Journal articles on the topic 'Hydraulic conductivity measurements'
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1
Olsen, Per Atle. "Estimation and Scaling of the Near-Saturated Hydraulic Conductivity." Hydrology Research 30, no. 3 (June 1, 1999): 177–90. http://dx.doi.org/10.2166/nh.1999.0010.
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The hydraulic conductivity in structured soils is known to increase drastically when approaching saturation. Tension infiltration allows in situ infiltration of water at predetermined matric potentials, thus allowing exploration of the hydraulic properties near saturation. In this study, the near saturated (ψ≥-0.15 m) hydraulic conductivity was estimated both in the top- and sub-soil of three Norwegian soils. A priory analysis of estimation errors due to measurement uncertainties was conducted. In order to facilitate the comparison between soils and depths, scaling analysis was applied. It was found that the increase in hydraulic conductivity with increasing matric potentials (increasing water content) was steeper in the sub-soil than in the top-soil. The estimated field saturated hydraulic conductivity was compared with laboratory measurements of the saturated hydraulic conductivity. The geometric means of the laboratory measurements was in the same order of magnitude as the field estimates. The variability of the field estimates of the hydraulic conductivity from one of the soils was also assessed. The variability of the field estimates was generally smaller than the laboratory measurements of the saturated hydraulic conductivity.
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Rovey, Charles W., and Douglas S. Cherkauer. "Scale Dependency of Hydraulic Conductivity Measurements." Ground Water 33, no. 5 (September 1995): 769–80. http://dx.doi.org/10.1111/j.1745-6584.1995.tb00023.x.
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Al, Tom A., and David W. Blowes. "Identification of preferential flow effects on hydraulic conductivity measurements using a fluorescent tracer." Canadian Geotechnical Journal 37, no. 2 (April 1, 2000): 479–84. http://dx.doi.org/10.1139/t99-113.
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Core samples were collected from fractured and unfractured zones within fine-grained, unconsolidated mine tailings. The hydraulic conductivity of the core samples was measured in a constant-head permeameter. A fluorescent dye tracer was added to the constant-head reservoir in the permeameter. The tests were run for approximately 48 h, then the cores were sectioned to observe the distribution of dye. Flow through the fractures results in hydraulic conductivity measurements up to one order of magnitude greater than that of unfractured tailings. Observations of the dye distribution in samples following permeameter measurements are used to identify cases where preferential flow in fractures has influenced the hydraulic conductivity measurements. The dye tracer distribution also indicates where measurement errors may be suspected due to flow leakage around the core sample.Key words: tracers, hydraulic conductivity, fractures, tailings.
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Siemens, Greg, and James A. Blatz. "Development of a hydraulic conductivity apparatus for bentonite soils." Canadian Geotechnical Journal 44, no. 8 (August 2007): 997–1005. http://dx.doi.org/10.1139/t07-025.
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Measurement and interpretation of hydraulic conductivity in porous media is a complicated process, and many laboratory apparatuses exist for different soil types and conditions. To use models for interpretation and prediction of hydraulic conductivity, accurate test measurements are required. A new hydraulic conductivity apparatus is presented that includes simultaneous control of volume and stress states. The apparatus includes the ability to automatically control volume to apply selected displacement boundary conditions while imposing radial flow conditions. The capabilities of the system are displayed using two selected hydraulic conductivity tests on an unsaturated sand–bentonite mixture, which is a swelling soil. Hydraulic conductivity on the order of 10−13 m/s was measured using the new system and compared closely with previously measured values using a similar material. Post-test measurements displayed internal water content, density, and saturation changes that occurred during testing.
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Rab, MA, ST Willatt, and KA Olsson. "Hydraulic properties of a duplex soil determined from in situ measurements." Soil Research 25, no. 1 (1987): 1. http://dx.doi.org/10.1071/sr9870001.
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The hydraulic conductivity characteristics of a duplex soil profile were determined in the field from in situ measurements. For a given soil water suction, hydraulic conductivity of the subsoil was generally lower than the surface soil. Hydraulic conductivity characteristics calculated using the equations of Marshall and Millington and Quirk were in good agreement with field-measured hydraulic conductivity after matching at low soil water suctions. Implications of hydraulic properties for crop production and water management are noted.
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Jung, Yong, Ranji S. Ranjithan, and G. Mahinthakumar. "Subsurface characterization using a D-optimality based pilot point method." Journal of Hydroinformatics 13, no. 4 (October 28, 2010): 775–93. http://dx.doi.org/10.2166/hydro.2010.111.
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Detailed hydraulic conductivity estimation is a difficult problem as the number of direct measurements available at a typical field site is relatively few and sparse. A common approach to estimate hydraulic conductivity is to combine direct hydraulic conductivity measurements with secondary measurements such as hydraulic head and tracer concentrations in an inverse modeling approach. Even with secondary measurements this may constitute an underdetermined (or over-parameterized) inverse problem giving rise to ‘non-unique’ and incorrect estimates. One approach to reduce over-parameterization is to estimate hydraulic conductivity at a few carefully chosen points called ‘pilot points’ (i.e. reduction in parameter space). This paper develops a D-optimality based criterion method (DBM) for pilot point selection and tests its effectiveness for estimating hydraulic conductivity fields using several synthetic cases. Results show that the selected pilot points using this approach lead to a more accurate hydraulic conductivity characterization than either random or sequential pilot point location selection methods.
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SUGIE, Shinsuke, and Renji NARUSE. "Measurements of unsaturated hydraulic conductivity of snow." Journal of the Japanese Society of Snow and Ice 62, no. 2 (2000): 117–27. http://dx.doi.org/10.5331/seppyo.62.117.
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COEN, G. M., and C. Wang. "ESTIMATING VERTICAL SATURATED HYDRAULIC CONDUCTIVITY FROM SOIL MORPHOLOGY IN ALBERTA." Canadian Journal of Soil Science 69, no. 1 (February 1, 1989): 1–16. http://dx.doi.org/10.4141/cjss89-001.
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Vertical saturated hydraulic conductivity, as an important soil characteristic, should be part of the information displayed on soil survey maps. As rigorous measurement techniques are relatively slow and cumbersome, a rapid procedure for estimating vertical saturated hydraulic conductivity of soils using soil morphology was tested for Prairie conditions. Morphological estimates of vertical saturated hydraulic conductivity were compared to field measurements using an air entry permeameter for 36 sites representing 25 soil series. Eighty-three percent of the estimated values were within one saturated hydraulic conductivity class of the mean measured value. It was concluded that morphological observations are sufficiently accurate to allow field characterization of pedons. In Alberta, in Chernozemic areas, management procedures do not appear to modify strongly the saturated hydraulic conductivity. This in turn allows useful predictions of saturated hydraulic conductivity to be related to soil series concepts and therefore allows extrapolation to manageable tracts of land using map unit concepts. Key words: Saturated hydraulic conductivity, soil morphology, Alberta, estimating
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Fallico, C., E. Migliari, and S. Troisi. "Characterization of the field saturated hydraulic conductivity on a hillslope: measurement techniques, data sensitivity analysis and spatial correlation modelling." Hydrology and Earth System Sciences Discussions 2, no. 4 (July 28, 2005): 1247–98. http://dx.doi.org/10.5194/hessd-2-1247-2005.
