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Sample records for hydraulic conductivity tests

  1. Formed Core Sampler Hydraulic Conductivity Testing

    Energy Technology Data Exchange (ETDEWEB)

    Miller, D. H.; Reigel, M. M.

    2012-09-25

    A full-scale formed core sampler was designed and functionally tested for use in the Saltstone Disposal Facility (SDF). Savannah River National Laboratory (SRNL) was requested to compare properties of the formed core samples and core drilled samples taken from adjacent areas in the full-scale sampler. While several physical properties were evaluated, the primary property of interest was hydraulic conductivity. Differences in hydraulic conductivity between the samples from the formed core sampler and those representing the bulk material were noted with respect to the initial handling and storage of the samples. Due to testing conditions, the site port samples were exposed to uncontrolled temperature and humidity conditions prior to testing whereas the formed core samples were kept in sealed containers with minimal exposure to an uncontrolled environment prior to testing. Based on the results of the testing, no significant differences in porosity or density were found between the formed core samples and those representing the bulk material in the test stand.

  2. Hydraulic Tomography and High-Resolution Slug Testing to Determine Hydraulic Conductivity Distributions - Year 1

    Science.gov (United States)

    2005-12-01

    the addition into a well of a known volume of water or a physical slug. More recently, pneumatic methods have become popular ( Zemansky and McElwee...and Zemansky , 2000), (Sellwood, 2001) and (Ross, 2004)]. The aquifer material at GEMS exhibits linear and non-linear responses to slug testing...1976; Zurbuchen et al., 2002; and Zemansky and McElwee, 2005). Slug tests have been a common method for obtaining information about the hydraulic

  3. Spatial variability of hydraulic conductivity of an unconfined sandy aquifer determined by a mini slug test

    DEFF Research Database (Denmark)

    Bjerg, Poul Løgstrup; Hinsby, Klaus; Christensen, Thomas Højlund;

    1992-01-01

    The spatial variability of the hydraulic conductivity in a sandy aquifer has been determined by a mini slug test method. The hydraulic conductivity (K) of the aquifer has a geometric mean of 5.05 × 10−4 m s−1, and an overall variance of 1n K equal to 0.37 which corresponds quite well to the results...... obtained by two large scale tracer experiments performed in the aquifer. A geological model of the aquifer based on 31 sediment cores, proposed three hydrogeological layers in the aquifer concurrent with the vertical variations observed with respect to hydraulic conductivity. The horizontal correlation...... length of the hydraulic conductivity has been determined for each of the three hydrogeological layers and is found to be small (1–2.5 m). The asymptotic longitudinal dispersivity of the aquifer has been estimated from the variance in hydraulic conductivity and the horizontal correlation length...

  4. Coordination of stem and leaf hydraulic conductance in southern California shrubs: a test of the hydraulic segmentation hypothesis.

    Science.gov (United States)

    Pivovaroff, Alexandria L; Sack, Lawren; Santiago, Louis S

    2014-08-01

    Coordination of water movement among plant organs is important for understanding plant water use strategies. The hydraulic segmentation hypothesis (HSH) proposes that hydraulic conductance in shorter lived, 'expendable' organs such as leaves and longer lived, more 'expensive' organs such as stems may be decoupled, with resistance in leaves acting as a bottleneck or 'safety valve'. We tested the HSH in woody species from a Mediterranean-type ecosystem by measuring leaf hydraulic conductance (Kleaf) and stem hydraulic conductivity (KS). We also investigated whether leaves function as safety valves by relating Kleaf and the hydraulic safety margin (stem water potential minus the water potential at which 50% of conductivity is lost (Ψstem-Ψ50)). We also examined related plant traits including the operating range of water potentials, wood density, leaf mass per area, and leaf area to sapwood area ratio to provide insight into whole-plant water use strategies. For hydrated shoots, Kleaf was negatively correlated with KS , supporting the HSH. Additionally, Kleaf was positively correlated with the hydraulic safety margin and negatively correlated with the leaf area to sapwood area ratio. Consistent with the HSH, our data indicate that leaves may act as control valves for species with high KS , or a low safety margin. This critical role of leaves appears to contribute importantly to plant ecological specialization in a drought-prone environment.

  5. Test of the rosetta pedotransfer function for saturated hydraulic conductivity

    NARCIS (Netherlands)

    Alvarez-Acosta, C.; Lascano, R.J.; Stroosnijder, L.

    2012-01-01

    Simulation models are tools that can be used to explore, for example, effects of cultural practices on soil erosion and irrigation on crop yield. However, often these models require many soil related input data of which the saturated hy- draulic conductivity (Ks) is one of the most important ones. T

  6. Hydraulic Conductivity Estimate via Tracer Test and Ensemble Kalman Filter Data Assimilation: Theoretical and Numerical Fundamentals

    Science.gov (United States)

    Crestani, E.; Camporese, M.; Salandin, P.

    2011-12-01

    Hydraulic properties of natural aquifers, such as porosity, hydraulic conductivity, and storativity, exhibit an erratic spatial variability at different scales that is difficult to recognize without expensive in situ sampling campaigns, laboratory analyses, and, when available, spatially distributed pumping tests. Nevertheless, the importance of the heterogeneous structure of natural formations on solute transport is well recognized, being the non-Fickian evolution of contaminant plumes and the relevant dispersive phenomena controlled by the variability of the hydraulic conductivity K at the local scale. Tracer test analyses have been widely adopted to identify the complex distribution of in situ hydraulic properties. In particular, the use of geophysical methods like the borehole Electrical Resistivity Tomography (ERT) have been in rapid increase, due to their potential to accurately describe the spatio-temporal evolution of the injected solute. Under the assumptions that the solute spreads as a passive tracer and with high values of the Peclet number, the plume evolution is controlled by the porosity and the spatial distribution of hydraulic conductivity. Combining the Lagrangian formulation of transport and the ensemble Kalman filter (EnKF) data assimilation technique, the purpose of this study is to infer the spatial distribution of K at the local scale from a sequence of time-lapse concentration imaging. The capabilities of the proposed approach are investigated simulating various assimilation experiments via synthetic tracer tests in a three-dimensional finite domain reproducing a heterogeneous aquifer. In a first scenario, all the available concentration measurements are assimilated and the entire hydraulic conductivity field is updated, while in the remaining scenarios the K values are updated only in a limited number of nodes by assimilating the concentrations in these same nodes, the hydraulic conductivity in the rest of the domain being the result of a

  7. Hydraulic conductivity of compacted zeolites.

    Science.gov (United States)

    Oren, A Hakan; Ozdamar, Tuğçe

    2013-06-01

    Hydraulic conductivities of compacted zeolites were investigated as a function of compaction water content and zeolite particle size. Initially, the compaction characteristics of zeolites were determined. The compaction test results showed that maximum dry unit weight (γ(dmax)) of fine zeolite was greater than that of granular zeolites. The γ(dmax) of compacted zeolites was between 1.01 and 1.17 Mg m(-3) and optimum water content (w(opt)) was between 38% and 53%. Regardless of zeolite particle size, compacted zeolites had low γ(dmax) and high w(opt) when compared with compacted natural soils. Then, hydraulic conductivity tests were run on compacted zeolites. The hydraulic conductivity values were within the range of 2.0 × 10(-3) cm s(-1) to 1.1 × 10(-7) cm s(-1). Hydraulic conductivity of all compacted zeolites decreased almost 50 times as the water content increased. It is noteworthy that hydraulic conductivity of compacted zeolite was strongly dependent on the zeolite particle size. The hydraulic conductivity decreased almost three orders of magnitude up to 39% fine content; then, it remained almost unchanged beyond 39%. Only one report was found in the literature on the hydraulic conductivity of compacted zeolite, which is in agreement with the findings of this study.

  8. Toward A 3-D Picture of Hydraulic Conductivity With Multilevel Slug Tests

    Science.gov (United States)

    McElwee, C. D.; McElwee, C. D.; Ross, H. C.

    2001-12-01

    The GEMS (Geohydrologic Experiment and Monitoring Site) field area has been established (in the Kansas River valley near Lawrence, Kansas) for a variety of reasons relating to research and teaching in hydrogeology at the University of Kansas. Over 70 wells have been installed for various purposes. The site overlies an alluvial aquifer with a total thickness of about 70 feet. The water table is typically about 20 feet below the surface, giving a total saturated thickness of about 50 feet. The upper part of the aquifer is finer material consisting of silt and clay. Typically, the lower 35 feet of the aquifer is sand and gravel. A number of wells through out the site are fully screened through the sand and gravel aquifer. Some of these fully screened wells are larger diameters; however, most wells are constructed of 2 inch PVC casing. Slug tests are widely used in hydrogeology to measure hydraulic conductivity. Over the last several years we have been conducting research to improve the slug test method. We have previously reported the detailed structure of hydraulic conductivity that can be seen in a 5 inch well (McElwee and Zemansky, EOS, v. 80, no. 46, p. F397, 1999) at this site, using multilevel slug tests. The existing 2 inch, fully screened wells are spread out over the site and offer the opportunity for developing a 3-D picture of the hydraulic conductivity distribution. However, it is difficult to develop a system that allows multilevel slug tests to be done accurately and efficiently in a 2 inch well. This is especially true in regions of very high hydraulic conductivity, where the water velocity in the casing will be relatively high. The resistance caused by frictional forces in the equipment must be minimized and a model taking account of these forces must be used. We have developed a system (equipment, software, and technique) for performing multilevel slug tests in 2 inch wells. Some equipment configurations work better than others. The data that we have

  9. Final Report - Hydraulic Conductivity with Depth for Underground Test Area (UGTA) Wells

    Energy Technology Data Exchange (ETDEWEB)

    P. Oberlander; D. McGraw; C. Russell

    2007-10-31

    Hydraulic conductivity with depth has been calculated for Underground Test Area (UGTA) wells in volcanic tuff and carbonate rock. The following wells in volcanic tuff are evaluated: ER-EC-1, ER-EC-2a, ER-EC-4, ER-EC-5, ER-5-4#2, ER-EC-6, ER-EC-7, and ER-EC-8. The following wells in carbonate rock are evaluated: ER-7-1, ER-6-1, ER-6-1#2, and ER-12-3. There are a sufficient number of wells in volcanic tuff and carbonate rock to associate the conductivity values with the specific hydrogeologic characteristics such as the stratigraphic unit, hydrostratigraphic unit, hydrogeologic unit, lithologic modifier, and alteration modifier used to describe the hydrogeologic setting. Associating hydraulic conductivity with hydrogeologic characteristics allows an evaluation of the data range and the statistical distribution of values. These results are relevant to how these units are considered in conceptual models and represented in groundwater models. The wells in volcanic tuff illustrate a wide range of data values and data distributions when associated with specific hydrogeologic characteristics. Hydraulic conductivity data within a hydrogeologic characteristic can display normal distributions, lognormal distributions, semi-uniform distribution, or no identifiable distribution. There can be multiple types of distributions within a hydrogeologic characteristic such as a single stratigraphic unit. This finding has implications for assigning summary hydrogeologic characteristics to hydrostratigraphic and hydrogeologic units. The results presented herein are specific to the hydrogeologic characteristic and to the wells used to describe hydraulic conductivity. The wells in carbonate rock are associated with a fewer number of hydrogeologic characteristics. That is, UGTA wells constructed in carbonate rock have tended to be in similar hydrogeologic materials, and show a wide range in hydraulic conductivity values and data distributions. Associations of hydraulic conductivity and

  10. Estimating Hydraulic Conductivities in a Fractured Shale Formation from Pressure Pulse Testing and 3d Modeling

    Science.gov (United States)

    Courbet, C.; DICK, P.; Lefevre, M.; Wittebroodt, C.; Matray, J.; Barnichon, J.

    2013-12-01

    In the framework of its research on the deep disposal of radioactive waste in shale formations, the French Institute for Radiological Protection and Nuclear Safety (IRSN) has developed a large array of in situ programs concerning the confining properties of shales in their underground research laboratory at Tournemire (SW France). One of its aims is to evaluate the occurrence and processes controlling radionuclide migration through the host rock, from the disposal system to the biosphere. Past research programs carried out at Tournemire covered mechanical, hydro-mechanical and physico-chemical properties of the Tournemire shale as well as water chemistry and long-term behaviour of the host rock. Studies show that fluid circulations in the undisturbed matrix are very slow (hydraulic conductivity of 10-14 to 10-15 m.s-1). However, recent work related to the occurrence of small scale fractures and clay-rich fault gouges indicate that fluid circulations may have been significantly modified in the vicinity of such features. To assess the transport properties associated with such faults, IRSN designed a series of in situ and laboratory experiments to evaluate the contribution of both diffusive and advective process on water and solute flux through a clay-rich fault zone (fault core and damaged zone) and in an undisturbed shale formation. As part of these studies, Modular Mini-Packer System (MMPS) hydraulic testing was conducted in multiple boreholes to characterize hydraulic conductivities within the formation. Pressure data collected during the hydraulic tests were analyzed using the nSIGHTS (n-dimensional Statistical Inverse Graphical Hydraulic Test Simulator) code to estimate hydraulic conductivity and formation pressures of the tested intervals. Preliminary results indicate hydraulic conductivities of 5.10-12 m.s-1 in the fault core and damaged zone and 10-14 m.s-1 in the adjacent undisturbed shale. Furthermore, when compared with neutron porosity data from borehole

  11. Ensemble Kalman filter versus ensemble smoother for assessing hydraulic conductivity via tracer test data assimilation

    Directory of Open Access Journals (Sweden)

    E. Crestani

    2013-04-01

    Full Text Available Estimating the spatial variability of hydraulic conductivity K in natural aquifers is important for predicting the transport of dissolved compounds. Especially in the nonreactive case, the plume evolution is mainly controlled by the heterogeneity of K. At the local scale, the spatial distribution of K can be inferred by combining the Lagrangian formulation of the transport with a Kalman-filter-based technique and assimilating a sequence of time-lapse concentration C measurements, which, for example, can be evaluated on site through the application of a geophysical method. The objective of this work is to compare the ensemble Kalman filter (EnKF and the ensemble smoother (ES capabilities to retrieve the hydraulic conductivity spatial distribution in a groundwater flow and transport modeling framework. The application refers to a two-dimensional synthetic aquifer in which a tracer test is simulated. Moreover, since Kalman-filter-based methods are optimal only if each of the involved variables fit to a Gaussian probability density function (pdf and since this condition may not be met by some of the flow and transport state variables, issues related to the non-Gaussianity of the variables are analyzed and different transformation of the pdfs are considered in order to evaluate their influence on the performance of the methods. The results show that the EnKF reproduces with good accuracy the hydraulic conductivity field, outperforming the ES regardless of the pdf of the concentrations.

  12. Integration of Tracer Test Data to Refine Geostatistical Hydraulic Conductivity Fields Using Sequential Self-Calibration Method

    Institute of Scientific and Technical Information of China (English)

    Bill X Hu; Jiang Xiaowei; Wan Li

    2007-01-01

    On the basis of local measurements of hydraulic conductivity, geostatistical methods have been found to be useful in heterogeneity characterization of a hydraulic conductivity field on a regional scale. However, the methods are not suited to directly integrate dynamic production data, such as,hydraulic head and solute concentration, into the study of conductivity distribution. These data, which record the flow and transport processes in the medium, are closely related to the spatial distribution of hydraulic conductivity. In this study, a three-dimensional gradient-based inverse method-the sequential self-calibration (SSC) method-is developed to calibrate a hydraulic conductivity field,initially generated by a geostatistical simulation method, conditioned on tracer test results. The SSC method can honor both local hydraulic conductivity measurements and tracer test data. The mismatch between the simulated hydraulic conductivity field and the reference true one, measured by its mean square error (MSE), is reduced through the SSC conditional study. In comparison with the unconditional results, the SSC conditional study creates the mean breakthrough curve much closer to the reference true curve, and significantly reduces the prediction uncertainty of the solute transport in the observed locations. Further, the reduction of uncertainty is spatially dependent, which indicates that good locations, geological structure, and boundary conditions will affect the efficiency of the SSC study results.

