Hydraulic Properties and Non-equilibrium Water Flow in Soils

2014 ◽  
pp. 403-434 ◽  
Author(s):  
Wolfgang Durner ◽  
Efstathios Diamantopoulos ◽  
Sascha C. Iden ◽  
Benedikt Scharnagl
Keyword(s):  
Water Flow ◽  
Hydraulic Properties ◽  
Non Equilibrium

Characterization of hydraulic properties in the upper vadose zone for two aquifers in Slovenia

2021 ◽  
Author(s):  
Vesna Zupanc ◽  
Matjaž Glavan ◽  
Miha Curk ◽  
Urša Pečan ◽  
Michael Stockinger ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Soil Water ◽  
Water Flow ◽  
Vadose Zone ◽  
Hydraulic Properties ◽  
Isotope Composition ◽  
Transport Processes ◽  
Precipitation Event ◽  
Water Fluxes ◽  
Flow And Transport

<p>Environmental tracers, present in the environment and provided by nature, provide integrative information about both water flow and transport. For studying water flow and solute transport, the hydrogen and oxygen isotopes are of special interest, as their ratios provide a tracer signal with every precipitation event and are seasonally distributed. In order to follow the seasonal distribution of stable isotopes in the soil water and use this information for identifying hydrological processes and hydraulic properties, soil was sampled three times in three profiles, two on Krško polje aquifer in SE Slovenia and one on Ljubljansko polje in central Slovenia. Isotope composition of soil water was measured with the water-vapor-equilibration method. Based on the isotope composition of soil water integrative information about water flow and transport processes with time and depth below ground were assessed. Porewater isotopes were in similar range as precipitation for all three profiles.  Variable isotope ratios in the upper 60 cm for the different sampling times indicated dynamic water fluxes in this upper part of the vadose zone. Results also showed more evaporation at one sampling location, Brege. The information from stable isotopes will be of importance for further analyzing the water fluxes in the vadose zone of the study sties. <br>This research was financed by the ARRS BIAT 20-21-32 and IAEA CRP 1.50.18 Multiple isotope fingerprints to identify sources and transport of agro-contaminants.  </p>

scholarly journals The contrasting influence of short-term hypoxia on the hydraulic properties of cells and roots of wheat and lupin

2010 ◽  
Vol 37 (3) ◽  
pp. 183 ◽  
Author(s):  
Helen Bramley ◽  
Neil C. Turner ◽  
David W. Turner ◽  
Stephen D. Tyerman
Keyword(s):  
Hydraulic Conductivity ◽  
Water Flow ◽  
Hydraulic Properties ◽  
Turgor Pressure ◽  
Lupinus Luteus ◽  
Yellow Lupin ◽  
Cortical Cells ◽  
Crop Species ◽  
Wheat Roots ◽  
Root Cells

Little is known about water flow across intact root cells and roots in response to hypoxia. Responses may be rapid if regulated by aquaporin activity, but only if water crosses membranes. We measured the transport properties of roots and cortical cells of three important crop species in response to hypoxia (0.05 mol O2 m–3): wheat (Triticum aestivum L.), narrow-leafed lupin (Lupinus angustifolius L.) and yellow lupin (Lupinus luteus L.). Hypoxia influenced solute transport within minutes of exposure as indicated by increases in root pressure (Pr) and decreases in turgor pressure (Pc), but these effects were only significant in lupins. Re-aeration returned Pr to original levels in yellow lupin, but in narrow-leafed lupin, Pr declined to zero or lower values without recovery even when re-aerated. Hypoxia inhibited hydraulic conductivity of root cortical cells (Lpc) in all three species, but only inhibited hydraulic conductivity of roots (Lpr) in wheat, indicating different pathways for radial water flow across lupin and wheat roots. The inhibition of Lpr of wheat depended on the length of the root, and inhibition of Lpc in the endodermis could account for the changes in Lpr. During re-aeration, aquaporin activity increased in wheat roots causing an overshoot in Lpr. The results of this study demonstrate that the roots of these species not only vary in hydraulic properties but also vary in their sensitivity to the same external O2 concentration.

scholarly journals Inversion of borehole-response test data for estimation of subglacial hydraulic properties

1997 ◽  
Vol 43 (143) ◽  
pp. 103-113 ◽  
Author(s):  
Dan B. Stone ◽  
Garry K. C. Clarke ◽  
Robert G. Еllis
Keyword(s):  
Theoretical Model ◽  
Water Flow ◽  
Test Data ◽  
Hydraulic Properties ◽  
Flow System ◽  
Yukon Territory ◽  
Sediment Layer ◽  
Water Drainage ◽  
Specific Storage ◽  
Response Test

AbstractResponse tests are widely used in ground-water studies to assess the hydraulic properties of sub-surface water-flow systems. The simplicity of such tests also makes them attractive for investigation of subglacial hydraulic conditions. This paper describes a systematic, quantitative approach to the analysis of borehole-response test data. The approach uses the theoretical model of Stone and Clarke (1993), which describes water motion in a coupled borehole—subglacial flow system; this framework provides the basis for an inversion scheme that is focused on quantifying physical properties of the basal-flow system, as it is characterized in the theoretical model. The inversion procedure was applied to response-test data from Trapridge Glacier, Yukon Territory, Canada. Results of the inversions suggest that the subglacial drainage network can be described as a confined layer comprising coarse-sand-to fine-gravel-sized sediments, having a thickness of 0.1 – 0.3 m, and a hydraulic conductivity of about 5 × 10−4ms−1. Based on the water-drainage rates from boreholes, as they connect with the subglacial water-flow system, specific storage of the sediment layer was estimated to be approximately 1 × 10−4m−1. Further consideration of subglacial water-flow conditions suggests that connection drainage test results may tend to underestimate specific storage of the overall glacier substrate.