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Abstract. In the context of studies aiming at the estimation of effective parameters for unsaturated zone modelling, this work tackles the problem of experimental data quality, considering the large collection of data gathered at an experimental site equipped for unsaturated zone hydraulic monitoring in the alluvial basin of a Calabrian river, in the South of Italy. Focusing attention on field saturated hydraulic conductivity, the in-site measurement techniques by tension disc and pressure ring infiltrometers are considered, pointing out the main indications for the correct use of each measuring approach; laboratory techniques are also considered. Statistical data analysis showed that the measurements performed by tension disc infiltrometer supplied values of hydraulic conductivity which are on average lower and more homogeneous than the values provided by the other measurement techniques considered. Sensitivity analysis was then carried out by Monte Carlo simulation on the parameter sampling achieved by field measurement techniques in order to evaluate the influence of any possible small measurement errors on the data. Sensitivity analysis showed that both ring and disc infiltrometer are tools reliable enough for the in situ measurements of field saturated hydraulic conductivity. Finally, after a data merging procedure giving origin to different sets of data, the spatial correlation structure of field saturated hydraulic conductivity is investigated, using well-known geostatistical techniques.
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Bird, TL, TM Willis, and GJ Melville. "Subsoil hydraulic conductivity estimates for the Lower Macquarie Valley." Soil Research 34, no. 2 (1996): 213. http://dx.doi.org/10.1071/sr9960213.
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Field saturated hydraulic conductivity was measured in situ, at two depths in the B horizon, on irrigated soils in the Lower Macquarie Valley. Measurements were made with constant head well permeameters, using the single-head method, and water of moderate sodicity and high salinity. The hydraulic conductivity data were log-normally distributed for all soil groups and there were significant differences between some of these soil groups in mean hydraulic conductivity. Three soils exhibited significant differences in mean hydraulic conductivity between depths. Hydraulic conductivity measurements ranged up to 3 orders of magnitude within a soil. Variation in hydraulic conductivity estimates, both between and within soil groups, confirmed the variation observed in previous predictions of deep drainage, which were obtained using a semi-empirical model. A cluster analysis on hydraulic conductivity indicated that similar morphological soil properties did not necessarily reflect similar hydrologic properties. There was a strong relationship between hydraulic conductivity and exchangeable sodium percentage (ESP), hydraulic conductivity and clay content, and ESP and clay content. A model was developed to predict field saturated hydraulic conductivity from ESP and clay content data. Hydraulic conductivity measured in this study may not have been representative of percolation rates which would occur with low salinity irrigation water, but can be used to assess the risk of recharge from irrigation on different soils in the lower Macquarie Valley. Shallow watertables may potentially develop when the application of irrigation water greatly exceeds crop water requirements. Quantification of groundwater recharge will allow the likelihood of shallow watertable development in the Lower Macquarie Valley to be assessed.
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Jenssen, Petter D. "Methods for Measuring the Saturated Hydraulic Conductivity of Tills." Hydrology Research 21, no. 2 (April 1, 1990): 95–106. http://dx.doi.org/10.2166/nh.1990.0007.
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The texture of tills excludes many of the traditional methods for measurement of the saturated hydraulic conductivity. The hydraulic conductivity is scale dependent and for massive relatively homogeneous till a representative sample volume of 104-105 cm3 is suggested. There are no ideal methods for measuring the saturated hydraulic conductivity in till and type of method and equipment should be carefully selected. Studies comparing and evaluating different methods for use in till are few. Comparative studies should be carried out. In the unsaturated zone a variant of the inverse auger hole method using a constant head and a lined pit is recommended. In the saturated zone measurements in dug wells are considered as the most representative method. Correlative methods can only be used for very approximate predictions of the saturated hydraulic conductivity in till.
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van den Berg, E. H., E. Perfect, C. Tu, P. S. K. Knappett, T. P. Leao, and R. W. Donat. "Unsaturated Hydraulic Conductivity Measurements with Centrifuges: A Review." Vadose Zone Journal 8, no. 3 (August 2009): 531–47. http://dx.doi.org/10.2136/vzj2008.0119.
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YOUNGS, E. G. "Estimating hydraulic conductivity values from ring infiltrometer measurements." Journal of Soil Science 38, no. 4 (December 1987): 623–32. http://dx.doi.org/10.1111/j.1365-2389.1987.tb02159.x.
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COOK, F. J. "CALCULATION OF HYDRAULIC CONDUCTIVITY FROM SUCTION PERMEAMETER MEASUREMENTS." Soil Science 152, no. 5 (November 1991): 321–25. http://dx.doi.org/10.1097/00010694-199111000-00002.
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Harvey, Charles F., and Steven M. Gorelick. "Mapping Hydraulic Conductivity: Sequential Conditioning with Measurements of Solute Arrival Time, Hydraulic Head, and Local Conductivity." Water Resources Research 31, no. 7 (July 1995): 1615–26. http://dx.doi.org/10.1029/95wr00547.
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Lichner, L., T. Orfánus, K. Novákova, M. Šír, and M. Tesař. "The impact of vegetation on hydraulic conductivity of sandy soil." Soil and Water Research 2, No. 2 (January 7, 2008): 59–66. http://dx.doi.org/10.17221/2115-swr.
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The objective of this study was to assess the impact of vegetation on the hydraulic conductivity of sandy soil at the locality Mláky II at Sekule (southwest Slovakia). The measurements were taken on the surface of a meadow (Meadow site), a 30-year old Scots pine (Pinus sylvestris) forest (Forest site) and a glade (Glade site). In the glade, the measurements were also taken in the depth of 50 cm (Pure sand) to reduce the influence of vegetation on the soil properties. It was found that the unsaturated hydraulic conductivity k<sub>r</sub>(−2 cm) as reduced due to the soil water repellency increased in the same order: Forest soil < Glade soil ≈ Meadow soil < Pure sand, similarly as decreased the water drop penetration time t<sub>p</sub>: Forest soil > Glade soil ≈ Meadow soil > Pure sand, which could refer to an inverse proportionality between the capillary suction and hydrophobic coating of the soil particles. The saturated hydraulic conductivity K<sub>s</sub> increased in the following order: Meadow soil < Glade soil ≈ Forest soil < Pure sand; more than two-times higher K<sub>s</sub> at both the Forest and Glade sites than that at the Meadow site could be the result of both the patchy growth of vegetation with some areas of bare soil at the Glade site and the macropores (dead roots) in more homogeneous humic top-layer at the Forest site. The share B<sub>r</sub> of flux through the pores with radii r longer than approximately 0.5 mm decreased in the order: Forest soil » Meadow soil > Glade soil » Pure sand, revealing the prevalence of preferential flow through macropores (dead roots) in the Forest site and a negligible share of macropores in the Pure sand.
