact that pumping and tracer tests, which depend on groundwater movement, are impossible. Those studies must utilize other methods, including particle size analysis (Nimmo et al, 2004;Dann et al, 2009), air permeability (Dixon and Nichols, 2005;Chief et al, 2008) and permeameter testing (Xiang et al, 1997;Reynolds, 2010;Miller et al, 2011). When the vadose zone is dominated by coarse gravel such efforts are made more difficult by the problems associated with sampling in gravel: large particles resist penetration by and clog samplers, excavated pits are prone to collapse, and high hydraulic conductivity rates require large volumes of water for in situ permeameter testing.…”

Section: Introductionmentioning

confidence: 99%

The hydraulic conductivity structure of gravel-dominated vadose zones within alluvial floodplains

Miller¹,

Heeren²,

Fox³

et al. 2014

Journal of Hydrology

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Section: Introductionmentioning

confidence: 99%

The hydraulic conductivity structure of gravel-dominated vadose zones within alluvial floodplains

Miller¹,

Heeren²,

Fox³

et al. 2014

Journal of Hydrology

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“…This variability can cause a problem of heterogeneity of response to irrigation or underground drainage [4]. However, the spatial variability of hydraulic conductivity can be used to analyse contamination in the unsaturated zone [15]. In this heterogeneous environment, the distribution of hydraulic conductivity obeys the log normal law [16] and hydraulic conductivity presents a strong random component [17].…”

Section: Discussionmentioning

confidence: 99%

Estimation of Hydraulic Conductivity of Soils at a Watershed-Scale Using Porchet’s Method: Application in the Olezoa Waterhed, Yaounde, Cameroon

Bon¹,

Ombolo²,

Mboudou³

et al. 2016

IJG

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Contamination analysis of the unsaturated zone requires information on the spatial variability of hydraulic conductivity. Two types of hydraulic tests (variable and constant charge) were identified to estimate the spatial variability of the hydraulic conductivity of the surface portion of the unsaturated zone in the Olezoa watershed. These tests were performed on 100 holes at depths ranging between 50 and 90 cm, spread throughout the watershed. The hydraulic conductivity values obtained at 50 and 90 cm are close to the absolute value for each method. However, they show a difference of 10 −1 m/s between the two types of test regardless of the depth of investigation. The representation of data in the graph indicates a staircase quartile distribution for the variable charge test. The test at constant charge, rather presents a log normal distribution which is also supported by the Kolmogorov-Smirnov test. Hydraulic conductivities have a random component and a spatial organization which results from soil and/or morphological factors. This organization thus permits the distinction of zones which could show high pollution risk.

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“…Similarly, gamma and neutron logs of boreholes only provide information on the vertical distribution of soil stratigraphy and water-filled porosity (Hodges et al, 2012). Xiang et al (1997) presented a multistep (constant head) permeameter test to determine K s value for a layered soil using the LAYERK model. LAYERK is an analytic code that was designed to determine the field-saturated hydraulic conductivity and the matric flux potential for individual layers using input parameters including layer thickness, the water level in the borehole, the radius of the borehole, and flow rate.…”

Section: Deterministic Heterogeneity -Layered Soil Profilementioning

confidence: 99%

“…Previous studies have attempted to estimate the effective saturated hydraulic conductivity of an unsaturated soil using a constant head borehole test. For example, analytical solutions have been developed to determine the hydraulic properties of a homogenous soil domain using constant head data and numerical simulations have been conducted to evaluate the accuracy of these analytical solutions (Reynolds and Elrick, 1985;Xiang et al, 1997). However, estimates of the hydraulic conductivity were often unrealistic due to the assumption of soil homogeneity in these analytical solutions (Reynolds and Elrick, 1985) and inherent soil heterogeneity.…”

Section: Introductionmentioning

confidence: 99%

“…However, estimates of the hydraulic conductivity were often unrealistic due to the assumption of soil homogeneity in these analytical solutions (Reynolds and Elrick, 1985) and inherent soil heterogeneity. Later, Xiang et al (1997) proposed an analytical approach to analyze the flow contribution of each layer to the total flow and numerically evaluated the approach and its assumptions. However, this test neglected unsaturated flow and was only suitable for determining the hydraulic conductivity of layered media in thick unsaturated zones.…”

Section: Introductionmentioning

confidence: 99%

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Drywell infiltration and hydraulic properties in heterogeneous soil profiles

Sasidharan

Bradford

Šimůnek

et al. 2019

Journal of Hydrology

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Effective hydraulic properties HYDRUS (2D/3D) A B S T R A C TDrywells are increasingly used to capture stormwater runoff for surface infiltration and aquifer recharge, but little research has examined the role of ubiquitous subsurface heterogeneity in hydraulic properties on drywell performance. Numerical experiments were therefore conducted using the HYDRUS (2D/3D) software to systematically study the influence of subsurface heterogeneity on drywell infiltration. Subsurface heterogeneity was described deterministically by defining soil layers or lenses, or by generating stochastic realizations of soil hydraulic properties with selected variance (σ) and horizontal (X) and vertical (Z) correlation lengths. The infiltration rate increased when a high permeability layer/lens was located at the bottom of the drywell, and had larger vertical and especially horizontal dimensions. Furthermore, the average cumulative infiltration (I) for 100 stochastic realizations of a given subsurface heterogeneity increased with σ and X, but decreased with Z. This indicates that the presence of many highly permeable, laterally extending lenses provides a larger surface area for enhanced infiltration than the presence of isolated, highly permeable lenses. The ability to inversely determine soil hydraulic properties from numerical drywell infiltration results was also investigated. The hydraulic properties and the lateral extension of a highly permeable lens could be accurately determined for certain idealized situations (e.g., simple layered profiles) using constant head tests. However, variability in soil hydraulic properties could not be accurately determined for systems that exhibited more realistic stochastic heterogeneity. In this case, the heterogeneous profile could be replaced with an equivalent homogeneous profile and values of an effective isotropic saturated conductivity (K s ) and the shape parameter in the soil water retention function ( ) could be inversely determined. The average value of K s for 100 stochastic realizations showed a similar dependency to I on σ, X, and Z. Whereas, the average value of had large confidence interval for soil heterogeneity parameters and played a secondary role in drywell infiltration. This research provides valuable insight on the selection of site, design, installation, and long-term performance of a drywell.

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A multistep constant-head borehole test to determine field saturated hydraulic conductivity of layered soils

Cited by 10 publications

References 15 publications

The hydraulic conductivity structure of gravel-dominated vadose zones within alluvial floodplains

The hydraulic conductivity structure of gravel-dominated vadose zones within alluvial floodplains

Estimation of Hydraulic Conductivity of Soils at a Watershed-Scale Using Porchet’s Method: Application in the Olezoa Waterhed, Yaounde, Cameroon

Drywell infiltration and hydraulic properties in heterogeneous soil profiles

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