  13. Ensemble Kalman filter versus ensemble smoother for assessing hydraulic conductivity via tracer test data assimilation

    Directory of Open Access Journals (Sweden)

    E. Crestani

    2012-11-01

    Full Text Available The significance of estimating the spatial variability of the hydraulic conductivity K in natural aquifers is relevant to the possibility of defining the space and time evolution of a non-reactive plume, since the transport of a solute is mainly controlled by the heterogeneity of K. At the local scale, the spatial distribution of K can be inferred by combining the Lagrangian formulation of the transport with a Kalman filter-based technique and assimilating a sequence of time-lapse concentration C measurements, which, for example, can be evaluated on-site through the application of a geophysical method. The objective of this work is to compare the ensemble Kalman filter (EnKF and the ensemble smoother (ES capabilities to retrieve the hydraulic conductivity spatial distribution in a groundwater flow and transport modeling framework. The application refers to a two-dimensional synthetic aquifer in which a tracer test is simulated. Moreover, since Kalman filter-based methods are optimal only if each of the involved variables fit to a Gaussian probability density function (pdf and since this condition may not be met by some of the flow and transport state variables, issues related to the non-Gaussianity of the variables are analyzed and different transformation of the pdfs are considered in order to evaluate their influence on the performance of the methods. The results show that the EnKF reproduces with good accuracy the hydraulic conductivity field, outperforming the ES regardless of the pdf of the concentrations.

  14. Testing hypotheses that link wood anatomy to cavitation resistance and hydraulic conductivity in the genus Acer.

    Science.gov (United States)

    Lens, Frederic; Sperry, John S; Christman, Mairgareth A; Choat, Brendan; Rabaey, David; Jansen, Steven

    2011-05-01

    • Vulnerability to cavitation and conductive efficiency depend on xylem anatomy. We tested a large range of structure-function hypotheses, some for the first time, within a single genus to minimize phylogenetic 'noise' and maximize detection of functionally relevant variation. • This integrative study combined in-depth anatomical observations using light, scanning and transmission electron microscopy of seven Acer taxa, and compared these observations with empirical measures of xylem hydraulics. • Our results reveal a 2 MPa range in species' mean cavitation pressure (MCP). MCP was strongly correlated with intervessel pit structure (membrane thickness and porosity, chamber depth), weakly correlated with pit number per vessel, and not related to pit area per vessel. At the tissue level, there was a strong correlation between MCP and mechanical strength parameters, and some of the first evidence is provided for the functional significance of vessel grouping and thickenings on inner vessel walls. In addition, a strong trade-off was observed between xylem-specific conductivity and MCP. Vessel length and intervessel wall characteristics were implicated in this safety-efficiency trade-off. • Cavitation resistance and hydraulic conductivity in Acer appear to be controlled by a very complex interaction between tissue, vessel network and pit characteristics.

  15. Variations in hydraulic conductivity with scale of measurement during aquifer tests in heterogeneous, porous carbonate rocks

    Science.gov (United States)

    Schulze-Makuch, Dirk; Cherkauer, Douglas S.

    Previous studies have shown that hydraulic conductivity of an aquifer seems to increase as the portion of the aquifer tested increases. To date, such studies have all relied on different methods to determine hydraulic conductivity at each scale of interest, which raises the possibility that the observed increase in hydraulic conductivity is due to the measurement method, not to the scale. This study analyzes hydraulic conductivity with respect to scale during individual aquifer tests in porous, heterogeneous carbonate rocks in southeastern Wisconsin, USA. Results from this study indicate that hydraulic conductivity generally increases during an individual test as the volume of aquifer impacted increases, and the rate of this increase is the same as the rate of increase determined by using different measurement methods. Thus, scale dependence of hydraulic conductivity during single tests does not depend on the method of measurement. This conclusion is supported by 22 of 26 aquifer tests conducted in porous-flow-dominated carbonate units within the aquifer. Instead, scale dependency is probably caused by heterogeneities within the aquifer, a conclusion supported by digital simulation. All of the observed types of hydraulic-conductivity variations with scale during individual aquifer tests can be explained by a conceptual model of a simple heterogeneous aquifer composed of high-conductivity zones within a low-conductivity matrix. Résumé Certaines études ont montré que la conductivité hydraulique d'un aquifère semble augmenter en même temps que la partie testée de l'aquifère s'étend. Jusqu'à présent, ces études ont toutes reposé sur des méthodes de détermination de la conductivité hydraulique différentes pour chaque niveau d'échelle, ce qui a conduit à penser que l'augmentation observée de la conductivité hydraulique pouvait être due aux méthodes de mesure et non à l'effet d'échelle. Cette étude analyse la conductivité hydraulique par

  16. A mini slug test method for determination of a local hydraulic conductivity of an unconfined sandy aquifer

    DEFF Research Database (Denmark)

    Hinsby, Klaus; Bjerg, Poul Løgstrup; Andersen, Lars J.;

    1992-01-01

    from level to level and thereby establish vertical profiles of the hydraulic conductivity. The head data from the test well are recorded with a 10 mm pressure transducer, and the initial head difference required is established by a small vacuum pump. The method described has provided 274 spatially......A new and efficient mini slug test method for the determination of local hydraulic conductivities in unconfined sandy aquifers is developed. The slug test is performed in a small-diameter (1 inch) driven well with a 0.25 m screen just above the drive point. The screened drive point can be driven...... distributed measurements of a local hydraulic conductivity at a tracer test site at Vejen, Denmark. The mini slug test results calculated by a modified Dax slug test analysing method, applying the elastic storativity in the Dax equations instead of the specific yield, are in good accordance with the results...

  17. Hydraulic conductivity of organomodified soil

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, R.B.; Grant, J.M.; Voice, T.C.; Rakhshandehroo, G.; Xu, S.; Boyd, S.A. [Michigan State Univ., East Lansing, MI (United States)

    1995-11-01

    The effects of organomodification on soil hydraulic conductivity were investigated. Hydraulic conductivity and porosity of treated and untreated samples of a sandy loam were measured as a function of effective stress. Batch treatment with hexadecyltrimethyl ammonium (HDTMA) and dry packing produced organomodified samples that were 79% less conducive than untreated samples prior to loading. Treated samples lost less hydraulic conductivity as a result of loading than untreated samples so that treated samples had higher conductivity at high loads. Observed differences in conductivity are explained in terms of the role of the treated and untreated clay in controlling initial effective pore size and its change during consolidation.

  18. Comparison of four methods to assess hydraulic conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Benson, C.H. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Civil and Environmental Engineering; Gunter, J.A. [Gunter (John A.), Round Rock, TX (United States); Boutwell, G.P. [STE, Inc., Baton Rouge, LA (United States); Trautwein, S.J. [Trautwein Soil Testing Equipment Co., Houston, TX (United States); Berzanskis, P.H. [Hoechst-Celanese, Inc., Pampa, TX (United States)

    1997-10-01

    A hydraulic conductivity assessment that was conducted on four test pads constructed to the same specifications with soil from the same source by four different contractors is described. The test pads had distinctly different field hydraulic conductivities, even though they were constructed with similar soil, to similar compaction conditions, and with similar machinery. Adequate hydration time was key in achieving low field hydraulic conductivity. More extensive processing was another factor responsible for low field hydraulic conductivity. Four different test methods were used to assess the hydraulic conductivity of each test pad: (1) sealed double-ring infiltrometers (SDRIs); (2) two-stage borehole permeameters; (3) laboratory hydraulic conductivity tests on large block specimens; and (4) laboratory hydraulic conductivity tests on small specimens collected in thin-wall sampling tubes. The tests were conducted independently by each of the writers. After the tests were completed, the results were submitted and compared. Analysis of the test results show that the three large-scale test methods generally yield similar hydraulic conductivities. For two of the test pads, however, the hydraulic conductivities of the specimens collected in sampling tubes were significantly lower than the field hydraulic conductivities. Both of these test pads had high field hydraulic conductivity. Thus, there is little value in using small specimens to assess field hydraulic conductivity.

  19. Interpretation of Flow Logs from Nevada Test Site Boreholes to Estimate Hydraulic Conductivity Using Numerical Simulations Constrained by Single-Well Aquifer Tests

    Science.gov (United States)

    Garcia, C. Amanda; Halford, Keith J.; Laczniak, Randell J.

    2010-01-01

    Hydraulic conductivities of volcanic and carbonate lithologic units at the Nevada Test Site were estimated from flow logs and aquifer-test data. Borehole flow and drawdown were integrated and interpreted using a radial, axisymmetric flow model, AnalyzeHOLE. This integrated approach is used because complex well completions and heterogeneous aquifers and confining units produce vertical flow in the annular space and aquifers adjacent to the wellbore. AnalyzeHOLE simulates vertical flow, in addition to horizontal flow, which accounts for converging flow toward screen ends and diverging flow toward transmissive intervals. Simulated aquifers and confining units uniformly are subdivided by depth into intervals in which the hydraulic conductivity is estimated with the Parameter ESTimation (PEST) software. Between 50 and 150 hydraulic-conductivity parameters were estimated by minimizing weighted differences between simulated and measured flow and drawdown. Transmissivity estimates from single-well or multiple-well aquifer tests were used to constrain estimates of hydraulic conductivity. The distribution of hydraulic conductivity within each lithology had a minimum variance because estimates were constrained with Tikhonov regularization. AnalyzeHOLE simulated hydraulic-conductivity estimates for lithologic units across screened and cased intervals are as much as 100 times less than those estimated using proportional flow-log analyses applied across screened intervals only. Smaller estimates of hydraulic conductivity for individual lithologic units are simulated because sections of the unit behind cased intervals of the wellbore are not assumed to be impermeable, and therefore, can contribute flow to the wellbore. Simulated hydraulic-conductivity estimates vary by more than three orders of magnitude across a lithologic unit, indicating a high degree of heterogeneity in volcanic and carbonate-rock units. The higher water transmitting potential of carbonate-rock units relative

  20. Interpretation of Flow Logs from Nevada Test Site Boreholes to Estimate Hydraulic conductivity Using Numerical Simulations Constrained by Single-Well Aquifer Tests

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, C. Amanda; Halford, Keith J.; Laczniak, Randell J.

    2010-02-12

    Hydraulic conductivities of volcanic and carbonate lithologic units at the Nevada Test Site were estimated from flow logs and aquifer-test data. Borehole flow and drawdown were integrated and interpreted using a radial, axisymmetric flow model, AnalyzeHOLE. This integrated approach is used because complex well completions and heterogeneous aquifers and confining units produce vertical flow in the annular space and aquifers adjacent to the wellbore. AnalyzeHOLE simulates vertical flow, in addition to horizontal flow, which accounts for converging flow toward screen ends and diverging flow toward transmissive intervals. Simulated aquifers and confining units uniformly are subdivided by depth into intervals in which the hydraulic conductivity is estimated with the Parameter ESTimation (PEST) software. Between 50 and 150 hydraulic-conductivity parameters were estimated by minimizing weighted differences between simulated and measured flow and drawdown. Transmissivity estimates from single-well or multiple-well aquifer tests were used to constrain estimates of hydraulic conductivity. The distribution of hydraulic conductivity within each lithology had a minimum variance because estimates were constrained with Tikhonov regularization. AnalyzeHOLE simulated hydraulic-conductivity estimates for lithologic units across screened and cased intervals are as much as 100 times less than those estimated using proportional flow-log analyses applied across screened intervals only. Smaller estimates of hydraulic conductivity for individual lithologic units are simulated because sections of the unit behind cased intervals of the wellbore are not assumed to be impermeable, and therefore, can contribute flow to the wellbore. Simulated hydraulic-conductivity estimates vary by more than three orders of magnitude across a lithologic unit, indicating a high degree of heterogeneity in volcanic and carbonate-rock units. The higher water transmitting potential of carbonate-rock units relative

  1. Fracture hydraulic conductivity in the Mexico City clayey aquitard: Field piezometer rising-head tests

    Science.gov (United States)

    Vargas, Carlos; Ortega-Guerrero, Adrián

    A regional lacustrine aquitard covers the main aquifer of the metropolitan area of Mexico City. The aquitard's hydraulic conductivity (K') is fundamental for evaluating the natural protection of the aquifer against a variety of contaminants present on the surface and its hydraulic response. This study analyzes the distribution and variation of K' in the plains of Chalco, Texcoco and Mexico City (three of the six former lakes that existed in the Basin of Mexico), on the basis of 225 field-permeability tests, in nests of existing piezometers located at depths of 2-85 m. Tests were interpreted using the Hvorslev method and some by the Bouwer-Rice method. Results indicate that the distribution of K' fits log-Gaussian regression models. Dominant frequencies for K' in the Chalco and Texcoco plains range between 1E-09 and 1E-08 m/s, with similar population means of 1.19E-09 and 1.7E-09 m/s, respectively, which are one to two orders of magnitude higher than the matrix conductivity. In the Mexico City Plain the population mean is near by one order of magnitude lower; K'=2.6E-10 m/s. The contrast between the measured K' and that of the matrix is attributed to the presence of fractures in the upper 25-40 m, which is consistent with the findings of previous studies on solute migration in the aquitard. Un imperméable régional d'origine lacustre recouvre le principal aquifère de la zone urbaine de la ville de Mexico. La conductivité hydraulique K' de cet imperméable est fondamentale pour évaluer la protection naturelle de l'aquifère, contre les différents contaminants présents en surface, et sa réponse hydraulique. Cette étude analyse et les variations de K' dans les plaines de Chalco, Texcoco et Mexico (trois des six anciens lacs qui existaient dans le Bassin de Mexico), sur la base de 225 essais de perméabilité sur le terrain, réalisés en grappes dans des piézomètres existants entre 2 et 85 m de profondeur. Les essais ont été interprétés avec la m

  2. Multi-level slug tests in highly permeable formations: 2. Hydraulic conductivity identification, method verification, and field applications

    Science.gov (United States)

    Zlotnik, V.A.; McGuire, V.L.

    1998-01-01

    Using the developed theory and modified Springer-Gelhar (SG) model, an identification method is proposed for estimating hydraulic conductivity from multi-level slug tests. The computerized algorithm calculates hydraulic conductivity from both monotonic and oscillatory well responses obtained using a double-packer system. Field verification of the method was performed at a specially designed fully penetrating well of 0.1-m diameter with a 10-m screen in a sand and gravel alluvial aquifer (MSEA site, Shelton, Nebraska). During well installation, disturbed core samples were collected every 0.6 m using a split-spoon sampler. Vertical profiles of hydraulic conductivity were produced on the basis of grain-size analysis of the disturbed core samples. These results closely correlate with the vertical profile of horizontal hydraulic conductivity obtained by interpreting multi-level slug test responses using the modified SG model. The identification method was applied to interpret the response from 474 slug tests in 156 locations at the MSEA site. More than 60% of responses were oscillatory. The method produced a good match to experimental data for both oscillatory and monotonic responses using an automated curve matching procedure. The proposed method allowed us to drastically increase the efficiency of each well used for aquifer characterization and to process massive arrays of field data. Recommendations generalizing this experience to massive application of the proposed method are developed.Using the developed theory and modified Springer-Gelhar (SG) model, an identification method is proposed for estimating hydraulic conductivity from multi-level slug tests. The computerized algorithm calculates hydraulic conductivity from both monotonic and oscillatory well responses obtained using a double-packer system. Field verification of the method was performed at a specially designed fully penetrating well of 0.1-m diameter with a 10-m screen in a sand and gravel alluvial

  3. Estimating hydraulic conductivity of fractured rocks from high‐pressure packer tests with an Izbash's law‐based empirical model

    National Research Council Canada - National Science Library

    Chen, Yi‐Feng; Hu, Shao‐Hua; Hu, Ran; Zhou, Chuang‐Bing

    2015-01-01

    ...‐pressure groundwater flow conditions. The interpretation of the HPPT data, however, remains difficult due to the transition of flow conditions in the conducting structures and the hydraulic fracturing...