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Weninger, Thomas, Gernot Bodner, Janis Kreiselmeier, Parvathy Chandrasekhar, Stefan Julich, Karl-Heinz Feger, Kai Schwärzel, and Andreas Schwen. "Combination of Measurement Methods for a Wide-Range Description of Hydraulic Soil Properties." Water 10, no. 8 (August 2, 2018): 1021. http://dx.doi.org/10.3390/w10081021.
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Established measurement methods for hydraulic soil properties cover a limited soil moisture range. Simulations of soil water dynamics based on such observations are therefore rarely representative for all conditions from saturation to drought. Recent technical developments facilitate efficient and cheap collecting of soil water characteristics data, but the quantitative benefit of extended measurement campaigns has not been adequately tested yet. In this study, a combination of four methods to measure water retention and hydraulic conductivity at different moisture ranges was applied. Evaporation method, dewpoint psychrometry, hood infiltrometer experiments, and falling head method for saturated conductivity were conducted at two experimental sites in eastern Austria. Effects of including the particular methods in the measurement strategy were examined by visual evaluation and a 1D-modelling sensitivity study including drainage, infiltration and drought conditions. The evaporation method was considered essential due to its broad measurement range both for water retention and hydraulic conductivity. In addition to that, the highest effect on simulated water balance components was induced by the inclusion of separate conductivity measurements near saturation. Water content after three days of drainage was 15 percent higher and the transpiration rate in a drought period was 22 percent higher without near-saturated conductivity measurements. Based on relative comparisons between different combinations, we suggested combining evaporation method and hood infiltrometer experiments as the basis for representative predictions of soil water dynamics.
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Asfahani, Jamal, and Zuhair Ahmad. "Estimation of hydraulic parameters by using VES sounding and neural network techniques in the semi-arid Khanasser valley region, Syria." Contributions to Geophysics and Geodesy 50, no. 1 (May 24, 2020): 113–33. http://dx.doi.org/10.31577/congeo.2020.50.1.6.
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This paper discusses the in near–real time processing of Global Navigation Satellite An alternative approach based on using Vertical Electrical Sounding (VES) measurements and Artificial Neural Network (ANN) technique is newly proposed for computing the hydraulic conductivity K and the transmissivity T of an aquifer. VES measurements in the locations, where available water samples exist are required in such an approach, in order to train a neural network with fitting capability to evaluate both the hydraulic conductivity and transmissivity. The hydraulic conductivity and transmissivity are thereafter extrapolated by the use of trained neural network, even in the VES points where no water samples exist. This approach is practiced and tested in the Khanasser valley, Northern Syria, where the hydraulic conductivity and the transmissivity of the Quaternary aquifer is computed. We find an acceptable agreement between the hydraulic conductivity values obtained by the new approach and those obtained by the pumping test, which range between 0.864 and 8.64 m/day.
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Garbulewski, Kazimierz, Stanisław Żakowicz, Simon Rabarijoely, and Anna Łada. "Sask method for testing hydraulic conductivity of soils by flat dilatometer (dmt)." Studia Geotechnica et Mechanica 34, no. 3 (October 1, 2012): 63–72. http://dx.doi.org/10.2478/sgm031205.
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Abstract DMT is one of the most popular methods of determining soil parameters needed to design a safe construction. Apart from the basic outcome parameter obtained from DMT measurements hydraulic conductivity (k) can be determined, previously proposed DMTA and DMTC methods were modified. The basic idea of the method is that the return of the deformed membrane is due to soil and water pressure. In the proposed SASK method the hydraulic conductivity of the soil is determined by measuring time-varying pressures A and C. Research has been performed at the experimental site of the Department of Geotechnical Engineering, WULS. In the paper, the assumptions of the new method for determining the hydraulic conductivity k are presented. The proposed method allows us to determine a reliable value for the hydraulic conductivity of clay soils. Using this method, the value of hydraulic conductivity (k = 5,47*10-11) is similar to the results of BAT, DMTA and laboratory measurements.
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Eisner, Nathan, Edward Gilman, Jason Grabosky, and Richard Beeson Jr. "Branch Junction Characteristics Affect Hydraulic Segmentation in Red Maple." Arboriculture & Urban Forestry 28, no. 6 (November 1, 2002): 245–51. http://dx.doi.org/10.48044/jauf.2002.037.
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The effect of branch morphological characteristics on hydraulic segmentation in red maple branch junctions was determined using hydraulic conductivity measurements. Relative branch size impacted hydraulic conductivity at the branch junction. Conductivity ratios were directly proportional to the ratio of branch diameter to stem diameter. Junctions with perpendicular branches showed lower hydraulic conductivities than more upright branches. The presence of visible branch collars was a good indicator of low branch junction conductivity. Branches having pith that was continuous with trunk pith were associated with codominant stems that had high branch junction conductivity. Branch junction hydraulic conductivity was positively correlated with the amount of discolored wood development after branch removal. This finding may indicate that similar anatomical properties are responsible for both branch junction decay resistance and hydraulic segmentation.
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Singh, D. N., and Sneha J. Kuriyan. "Estimation of unsaturated hydraulic conductivity using soil suction measurements obtained by an insertion tensiometer." Canadian Geotechnical Journal 40, no. 2 (April 1, 2003): 476–83. http://dx.doi.org/10.1139/t02-112.
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To estimate the unsaturated soil hydraulic conductivity of a silty soil, an insertion tensiometer has been used for measuring its suction corresponding to different water contents. These suction values have been used for developing the soil-water characteristic curve (SWCC). The obtained SWCC has been compared with the trends predicted by various fits available in the literature. Further, with the help of the obtained SWCC, the unsaturated soil hydraulic conductivity has been estimated. The study demonstrates the usefulness of insertion tensiometers for measuring soil suction and for estimating its hydraulic conductivity.Key words: silty soil, suction, insertion tensiometer, soil-water characteristic curve, unsaturated soil hydraulic conductivity.
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Allaire, S. E., J. Caron, and J. Gallichand. "Measuring the saturated hydraulic conductivity of peat substrates in nursery containers." Canadian Journal of Soil Science 74, no. 4 (November 1, 1994): 431–37. http://dx.doi.org/10.4141/cjss94-056.
