Water flow in soil at small water contents: a simple approach to estimate the relative hydraulic conductivity in sandy soil

AbstractPines, used for sand dune stabilization, can influence the hydrophysical parameters and water flow in an aeolian sandy soil considerably, mainly due to soil water repellency. Two sites, separated by distance of about 20 m, formed the basis of our study. A control soil (“Pure sand“) with limited impact of vegetation or organic matter was formed at 50 cm depth beneath a forest glade area. This was compared to a “Forest soil” in a 30-year old Scots pine (Pinus sylvestris) forest. Most of the hydrophysical parameters were substantially different between the two soil surfaces. The forest soil was substantially more water repellent and had two-times the degree of preferential flow compared to pure sand. Water and ethanol sorptivities, hydraulic conductivity, and saturated hydraulic conductivity were 1%, 84%, 2% and 26% those of the pure sand, respectively. The change in soil hydrophysical parameters due to soil water repellency resulted in preferential flow in the forest soil, emerging during a simulated heavy rain following a long hot, dry period. The wetting front established in pure sand exhibited a form typical of that for stable flow. Such a shape of the wetting front can be expected in the forest soil in spring, when soil water repellency is alleviated substantially.

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Scaling the Hydraulic Functions of A Water Repellent Sandy Soil

International Agrophysics ◽

10.2478/intag-2014-0025 ◽

2014 ◽

Vol 28 (3) ◽

pp. 349-358 ◽

Cited By ~ 3

Author(s):

Heiner Stoffregen ◽

Gerd Wessolek

Keyword(s):

Numerical Simulation ◽

Hydraulic Conductivity ◽

Sandy Soil ◽

Water Retention ◽

High Spatial Resolution ◽

Water Repellent ◽

Soil Cores ◽

Initial Water ◽

Unsaturated Hydraulic Conductivity ◽

Water Contents

Abstract The heterogeneity of both unsaturated hydraulic conductivity and water retention was measured with a high spatial resolution on a transect using an evaporation method. Fifteen undisturbed 100 cm3 soil cores were taken on a transect every 10 cm from the topsoil of a water repellent sandy site. Five dynamic water retention curves and four unsaturated conductivity curves were determined for each core. We conducted measurements without further saturation in the laboratory in order to achieve field-like conditions. The initial water contents were heterogeneous, indicating different hysteretic conditions and water repellent areas. The scattering of the water retention curves was high, while the heterogeneity of unsaturated conductivity curves was unexpectedly low. Two scaling approaches were used to describe the heterogeneity: one with and one without considering hysteresis. The concept of scaling applies well to describing the heterogeneity of both hydraulic functions. Including hysteresis leads to similar results than excluding hysteresis. The distribution of the hydraulic conductivity and the water retention were independent from each other. The results give important information for numerical simulation of the water flow with heterogeneous hydraulic functions.

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Estimating high hydraulic conductivity locations through a 3D simulation of water flow in soil and a resistivity survey

Exploration Geophysics ◽

10.1071/eg17054 ◽

2018 ◽

Vol 49 (3) ◽

pp. 299-308 ◽

Cited By ~ 1

Author(s):

Keisuke Inoue ◽

Hiroomi Nakazato ◽

Tomijiro Kubota ◽

Koji Furue ◽

Hiroshi Yoshisako ◽

...

Keyword(s):

Hydraulic Conductivity ◽

Water Flow ◽

3D Simulation ◽

Resistivity Survey ◽

High Hydraulic Conductivity

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Inter-laboratory comparison of small water flow calibration facilities with extremely low uncertainty

Measurement ◽

10.1016/j.measurement.2016.05.088 ◽

2016 ◽

Vol 91 ◽

pp. 548-556 ◽

Cited By ~ 1

Author(s):

Noriyuki Furuichi ◽

Yoshiya Terao ◽

Shunichiro Ogawa ◽

Leopoldo Cordova ◽

Takashi Shimada

Keyword(s):

Water Flow ◽

Small Water ◽

Low Uncertainty

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Effect of Nano-Carbon on Water Holding Capacity in a Sandy Soil of the Loess Plateau