  4. HYDRAULIC CONDUCTIVITY OF THREE GEOSYNTHETIC CLAY LINERS

    Science.gov (United States)

    The hydraulic conductivity of three 2.9 m2 (32 sq ft) geosynthetic clay liners (GCLs) was measured. Tests were performed on individual sheets of the GCLs, on overlapped pieces of GCLs, and on composite liners consisting of a punctured geomembrane overlying a GCL. Hyd...

  5. Estimation of hydraulic parameters from an unconfined aquifer test conducted in a glacial outwash deposit, Cape Cod, Massachusetts

    Science.gov (United States)

    Moench, A.F.; Garabedian, Stephen P.; LeBlanc, Denis R.

    2000-01-01

    An aquifer test conducted in a sand and gravel, glacial outwash deposit on Cape Cod, Massachusetts was analyzed by means of a model for flow to a partially penetrating well in a homogeneous, anisotropic unconfined aquifer. The model is designed to account for all significant mechanisms expected to influence drawdown in observation piezometers and in the pumped well. In addition to the usual fluid-flow and storage processes, additional processes include effects of storage in the pumped well, storage in observation piezometers, effects of skin at the pumped-well screen, and effects of drainage from the zone above the water table. The aquifer was pumped at a rate of 320 gallons per minute for 72-hours and drawdown measurements were made in the pumped well and in 20 piezometers located at various distances from the pumped well and depths below the land surface. To facilitate the analysis, an automatic parameter estimation algorithm was used to obtain relevant unconfined aquifer parameters, including the saturated thickness and a set of empirical parameters that relate to gradual drainage from the unsaturated zone. Drainage from the unsaturated zone is treated in this paper as a finite series of exponential terms, each of which contains one empirical parameter that is to be determined. It was necessary to account for effects of gradual drainage from the unsaturated zone to obtain satisfactory agreement between measured and simulated drawdown, particularly in piezometers located near the water table. The commonly used assumption of instantaneous drainage from the unsaturated zone gives rise to large discrepancies between measured and predicted drawdown in the intermediate-time range and can result in inaccurate estimates of aquifer parameters when automatic parameter estimation procedures are used. The values of the estimated hydraulic parameters are consistent with estimates from prior studies and from what is known about the aquifer at the site. Effects of

  6. Hydraulic conductivity and diffusion characterization of GCLs

    Energy Technology Data Exchange (ETDEWEB)

    Mukunoki, T.; Rowe, R.K.; Li, H.M.; Sangam, H.P.; Hurst, P.; Bathurst, R.J. [Queen' s Univ., Kingston, ON (Canada)]|[Royal Military Coll. of Canada, Kingston, ON (Canada); Badv, K. [Urmia Univ. (Iran, Islamic Republic of)

    2003-07-01

    This paper reports on the characterization of the hydraulic conductivity and diffusion of a geosynthetic clay liner (GCL) installed at a site off the southeast coast of Baffin Island, in the Canadian Arctic, following different levels of freeze-thaw exposure and under low temperature conditions. The authors presented a summary of the results obtained for hydraulic conductivity tests on GCLs subjected to freeze-thaw cycles, and specimens permeated with jet fuel (Arctic diesel). They also reported on diffusion tests conducted at 22 Celsius and 5 Celsius, followed by a discussion of the effect of temperature. The results indicate that there is no significant impact on GCL performance due to freeze-thaw cycles, permeation by jet fuel or diffusion at the lower temperatures expected in the north for the short term (up to approximately four years). Additional studies are needed to confirm long term behaviour. 24 refs., 2 tabs., 4 figs.

  7. Soil hydraulic properties near saturation, an improved conductivity model

    DEFF Research Database (Denmark)

    Børgesen, Christen Duus; Jacobsen, Ole Hørbye; Hansen, Søren;

    2006-01-01

    The hydraulic properties near saturation can change dramatically due to the presence of macropores that are usually difficult to handle in traditional pore size models. The purpose of this study is to establish a data set on hydraulic conductivity near saturation, test the predictive capability...... of commonly used hydraulic conductivity models and give suggestions for improved models. Water retention and near saturated and saturated hydraulic conductivity were measured for a variety of 81 top and subsoils. The hydraulic conductivity models by van Genuchten [van Genuchten, 1980. A closed-form equation...... for predicting the hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J. 44, 892–898.] (vGM) and Brooks and Corey, modified by Jarvis [Jarvis, 1991. MACRO—A Model of Water Movement and Solute Transport in Macroporous Soils. Swedish University of Agricultural Sciences. Department of Soil Sciences...

  8. Hydraulic conductivity of GCLs in MSW landfills

    Institute of Scientific and Technical Information of China (English)

    LI Guo-cheng; YANG Wu-chao; DAN Tang-hui

    2008-01-01

    The state of the art of the study on the hydraulic conductivity of GCLs is presented in terms of the in-fluence of the effective stress, chemical interactions, freeze - thaw cycles and temperature gradients. The chan-ges of void ratio caused by changes of effective stress have a direct linear effect on the hydraulic conductivity, regardless of the cation concentration or the thickness of the adsorbed layer. The hydraulic conductivity is relat-ed to the relative abundance of monovalent and divalent cation(RMD), and RMD has a great effect on the hy-draulic conductivity in weak solution. The long-term susceptibility of GCLs to increased hydraulic conductivity as a response to repeated freeze-thaw cycling is minimal, which has been proved after 150 freeze-thaw cycles. The potential of desiccation cracking increases with the increasing temperature gradient and is related to the ini-tial subsoil water content, the applied overburden stress, etc.

  9. Analysis of hydraulic tests of the Culebra and Magenta Dolomites and Dewey Lake Redbeds conducted at the Waste Isolation Pilot Plant Site

    Energy Technology Data Exchange (ETDEWEB)

    Beauheim, R.L. [Sandia National Labs., Albuquerque, NM (United States). Geohydrology Dept.; Ruskauff, G.J. [Duke Engineering and Services, Inc., Albuquerque, NM (United States)

    1998-09-01

    This report presents interpretations of hydraulic tests conducted at 15 well locations in the vicinity of the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico between 1980 and 1996. The WIPP is a US Department of Energy (DOE) facility to demonstrate safe disposal of transuranic wastes arising form the nation`s defense programs. The WIPP repository lies within bedded halite of the Salado Formation, 2,155 ft below ground surface. The tests reported herein were, with two exceptions, conducted in the Culebra Dolomite member of the Rustler Formation, which overlies the Salado Formation. The remaining tests were conducted in the Magenta Member of the Rustler and in the overlying formation, the Dewey Lake Redbeds. This report completes the documentation of hydraulic-test interpretations used as input to the WIPP Compliance Certification Application (US DOE, 1996).

  10. Geostatistical Estimations of Regional Hydraulic Conductivity Fields

    Science.gov (United States)

    Patriarche, D.; Castro, M. C.; Goovaerts, P.

    2004-12-01

    Direct and indirect measurements of hydraulic conductivity (K) are commonly performed, providing information on the magnitude of this parameter at the local scale (tens of centimeters to hundreds of meters) and at shallow depths. By contrast, field information on hydraulic conductivities at regional scales of tens to hundreds of kilometers and at greater depths is relatively scarce. Geostatistical methods allow for sparsely sampled observations of a variable (primary information) to be complemented by a more densely sampled secondary attribute. Geostatistical estimations of the hydraulic conductivity field in the Carrizo aquifer, a major groundwater flow system extending along Texas, are performed using available primary (e.g., transmissivity, hydraulic conductivity) and secondary (specific capacity) information, for depths up to 2.2 km, and over three regional domains of increasing extent: 1) the domain corresponding to a three-dimensional groundwater flow model previously built (model domain); 2) the area corresponding to the ten counties encompassing the model domain (County domain), and; 3) the full extension of the Carrizo aquifer within Texas (Texas domain). Two different approaches are used: 1) an indirect approach are transmissivity (T) is estimated first and (K) is retrieved through division of the T estimate by the screening length of the wells, and; 2) a direct approach where K data are kriged directly. Prediction performances of the tested geostatistical procedures (kriging combined with linear regression, kriging with known local means, kriging of residuals, and cokriging) are evaluated through cross validation for both log-transformed variables and back-transformed ones. For the indirect approach, kriging of log T residuals yields the best estimates for both log-transformed and back-transformed variables in the model domain. For larger regional scales (County and Texas domains), cokriging performs generally better than univariate kriging procedures

  11. Hydraulic conductivity of a firn aquifer system in southeast Greenland

    Science.gov (United States)

    Miller, Olivia L.; Solomon, D. Kip; Miège, Clément; Koenig, Lora S.; Forster, Richard R.; Montgomery, Lynn N.; Schmerr, Nicholas; Ligtenberg, Stefan R. M.; Legchenko, Anatoly; Brucker, Ludovic

    2017-05-01

    Some regions of the Greenland ice sheet, where snow accumulation and melt rates are high, currently retain substantial volumes of liquid water within the firn pore space throughout the year. These firn aquifers, found between 10-30 m below the snow surface, may significantly affect sea level rise by storing or draining surface meltwater. The hydraulic gradient and the hydraulic conductivity control flow of meltwater through the firn. Here we describe the hydraulic conductivity of the firn aquifer estimated from slug tests and aquifer tests at six sites located upstream of Helheim Glacier in southeastern Greenland. We conducted slug tests using a novel instrument, a piezometer with a heated tip that melts itself into the ice sheet. Hydraulic conductivity ranges between 2.5x10-5 and 1.1x10-3 m/s. The geometric mean of hydraulic conductivity of the aquifer is 2.7x10-4 m/s with a geometric standard deviation of 1.4 from both depth specific slug tests (analyzed using the Hvorslev method) and aquifer tests during the recovery period. Hydraulic conductivity is relatively consistent between boreholes and only decreases slightly with depth. The hydraulic conductivity of the firn aquifer is crucial for determining flow rates and patterns within the aquifer, which inform hydrologic models of the aquifer, its relation to the broader glacial hydrologic system, and its effect on sea level rise.

  12. Hydraulic Conductivity of a Firn Aquifer in Southeast Greenland

    Directory of Open Access Journals (Sweden)

    Olivia L. Miller

    2017-05-01

    Full Text Available Some regions of the Greenland ice sheet, where snow accumulation and melt rates are high, currently retain substantial volumes of liquid water within the firn pore space throughout the year. These firn aquifers, found between ~10 and 30 m below the snow surface, may significantly affect sea level rise by storing or draining surface meltwater. The hydraulic gradient and the hydraulic conductivity control flow of meltwater through the firn. Here we describe the hydraulic conductivity of the firn aquifer estimated from slug tests and aquifer tests at six sites located upstream of Helheim Glacier in southeastern Greenland. We conducted slug tests using a novel instrument, a piezometer with a heated tip that melts itself into the ice sheet. Hydraulic conductivity ranges between 2.5 × 10−5 and 1.1 × 10−3 m/s. The geometric mean of hydraulic conductivity of the aquifer is 2.7 × 10−4 m/s with a geometric standard deviation of 1.4 from both depth specific slug tests (analyzed using the Hvorslev method and aquifer tests during the recovery period. Hydraulic conductivity is relatively consistent between boreholes and only decreases slightly with depth. The hydraulic conductivity of the firn aquifer is crucial for determining flow rates and patterns within the aquifer, which inform hydrologic models of the aquifer, its relation to the broader glacial hydrologic system, and its effect on sea level rise.

  13. Hydraulic test for evaluation of hydrophone VSP

    Energy Technology Data Exchange (ETDEWEB)

    Yabuuchi, Satoshi; Koide, Kaoru [Power Reactor and Nuclear Fuel Development Corp., Toki, Gifu (Japan). Tono Geoscience Center

    1997-12-01

    This hydraulic test was carried out at the test site of Tono Geoscience Center, Mizunami-shi, Gifu Pref. in order to evaluate the reliability of the hydraulic conductivity estimated from hydrophone VSP experiment. From March to April 1997, we carried out measurements of pore-water pressure at five depths and permeability tests at seven depths down to G.L.-300m, within a borehole drilled in granitic rock. We compared the results of hydraulic test with hydrophone VSP experiment on condition that a single open fracture existed, and we obtained two notable results. First, for the granitic rock at which a single open fracture was found by BTV and also detected by hydrophone VSP experiment, the hydraulic conductivity was 1.54 x 10{sup -7} cm/sec, while for the same granitic rock at which another single open fracture was found by BTV but not detected by hydrophone VSP experiment, the hydraulic conductivity was less than 6 x 10{sup -10} cm/sec. Second, we converted the hydraulic conductivity of 1.54 x 10{sup -7} cm/sec which was obtained in a hydraulic test section of length 2.5 m into an equivalent value for a single open fracture of width 1 mm. The converted value (3.8 x 10{sup -4} cm/sec) was similar to the hydraulic conductivity estimated from hydrophone VSP experiment. In conclusion, the hydraulic test result shows that hydrophone VSP is useful to estimate an approximate hydraulic conductivity of a single open fracture. (author)

  14. A method for mapping topsoil field-saturated hydraulic conductivity in the Cévennes-Vivarais region using infiltration tests conducted with different techniques

    Science.gov (United States)

    Braud, Isabelle; Desprats, Jean-François; Ayral, Pierre-Alain; Bouvier, Christophe; Vandervaere, Jean-Pierre

    2017-04-01

    Topsoil field-saturated hydraulic conductivity, Kfs, is a parameter that controls the partition of rainfall between infiltration and runoff. It is a key parameter in most distributed hydrological models. However, there is a mismatch between the scale of local in situ measurements and the scale at which the parameter is required in models. Therefore it is necessary to design methods to regionally map this parameter at the model scale. The paper propose a method for mapping Kfs in the Cévennes-Vivarais region, south-east France, using more easily available GIS data: geology and land cover. The mapping is based on a data set gathering infiltration tests performed in the area or close to it for more than ten years. The data set is composed of infiltration tests performed using various techniques: Guelph permeameter, double ring and single ring infiltration tests, infiltrometers with multiple suctions. The different methods lead to different orders of magnitude for Kfs rendering the pooling of all the data challenging. Therefore, a method is first proposed to pool the data from the different infiltration methods, leading to a homogenized set of Kfs, based on an equivalent double ring/tension disk infiltration value. Statistical tests showed significant differences in distributions among different geologies and land covers. Thus those variables were retained as proxy for mapping Kfs at the regional scale. This map was compared to a map based on the Rawls and Brakensiek (RB) pedo-transfer function (Manus et al., 2009, Vannier et al., 2016), showing very different patterns between both maps. In addition, RB values did not fit observed values at the plot scale, highlighting that soil texture only is not a good predictor of Kfs. References Manus, C., Anquetin, S., Braud, I., Vandervaere, J.P., Viallet, P., Creutin, J.D., Gaume, E., 2009. A modelling approach to assess the hydrological response of small Mediterranean catchments to the variability of soil characteristics in a

  15. Spatial variability in streambed hydraulic conductivity of contrasting stream morphologies

    DEFF Research Database (Denmark)

    Sebök, Éva; Calvache, Carlos Duque; Engesgaard, Peter Knudegaard;

    2015-01-01

    Streambed hydraulic conductivity is one of the main factors controlling variability in surface water-groundwater interactions, but only few studies aim at quantifying its spatial and temporal variability in different stream morphologies. Streambed horizontal hydraulic conductivities (Kh) were...... therefore determined from in-stream slug tests, vertical hydraulic conductivities (Kv) were calculated with in-stream permeameter tests and hydraulic heads were measured to obtain vertical head gradients at eight transects, each comprising five test locations, in a groundwater-dominated stream. Seasonal...... small-scale measurements were taken in December 2011 and August 2012, both in a straight stream channel with homogeneous elevation and downstream of a channel meander with heterogeneous elevation. All streambed attributes showed large spatial variability. Kh values were the highest at the depositional...

  16. Soil Structure and Saturated Hydraulic Conductivity

    Science.gov (United States)

    Houskova, B.; Nagy, V.