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Pore size, distribution and continuity are important characteristics for the exchange and storage of air and water in artificial mixes. Saturated hydraulic conductivity (Ks) measurements can be used to obtain such a characterization. However, two difficulties are encountered when using Ks in potting media. First, the validity of Ks may be limited because it may not apply in media composed of coarse material or peat. Second, the structure of peat substrates is very sensitive and in situ measurements of potted peat substrates (i.e. measurements made directly in the pots) should be carried out to avoid any disruptive effect due to handling. Such a measurement, when made in pots, may require the evaluation of the water flux reduction resulting from the container outflow configuration. The objectives of this study were therefore to check the validity of Darcy’s law for peat substrates and to propose an approach for estimating the saturated hydraulic conductivity from flow measurements made in nursery containers. For three different substrates, water flow in artificial mixes followed Darcy’s law for hydraulic gradients ranging from 1.1 to 1.6 cm cm−1. Experimental results showed that the measured fluxes in 5-L nursery container filled at five different substrate heights (9, 11.5, 14, 16.5 and 19 cm) with laterally located drainage holes were significantly different from those measured in pots with the bottom removed (therefore equivalent to measurement currently made in cylinders) at P = 0.0022. Fluxes in containers with bottoms removed were 7–31% higher than in intact pots. Water flux measurements may therefore need to be corrected for this flux reduction in order to accurately estimate hydraulic conductivity from flow experiments run in pots. A correction factor based on the results obtained from a finite difference model was derived and calibrated. Then, this correction factor was used to convert flux measurements made in pots with lateral holes into equivalent flux that would have been obtained had the pot had an open bottom. After correction, no significant flux reductions were found between pots with open bottoms and pots with lateral holes (P = 0.55). A correction factor estimated from Laplace’s equation, once calibrated, can therefore be applied to flux measurements obtained from pots to obtain estimates of Ks of undisturbed potted media. Key words: Hydraulic conductivity, peat substrates, container
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Zhang, Peng, Williams Ozowe, Rodney T. Russell, and Mukul M. Sharma. "Characterization of an electrically conductive proppant for fracture diagnostics." GEOPHYSICS 86, no. 1 (January 1, 2021): E13—E20. http://dx.doi.org/10.1190/geo2019-0367.1.
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Fracture diagnosis with electromagnetic (EM) and electrical tools requires proppants with high electrical conductivity and mechanical strength. Lab measurements of the electrical and hydraulic conductivity of proppants are critical for selecting the best candidates. Such measurements greatly benefit simulations, field tests, and the ultimate application of such proppants in the field. To that end, a new lab protocol is developed for measuring the electrical and hydraulic conductivity of proppants. The lab setup, which mainly includes a resistivity core holder and a Hassler sleeve core holder, allows for simulation of realistic pressure and temperature conditions when making measurements. Petroleum coke (PC) is proposed as a candidate proppant because of its widespread availability and low cost. Lab measurements show that the effective electrical conductivity of pure PC in a model fracture is approximately 5000 S/m, under a closure stress greater than [Formula: see text] (4000 psi). When PC is mixed with sand, the effective electrical conductivity of the mixture decreases with an increasing weight percentage of sand. Although sand degrades the contact between PC particles, the electrical conductivity stays reasonably high (approximately 1700 S/m) when 50% sand is added. Hydraulic conductivity measurements show that when a fracture is propped with pure PC, the measured fracture conductivity is greater than [Formula: see text] ([Formula: see text]) (dimensionless fracture conductivity greater than 100 for a shale with [Formula: see text] or 100 nD permeability) under a confining pressure of [Formula: see text] (6000 psi). This means that a fracture propped with PC is infinitely conductive in a typical shale formation. When sand is added, the fracture’s hydraulic conductivity becomes even higher, which clearly shows PC’s ability of sustaining high stresses. The proposed protocol provides a robust and effective method that can be generalized for lab testing for other candidate proppants. The data presented clearly show that PC has the potential for field-scale applications in EM hydraulic fracture diagnostics.
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McCarter, W. J., J. Blewett, T. M. Chrisp, and G. Starrs. "Electrical property measurements using a modified hydraulic oedometer." Canadian Geotechnical Journal 42, no. 2 (April 1, 2005): 655–62. http://dx.doi.org/10.1139/t04-107.
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The work presented focuses on modifying a hydraulic oedometer (Rowe cell) to facilitate monitoring of the electrical conductivity of soil, in conjunction with loaddeformation characteristics. Technical issues are addressed and data presented to show the change in the electrical properties of saturated clay, both parallel and normal to the direction of loading, taken through a loadingunloadingreloading cycle. The electrical response can be interpreted in terms of bulk changes in porosity void ratio and fabric features such as pore tortuosity and particle alignment. The modified cell and testing methodology offer scope for development as a noninvasive, real time monitoring technique to study fabric changes in soil.Key words: clay, electrical conductivity, consolidation, porosity, fabric, anisotropy.
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Dubreuil-Boisclair, Camille, Erwan Gloaguen, Denis Marcotte, and Bernard Giroux. "Heterogeneous aquifer characterization from ground-penetrating radar tomography and borehole hydrogeophysical data using nonlinear Bayesian simulations." GEOPHYSICS 76, no. 4 (July 2011): J13—J25. http://dx.doi.org/10.1190/1.3571273.
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It is known that the heterogeneity of hydraulic conductivity drives the groundwater flow and the transport of contaminants. However, in conventional characterization methods, the lack of densely sampled hydrological data does not permit us to describe the aquifer heterogeneity at an appropriate scale. In this study, we integrate ground-penetrating radar (GPR) tomographic data with hydraulic conductivity logs to estimate the hydraulic conductivity of a heterogeneous unconsolidated aquifer at a decimetric scale between two boreholes. The integration of these different data sets is achieved using a nonlinear Bayesian simulation algorithm. The prior hydraulic conductivity distribution is estimated, under Gaussian hypothesis, by simple kriging of the hydraulic well data. The likelihood of hydraulic conductivity given the relative permittivity and the electrical conductivity functions is obtained from a kernel probability density function estimator that describes the in-situ relationship between the electric and the hydraulic properties measured along boreholes. The proposed method is tested on a synthetic heterogeneous model of permeability to validate the methodology. We show that permeability realizations obtained from the proposed algorithm present a higher correlation with the synthetic model than other classical simulation methods. The method is then applied on data acquired over an unconsolidated aquifer located in Saint-Lambert-de-Lauzon, Quebec, Canada. The data set consists of measurements from (i) GPR crosshole acquisition, (ii) cone penetration testing with pressure measurement combined with soil moisture resistivity, and (iii) a borehole electromagnetic flowmeter. By using the presented Bayesian approach, we generated multiple hydraulic conductivity realizations that are in good agreement with the hydrogeological model of the area.
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White, I., and K. M. Perroux. "Estimation of Unsaturated Hydraulic Conductivity from Field Sorptivity Measurements." Soil Science Society of America Journal 53, no. 2 (March 1989): 324–29. http://dx.doi.org/10.2136/sssaj1989.03615995005300020002x.
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Tao, Gaoliang, Xueliang Zhu, Jianchao Cai, Henglin Xiao, Qingsheng Chen, and Yin Chen. "A Fractal Approach for Predicting Unsaturated Hydraulic Conductivity of Deformable Clay." Geofluids 2019 (May 2, 2019): 1–9. http://dx.doi.org/10.1155/2019/8013851.