Earth Sciences Research Journal ◽

10.15446/esrj.v21n4.66104 ◽

2017 ◽

Vol 21 (4) ◽

pp. 189-195 ◽

Cited By ~ 2

Author(s):

Beibei Zhou ◽

Xiaopeng Chen

Keyword(s):

Water Content ◽

Soil Water ◽

Loess Plateau ◽

Sandy Soil ◽

Water Retention ◽

Soil Mixture ◽

Cumulative Infiltration ◽

Nano Carbon ◽

Water Contents ◽

Soil Water Contents

The poor water retention capacity of sandy soils commonly aggregate soil erosion and ecological environment on the Chinese Loess Plateau. Due to its strong capacity for absorption and large specific surface area, the use of nanocarbon made of coconut shell as a soil amendment that could improve water retention was investigated. Soil column experiments were conducted in which a layer of nanocarbon mixed well with the soil was formed at a depth of 20 cm below the soil surface. Four different nanocarbon contents by weight (0%, 0.1%, 0.5%, and 1%) and five thicknesses of the nanocarbon- soil mixture layer ranging from 1 to 5 cm were considered. Cumulative infiltration and soil water content distributions were determined when water was added to soil columns. Soil Water Characteristic Curves (SWCC) were obtained using the centrifuge method. The principal results showed that the infiltration rate and cumulative infiltration increased with the increases of nanocarbon contents, to the thicknesses of the nano carbon-soil mixture layer. Soil water contents that below the soil-nano carbon layer decreased sharply. Both the Brooks-Corey and van Genuchten models could describe well the SWCC of the disturbed sandy soil with various nano carbon contents. Both the saturated water content (θs), residual water content (θr) and empirical parameter (α) increased with increasing nano carbon content, while the pore-size distribution parameter (n) decreased. The available soil water contents were efficiently increased with the increase in nanocarbon contents.

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Simulation of ground-water flow in the Shenandoah Valley, Virginia and West Virginia, using variable-direction anisotropy in hydraulic conductivity to represent bedrock structure

Scientific Investigations Report ◽

10.3133/sir20085002 ◽

2008 ◽

Cited By ~ 2

Author(s):

Richard M. Yager ◽

Scott C. Southworth ◽

Clifford I. Voss

Keyword(s):

Hydraulic Conductivity ◽

West Virginia ◽

Ground Water ◽

Water Flow ◽

Ground Water Flow ◽

Shenandoah Valley ◽

Variable Direction

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Historical development of soil-water physics and solute transport in porous media

Water Science & Technology Water Supply ◽

10.2166/ws.2007.007 ◽

2007 ◽

Vol 7 (1) ◽

pp. 59-66 ◽

Cited By ~ 4

Author(s):

D.E. Rolston

Keyword(s):

Porous Media ◽

Hydraulic Conductivity ◽

Solute Transport ◽

Soil Water ◽

20Th Century ◽

Water Flow ◽

Unsaturated Soils ◽

Transport Processes ◽

Transport In Porous Media ◽

Unsaturated Hydraulic Conductivity

The science of soil-water physics and contaminant transport in porous media began a little more than a century ago. The first equation to quantify the flow of water is attributed to Darcy. The next major development for unsaturated media was made by Buckingham in 1907. Buckingham quantified the energy state of soil water based on the thermodynamic potential energy. Buckingham then introduced the concept of unsaturated hydraulic conductivity, a function of water content. The water flux as the product of the unsaturated hydraulic conductivity and the total potential gradient has become the accepted Buckingham-Darcy law. Two decades later, Richards applied the continuity equation to Buckingham's equation and obtained a general partial differential equation describing water flow in unsaturated soils. For combined water and solute transport, it had been recognized since the latter half of the 19th century that salts and water do not move uniformly. It wasn't until the middle of the 20th century that scientists began to understand the complex processes of diffusion, dispersion, and convection and to develop mathematical formulations for solute transport. Knowledge on water flow and solute transport processes has expanded greatly since the early part of the 20th century to the present.

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