    The role of soil structure on saturated hydraulic conductivity changes is studied in plough layers of texturally different soils. Three localities in western part of Slovakia in Zitny ostrov (Corn Island) were under investigation: locality Kalinkovo with light Calcaric Fluvisol (FAO 1970), Macov with medium heavy Calcari-mollic Fluvisol and Jurova with heavy Calcari-mollic Fluvisol. Soil structure was determined in dry as well as wet state and in size of macro and micro aggregates. Saturated hydraulic conductivity was measured by the help of double ring method. During the period of ring filling the soil surface was protected against aggregates damage by falling water drops. Spatial and temporal variability of studied parameters was evaluated. Cultivated crops were ensilage maize at medium heavy and heavy soil and colza at light soil. Textural composition of soil and actual water content at the beginning of measurement are one of major factor affecting aggregate stability and consequently also saturated hydraulic conductivity.

  17. Hydraulic Conductivity Anisotropy of Heterogeneous Unsaturated Soils

    Science.gov (United States)

    Sun, Dongmin; Zhu, Jianting

    2010-05-01

    The effects of saturation degree (or capillary pressure) on hydraulic conductivity anisotropy in unsaturated soils have not been fully understood. This study developed an approach based on a conceptualization of combining the neural network based pedo-transfer function (PTF) results with the thin layer concept to explore the capillary pressure-dependent anisotropy in relation to soil texture and soil bulk density. The main objective is to examine how anisotropy characteristics are related to the relationships between hydraulic parameters and the basic soil attributes such as texture and bulk density. The hydraulic parameters are correlated with the texture and bulk density based on the pedo-transfer function (PTF) results. It is demonstrated that non-monotonic behavior of the unsaturated soil anisotropy in relation to the capillary pressure is only observed when the saturated hydraulic conductivity and the shape parameter are both related to the mean particle diameter. When only one hydraulic parameter is related to the grain diameter or when both are not related to the same attribute simultaneously, the unsaturated soil anisotropy increases monotonically with the increasing capillary pressure head. Therefore, it is suggested that this behavior is mainly due to the coupled dependence of the layer saturated hydraulic conductivities and the shape factors on the texture and bulk density. The correlation between the soil grain diameter and bulk density decreases the anisotropy effects of the unsaturated layered soils. The study illustrates that the inter-relationships of soil texture, bulk density, and hydraulic properties may cause vastly different characteristics of anisotropic unsaturated soils.

  18. Measurement and modeling of unsaturated hydraulic conductivity

    Science.gov (United States)

    Perkins, Kim S.; Elango, Lakshmanan

    2011-01-01

    The unsaturated zone plays an extremely important hydrologic role that influences water quality and quantity, ecosystem function and health, the connection between atmospheric and terrestrial processes, nutrient cycling, soil development, and natural hazards such as flooding and landslides. Unsaturated hydraulic conductivity is one of the main properties considered to govern flow; however it is very difficult to measure accurately. Knowledge of the highly nonlinear relationship between unsaturated hydraulic conductivity (K) and volumetric water content is required for widely-used models of water flow and solute transport processes in the unsaturated zone. Measurement of unsaturated hydraulic conductivity of sediments is costly and time consuming, therefore use of models that estimate this property from more easily measured bulk-physical properties is common. In hydrologic studies, calculations based on property-transfer models informed by hydraulic property databases are often used in lieu of measured data from the site of interest. Reliance on database-informed predicted values with the use of neural networks has become increasingly common. Hydraulic properties predicted using databases may be adequate in some applications, but not others. This chapter will discuss, by way of examples, various techniques used to measure and model hydraulic conductivity as a function of water content, K. The parameters that describe the K curve obtained by different methods are used directly in Richards’ equation-based numerical models, which have some degree of sensitivity to those parameters. This chapter will explore the complications of using laboratory measured or estimated properties for field scale investigations to shed light on how adequately the processes are represented. Additionally, some more recent concepts for representing unsaturated-zone flow processes will be discussed.

  19. Dentin permeability: determinants of hydraulic conductance.

    Science.gov (United States)

    Reeder, O W; Walton, R E; Livingston, M J; Pashley, D H

    1978-02-01

    A technique is described which permits measurements of the ease with which fluid permeates dentin. This value, the hydraulic conductance of dentin, increased as surface area increases and/or as dentin thickness decreases. It increased 32-fold when dentin was acid etched due to removal of surface debris occluding the tubules.

  20. Hydraulic Conductivity of Residual Soil-Cement Mix

    Science.gov (United States)

    Govindasamy, P.; Taha, M. R.

    2016-07-01

    In Malaysia, although there are several researches on engineering properties of residual soils, however study on the hydraulic conductivity properties of metasedimentary residual soils is still lacking. Construction of containment walls like slurry wall techniques can be achieved with hydraulic conductivity of approximately 5 x 10-7cm/sec. The objectives of the study were to determine the physical properties of metasedimentary residual soils and to determine the influence of 1%, 3%, 5% and 10% of cement on hydraulic conductivity parameters. The coefficient of hydraulic conductivity of the soil naturally and soil-cement mixtures were determined by using the falling head test. According to the test, the hydraulic conductivity of the original soil was 4.16 x 10-8 m/s. The value decreases to 3.89 x 10-8 m/s, 2.78 x 10-8 m/s then 6.83 x 10-9 m/s with the addition of 1%, 3% and 5% of cement additives, respectively. During the hydration process, cement hydrates is formed followed by the increase in pH value and Ca(OH)2 which will alter the modification of pores size and distribution. When the quantity of cement increases, the pores size decrease. But, the addition of 10% cement gives an increased hydraulic conductivity value to 2.78 x 10-8 m/s. With 10%, the pore size increase might due to flocculation and agglomeration reaction. The generated hydraulic conductivity values will indirectly become a guide in the preliminary soil cement stabilization to modify the properties of the soil to become more like the properties of a soft rock.1. Introduction

  1. Hydraulic conductivities of fractures and matrix in Slovenian carbonate aquifers

    Directory of Open Access Journals (Sweden)

    Timotej Verbovšek

    2008-12-01

    Full Text Available Hydraulic conductivities and specific storage coefficients of fractures and matrix in Slovenian carbonate aquifers were determined by Barker’s method for pumping test analysis, based on fractional flow dimension. Values are presented for limestones and mainly for dolomites, and additionally for separate aquifers, divided by age andlithology in several groups. Data was obtained from hydrogeological reports for 397 water wells, and among these, 79 pumping tests were reinterpreted. Hydraulic conductivities of fractures are higher than the hydraulic conductivities of matrix, and the differences are highly statistically significant. Likewise, differences are significant for specific storage, and the values of these coefficients are higher in the matrix. Values of all coefficients vary in separate aquifers, and the differences can be explained by diagenetic effects, crystal size, degree of fracturing, andcarbonate purity. Comparison of the methods, used in the reports, and the Barker’s method (being more suitable for karstic and fractured aquifers, shows that the latter fits real data better.

  2. Hydraulic conductivity of natural soils permeated with acid mine drainage

    Energy Technology Data Exchange (ETDEWEB)

    Yanful, E.K.; Shikatani, K.S.; Quirt, D.H. [University of Western Ontario, London, ON (Canada). Department of Civil Engineering

    1995-08-01

    The results of a laboratory study on the interactions of three natural soils (some under consideration as candidate cover materials) with acid mine drainage (AMD) are presented. Soil hydraulic conductivity measurements were used to assess soil compatibility with AMD. A silty clay from the decommissioned Waite Amulet tailings site in Quebec, glacial tills from the Heath Steele mine site in New Brunswick, and soil from the Faro mine site in the Yukon Territory were examined. Soil mineralogy and chemistry were examined before and after hydraulic conductivity testing to identify any changes. 20 refs., 25 figs., 8 tabs.

  3. Theoretical aspects for estimating anisotropic saturated hydraulic conductivity from in-well or direct-push probe injection tests in uniform media

    Science.gov (United States)

    Klammler, Harald; Layton, Leif; Nemer, Bassel; Hatfield, Kirk; Mohseni, Ana

    2017-06-01

    Hydraulic conductivity and its anisotropy are fundamental aquifer properties for groundwater flow and transport modeling. Current in-well or direct-push field measurement techniques allow for relatively quick determination of general conductivity profiles with depth. However, capabilities for identifying local scale conductivities in the horizontal and vertical directions are very limited. Here, we develop the theoretical basis for estimating horizontal and vertical conductivities from different types of steady-state single-well/probe injection tests under saturated conditions and in the absence of a well skin. We explore existing solutions and a recent semi-analytical solution approach to the flow problem under the assumption that the aquifer is locally homogeneous. The methods are based on the collection of an additional piece of information in the form of a second injection (or recirculation) test at a same location, or in the form of an additional head or flow observation along the well/probe. Results are represented in dimensionless charts for partial validation against approximate solutions and for practical application to test interpretation. The charts further allow for optimization of a test configuration to maximize sensitivity to anisotropy ratio. The two methods most sensitive to anisotropy are found to be (1) subsequent injection from a lateral screen and from the bottom of an otherwise cased borehole, and (2) single injection from a lateral screen with an additional head observation along the casing. Results may also be relevant for attributing consistent divergences in conductivity measurements from different testing methods applied at a same site or location to the potential effects of anisotropy. Some practical aspects are discussed and references are made to existing methods, which appear easily compatible with the proposed procedures.

  4. An Integrated View of Whole-Tree Hydraulic Architecture. Does Stomatal or Hydraulic Conductance Determine Whole Tree Transpiration?

    Directory of Open Access Journals (Sweden)

    Juan Rodríguez-Gamir

    Full Text Available Hydraulic conductance exerts a strong influence on many aspects of plant physiology, namely: transpiration, CO2 assimilation, growth, productivity or stress response. However we lack full understanding of the contribution of root or shoot water transport capacity to the total water balance, something which is difficult to study in trees. Here we tested the hypothesis that whole plant hydraulic conductance modulates plant transpiration using two different seedlings of citrus rootstocks, Poncirus trifoliata (L. Raf. and Cleopatra mandarin (Citrus reshni Hort ex Tan.. The two genotypes presented important differences in their root or shoot hydraulic conductance contribution to whole plant hydraulic conductance but, even so, water balance proved highly dependent on whole plant conductance. Further, we propose there is a possible equilibrium between root and shoot hydraulic conductance, similar to that between shoot and root biomass production, which could be related with xylem anatomy.

  5. An Integrated View of Whole-Tree Hydraulic Architecture. Does Stomatal or Hydraulic Conductance Determine Whole Tree Transpiration?

    Science.gov (United States)

    Rodríguez-Gamir, Juan; Primo-Millo, Eduardo; Forner-Giner, María Ángeles

    2016-01-01

    Hydraulic conductance exerts a strong influence on many aspects of plant physiology, namely: transpiration, CO2 assimilation, growth, productivity or stress response. However we lack full understanding of the contribution of root or shoot water transport capacity to the total water balance, something which is difficult to study in trees. Here we tested the hypothesis that whole plant hydraulic conductance modulates plant transpiration using two different seedlings of citrus rootstocks, Poncirus trifoliata (L.) Raf. and Cleopatra mandarin (Citrus reshni Hort ex Tan.). The two genotypes presented important differences in their root or shoot hydraulic conductance contribution to whole plant hydraulic conductance but, even so, water balance proved highly dependent on whole plant conductance. Further, we propose there is a possible equilibrium between root and shoot hydraulic conductance, similar to that between shoot and root biomass production, which could be related with xylem anatomy.

  6. A tensor approach to the estimation of hydraulic conductivities in ...

    African Journals Online (AJOL)

    2006-07-03

    Jul 3, 2006 ... The HC values computed from the data measured on the weathered or ... Keywords: hydraulic conductivity tensor, roughness, combined stress, hydraulic aperture, Table Mountain ... the anisotropic nature of studied media.

  7. Characterizing hydraulic conductivity with the direct-push permeameter

    Science.gov (United States)

    Butler, J.J.; Dietrich, P.; Wittig, V.; Christy, T.

    2007-01-01

    The direct-push permeameter (DPP) is a promising approach for obtaining high-resolution information about vertical variations in hydraulic conductivity (K) in shallow unconsolidated settings. This small-diameter tool, which consists of a short screened section with a pair of transducers inset in the tool near the screen, is pushed into the subsurface to a depth at which a K estimate is desired. A short hydraulic test is then performed by injecting water through the screen at a constant rate (less than 4 L/min) while pressure changes are monitored at the transducer locations. Hydraulic conductivity is calculated using the injection rate and the pressure changes in simple expressions based on Darcy's Law. In units of moderate or higher hydraulic conductivity (more than 1 m/d), testing at a single level can be completed within 10 to 15 min. Two major advantages of the method are its speed and the insensitivity of the K estimates to the zone of compaction created by tool advancement. The potential of the approach has been assessed at two extensively studied sites in the United States and Germany over a K range commonly faced in practical field investigations (0.02 to 500 m/d). The results of this assessment demonstrate that the DPP can provide high-resolution K estimates that are in good agreement with estimates obtained through other means. ?? 2007 National Ground Water Association.

  8. Variation in reach-scale hydraulic conductivity of streambeds

    Science.gov (United States)

    Stewardson, M. J.; Datry, T.; Lamouroux, N.; Pella, H.; Thommeret, N.; Valette, L.; Grant, S. B.

    2016-04-01

    Streambed hydraulic conductivity is an important control on flow within the hyporheic zone, affecting hydrological, ecological, and biogeochemical processes essential to river ecosystem function. Despite many published field measurements, few empirical studies examine the drivers of spatial and temporal variations in streambed hydraulic conductivity. Reach-averaged hydraulic conductivity estimated for 119 surveys in 83 stream reaches across continental France, even of coarse bed streams, are shown to be characteristic of sand and finer sediments. This supports a model where processes leading to the accumulation of finer sediments within streambeds largely control hydraulic conductivity rather than the size of the coarse bed sediment fraction. After describing a conceptual model of relevant processes, we fit an empirical model relating hydraulic conductivity to candidate geomorphic and hydraulic drivers. The fitted model explains 72% of the deviance in hydraulic conductivity (and 30% using an external cross-validation). Reach hydraulic conductivity increases with the amplitude of bedforms within the reach, the bankfull channel width-depth ratio, stream power and upstream catchment erodibility but reduces with time since the last streambed disturbance. The correlation between hydraulic conductivity and time since a streambed mobilisation event is likely a consequence of clogging processes. Streams with a predominantly suspended load and less frequent streambed disturbances are expected to have a lower streambed hydraulic conductivity and reduced hyporheic fluxes. This study suggests a close link between streambed sediment transport dynamics and connectivity between surface water and the hyporheic zone.

  9. The steady-state dipole-flow test for characterization of hydraulic conductivity statistics in a highly permeable aquifer: Horkheimer Insel site, Germany.

    Science.gov (United States)

    Zlotnik, V A; Zurbuchen, B R; Ptak, T

    2001-01-01

    Over the last decade the dipole-flow test (DFT) evolved from the general idea of using recirculatory flow to evaluate aquifer properties, to the development of prototype instrumentation and feasibility studies, to a reliable tool for characterization of aquifer heterogeneity. The DFT involves the interpretation of head in recirculatory flow between injection and extraction sections (chambers) in a single well isolated from each other by a multipacker system. In this study, the steady-state dipole flow test (DFT) has been used to characterize the statistics of horizontal hydraulic conductivity (Kr) of the highly permeable, heterogeneous, and thin aquifer at the Horkheimer Insel site, Germany. In previous studies, Kr estimates were based on the steady-state head difference between chambers. A new by-chamber interpretation is proposed that is based on drawdown within each individual chamber. This interpretation yields more detailed information on structure of heterogeneity of the aquifer without introducing complexity into the analysis. The DFT results indicate that Kr ranges from 49 to 6000 m/day (mean ln Kr [(m/s)] approximately -4, and variance of ln Kr [(m/s)] approximately 1-2). Descriptive statistics from the DFT compare well with those from previous field and laboratory tests (pumping, borehole flowmeter, and permeameter tests and grain-size analysis) at this site. It is shown that the role of confining boundaries in the DFT interpretation is negligible even in this case of a thin (< 4 m thick) aquifer. This study demonstrates the flexibility of the DFT and expands the potential application of this method to a wide range of hydrogeologic settings.