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The relative hydraulic conductivity is one of the key parameters for unsaturated soils in numerous fields of geotechnical engineering. The quantitative description of its variation law is of significant theoretical and technical values. Parameters in a classical hydraulic conductivity model are generally complex; it is difficult to apply these parameters to predict and estimate the relative hydraulic conductivity under deformation condition. Based on the fractal theory, a simple method is presented in this study for predicting the relative hydraulic conductivity under deformation condition. From the experimental soil-water characteristic curve at a reference state, the fractal dimension and air-entry value are determined at a reference state. By using the prediction model of air-entry value, the air-entry values at the deformed state are then determined. With the two parameters determined, the relative hydraulic conductivity at the deformed state is predicted using the fractal model of relative hydraulic conductivity. The unsaturated hydraulic conductivity of deformable Hunan clay is measured by the instantaneous profile method. Values of relative hydraulic conductivity predicted by the fractal model are compared with those obtained from experimental measurements, which proves the rationality of the proposed prediction method.
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Jamshidi, Reza Jolous, and Craig B. Lake. "Hydraulic and strength properties of unexposed and freeze–thaw exposed cement-stabilized soils." Canadian Geotechnical Journal 52, no. 3 (March 2015): 283–94. http://dx.doi.org/10.1139/cgj-2014-0100.
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A total of 108 specimens were prepared to examine the hydraulic performance and strength performance of nine different cement-stabilized soils under unexposed and freeze–thaw exposed conditions. Specimens from each mix design were evaluated under two levels of curing conditions (i.e., immature versus mature). Hydraulic conductivity and unconfined compressive strength (UCS) measurements were performed to assess changes in the performance of specimens after 12 cycles of freezing at −10 ± 1 °C and thawing at 22 ± 1 °C. Measured mass losses of the specimens from a standard brushing test were also monitored at different freeze–thaw cycles, and results were compared with the changes in the hydraulic performance for each mix design. Hydraulic conductivity measurements on unexposed mature specimens showed that the lowest values likely occurred at water contents slightly wet of optimum water content (OWC). The UCS values showed a general decreasing trend with the increase in the water content for both immature and mature specimens under unexposed conditions. After freeze–thaw exposure, specimens showed minor reductions as well as increases of up to 5250 times in hydraulic conductivity values. Increases of up to 14% and reductions of up to 58% in compressive strength were also observed, compared with unexposed conditions. For most cases, mature specimens resulted in a higher degree of damage compared with immature specimens. Results from the brushing tests showed this test method is not a suitable indicator for predicting changes in the hydraulic performance of cement-stabilized soils. Hydraulic conductivity measurements after a period of post-exposure healing showed damaged specimens have some potential in recovering parts of the increased hydraulic conductivity value due to the healing process.
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Wells, Tony, Stephen Fityus, David W. Smith, and Hlwan Moe. "The indirect estimation of saturated hydraulic conductivity of soils, using measurements of gas permeability. I. Laboratory testing with dry granular soils." Soil Research 44, no. 7 (2006): 719. http://dx.doi.org/10.1071/sr06037.
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A comprehensive knowledge of soil hydraulic conductivity is essential when modelling the distribution of soil moisture within soil profiles and across catchments. The high spatial variability of soil hydraulic conductivity, however, necessitates the taking of many in situ measurements, which are costly, time-consuming, and labour-intensive. This paper presents an improved method for indirectly determining the saturated hydraulic conductivity of granular materials via an in situ gas flow technique. The apparatus employed consists of a cylindrical tube which is embedded in the soil to a prescribed depth. Nitrogen at a range of pressures was supplied to the tube and allowed to escape by permeating through the soil. A 3-dimensional, axisymmetric, steady-state, finite element flow model was then used to determine the value of the soil intrinsic gas permeability which produces the best fit to the pressure–air flow data. Saturated hydraulic conductivities estimated from the application of the gas flow technique to 5 granular soils covering a wide range of permeabilities were in close agreement with values determined using a conventional permeameter. The results of this preliminary study demonstrate the potential of this approach to the indirect determination of saturated hydraulic conductivity based on measurement of gas flow rates in granular and structured soils.
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Abdalla Sabtow, Hassan, and Fatih Mehmet Kızıloğlu. "Stabilize Kent Çamuru ve Jips Uygulanmış Tuzlu Sodyumlu Topraklarda Arıtılmış Atıksuyun Islanma-Kuruma Döngülerinin Hidrolik İletkenliğe Etkisi." Turkish Journal of Agriculture - Food Science and Technology 10, no. 9 (October 9, 2022): 1741–46. http://dx.doi.org/10.24925/turjaf.v10i9.1741-1746.5435.
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This study was carried out to determine changes in hydraulic conductivity of a saline sodic soil subjected to different wetting-drying cycles and treated wastewater after stabilized sludge sewage and gypsum application. In a factorial experimental design, the study was conducted with three replication by using 3 treatment sewage sludge doses (50, 100 and 150 t ha-1), 3 wetting-drying cycles (0, 7 and 14 days) and 2 different water types (fresh water and treated wastewater). The hydraulic conductivity values of the saturated saline-sodic soils were measured at 2, 12 and 24 hour intervals by using a constant level ICW laboratory permemeter. The increase in the applied treatment sludge dose significantly affected the hydraulic conductivity value of the soils and significantly depending on the measurement range. It was determined that irrigation waters have different properties caused a significant change in the hydraulic conductivity value of the soils, with measurements made at intervals of 2 and 24 hours. Depending on the measurement interval, it was determined that the increase in sewage sludge doses caused significant effect and very important on the soil hydraulic conductivity. The study results indicated that the application of gypsum and stabilized waste sludge to the soil cause an increase in hydraulic conductivity values. The study results indicated that the application of gypsum and sewage sludge to the soil cause an increase in hydraulic conductivity values of saline sodic soils. The study results also showed that treated wastewater containing low amount of suspended solids can be used safely for irrigation on the land have saline-sodic soils. The study result also indicated that by applying solid and liquid wastes obtained from treatment units to the saline-sodic soils can be significant contribution in terms of waste management and environmental protection.
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Camargo, Mário A., Paulo C. Facin, and Luiz F. Pires. "Lattice Boltzmann Method for Evaluating Hydraulic Conductivity of Finite Array of Spheres." Scientific World Journal 2012 (2012): 1–8. http://dx.doi.org/10.1100/2012/527618.
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The hydraulic conductivity (K) represents an important hydrophysical parameter in a porous media.Kdirect measurements, usually demand a lot of work, are expensive and time consuming. Factors such as the media spatial variability, sample size, measurement method, and changes in the sample throughout the experiment directly affectKevaluations. One alternative toKmeasurement is computer simulation using the Lattice Boltzmann method (LBM), which can help to minimize problems such as changes in the sample structure during experimental measurements. This work presentsKexperimental and theoretical results (simulated) for three regular finite arrangements of spheres. Experimental measurements were carried out aiming at corroborating the LBM potential to predictKonce the smallest relative deviation between experimental and simulated results was 1.4%.