scholarly journals An experimental approach for determining unsaturated hydraulic properties of rock fractures

2004 ◽  
Vol 35 (3) ◽  
pp. 251-260 ◽  
Author(s):  
Hu Yunjin ◽  
Su Baoyu ◽  
Mao Genhai
Keyword(s):  
Hydraulic Conductivity ◽  
Capillary Pressure ◽  
Water Flow ◽  
Hydraulic Properties ◽  
Experimental Approach ◽  
Single Fracture ◽  
Rock Fractures ◽  
Unsaturated Hydraulic Conductivity ◽  
Connected Channels ◽  
Theoretical Saturation

An experimental approach for determining the unsaturated hydraulic properties (the relations between capillary pressure, saturation and unsaturated hydraulic conductivity) of rock fractures is developed and tested. Applying this approach to a single fracture, and with only water flowing, the capillary pressure–saturation and unsaturated hydraulic conductivity–capillary pressure relationships of the fracture during drainage and imbibition can be determined simultaneously. To facilitate the test of the validity of the experimental approach and to elucidate the characteristics of water flow in unsaturated fractures, an analogous fracture with parallel, connected channels of different apertures was fabricated. Experiments of unsaturated water flow in the analogous fracture were carried out. Some characteristics of water flow in unsaturated fractures (hysteresis between drainage and imbibition, etc.) were elucidated. Comparison of measured saturation values and theoretical saturation values corresponding to different apertures at the beginning of drainage and imbibition shows that the experimental approach presented in this paper is valid.

scholarly journals Comparison between field measurements and numerical simulation of steady-state solute transport in a heterogeneous soil profile

1997 ◽  
Vol 1 (4) ◽  
pp. 853-871 ◽  
Author(s):  
J. Vanderborght ◽  
D. Jacques ◽  
D. Mallants ◽  
P.-H. Tseng ◽  
J. Feyen
Keyword(s):  
Solute Transport ◽  
Water Flow ◽  
Random Fields ◽  
Hydraulic Properties ◽  
Soil Hydraulic Properties ◽  
Field Scale ◽  
Flow Heterogeneity ◽  
Heterogeneous Soil ◽  
Soil Hydraulic ◽  
Second Procedure

Abstract. Abstract: Field-scale solute dispersion is determined by water flow heterogeneity which results from spatial variability of soil hydraulic properties and soil moisture state. Measured variabilities of soil hydraulic properties are highly sensitive to the experimental method. Field-scale dispersion derived from leaching experiments in a macroporous loam soil was compared with field-scale dispersion obtained with numerical simulations in heterogeneous random fields. Four types of random fields of hydraulic properties having statistical properties derived from four different types of laboratory measurements were considered. Based on this comparison, the measurement method depicting heterogeneities of hydraulic properties most relevant to field-scale solute transport was identified. For unsaturated flow, the variability of the hydraulic conductivity characteristic measured on a small soil volume was the most relevant parameter. For saturated flow, simulated dispersion underestimated the measured dispersion and it was concluded that heterogeneity of macroscopic hydraulic properties could not represent solute flow heterogeneity under these flow conditions. Field-scale averaged solute concentrations depend both on the detection method and the averaging procedure. Flux-averaged concentrations (relevant to practical applications) differ from volume-averaged or resident concentrations (easy to measure), especially when water flow is more heterogeneous. Simulated flux and resident concentrations were subsequently used to test two simple one-dimensional transport models in predicting flux concentrations when they are calibrated on resident concentrations. In the first procedure, solute transport in a heterogeneous soil is represented by a 1-D convection dispersion process. The second procedure was based on the relation between flux and resident concentrations for a stochastic convective process. Better predictions of flux concentrations were obtained using the second procedure, especially when water flow and solute transport are very heterogeneous.

scholarly journals Mapping Soil Surface Macropores Using Infrared Thermography: An Exploratory Laboratory Study

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
João L. M. P. de Lima ◽  
João R. C. B. Abrantes ◽  
Valdemir P. Silva ◽  
M. Isabel P. de Lima ◽  
Abelardo A. A. Montenegro
Keyword(s):  
Infrared Thermography ◽  
Water Flow ◽  
Exploratory Study ◽  
Hydraulic Properties ◽  
Preferential Flow ◽  
Soil Surface ◽  
Small Scale ◽  
Nonequilibrium Flow ◽  
Study Laboratory

Macropores and water flow in soils and substrates are complex and are related to topics like preferential flow, nonequilibrium flow, and dual-continuum. Hence, the quantification of the number of macropores and the determination of their geometry are expected to provide a better understanding on the effects of pores on the soil’s physical and hydraulic properties. This exploratory study aimed at evaluating the potential of using infrared thermography for mapping macroporosity at the soil surface and estimating the number and size of such macropores. The presented technique was applied to a small scale study (laboratory soil flume).

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