  10. Assessing the likely value of gravity and drawdown measurements to constrain estimates of hydraulic conductivity and specific yield during unconfined aquifer testing

    Science.gov (United States)

    Blainey, J.B.; Ferre, T. P. A.; Cordova, J.T.

    2007-01-01

    Pumping of an unconfined aquifer can cause local desaturation detectable with high-resolution gravimetry. A previous study showed that signal-to-noise ratios could be predicted for gravity measurements based on a hydrologic model. We show that although changes should be detectable with gravimeters, estimations of hydraulic conductivity and specific yield based on gravity data alone are likely to be unacceptably inaccurate and imprecise. In contrast, a transect of low-quality drawdown data alone resulted in accurate estimates of hydraulic conductivity and inaccurate and imprecise estimates of specific yield. Combined use of drawdown and gravity data, or use of high-quality drawdown data alone, resulted in unbiased and precise estimates of both parameters. This study is an example of the value of a staged assessment regarding the likely significance of a new measurement method or monitoring scenario before collecting field data. Copyright 2007 by the American Geophysical Union.

  11. Measurement of Fracture Geometry for Accurate Computation of Hydraulic Conductivity

    Science.gov (United States)

    Chae, B.; Ichikawa, Y.; Kim, Y.

    2003-12-01

    Fluid flow in rock mass is controlled by geometry of fractures which is mainly characterized by roughness, aperture and orientation. Fracture roughness and aperture was observed by a new confocal laser scanning microscope (CLSM; Olympus OLS1100). The wavelength of laser is 488nm, and the laser scanning is managed by a light polarization method using two galvano-meter scanner mirrors. The system improves resolution in the light axis (namely z) direction because of the confocal optics. The sampling is managed in a spacing 2.5 μ m along x and y directions. The highest measurement resolution of z direction is 0.05 μ m, which is the more accurate than other methods. For the roughness measurements, core specimens of coarse and fine grained granites were provided. Measurements were performed along three scan lines on each fracture surface. The measured data were represented as 2-D and 3-D digital images showing detailed features of roughness. Spectral analyses by the fast Fourier transform (FFT) were performed to characterize on the roughness data quantitatively and to identify influential frequency of roughness. The FFT results showed that components of low frequencies were dominant in the fracture roughness. This study also verifies that spectral analysis is a good approach to understand complicate characteristics of fracture roughness. For the aperture measurements, digital images of the aperture were acquired under applying five stages of uniaxial normal stresses. This method can characterize the response of aperture directly using the same specimen. Results of measurements show that reduction values of aperture are different at each part due to rough geometry of fracture walls. Laboratory permeability tests were also conducted to evaluate changes of hydraulic conductivities related to aperture variation due to different stress levels. The results showed non-uniform reduction of hydraulic conductivity under increase of the normal stress and different values of

  12. Measurement of 3-D hydraulic conductivity in aquifer cores at in situ effective stresses.

    Science.gov (United States)

    Wright, Martin; Dillon, Peter; Pavelic, Paul; Peter, Paul; Nefiodovas, Andrew

    2002-01-01

    An innovative and nondestructive method to measure the hydraulic conductivity of drill core samples in horizontal and vertical directions within a triaxial cell has been developed. This has been applied to characterizing anisotropy and heterogeneity of a confined consolidated limestone aquifer. Most of the cores tested were isotropic, but hydraulic conductivity varied considerably and the core samples with lowest values were also the most anisotropic. Hydraulic conductivity decreased with increasing effective stress due to closure of microfractures caused by sampling for all core samples. This demonstrates the importance of replicating in situ effective stresses when measuring hydraulic conductivity of cores of deep aquifers in the laboratory.

  13. [Effects of invertebrate bioturbation on vertical hydraulic conductivity of streambed for a river].

    Science.gov (United States)

    Ren, Chao-Liang; Song, Jin-Xi; Yang, Xiao-Gang; Xue, Jian

    2013-11-01

    Streambed hydraulic conductivity is a key factor influencing water exchange between surface water and groundwater. However, the streambed invertebrate bioturbation has a great effect on the hydraulic conductivity. In order to determine the impact of invertebrate bioturbation on streambed hydraulic conductivity, the investigation of invertebrate bioturbation and in-situ test of vertical hydraulic conductivity of streambed are simultaneously conducted at five points along the main stream of the Weihe River. Firstly, correlation between the streambed vertical hydraulic conductivity and grain size distribution is analyzed. Secondly, type and density of the invertebrate and their correlation to hydraulic conductivity are determined. Finally, the effect of invertebrate bioturbation on the streambed hydraulic conductivity is illustrated. The results show that the vertical hydraulic conductivity and biological density of invertebrate are 18.479 m x d(-1) and 139 ind x m(-2), respectively for the Caotan site, where sediment composition with a large amount of sand and gravel particles. For Meixian site, the sediment constitutes a large amount of silt and clay particles, in which the vertical hydraulic conductivity and biological density of invertebrate are 2.807 m x d(-1) and 2 742 ind x m(-2) respectively. Besides, for the low permeability of four sites (Meixian, Xianyang, Lintong and Huaxian), grain size particles are similar while the vertical hydraulic conductivity and biological density of invertebrate are significantly different from one site to another. However, for each site, the vertical hydraulic conductivity closely related to biological density of invertebrate, the Pearson correlation coefficient is 0.987. It can be concluded that both grain size particles and invertebrate bioturbation influence sediment permeability. For example, higher values of streambed hydraulic conductivity from strong permeability site mainly due to the large amount of large-size particles

  14. HYDRAULIC CONDUCTIVITY OF GCL WITH BENTONITE – SILICA FUME MATRIX

    Directory of Open Access Journals (Sweden)

    Mudimby Andal

    2012-12-01

    Full Text Available This paper presents the influence of partial replacement of bentonite by silica fume which is used in the manufacture of Geosynthetic Clay Liner (GCL. Geosynthetic Clay Liners consist bentonite (Sodium Based sandwiched between two geotextile. Benotinite, having low permeability imparts better hydraulic performance to the GCL to act as liner. In this investigation, an attempt has been made to study the hydraulic conductivity of GCL with modified Bentonite. The bentonite is partially replaced by silica fume, a waste product of ferroalloy industries. Silica fume reduces the cracking characteristics of bentonite on desiccation. The replacement levels varied from 0% to 50% at a gradual increment of 5%. The test results indicated that partial replacement of bentonite by silica fume did not affected the permeability of bentonite even at 30%. Beyond 45% replacement levels the bentonite- silica fume mixtures showed increased permeability. This increased permeability also well within permeability limits of liners 1×10-9 m/sec.

  15. HYDRAULIC CONDUCTIVITY OF GCL WITH BENTONITE - SILICA FUME MATRIX

    Directory of Open Access Journals (Sweden)

    M. Andal

    2012-01-01

    Full Text Available This paper presents the influence of partial replacement of bentonite by silica fume which is used in the manufacture of Geosynthetic Clay Liner (GCL. Geosynthetic Clay Liners consist bentonite (Sodium Based sandwiched between two geotextile. Benotinite, having low permeability imparts better hydraulic performance to the GCL to act as liner. In this investigation, an attempt has been made to study the hydraulic conductivity of GCL with modified Bentonite. The bentonite is partially replaced by silica fume, a waste product of ferroalloy industries. Silica fume reduces the cracking characteristics of bentonite on desiccation. The replacement levels varied from 0% to 50% at a gradual increment of 5%. The test results indicated that partial replacement of bentonite by silica fume did not affected the permeability of bentonite even at 30%. Beyond 45% replacement levels the bentonite- silica fume mixtures showed increased permeability. This increased permeability also well within permeability limits of liners 1×10-9m/sec.

  16. Determining the Porosity and Saturated Hydraulic Conductivity of Binary Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z. F.; Ward, Anderson L.; Keller, Jason M.

    2009-09-27

    Gravels and coarse sands make up significant portions of some environmentally important sediments, while the hydraulic properties of the sediments are typically obtained in the laboratory using only the fine fraction (e.g., <2 mm or 4.75 mm). Researchers have found that the content of gravel has significant impacts on the hydraulic properties of the bulk soils. Laboratory experiments were conducted to measure the porosity and the saturated hydraulic conductivity of binary mixtures with different fractions of coarse and fine components. We proposed a mixing-coefficient model to estimate the porosity and a power-averaging method to determine the effective particle diameter and further to predict the saturated hydraulic conductivity of binary mixtures. The proposed methods could well estimate the porosity and saturated hydraulic conductivity of the binary mixtures for the full range of gravel contents and was successfully applied to two data sets in the literature.

  17. In-situ falling-head test for hydraulic conductivity: Evaluation in layered sediments of an analysis derived for homogenous sediments

    Science.gov (United States)

    Burnette, Matthew C.; Genereux, David P.; Birgand, François

    2016-08-01

    The hydraulic conductivity (K) of streambeds is a critical variable controlling interaction of groundwater and surface water. The Hvorslev analysis for estimating K from falling-head test data has been widely used since the 1950s, but its performance in layered sandy sediments common in streams and lakes has not previously been examined. Our numerical simulations and laboratory experiments show that the Hvorslev analysis yields accurate K values in both homogenous sediment (for which the analysis was originally derived) and layered deposits with low-K sand over high-K sand. K from the Hvorslev analysis deviated significantly from true K only when two conditions were present together: (1) high-K sand was present over low-K sand, and (2) the bottom of the permeameter in which K was measured was at or very near the interface between high-K and low-K. When this combination of conditions exists, simulation and laboratory sand tank results show that in-situ Hvorslev K underestimates the true K of the sediment within a permeameter, because the falling-head test is affected by low-K sediment outside of (below the bottom of) the permeameter. In simulation results, the maximum underestimation (occurring when the bottom of the permeameter was at the interface of high K over low K) was by a factor of 0.91, 0.59, and 0.12 when the high-K to low-K ratio was 2, 10, and 100, respectively. In laboratory sand tank experiments, the underestimation was by a factor of about 0.83 when the high-K to low-K ratio was 2.3. Also, this underestimation of K by the Hvorslev analysis was about the same whether the underlying low-K layer was 2 cm or 174 cm thick (1% or 87% of the domain thickness). Numerical model simulations were useful in the interpretation of in-situ field K profiles at streambed sites with layering; specifically, scaling the model results to the maximum measured K at the top of the field K profiles helped constrain the likely ratio of high K to low K at field locations with

  18. Gas Test Loop Booster Fuel Hydraulic Testing

    Energy Technology Data Exchange (ETDEWEB)

    Gas Test Loop Hydraulic Testing Staff

    2006-09-01

    The Gas Test Loop (GTL) project is for the design of an adaptation to the Advanced Test Reactor (ATR) to create a fast-flux test space where fuels and materials for advanced reactor concepts can undergo irradiation testing. Incident to that design, it was found necessary to make use of special booster fuel to enhance the neutron flux in the reactor lobe in which the Gas Test Loop will be installed. Because the booster fuel is of a different composition and configuration from standard ATR fuel, it is necessary to qualify the booster fuel for use in the ATR. Part of that qualification is the determination that required thermal hydraulic criteria will be met under routine operation and under selected accident scenarios. The Hydraulic Testing task in the GTL project facilitates that determination by measuring flow coefficients (pressure drops) over various regions of the booster fuel over a range of primary coolant flow rates. A high-fidelity model of the NW lobe of the ATR with associated flow baffle, in-pile-tube, and below-core flow channels was designed, constructed and located in the Idaho State University Thermal Fluids Laboratory. A circulation loop was designed and constructed by the university to provide reactor-relevant water flow rates to the test system. Models of the four booster fuel elements required for GTL operation were fabricated from aluminum (no uranium or means of heating) and placed in the flow channel. One of these was instrumented with Pitot tubes to measure flow velocities in the channels between the three booster fuel plates and between the innermost and outermost plates and the side walls of the flow annulus. Flow coefficients in the range of 4 to 6.5 were determined from the measurements made for the upper and middle parts of the booster fuel elements. The flow coefficient for the lower end of the booster fuel and the sub-core flow channel was lower at 2.3.

  19. Comparison of Laboratory and Field Methods for Determining the Quasi-Saturated Hydraulic Conductivity of Soils

    Energy Technology Data Exchange (ETDEWEB)

    Faybishenko, Boris

    1997-08-01

    Laboratory and field ponded infiltration tests in quasi-saturated soils (containing entrapped air) exhibit the same three-stage temporal variability for the flow rate and hydraulic conductivity. However, the values for the hydraulic conductivity may differ by as much as two orders of magnitude due to differences in the geometry and physics of flow when different laboratory and field methods are applied. The purpose of this paper is to investigate this variability using a comparison of results of ponded infiltration tests conducted under laboratory conditions using confined cores, with results of field tests conducted using partially isolated cores and double-ring infiltrometers. Under laboratory conditions in confined cores, during the firs stage, the water flux decreases over time because entrapped air plugs the largest pores in the soils; during the second stage, the quasi-saturated hydraulic conductivity increases by one to two orders of magnitude, essentially reaching the saturated hydraulic conductivity, when entrapped air is discharged from the soils; during the third stage, the hydraulic conductivity decreases to minimum values due to sealing of the soil surface and the effect of biofilms sealing the pores within the wetted zone. Under field conditions, the second stage is only partially developed, and when the surface sealing process begins, the hydraulic pressure drops below the air entry value, thereby causing atmospheric air to enter the soils. As a result, the soils become unsaturated with a low hydraulic conductivity, and the infiltration rate consequently decreases. Contrary to the laboratory experiments in confined cores, the saturated hydraulic conductivity cannot be reached under field conditions. In computations of infiltration one has to take into account the variations in the quasi-saturated and unsaturated hydraulic conductivities, moisture and entrapped air content, and the hydraulic gradient in the quasi-saturated or unsaturated soils.

  20. Hydraulic Conductivity of Compacted Laterite Treated with Iron Ore Tailings

    Directory of Open Access Journals (Sweden)

    Umar Sa’eed Yusuf

    2016-01-01

    Full Text Available The objective of this study was to investigate the effect of iron ore tailings (IOT on hydraulic conductivity of compacted laterite. The IOT conforms to ASTM C 618-15 Type F designations. In the present study, soil was admixed with 0–20% IOT and compacted at moulding water content ranging from 10 to 25% using four types of compactive efforts. Hydraulic conductivities of the compacted soil-IOT mixtures were determined using deionized water and municipal solid waste leachate as the permeant fluids, respectively. Deionized water was the reference permeant fluid. Results of this study showed that hydraulic conductivity decreased with increase in IOT content as a result of improvement in mechanical properties of the soil. Permeation of the soil-IOT mixtures with leachate caused the hydraulic conductivity to drop to less than 1 × 10−9 m/s especially at higher compactive efforts. Also, bioclogging of the soil pores due to accumulation of biomass from bacteria and yeast present in the leachate tends to significantly reduce the hydraulic conductivity. From an economic point of view, it has been found from the results of this study that soil specimens treated with up to 20% IOT and compacted at the British Standard Light (BSL compactive effort met the maximum regulatory hydraulic conductivity of less than or equal to 1 × 10−9 m/s for hydraulic barrier system.

  1. Frequency-dependent effective hydraulic conductivity of strongly heterogeneous media.

    Science.gov (United States)

    Caspari, E; Gurevich, B; Müller, T M

    2013-10-01

    The determination of the transport properties of heterogeneous porous rocks, such as an effective hydraulic conductivity, arises in a range of geoscience problems, from groundwater flow analysis to hydrocarbon reservoir modeling. In the presence of formation-scale heterogeneities, nonstationary flows, induced by pumping tests or propagating elastic waves, entail localized pressure diffusion processes with a characteristic frequency depending on the pressure diffusivity and size of the heterogeneity. Then, on a macroscale, a homogeneous equivalent medium exists, which has a frequency-dependent effective conductivity. The frequency dependence of the conductivity can be analyzed with Biot's equations of poroelasticity. In the quasistatic frequency regime of this framework, the slow compressional wave is a proxy for pressure diffusion processes. This slow compressional wave is associated with the out-of-phase motion of the fluid and solid phase, thereby creating a relative fluid-solid displacement vector field. Decoupling of the poroelasticity equations gives a diffusion equation for the fluid-solid displacement field valid in a poroelastic medium with spatial fluctuations in hydraulic conductivity. Then, an effective conductivity is found by a Green's function approach followed by a strong-contrast perturbation theory suggested earlier in the context of random dielectrics. This theory leads to closed-form expressions for the frequency-dependent effective conductivity as a function of the one- and two-point probability functions of the conductivity fluctuations. In one dimension, these expressions are consistent with exact solutions in both low- and high-frequency limits for arbitrary conductivity contrast. In 3D, the low-frequency limit depends on the details of the microstructure. However, the derived approximation for the effective conductivity is consistent with the Hashin-Shtrikman bounds.