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Fredericia, Johnny. "Saturated Hydraulic Conductivity of Clayey Tills and the Role of Fractures." Hydrology Research 21, no. 2 (April 1, 1990): 119–32. http://dx.doi.org/10.2166/nh.1990.0009.
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The background for the present knowledge about hydraulic conductivity of clayey till in Denmark is summarized. The data show a difference of 1-2 orders of magnitude in the vertical hydraulic conductivity between values from laboratory measurements and field measurements. This difference is discussed and based on new data, field observations and comparison with North American studies, it is concluded to be primarily due to fractures in the till.
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Smettem, K. R. J., and K. L. Bristow. "Obtaining soil hydraulic properties for water balance and leaching models from survey data. 2. Hydraulic conductivity." Australian Journal of Agricultural Research 50, no. 7 (1999): 1259. http://dx.doi.org/10.1071/ar97075.
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Regional scale application of water and solute transport models is often limited by the lack of available data describing soil hydraulic properties and their variability. Direct measurement over large areas is expensive and time consuming. Physico-empirical models derived from soil survey data are therefore an attractive alternative. If the Marshall method of estimating the saturated hydraulic conductivity is simplified to depend primarily on the maximum pore radius, given by the bubbling pressure, then it is equivalent to the Campbell model of saturated hydraulic conductivity which relies entirely on an estimate of the bubbling pressure obtained from particle size data. We apply this simplified physico-empirical model to estimate the ‘matrix’, or textural saturated hydraulic conductivity, K m, using estimates of the bubbling pressure derived entirely from clay content data that are readily available in soil surveys. Model estimates are compared with in situ measurements on surface soils obtained using a disc permeameter with a negative pressure head at the supply surface of 40 mm. Results appear to be satisfactory for broad-scale water balance and leaching risk models that require specification of a matching point for the unsaturated hydraulic conductivity function and for modelling applications requiring generalised application of results from experimental sites.
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Jacobsen, O. H., and H. E. Jensen. "Unsaturated Hydraulic Conductivity Determined by the Hot Air Method for Some Danish Till Soils." Hydrology Research 21, no. 2 (April 1, 1990): 133–40. http://dx.doi.org/10.2166/nh.1990.0010.
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Unsaturated hydraulic conductivity relations for topsoil and subsoil in 12 Danish till soils were obtained from measurements by the hot air method. In the range of pressure potentials (pF-values from 1.7 to 3.0) within which the method is most suitable the hydraulic conductivities were found to be within the range of 10-10-10-7 m s-1 for topsoils and 10-11-10-8 m s-1 for subsoils. The hydraulic conductivity relations obtained were briefly discussed in relation to the corresponding pF-curves. At any pF-value the subsoils differed more than the topsoils in hydraulic conductivity.
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Qiao, R. L., R. Sadurski, and J. Bhattacharya. "Hydraulic conductivity of ischemic pulmonary venules." American Journal of Physiology-Lung Cellular and Molecular Physiology 264, no. 4 (April 1, 1993): L382—L386. http://dx.doi.org/10.1152/ajplung.1993.264.4.l382.
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We report the first determination of lung endothelial barrier properties in ischemic, nonreperfused microvessels. We quantified the endothelial barrier in terms of hydraulic conductivity (Lp) in single pulmonary venules (diameter 20–50 microns) of isolated blood perfused lungs (dog, rat), held at constant inflation pressure (5 cmH2O) with a gas mixture containing 21% oxygen. Lp were determined by our split-drop technique in which an oil drop is first microinjected into a venule and then split by microinjection of a protein solution. Lp was interpreted from measurements of the rate of oil drop movement. Baseline Lp recorded in the first 30 min of perfusion averaged 3.4 +/- 0.9 x 10(-7) ml/(cm2.s.cmH2O). Then, in two separate groups of venules in which we established 1.3 +/- 0.1 h and 3.4 +/- 0.8 h of ischemia, we determined Lp which were, respectively, 145 +/- 6.5 and 308 +/- 13% above baseline (P < 0.05). We conclude that ischemia alone, in the absence of reperfusion, significantly deteriorates the lung endothelial barrier.
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Amin, Abdulla Karim. "Evaluation of Aquifer Porosity And Hydraulic Conductivity From Empirical Equations Using Geoelectrical Sounding Measurements In Piramagroon Area NE-Iraq." Journal of University of Raparin 7, no. 4 (December 8, 2020): 307–21. http://dx.doi.org/10.26750/vol(7).no(4).paper16.
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Application of Vertical Electrical Sounding (VES) with Schlumberger array as a low-cost technique and veritable method in groundwater exploration is more suitable for hydrogeological survey of sedimentary basins. This method is regularly used to solve a wide variety of ground water problems and hydraulic parameters. The main objective of this research therefore, is to evaluate aquifer porosity and hydraulic conductivity using the empirical equations of porosity and hydraulic conductivity with resistivity conducted in the continuation of the adjacent Sharazoor basin. For this purpose, four profiles were taken in studied area (Piramagroon district), and each profile includes five VES points of measurements. Then each VES was interpreted manually as well as by IPI2 win program for determining aquifer depth ranging from (40 m.) to (80 m.) in piramagroon district) and resistivity values range between (37.0 Ω.m) to (102 Ω.m), which are substituted in the empirical porosity-resistivity and hydraulic conductivity-resistivity equations for evaluating aquifer porosity and hydraulic conductivity of the studied area. The estimated aquifer porosity values range along the studied area range between (21%) to (39 %), and for hydraulic conductivity values range from (1 m/day) to (4 m/day), which shows the increasing of the both aquifer porosity from the top of uplifted subsurface layers underlying the piramagroon district toward both limbs according to increasing of rock fragments (gravel, pebble) and (sand sediments) and decreasing of clay content overlying upper part of Middle Tanjero Formation.
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McKenzie, N. J., H. P. Cresswell, H. Rath, and D. Jacquier. "Measurement of unsaturated hydraulic conductivity using tension and drip infiltrometers." Soil Research 39, no. 4 (2001): 823. http://dx.doi.org/10.1071/sr99136.
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We investigated differences between constant flux and constant potential methods for determining unsaturated hydraulic conductivity in the laboratory. A cheap and robust method was required. The constant flux drip infiltrometer has been used with large intact cores on a wide range of Australian soils. However, the method can be simplified by replacing the drip infiltrometer with a constant potential tension infiltrometer (disc permeameter). We conducted a series of measurements using 9 soil cores to determine whether the measured hydraulic conductivity differed with each method at matric potentials of –10, –20, or –50 mm. Hysteresis effects were also examined because tension infiltrometer measurements are usually made on the adsorption curve of the hydraulic conductivity and matric potential [K(Ψ)] relationship. Drip infiltrometer measurements are often made on the desorption curve. The reproducibility of measurements on a single core was also examined. A large decline in K(Ψ ) was observed on some cores with repeated measurements and this effect was larger than differences between the methods. In the absence of evidence of slaking or dispersion, the suspected cause of the decline in K(Ψ) was clogging of pores from accumulation of microbial biomass and their by-products. The results support the view that K(Ψ) in some soils is a dynamic property. There were consistent differences between the constant flux and constant potential methods on those soil cores not exhibiting a large decline in K(Ψ) (the others were omitted from the method comparison). The tension infiltrometer method indicated greater hydraulic conductivity in soils with well-developed macrostructure when matric potential was greater than –50 mm. Hysteresis effects were significant with both methods and measurements made on desorption and adsorption curves are not considered comparable. Overall, we concluded that the tension infiltrometer method was more suited than the drip method for routine processing of large numbers of samples at low cost.
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Dirksen, C., and S. Matula. "Automatic Atomized Water Spray System for Soil Hydraulic Conductivity Measurements." Soil Science Society of America Journal 58, no. 2 (March 1994): 319–25. http://dx.doi.org/10.2136/sssaj1994.03615995005800020009x.
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Philip, HJ, AL Ngala, and UU Waniyo. "Comparison of empirical models and laboratory saturated hydraulic conductivity measurements." Ethiopian Journal of Environmental Studies and Management 7, no. 3 (May 30, 2014): 305. http://dx.doi.org/10.4314/ejesm.v7i3.10.
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Petsonk, Andrew M. "Hydraulic Conductivity Measurements in Unsaturated Materials-Field vs. Lab Methods." Groundwater Monitoring & Remediation 8, no. 2 (June 1988): 50–51. http://dx.doi.org/10.1111/j.1745-6592.1988.tb00987.x.
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Fatehnia, M., K. Tawfiq, and M. Ye. "Estimation of saturated hydraulic conductivity from double-ring infiltrometer measurements." European Journal of Soil Science 67, no. 2 (March 2016): 135–47. http://dx.doi.org/10.1111/ejss.12322.
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Wen, Xian-Huan. "Estimation of statistical parameters for censored lognormal hydraulic conductivity measurements." Mathematical Geology 26, no. 6 (August 1994): 717–31. http://dx.doi.org/10.1007/bf02086868.
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Nyborg, Mats R. "A Model for the Relationship between the Hydraulic Conductivity and Primary Sedimentary Structures of Till." Hydrology Research 20, no. 3 (June 1, 1989): 137–52. http://dx.doi.org/10.2166/nh.1989.0011.
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An investigation has been made of the relationships between saturated hydraulic conductivity, porosity and micro-structure of undisturbed lodgement till samples. 35 measurements with a constant head laboratory permeameter are the basis for the discussion. All the measurements were made on undisturbed till samples. In order to minimize the effects of soil forming processes and to have the most homogeneous conditions all sampling were made from the C-horizon. The samples have a size of about 300 cm3. Porosity data were derived from capillary pressure curves. A model for how flow direction and long-axis orientations of elongated grains relate to the saturated hydraulic conductivity is presented. For an unsorted sediment such factors as grain size are concluded to be of minor importance for the hydraulic conductivity. The structural properties seem to be a more important factor. This effect can be explained in two ways. Either due to directional relations between sorted lenses and bands which have higher permeability and the flow route through the sample. The other explanation is due to a more continuous pore pattern parallel to the grain orientation. The hydraulic conductivity takes on a directional property, being smaller in directions normal to the structural long-axis orientation than in directions parallel to the orientation. A study of the effective porosity Versus hydraulic conductivity exhibits weak correlation.
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Ofomola, M. O., O. P. Otheremu, O. Ohwoghere‑asuma, and O. Anomohanran. "Determination of Aquifer Hydraulic Characteristics from Surface Electrical and Borehole Measurements in Ozoro, Nigeria." Nigerian Journal of Technological Development 19, no. 3 (September 23, 2022): 240–49. http://dx.doi.org/10.4314/njtd.v19i3.6.
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Surface electrical and borehole measurements were undertaken in order to establish the hydraulic characteristics of alluvial aquifer in Ozoro, Delta State. Ten vertical electrical sounding data were acquired using Schlumberger Configuration. Borehole measurements which included pumping test, well logging and the distribution of grain size analysis were also carried out. The results of the electrical sounding indicate that the aquiferous layer is located between the fourth and fifth layers with resistivity ranged from 53.5 Ωm - 1279 Ωm. The aquifer thickness ranged from 7.67 m - 49.4 m and transmissivity values ranged from 41.4 - 330.5 𝑚2/day. The average hydraulic conductivity (k) value obtained is 6.2 m/day. The borehole lithology, resistivity and spontaneous potential log indicate the subsurface lithology to consists of top soil (brownish), clayey sand, clay, fine sand and gravelly sand. The Cooper Jacob solution was used in the analysis of the borehole pumping experiment and the obtained hydraulic conductivity, transmissivity, storativity and specific capacity are 6.8 m/day, 0.067 m2/min (96.48 𝑚2/day), 25.47 and 0.364 m2/min (524.6 m2/day) respectively. Also, the grain size distribution analysis using the Hazen approximation gave hydraulic conductivity as 11.55 m/day. The results showed that all three methods are applicable for determining aquifer hydraulic parameters.
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Cichota, Rogerio, Iris Vogeler, Val O. Snow, and Trevor H. Webb. "Ensemble pedotransfer functions to derive hydraulic properties for New Zealand soils." Soil Research 51, no. 2 (2013): 94. http://dx.doi.org/10.1071/sr12338.
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Modelling water and solute transport through soil requires the characterisation of the soil hydraulic functions; however, determining these functions based on measurements is time-consuming and costly. Pedotransfer functions (PTFs), which make use of easily measurable soil properties to predict the hydraulic functions, have been proposed as an alternative to measurements. The better known and more widely used PTFs were developed in the USA or Europe, where large datasets exist. No specific PTFs have been published for New Zealand soils. To address this gap, we evaluated a range of published PTFs against an available dataset comprising a range of different soils from New Zealand and selected the best PTFs to construct an ensemble PTF (ePTF). Assessment (and adjustment when required) of published PTFs was done by comparing measurements and estimates of soil water content and the hydraulic conductivity at selected matric suction values. For each point, the best two or three PTFs were chosen to compose the ePTF, with correcting constants if needed. The outputs of the ePTF are the hydraulic properties at selected matric suctions, akin to obtaining measurements, thus allowing the fit of different equations as well as combining any available measurements. Testing of the ePTF showed promising performance, with reasonably accurate estimates of the water retention of an independent dataset. Root mean square error values averaged 0.06 m3 m–3 for various New Zealand soils, which is within the accuracy level of published PTF studies. The largest errors were found for soils with high clay content, for which the ePTF should be used with care. The performance of the ePTF for estimating soil hydraulic conductivity was not as reliable as for water content, exhibiting large scatter. Predictions of saturated hydraulic conductivity were of the same magnitude as the measurements, whereas the unsaturated values were generally under-predicted. The conductivity data available for this study were limited and highly variable. The estimates for hydraulic conductivity should therefore be used with much care, and future research should address measurements and analysis to improve the predictions. The ePTF was also used to parameterise the SWIM soil module for use in Agricultural Production Systems Simulator (APSIM) simulations. Comparisons of drainage predicted by APSIM against results from lysimeter experiments suggest that the use of the derived ePTF is suited for the estimation of soil parameters for use in modelling. The ePTF is not envisaged as a substitute for measurements but is a useful tool to complement datasets with limited amounts of measured data.