  2. Hydraulic conductivity and soil-sewage sludge interactions

    Directory of Open Access Journals (Sweden)

    Silvio Romero de Melo Ferreira

    2011-10-01

    Full Text Available One of the main problems faced by humanity is pollution caused by residues resulting from the production and use of goods, e.g, sewage sludge. Among the various alternatives for its disposal, the agricultural use seems promising. The purpose of this study was to evaluate the hydraulic conductivity and interaction of soil with sandy-silty texture, classified as Spodosols, from the Experimental Station Itapirema - IPA, in Goiana, state of Pernambuco, in mixtures with sewage sludge from the Mangueira Sewage Treatment Station, in the city of Recife, Pernambuco at rates of 25, 50 and 75 Mg ha-1. Tests were conducted to let water percolate the natural saturated soil and soil-sludge mixtures to characterize their physical, chemical, and microstructural properties as well as hydraulic conductivity. Statistical data analysis showed that the presence of sewage sludge in soils leads to an increase of the < 0.005 mm fraction, reduction in real specific weight and variation in optimum moisture content from 11.60 to 12.90 % and apparent specific dry weight from 17.10 and 17.50 kN m-3. In the sludge-soil mixture, the quartz grains were covered by sludge and filling of the empty soil macropores between grains. There were changes in the chemical characteristics of soil and effluent due to sewage sludge addition and a small decrease in hydraulic conductivity. The results indicate the possibility that soil acidity influenced the concentrations of the elements found in the leachate, showing higher levels at higher sludge doses. It can be concluded that the leaching degree of potentially toxic elements from the sewage sludge treatments does not harm the environment.

  3. INFORMATION-MEASURING TEST SYSTEM OF DIESEL LOCOMOTIVE HYDRAULIC TRANSMISSIONS

    Directory of Open Access Journals (Sweden)

    I. V. Zhukovytskyy

    2015-08-01

    Full Text Available Purpose. The article describes the process of developing the information-measuring test system of diesel locomotives hydraulic transmission, which gives the possibility to obtain baseline data to conduct further studies for the determination of the technical condition of diesel locomotives hydraulic transmission. The improvement of factory technology of post-repair tests of hydraulic transmissions by automating the existing hydraulic transmission test stands according to the specifications of the diesel locomotive repair enterprises was analyzed. It is achieved based on a detailed review of existing foreign information-measuring test systems for hydraulic transmission of diesel locomotives, BelAZ earthmover, aircraft tug, slag car, truck, BelAZ wheel dozer, some brands of tractors, etc. The problem for creation the information-measuring test systems for diesel locomotive hydraulic transmission is being solved, starting in the first place from the possibility of automation of the existing test stand of diesel locomotives hydraulic transmission at Dnipropetrovsk Diesel Locomotive Repair Plant "Promteplovoz". Methodology. In the work the researchers proposed the method to create a microprocessor automated system of diesel locomotives hydraulic transmission stand testing in the locomotive plant conditions. It acts by justifying the selection of the necessary sensors, as well as the application of the necessary hardware and software for information-measuring systems. Findings. Based on the conducted analysis there was grounded the necessity of improvement the plant hydraulic transmission stand testing by creating a microprocessor testing system, supported by the experience of developing such systems abroad. Further research should be aimed to improve the accuracy and frequency of data collection by adopting the more modern and reliable sensors in tandem with the use of filtering software for electromagnetic and other interference. Originality. The

  4. Hydraulic conductivity tests on damaged geosynthetic clay liners%带缺陷膨润土防水毯的渗透试验

    Institute of Scientific and Technical Information of China (English)

    何俊; 肖衡林; 孔祥怡

    2011-01-01

    分别以自来水和0.05 mol/L的CaCl2溶液作为渗滤溶液研究带缺陷膨润土防水毯(GCL)的渗透性能.试验结果表明:自来水渗滤时,GCL的渗透系数随着缺陷直径的增大而增大,缺陷直径达11mm时缺陷不能完全愈合,致使渗透系数超过1×10-9m/s.CaCl2溶液渗滤时,随着离子交换作用的进行,渗透系数随孔隙体积流量的增大有增大的趋势;缺陷直径小于5mm时GCL具有一定的自愈能力,但增至7mm时缺陷不能愈合,溶液和缺陷的共同作用使得GCL的防渗性能很差.%The permeability of damaged geosynthetic clay liner (GCL) was studied fay using the tap water and the 0.05mol/L CaCl2 solution as the percolating liquid, respectively. The results show that for the taper water, the hydraulic conductivity of the damaged GCL increases with the increase of hole diameter. The damaged GCL can not self-heal when the hole diameter reaches 11mm, and the hydraulic conductivity will be larger than 1 × 10-9 m/s. For the 0.05mol/L CaCl2 solution, the hydraulic conductivity of the damaged GCL increases with the increase of pore volume flows due to ion exchange. The damaged GCL have certain self-healing capacity when the hole diameter is less than 5 mm and can not self-heal when the hole diameter reaches 7 mm. The combined action of the solution and the defect results in poor permeability performance of the damaged GCL.

  5. Xylem hydraulic conductivity related to conduit dimensions along chrysanthemum stems.

    NARCIS (Netherlands)

    Nijsse, J.; Heijden, van der G.W.A.M.; Ieperen, van W.; Keijzer, C.J.; Meeteren, van U.

    2001-01-01

    The stem xylem conduit dimensions and hydraulic conductivity of chrysanthemum plants (Dendranthemaxgrandiflorum Tzvelev cv. Cassa) were analysed and quantified. Simple exponential relations describe conduit length distribution, height dependency of conduit length distribution, and height dependency

  6. HYDRAULIC CONDUCTIVITY OF GCL WITH BENTONITE – SILICA FUME MATRIX

    OpenAIRE

    M. Andal; Chandrasekhar, M.; G. K. Viswanadh

    2012-01-01

    This paper presents the influence of partial replacement of bentonite by silica fume which is used in the manufacture of Geosynthetic Clay Liner (GCL). Geosynthetic Clay Liners consist bentonite (Sodium Based) sandwiched between two geotextile. Benotinite, having low permeability imparts better hydraulic performance to the GCL to act as liner. In this investigation, an attempt has been made to study the hydraulic conductivity of GCL with modified Bentonite. The bentonite is partially replaced...

  7. Rapid shoot‐to‐root signalling regulates root hydraulic conductance via aquaporins

    National Research Council Canada - National Science Library

    VANDELEUR, REBECCA K; SULLIVAN, WENDY; ATHMAN, ASMINI; JORDANS, CHARLOTTE; GILLIHAM, MATTHEW; KAISER, BRENT N; TYERMAN, STEPHEN D

    2014-01-01

    Investigating the relationship between transpiration and root hydraulic conductance Vandeleur et al report that leaf area reduction reduces root hydraulic conductance in grapevine, soybean and maize...

  8. The Comparison of Predicted and Measured Hydraulic Conductivities of Soils having Different Physical Properties

    Science.gov (United States)

    Zengin, Enes; Abiddin Erguler, Zeynal; Karakuş, Hüseyin

    2015-04-01

    Hydraulic conductivity is one of the most important parameter of earth science related studies such as engineering geology, soil physics, agriculture etc. In order to estimate the ability of soils to transport fluid through particles, field and laboratory tests have been performed since last decades of 19th century. Constant and falling head tests are widely used to directly measure hydraulic conductivity values in laboratory conditions for soils having different particle size distributions. The determination of hydraulic conductivity of soils by performing these methods are time consuming processes and also requires undisturbed samples to reflect in-situ natural condition. Considering these limitations, numerous approaches have been proposed to practically estimate hydraulic conductivity of soils by utilizing empirical equations based on simple physical and index properties such as grain size distribution curves related parameters, porosity, void ratio, etc. Many previous studies show that the hydraulic conductivity values calculated by empirical equations deviate more than two order magnitude than the measured hydraulic conductivity values obtained from convenient permeability tests. In order to investigate the main controlling parameters on hydraulic conductivity of soils, a comprehensive research program was carried out on some disturbed and undisturbed soil samples collected from different locations in Turkey. The hydraulic conductivity values of samples were determined as changing between 10-6 and 10-9 m/s by using falling head tests. In addition to these tests, basic soil properties such as natural water content, Atterberg limits, specific gravity and grain size analyses of these samples were also defined to be used as an input parameters of empirical equations for prediction hydraulic conductivity values. In addition, data from previous studies were also used for the aim of this study. The measured hydraulic conductivity values were correlated with all

  9. Periodic Hydraulic Testing for Discerning Fracture Network Connections

    Science.gov (United States)

    Becker, M.; Le Borgne, T.; Bour, O.; Guihéneuf, N.; Cole, M.

    2015-12-01

    Discrete fracture network (DFN) models often predict highly variable hydraulic connections between injection and pumping wells used for enhanced oil recovery, geothermal energy extraction, and groundwater remediation. Such connections can be difficult to verify in fractured rock systems because standard pumping or pulse interference tests interrogate too large a volume to pinpoint specific connections. Three field examples are presented in which periodic hydraulic tests were used to obtain information about hydraulic connectivity in fractured bedrock. The first site, a sandstone in New York State, involves only a single fracture at a scale of about 10 m. The second site, a granite in Brittany, France, involves a fracture network at about the same scale. The third site, a granite/schist in the U.S. State of New Hampshire, involves a complex network at scale of 30-60 m. In each case periodic testing provided an enhanced view of hydraulic connectivity over previous constant rate tests. Periodic testing is particularly adept at measuring hydraulic diffusivity, which is a more effective parameter than permeability for identify the complexity of flow pathways between measurement locations. Periodic tests were also conducted at multiple frequencies which provides a range in the radius of hydraulic penetration away from the oscillating well. By varying the radius of penetration, we attempt to interrogate the structure of the fracture network. Periodic tests, therefore, may be uniquely suited for verifying and/or calibrating DFN models.

  10. Effects of hedgerow systems on soil moisture and unsaturated hydraulics conductivity measured by the Libardi method

    Directory of Open Access Journals (Sweden)

    S . Prijono

    2016-01-01

    Full Text Available The hedgerow systems are the agroforestry practices suggesting any positive impacts and negative impacts on soil characteristics. This study evaluated the effects of hedgerows on the unsaturated hydraulic conductivity of soil with the Libardi method approach. This study was conducted in North Lampung for 3 months on the hedgerow plots of Peltophorum dassyrachis (P, Gliricidia sepium (G, and without hedgerow plot (K, with four replications. Each plot was watered as much as 150 liters of water until saturated, then the soil surface were covered with the plastic film. Observation of soil moisture content was done to a depth of 70 cm by the 10 cm intervals. Soil moisture content was measured using the Neutron probe that was calibrated to get the value of volumetric water content. Unsaturated hydraulic conductivity of soil was calculated by using the Libardi Equation. Data were tested using the analysis of variance, the least significant different test (LSD, Duncan Multiple Range Test (DMRT, correlation and regression analysis. The results showed that the hedgerow significantly affected the soil moisture content and unsaturated hydraulic conductivity. Soil moisture content on the hedgerow plots was lower than the control plots. The value of unsaturated hydraulic conductivity in the hedgerow plots was higher than the control plots. Different types of hedgerows affected the soil moisture content and unsaturated hydraulic conductivity. The positive correlation was found between the volumetric soil moisture content and the unsaturated hydraulic conductivity of soil.

  11. VARIABILITY OF HYDRAULIC CONDUCTIVITY DUE TO MULTIPLE FACTORS

    Directory of Open Access Journals (Sweden)

    Sanjit K. Deb

    2012-01-01

    Full Text Available Soil properties are greatly influenced by intrinsic factors of soil formation as well as extrinsic factors associated with land use and management and vary both in time and space. Intrinsic variability is caused by the pedogenesis and usually takes place at large time scales. The variability caused by extrinsic factors could take effect relatively quickly and could not be treated as regionalized. Saturated hydraulic conductivity is one of the most important soil properties for soil-water-plant interactions, water and contaminant movement and retention through the soil profile. It is a critically important parameter for estimation of various other soil hydrological parameters necessary for modeling flow through the naturally unsaturated vadose zone. Among different soil hydrological properties, saturated hydraulic conductivity is reported to have the greatest statistical variability, which is associated with soil types, land uses, positions on landscape, depths, instruments and methods of measurement and experimental errors. The variability of saturated hydraulic conductivity has a profound influence on the overall hydrology of the soil system. Therefore, focus of this review is centered on the variability of saturated/unsaturated hydraulic conductivity due to a large number of factors. This study reviews recent experimental and field studies addressing the measurements and variability of hydraulic conductivity. A synthesis of a large amount of data available in literature is presented and the possible sources of the variability and its implications are discussed. The variability of a soil hydraulic conductivity can be expressed by range, interquartile range, variance and standard deviation, coefficient of variation, skewness and kurtosis. The spatial and temporal variability of hydraulic conductivity and the influences of sample support, measurement devices/methods, soils, land uses and agricultural management on hydraulic conductivity are

  12. Changes in Root Hydraulic Conductivity During Wheat Evolution

    Institute of Scientific and Technical Information of China (English)

    Chang-Xing ZHAO; Xi-Ping DENG; Lun SHAN; Ernst STEUDLE; Sui-Qi ZHANG; Qing YE

    2005-01-01

    A better understanding of the mechanisms of water uptake by plant roots should be vital for improving drought resistance and water use efficiency (WUE). In the present study, we have demonstrated correlations between root system hydraulic conductivity and root characteristics during evolution using six wheat evolution genotypes (solution culture) with different ploidy chromosome sets (Triticum boeoticum Bioss., T. monococcum L.: 2n = 2x = 14; T. dicoccides Koern., T. dicoccon (Schrank) Schuebl.: 2n = 4x = 28;T. vulgare Vill., T. aestivum L. cv. Xiaoyan No. 6: 2n = 6x = 42). The experimental results showed that significant correlations were found between root system hydraulic conductivity and root characteristics of the materials with the increase in ploidy chromosomes (2x→6x) during wheat evolution. Hydraulic conductivity of the wheat root system at the whole-plant level was increased with chromosome ploidy during evolution, which was positively correlated with hydraulic conductivity of single roots, whole plant biomass,root average diameter, and root growth (length, area), whereas the root/shoot ratio had an inverse correlation with the hydraulic conductivity of root system with increasing chromosome ploidy during wheat evolution. Therefore, it is concluded that that the water uptake ability of wheat roots was strengthened from wild to modern cultivated species during evolution, which will provide scientific evidence for genetic breeding to improve the WUE of wheat by genetic engineering.

  13. Measurement and modeling of unsaturated hydraulic conductivity: Chapter 21

    Science.gov (United States)

    Perkins, Kim S.; Elango, Lakshmanan

    2011-01-01

    The unsaturated zone plays an extremely important hydrologic role that influences water quality and quantity, ecosystem function and health, the connection between atmospheric and terrestrial processes, nutrient cycling, soil development, and natural hazards such as flooding and landslides. Unsaturated hydraulic conductivity is one of the main properties considered to govern flow; however it is very difficult to measure accurately. Knowledge of the highly nonlinear relationship between unsaturated hydraulic conductivity (K) and volumetric water content () is required for widely-used models of water flow and solute transport processes in the unsaturated zone. Measurement of unsaturated hydraulic conductivity of sediments is costly and time consuming, therefore use of models that estimate this property from more easily measured bulk-physical properties is common. In hydrologic studies, calculations based on property-transfer models informed by hydraulic property databases are often used in lieu of measured data from the site of interest. Reliance on database-informed predicted values with the use of neural networks has become increasingly common. Hydraulic properties predicted using databases may be adequate in some applications, but not others.

  14. Measurement of soil hydraulic conductivity in relation with vegetation

    Science.gov (United States)

    Chen, Xi; Cheng, Qinbo

    2010-05-01

    Hydraulic conductivity is a key parameter which influences hydrological processes of infiltration, surface and subsurface runoff. Vegetation alters surface characteristics (e.g., surface roughness, litter absorption) or subsurface characteristics (e.g. hydraulic conductivity). Field infiltration experiment of a single ring permeameter is widely used for measuring soil hydraulic conductivity. Measurement equipment is a simple single-ring falling head permeameter which consists of a hollow cylinder that is simply inserted into the top soil. An optimization method on the basis of objective of minimum error between the measured and simulated water depths in the single-ring is developed for determination of the soil hydraulic parameters. Using the single ring permeameter, we measured saturated hydraulic conductivities (Ks) of the red loam soil with and without vegetation covers on five hillslopes at Taoyuan Agro-Ecology Experimental Station, Hunan Province of China. For the measurement plots without vegetation roots, Ks value of the soil at 25cm depth is much smaller than that of surface soil (1.52×10-4 vs. 1.10×10-5 m/s). For the measurement plots with vegetation cover, plant roots significantly increase Ks of the lower layer soil but this increase is not significant for the shallow soil. Moreover, influences of vegetation root on Ks depend on vegetation species and ages. Ks value of the Camellia is about three times larger than that of seeding of Camphor (2.62×10-4 vs. 9.82×10-5 m/s). Ks value of the matured Camellia is 2.72×10-4 m/s while Ks value of the young Camellia is only 2.17×10-4 m/s. Key words: single ring permeameter; soil hydraulic conductivity; vegetation

  15. Measuring lateral saturated soil hydraulic conductivity at different spatial scales

    Science.gov (United States)

    Di Prima, Simone; Marrosu, Roberto; Pirastru, Mario; Niedda, Marcello

    2017-04-01

    Among the soil hydraulic properties, saturated soil hydraulic conductivity, Ks, is particularly important since it controls many hydrological processes. Knowledge of this soil property allows estimation of dynamic indicators of the soil's ability to transmit water down to the root zone. Such dynamic indicators are valuable tools to quantify land degradation and developing 'best management' land use practice (Castellini et al., 2016; Iovino et al., 2016). In hillslopes, lateral saturated soil hydraulic conductivity, Ks,l, is a key factor since it controls subsurface flow. However, Ks,l data collected by point-scale measurements, including infiltrations tests, could be unusable for interpreting field hydrological processes and particularly subsurface flow in hillslopes. Therefore, they are generally not representative of subsurface processes at hillslope-scale due mainly to soil heterogeneities and the unknown total extent and connectivity of macropore network in the porous medium. On the other hand, large scale Ks,l measurements, which allow to average soil heterogeneities, are difficult and costly, thus remain rare. Reliable Ks,l values should be measured on a soil volume similar to the representative elementary volume (REV) in order to incorporate the natural heterogeneity of the soil. However, the REV may be considered site-specific since it is expected to increase for soils with macropores (Brooks et al., 2004). In this study, laboratory and in-situ Ks,l values are compared in order to detect the dependency Ks,l from the spatial scale of investigation. The research was carried out at a hillslope located in the Baratz Lake watershed, in northwest Sardinia, Italy, characterized by degraded vegetation (grassland established after fire or clearing of the maquis). The experimental area is about 60 m long, with an extent of approximately 2000 m2, and a mean slope of 30%. The soil depth is about 35 to 45 cm. The parent material is a very dense grayish, altered

  16. DEPTH CONTINUOUS HYDRAULIC CONDUCTIVITY PROFILING USING AN ACTIVE SOURCE PENETROMETER

    Science.gov (United States)

    Fitzgerald, M.; Elsworth, D.

    2009-12-01

    A method is developed to recover depth-continuous hydraulic conductivity profiles of an unconsolidated saturated aquifer using an active source penetrometer, the Hydraulic Profiling Tool (HPT). The tool yields estimates of K through continuous injection of fluid in the subsurface from a small port on the probe shaft while controlled measurements of net applied fluid pressure required to maintain a specified flow rate (typically 350 mL/min) are recorded. The tool gathers these data of flow rate and measured applied pressure during halted and constant-rate penetration (typically 2cm/sec) of the probe. The analysis is developed in two parts, first to explore the interplay between advective effects controlled by penetration rate and secondly flow volume effects controlled by the targeted flow rate. These two effects are analyzed through their respective influence on the measured applied pressure response in ΔP/σv’-Q/ΔP space, which shows a linear relationship for the flow rate to applied pressure response when Q/ΔP > 1 and when Q/ΔP 1. The analysis shows that penetration rate does not significantly influence the applied pressure response at the tested penetration rates (0 ≤ U(cm/s)≤ 4). The targeted applied flow rate does however influence the applied pressure response as flow rates less than ~300 mL/min show a scattering of the data in ΔP/σv’-Q/ΔP space, where above 300 mL/min the data begins to form a linear response. A targeted flow rate of QT = 400mL/min is suggested as a suitable flow rate based on this analysis. Measurements of hydraulic conductivity are then obtained for the HPT data through the derivation of an equation based on a recast form of Darcy’s law where considerations of the flow geometry as K = (QHPT/ΔP)(δw/πΦ). K profiles obtained for the HPT system are then compared against K profiles obtained from an independent method (PSU permeameter) and yield a good correlation between the two methods.

  17. EVALUATION OF HYDRAULIC CONDUCTIVITIES CALCULATED FROM MULTIPORT-PERMEAMETER MEASUREMENTS

    Science.gov (United States)

    A multiport permeameter was developed for use in estimating hydraulic conductivity over intact sections of aquifer core using the core liner as the permeameter body. Six cores obtained from one borehole through the upper 9 m of a stratified glacial-outwash aquifer were used to ev...

  18. Water Infiltration and Hydraulic Conductivity in Sandy Cambisols

    DEFF Research Database (Denmark)

    Bens, Oliver; Wahl, Niels Arne; Fischer, Holger

    2006-01-01

    Soil hydrological properties like infiltration capacity and hydraulic conductivity have important consequences for hydrological properties of soils in river catchments and for flood risk prevention. They are dynamic properties due to varying land use management practices. The objective of this st......Soil hydrological properties like infiltration capacity and hydraulic conductivity have important consequences for hydrological properties of soils in river catchments and for flood risk prevention. They are dynamic properties due to varying land use management practices. The objective...... of this study was to characterize the variation of infiltration capacity, hydraulic conductivity and soil organoprofile development on forest sites with comparable geological substrate, soil type and climatic conditions, but different stand ages and tree species in terms of the effects of forest transformation...... from pure Scots pine stands towards pure European beech stands. The water infiltration capacity and hydraulic conductivity (K) of the investigated sandy-textured soils are low and very few macropores exist. Additionally these pores are marked by poor connectivity and therefore do not have any...

  19. Verification of HYDRASTAR: Analysis of hydraulic conductivity fields and dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Morris, S.T.; Cliffe, K.A. [AEA Technology, Harwell (United Kingdom)

    1994-10-01

    HYDRASTAR is a code for the stochastic simulation of groundwater flow. It can be used to simulate both time-dependent and steady-state groundwater flow at constant density. Realizations of the hydraulic conductivity field are generated using the Turning Bands algorithm. The realizations can be conditioned on measured values of the hydraulic conductivity using Kriging. This report describes a series of verification studies that have been carried out on the code. The first study concerns the accuracy of the implementation of the Turning Bands algorithm in HYDRASTAR. The implementation has been examined by evaluating the ensemble mean and covariance of the generated fields analytically and comparing them with their prescribed values. Three other studies were carried out in which HYDRASTAR was used to solve problems of uniform mean flow and to calculate the transport and dispersion of fluid particles. In all three cases the hydraulic conductivity fields were unconditioned. The first two were two-dimensional: one at small values of the variance of the logarithm of the hydraulic conductivity for which there exists analytical results that the code can be compared with, and one at moderate variance where the results can only be compared with those obtained by another code. The third problem was three dimensional with a small variance and again analytical results are available for comparison. 14 refs, 24 figs.

  20. The Thermal Hydraulic Test of SFR Irradiation Test Capsule

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chul Yong; Park, Sung Jae; Choo, Kee Nam [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-10-15

    Irradiation test using a capsule has been performed for fuel or material performance test in the test reactor. Irradiation capsule for the HANARO reactor must satisfy the hydraulic conditions and structural integrity from a out-pile test. Items of a out-pile test are pressure drop, flow-induced vibration test and endurance test. The results of test must show that a test capsule satisfy the HANARO operational requirement with sufficient margin. This paper describes the devices of thermal hydraulic test and the results of SFR test capsule

  1. Effect of Irrigation Water Quality on Soil Hydraulic Conductivity

    Institute of Scientific and Technical Information of China (English)

    XIAOZHEN-HUA; B.PRENDERGAST; 等

    1992-01-01

    The effect of irrigation water quality on unsaturated hydraulic conductivity (HC) of undisturbed soil in field was studied.Results show that within the operating soil suction range (0-1.6 KPa) of disc permeameters,the higher the electric conductivity (EC) of irrigation water,the higher the soil HC became.The soil HC doubled when EC increased from 0.1 to 6.0ds m-1.High sodium-adsorption ratio(SAR) of irrigation water would have an unfavorable effect on soil HC.Soil HC decreased with the increasing of SAR,especially in the case of higher soil suction.An interaction existed between the effects of EC and SAR of irrigation water on soil HC.The HC of unsaturated soil dependent upon the macropores in surface soil decreased by one order of magnitude with 1 KPa increase of soil suction.In the study on the effect of very low soluble salt concentration (EC=0.1 ds m-1 of irrigation water on soil HC,soil HC was found to be lowered by 30% as a consequence of blocking up of some continuous pores by the dispersed and migrated clay particles.Nonlinear successive regression analysis and significance test show that the effects of EC and SAR of irrigation water on soil HC reached the extremely significant level.

  2. The relationship between hydraulic conductivity and diffusion in granitic rock matrix

    Science.gov (United States)

    Najser, J.; Gvozdik, L.; Havlova, V.; Sosna, K.; Vecernik, P.; Zaruba, J.

    2012-12-01

    In the Czech Republic, granite is being considered as the host rock for a radioactive waste repository. The aim of the current research project is to study of the hydraulic properties of the low-permeable rock matrix. 45 granitic samples from ten sites have been subjected to hydraulic conductivity (K) and diffusivity (De) tests. Hydraulic conductivity was measured in pressure cells. A constant pressure difference of Δ = 50 kPa was applied by pressure controllers and the volume of water that passed through the sample was recorded. The effective diffusion coefficient De was measured using 3H tracer in through-diffusion experiments. The activities in both input and output reservoirs were regularly monitored using liquid scintillation spectrometry. The hydraulic conductivities of fresh granite varied from 1.65 x 10-10 to 1 x 10-14 m.s-1 while the effective diffusion coefficient ranged from 7.4 x 10-12 to 4 x 10-13 m2.s-1. Comparison of measured "K" and "De" values reveals significant scatter, despite clear trends. Numerical simulation of both hydraulic conductivity and diffusivity was undertaken using finite-element code NAPSAC. The results show that reduced microcrack length influences the connectivity of the microcrack network, increases diffusivity, and decreases hydraulic conductivity. The imperfect correlation between experimental "K" and "De" is explained by the different geometries of the microcrack networks within the studied granites.

  3. Getting saturated hydraulic conductivity from surface Ground-Penetrating Radar measurements inside a ring infiltrometer

    Science.gov (United States)

    Leger, E.; Saintenoy, A.; Coquet, Y.

    2013-12-01

    Hydraulic properties of soils, described by the soil water retention and hydraulic conductivity functions, strongly influence water flow in the vadoze zone, as well as the partitioning of precipitation between infiltration into the soil and runoff along the ground surface. Their evaluation has important applications for modelling available water resources and for flood forecasting. It is also crucial to evaluate soil's capacity to retain chemical pollutants and to assess the potential of groundwater pollution. The determination of the parameters involved in soil water retention functions, 5 parameters when using the van Genuchten function, is usually done by laboratory experiments, such as the water hanging column. Hydraulic conductivity, on the other hand can be estimated either in laboratory, or in situ using infiltrometry tests. Among the large panel of existing tests, the single or double ring infiltrometers give the field saturated hydraulic conductivity by applying a positive charge on soils, whereas the disk infiltrometer allows to reconstruct the whole hydraulic conductivity curve, by applying different charges smaller than or equal to zero. In their classical use, volume of infiltrated water versus time are fitted to infer soil's hydraulic conductivity close to water saturation. Those tests are time-consuming and difficult to apply to landscape-scale forecasting of infiltration. Furthermore they involve many assumptions concerning the form of the infiltration bulb and its evolution. Ground-Penetrating Radar (GPR) is a geophysical method based on electromagnetic wave propagation. It is highly sensitive to water content variations directly related to the dielectric permittivity. In this study GPR was used to monitor water infiltration inside a ring infiltrometer and retrieve the saturated hydraulic conductivity. We carried out experiments in a quarry of Fontainebleau sand, using a Mala RAMAC system with antennae centered on 1600 MHz. We recorded traces at

  4. Mechanization of hydraulic testing of chemical equipment

    Energy Technology Data Exchange (ETDEWEB)

    Bannikov, M.T.; Fridman, R.N.; Petrovnin, A.I.

    1982-09-01

    The Institute VNIIPTKhimmash has worked out a comprehensive list of equipment for testing for strength and tightness containers and heat exchangers with jackets, with mixers, also of individual parts and subassemblies for this equipment. Points out that in the test stands developed for hydraulic testing of vessels both individual and centralized recirculating water supply can be used. Concludes that a reduction in labor consumption in hydraulic testing and in servicing of all the equipment used, an increase in the mechanization of this kind of chemical equipment, and the solution of the problem of standardization not only with regard to dimensions and parameters, but also with regard to the makes and types of the materials used, will make possible a considerable increase in labor productivity and product quality.

  5. Hydraulic conductivity study of compacted clay soils used as landfill liners for an acidic waste.

    Science.gov (United States)

    Hamdi, Noureddine; Srasra, Ezzeddine

    2013-01-01

    Three natural clayey soils from Tunisia were studied to assess their suitability for use as a liner for an acid waste disposal site. An investigation of the effect of the mineral composition and mechanical compaction on the hydraulic conductivity and fluoride and phosphate removal of three different soils is presented. The hydraulic conductivity of these three natural soils are 8.5 × 10(-10), 2.08 × 10(-9) and 6.8 × 10(-10)m/s for soil-1, soil-2 and soil-3, respectively. Soil specimens were compacted under various compaction strains in order to obtain three wet densities (1850, 1950 and 2050 kg/m(3)). In this condition, the hydraulic conductivity (k) was reduced with increasing density of sample for all soils. The test results of hydraulic conductivity at long-term (>200 days) using acidic waste solution (pH=2.7, charged with fluoride and phosphate ions) shows a decrease in k with time only for natural soil-1 and soil-2. However, the specimens of soil-2 compressed to the two highest densities (1950 and 2050 kg/m(3)) are cracked after 60 and 20 days, respectively, of hydraulic conductivity testing. This damage is the result of a continued increase in the internal stress due to the swelling and to the effect of aggressive wastewater. The analysis of anions shows that the retention of fluoride is higher compared to phosphate and soil-1 has the highest sorption capacity.