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Johnson, Mark, and John M. Tarbell. "A Biphasic, Anisotropic Model of the Aortic Wall." Journal of Biomechanical Engineering 123, no. 1 (August 29, 2000): 52–57. http://dx.doi.org/10.1115/1.1339817.
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A biphasic, anisotropic elastic model of the aortic wall is developed and compared to literature values of experimental measurements of vessel wall radii, thickness, and hydraulic conductivity as a function of intraluminal pressure. The model gives good predictions using a constant wall modulus for pressures less than 60 mmHg, but requires a strain-dependent modulus for pressures greater than this. In both bovine and rabbit aorta, the tangential modulus is found to be approximately 20 times greater than the radial modulus. These moduli lead to predictions that, when perfused in a cylindrical geometry, the aortic volume and its specific hydraulic conductivity are relatively independent of perfusion pressure, in agreement with experimental measurements. M, the parameter that relates specific hydraulic conductivity to tissue dilation, is found to be a positive quantity correcting a previous error in the literature.
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Chung, Choong-Ki, Joon-Hyoun Kim, Joonyoung Kim, and Taesik Kim. "Hydraulic Conductivity Variation of Coarse-Fine Soil Mixture upon Mixing Ratio." Advances in Civil Engineering 2018 (2018): 1–11. http://dx.doi.org/10.1155/2018/6846584.
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This paper presents the theoretical and experimental investigations of the hydraulic conductivity variation of the soil mixture that contains two distinct particle size distributions, coarse and fine soils. A new model for the hydraulic conductivity is introduced that focuses on the relationship between the coarse-fine soil mixing ratio and the hydraulic conductivity of the mixture. For the model verification, permeability tests were conducted. The glass beads and quality-controlled standard sand and soils obtained from fields were used for the specimen. The experiment results showed that the hydraulic conductivity of the soil mixture strongly depends on the mixing ratio. As the amount of the coarse soil contained in the fine soil increased, the hydraulic conductivity of the mixture decreased from that for the fine soil until the critical mixing ratio. This ratio is defined as the fine soils perfectly fill the voids between the coarse soils without remains. When the ratio is greater than the critical mixing ratio, the hydraulic conductivity is drastically increased with the mixing ratio up to that of the coarse soil. The comparison between the computed values and the test results shows that the introduced model successfully describes the measurements.
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Nam, Soonkie, Marte Gutierrez, Panayiotis Diplas, and John Petrie. "Laboratory and In Situ Determination of Hydraulic Conductivity and Their Validity in Transient Seepage Analysis." Water 13, no. 8 (April 20, 2021): 1131. http://dx.doi.org/10.3390/w13081131.
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This paper critically compares the use of laboratory tests against in situ tests combined with numerical seepage modeling to determine the hydraulic conductivity of natural soil deposits. Laboratory determination of hydraulic conductivity used the constant head permeability and oedometer tests on undisturbed Shelby tube and block soil samples. The auger hole method and Guelph permeameter tests were performed in the field. Groundwater table elevations in natural soil deposits with different hydraulic conductivity values were predicted using finite element seepage modeling and compared with field measurements to assess the various test results. Hydraulic conductivity values obtained by the auger hole method provide predictions that best match the groundwater table’s observed location at the field site. This observation indicates that hydraulic conductivity determined by the in situ test represents the actual conditions in the field better than that determined in a laboratory setting. The differences between the laboratory and in situ hydraulic conductivity values can be attributed to factors such as sample disturbance, soil anisotropy, fissures and cracks, and soil structure in addition to the conceptual and procedural differences in testing methods and effects of sample size.
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Cyr, Robert Y., and Paul Chiasson. "Modeling subsoil drainage systems for urban roadways." Canadian Journal of Civil Engineering 26, no. 6 (December 1, 1999): 799–809. http://dx.doi.org/10.1139/l99-048.
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Water infiltration and seepage in a roadway infrastructure is modeled from a cross section design of a residential street used by the City of Moncton (Department of Engineering). Field hydraulic conductivity measurements necessary for the modeling are also presented. Benefits of having a subsoil drainage systems (perforated drainage pipe and drainage mat) are well demonstrated. Some drainage problems caused by insufficient hydraulic conductivity, segregation, and limits on gradation curves for the gravel base foundation, as specified by the City of Moncton, are also discussed.Key words: roadway design, subsoil drainage, seepage modeling, field permeability measurements.
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Neyshabouri, Mohammad Reza, Mehdi Rahmati, Claude Doussan, and Boshra Behroozinezhad. "Simplified estimation of unsaturated soil hydraulic conductivity using bulk electrical conductivity and particle size distribution." Soil Research 51, no. 1 (2013): 23. http://dx.doi.org/10.1071/sr12158.
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Unsaturated soil hydraulic conductivity K is a fundamental transfer property of soil but its measurement is costly, difficult, and time-consuming due to its large variations with water content (θ) or matric potential (h). Recently, C. Doussan and S. Ruy proposed a method/model using measurements of the electrical conductivity of soil core samples to predict K(h). This method requires the measurement or the setting of a range of matric potentials h in the core samples—a possible lengthy process requiring specialised devices. To avoid h estimation, we propose to simplify that method by introducing the particle-size distribution (PSD) of the soil as a proxy for soil pore diameters and matric potentials, with the Arya and Paris (AP) model. Tests of this simplified model (SM) with laboratory data on a broad range of soils and using the AP model with available, previously defined parameters showed that the accuracy was lower for the SM than for the original model (DR) in predicting K (RMSE of logK = 1.10 for SM v. 0.30 for DR; K in m s–1). However, accuracy was increased for SM when considering coarse- and medium-textured soils only (RMSE of logK = 0.61 for SM v. 0.26 for DR). Further tests with 51 soils from the UNSODA database and our own measurements, with estimated electrical properties, confirmed good agreement of the SM for coarse–medium-textured soils (<35–40% clay). For these textures, the SM also performed well compared with the van Genuchten–Mualem model. Error analysis of SM results and fitting of the AP parameter showed that most of the error for fine-textured soils came from poorer adequacy of the AP model’s previously defined parameters for defining the water retention curve, whereas this was much less so for coarse-textured soils. The SM, using readily accessible soil data, could be a relatively straightforward way to estimate, in situ or in the laboratory, K(h) for coarse–medium-textured soils. This requires, however, a prior check of the predictive efficacy of the AP model for the specific soil investigated, in particular for fine-textured/structured soils and when using previously defined AP parameters.