  6. Improving prediction of hydraulic conductivity by constraining capillary bundle models to a maximum pore size

    Science.gov (United States)

    Iden, Sascha; Peters, Andre; Durner, Wolfgang

    2017-04-01

    Soil hydraulic properties are required to solve the Richards equation, the most widely applied model for variably-saturated flow. While the experimental determination of the water retention curve does not pose significant challenges, the measurement of unsaturated hydraulic conductivity is time consuming and costly. The prediction of the unsaturated hydraulic conductivity curve from the soil water retention curve by pore-bundle models is a cost-effective and widely applied technique. A well-known problem of conductivity prediction for retention functions with wide pore-size distributions is the sharp drop in conductivity close to water saturation. This problematic behavior is well known for the van Genuchten model if the shape parameter n assumes values smaller than about 1.3. So far, the workaround for this artefact has been to introduce an explicit air-entry value into the capillary saturation function. However, this correction leads to a retention function which is not continuously differentiable and thus a discontinuous water capacity function. We present an improved parametrization of the hydraulic properties which uses the original capillary saturation function and introduces a maximum pore radius only in the pore-bundle model. Closed-form equations for the hydraulic conductivity function were derived for the unimodal and multimodal retention functions of van Genuchten and have been tested by sensitivity analysis and applied in curve fitting and inverse modeling of multistep outflow experiments. The resulting hydraulic conductivity function is smooth, increases monotonically close to saturation, and eliminates the sharp drop in conductivity close to saturation. Furthermore, the new model retains the smoothness and continuous differentiability of the water retention curve. We conclude that the resulting soil hydraulic functions are physically more reasonable than the ones predicted by previous approaches, and are thus ideally suited for numerical simulations

  7. Pilot testing of a hydraulic bridge exciter

    Directory of Open Access Journals (Sweden)

    Andersson Andreas

    2015-01-01

    Full Text Available This paper describes the development of a hydraulic bridge exciter and its first pilot testing on a full scale railway bridge in service. The exciter is based on a hydraulic load cylinder with a capacity of 50 kN and is intended for controlled dynamic loading up to at least 50 Hz. The load is applied from underneath the bridge, enabling testing while the railway line is in service. The system is shown to produce constant load amplitude even at resonance. The exciter is used to experimentally determine frequency response functions at all sensor locations, which serve as valuable input for model updating and verification. An FE-model of the case study bridge has been developed that is in good agreement with the experimental results.

  8. Deciphering transmissivity and hydraulic conductivity of the aquifer by vertical electrical sounding (VES) experiments in Northwest Bangladesh

    Science.gov (United States)

    Sattar, Golam Shabbir; Keramat, Mumnunul; Shahid, Shamsuddin

    2016-03-01

    The vertical electrical soundings (VESs) are carried out in 24 selective locations of Chapai-Nawabganj area of northwest Bangladesh to determine the transmissivity and hydraulic conductivity of the aquifer. Initially, the transmissivity and hydraulic conductivity are determined from the pumping data of nearby available production wells. Afterwards, the T and K are correlated with geoelectrical resistance and the total resistivity of the aquifer. The present study deciphers the functional analogous relations of the geoelectrical resistance with the transmissivity and the total resistivity with the hydraulic conductivity of the aquifer in northwest Bangladesh. It has been shown that the given equations provide reasonable values of transmissivity and hydraulic conductivity where pumping test information is unavailable. It can be expected that the aquifer properties viz. transmissivity and hydraulic conductivity of geologically similar area can be determined with the help of the obtained equations by conducting VES experiments.

  9. Evaluation of Regression and Neuro_Fuzzy Models in Estimating Saturated Hydraulic Conductivity

    Directory of Open Access Journals (Sweden)

    J. Behmanesh

    2015-06-01

    Full Text Available Study of soil hydraulic properties such as saturated and unsaturated hydraulic conductivity is required in the environmental investigations. Despite numerous research, measuring saturated hydraulic conductivity using by direct methods are still costly, time consuming and professional. Therefore estimating saturated hydraulic conductivity using rapid and low cost methods such as pedo-transfer functions with acceptable accuracy was developed. The purpose of this research was to compare and evaluate 11 pedo-transfer functions and Adaptive Neuro-Fuzzy Inference System (ANFIS to estimate saturated hydraulic conductivity of soil. In this direct, saturated hydraulic conductivity and physical properties in 40 points of Urmia were calculated. The soil excavated was used in the lab to determine its easily accessible parameters. The results showed that among existing models, Aimrun et al model had the best estimation for soil saturated hydraulic conductivity. For mentioned model, the Root Mean Square Error and Mean Absolute Error parameters were 0.174 and 0.028 m/day respectively. The results of the present research, emphasises the importance of effective porosity application as an important accessible parameter in accuracy of pedo-transfer functions. sand and silt percent, bulk density and soil particle density were selected to apply in 561 ANFIS models. In training phase of best ANFIS model, the R2 and RMSE were calculated 1 and 1.2×10-7 respectively. These amounts in the test phase were 0.98 and 0.0006 respectively. Comparison of regression and ANFIS models showed that the ANFIS model had better results than regression functions. Also Nuro-Fuzzy Inference System had capability to estimatae with high accuracy in various soil textures.

  10. Evaluation of actual and estimated hydraulic conductivity of sands with different gradation and shape.

    Science.gov (United States)

    Cabalar, Ali Firat; Akbulut, Nurullah

    2016-01-01

    Hydraulic conductivities of sands with different gradation and grain shape were estimated experimentally at a relative density (Dr) of about 40 % and a 22 ± 2 °C of constant temperature. Narli Sand (NS) with 0.67 of sphericity (S) and 0.72 of roundness (R), and Crushed Stone Sand (CSS) with 0.55 of S and 0.15 of R values were artificially graded into sixteen different grain-size fractions (4.75-2, 2-1.18, 1.18-0.6, 0.6-0.425, 0.425-0.3, 0.3-0.075, 4.75-0.075, 2-0.075, 1.18-0.075, 0.6-0.075, 0.425-0.075, 4.75-0.6, 2-0.6, 4.75-0.425, 2-0.425, 1.18-0.425 mm). Hydraulic conductivities of the NS estimated by use of constant head test ranged from 1.61 to 0.01 cm/s, whilst those of the CSS estimated by the same test ranged from 2.45 to 0.012 cm/s. It was observed that the hydraulic conductivity values of the NS are lower than those of the CSS samples, which is likely to be the result of differences in shape, particularly in R values. The results clearly demonstrated that the hydraulic conductivity can be significantly influenced by grading characteristics (d10, d20, d30, d50, d60, cu, cc, n, Io). Furthermore, comparisons between results obtained in the present study and hydraulic conductivity estimated with other formulas available in the literature were made. The comparisons indicated that the best estimation of hydraulic conductivity changes based on the gradation and shape properties of the sands tested.

  11. Temporal changes in hydraulic conductivity of sand porous media biofilters during wastewater infiltration due to biomat formation

    Science.gov (United States)

    Beach, Deborah N. H.; McCray, John E.; Lowe, Kathryn S.; Siegrist, Robert L.

    2005-09-01

    Porous media biofilters (PMBs) are commonly used to treat domestic wastewater. Biomats develop at the infiltrative surface of PMBs due to continued wastewater application and create an impedance to flow. The goal of this research is to quantify the temporal evolution of normalized biomat hydraulic conductivity ( Kbm/ bbm) and effective hydraulic conductivity ( Ke). Ke is the overall hydraulic conductivity of the infiltrative zone, including biomat and unsaturated media below the biomat. Research was conducted using eight one-dimensional (1D) sand columns with gravel-free and gravel-laden infiltrative surfaces. The columns were loaded at design rates of 100-200 cm/d for 20 weeks of column operation. The Ke values for these continuously loaded columns were determined from analyses of bromide-tracer tests, falling-head permeability tests, and volumetric water content measurements during biomat development. The reduction in the Ke due to biomat formation is due to two factors: reduced hydraulic conductivity of the thin biomat, and a reduced hydraulic conductivity of the subsoil due to development of a biomat-induced unsaturated flow regime. Unsaturated hydraulic conductivities of the subsoil below the biomat ( Kss) were estimated from capillary curves and water content measurements. For observed final biomat thicknesses (less than 1 cm), the biomat hydraulic conductivity, Kbm, is three orders of magnitude smaller than the unsaturated hydraulic conductivity ( Kss). However, the relatively large thickness of the vadose zone causes the Kss to be an important contributor to the overall Ke value. For these columns, the final Ke values were approximately two orders of magnitude smaller than the original value. Because the exact thickness of the biomat ( bbm) is unknown during the flow experiments, the hydraulic conductance of the biomat zone is presented using a normalized hydraulic conductivity function ( Kbm/ bbm). A similar Kbm/ bbm is reached regardless of wastewater

  12. Estimating the hydraulic conductivity of two-dimensional fracture networks

    Science.gov (United States)

    Leung, C. T.; Zimmerman, R. W.

    2010-12-01

    Most oil and gas reservoirs, as well as most potential sites for nuclear waste disposal, are naturally fractured. In these sites, the network of fractures will provide the main path for fluid to flow through the rock mass. In many cases, the fracture density is so high as to make it impractical to model it with a discrete fracture network (DFN) approach. For such rock masses, it would be useful to have recourse to analytical, or semi-analytical, methods to estimate the macroscopic hydraulic conductivity of the fracture network. We have investigated single-phase fluid flow through stochastically generated two-dimensional fracture networks. The centres and orientations of the fractures are uniformly distributed, whereas their lengths follow either a lognormal distribution or a power law distribution. We have considered the case where the fractures in the network each have the same aperture, as well as the case where the aperture of each fracture is directly proportional to the fracture length. The discrete fracture network flow and transport simulator NAPSAC, developed by Serco (Didcot, UK), is used to establish the “true” macroscopic hydraulic conductivity of the network. We then attempt to match this conductivity using a simple estimation method that does not require extensive computation. For our calculations, fracture networks are represented as networks composed of conducting segments (bonds) between nodes. Each bond represents the region of a single fracture between two adjacent intersections with other fractures. We assume that the bonds are arranged on a kagome lattice, with some fraction of the bonds randomly missing. The conductance of each bond is then replaced with some effective conductance, Ceff, which we take to be the arithmetic mean of the individual conductances, averaged over each bond, rather than over each fracture. This is in contrast to the usual approximation used in effective medium theories, wherein the geometric mean is used. Our

  13. Effective soil hydraulic conductivity predicted with the maximum power principle

    Science.gov (United States)

    Westhoff, Martijn; Erpicum, Sébastien; Archambeau, Pierre; Pirotton, Michel; Zehe, Erwin; Dewals, Benjamin

    2016-04-01

    Drainage of water in soils happens for a large extent through preferential flowpaths, but these subsurface flowpaths are extremely difficult to observe or parameterize in hydrological models. To potentially overcome this problem, thermodynamic optimality principles have been suggested to predict effective parametrization of these (sub-grid) structures, such as the maximum entropy production principle or the equivalent maximum power principle. These principles have been successfully applied to predict heat transfer from the Equator to the Poles, or turbulent heat fluxes between the surface and the atmosphere. In these examples, the effective flux adapts itself to its boundary condition by adapting its effective conductance through the creation of e.g. convection cells. However, flow through porous media, such as soils, can only quickly adapt its effective flow conductance by creation of preferential flowpaths, but it is unknown if this is guided by the aim to create maximum power. Here we show experimentally that this is indeed the case: In the lab, we created a hydrological analogue to the atmospheric model dealing with heat transport between Equator and poles. The experimental setup consists of two freely draining reservoirs connected with each other by a confined aquifer. By adding water to only one reservoir, a potential difference will build up until a steady state is reached. From the steady state potential difference and the observed flow through the aquifer, and effective hydraulic conductance can be determined. This observed conductance does correspond to the one maximizing power of the flux through the confined aquifer. Although this experiment is done in an idealized setting, it opens doors for better parameterizing hydrological models. Furthermore, it shows that hydraulic properties of soils are not static, but they change with changing boundary conditions. A potential limitation to the principle is that it only applies to steady state conditions

  14. Root hydraulic conductivity and adjustments in stomatal conductance: hydraulic strategy in response to salt stress in a halotolerant species.

    Science.gov (United States)

    Vitali, Victoria; Bellati, Jorge; Soto, Gabriela; Ayub, Nicolás D; Amodeo, Gabriela

    2015-11-24

    Recent advances at the molecular level are introducing a new scenario that needs to be integrated into the analysis of plant hydraulic properties. Although it is not yet clear to what extent this scenario alters the current proposal for the hydraulic circuit models, it introduces new insights when studying plants that are able to easily overcome water restrictions. In this context, our aim was to explore water adjustments in a halotolerant model (Beta vulgaris) by studying the coordination between the root in terms of root hydraulic conductivity (Lpr) and the shoot as reflected in the stomatal conductance (gs). The root water pathways were also analysed in terms of root suberization (apoplastic barrier) and aquaporin transcript levels (cell-to-cell pathway). Beta vulgaris showed the ability to rapidly lose (4 h) and gain (24 h) turgor when submitted to salt stress (200 mM). The reduction profile observed in Lpr and gs was consistent with a coupled process. The tuning of the root water flow involved small variations in the studied aquaporin's transcripts before anatomical modifications occurred. Exploring Lpr enhancement after halting the stress contributed to show not only a different profile in restoring Lpr but also the capacity to uncouple Lpr from gs. Beta vulgaris root plays a key role and can anticipate water loss before the aerial water status is affected.

  15. Hydraulic testing of low-permeability Silurian and Ordovician strata, Michigan Basin, southwestern Ontario

    Science.gov (United States)

    Beauheim, Richard L.; Roberts, Randall M.; Avis, John D.

    2014-02-01

    Straddle-packer hydraulic testing was performed in 31 Silurian intervals and 66 Ordovician intervals in six deep boreholes at the Bruce nuclear site, located near Tiverton, Ontario, as part of site-characterization activities for a proposed deep geologic repository (DGR) for low- and intermediate-level radioactive waste. The straddle-packer assembly incorporated a hydraulic piston to initiate in situ pulse tests within low hydraulic conductivity (condition and relative to the overlying Silurian strata and underlying Black River Group and Cambrian strata. These underpressures could not persist if hydraulic conductivities were not as low as those measured.

  16. Changes in entrapped gas content and hydraulic conductivity with pressure.

    Science.gov (United States)

    Marinas, Maricris; Roy, James W; Smith, James E

    2013-01-01

    Water table fluctuations continuously introduce entrapped air bubbles into the otherwise saturated capillary fringe and groundwater zone, which reduces the effective (quasi-saturated) hydraulic conductivity, K(quasi), thus impacting groundwater flow, aquifer recharge and solute and contaminant transport. These entrapped gases will be susceptible to compression or expansion with changes in water pressure, as would be expected with water table (and barometric pressure) fluctuations. Here we undertake laboratory experiments using sand-packed columns to quantify the effect of water table changes of up to 250 cm on the entrapped gas content and the quasi-saturated hydraulic conductivity, and discuss our ability to account for these mechanisms in ground water models. Initial entrapped air contents ranged between 0.080 and 0.158, with a corresponding K(quasi) ranging between 2 and 6 times lower compared to the K(s) value. The application of 250 cm of water pressure caused an 18% to 26% reduction in the entrapped air content, resulting in an increase in K(quasi) by 1.16 to 1.57 times compared to its initial (0 cm water pressure) value. The change in entrapped air content measured at pressure step intervals of 50 cm, was essentially linear, and could be modeled according to the ideal gas law. Meanwhile, the changes in K(quasi) with compression-expansion of the bubbles because of pressure changes could be adequately captured with several current hydraulic conductivity models. © Ground Water 2012 and © Her Majesty the Queen in Right of Canada 2012. Ground Water © 2012, National Ground Water Association.

  17. Simple Predictive Models for Saturated Hydraulic Conductivity of Technosands

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Razzaghi, Fatemeh; Møldrup, Per

    2012-01-01

    Accurate estimation of saturated hydraulic conductivity (Ks) of technosands (gravel-free, coarse sands with negligible organic matter content) is important for irrigation and drainage management of athletic fields and golf courses. In this study, we developed two simple models for predicting Ks......-connectivity parameter (m) obtained for pure coarse sand after fitting to measured Ks data was 1.68 for both models and in good agreement with m values obtained from recent solute and gas diffusion studies. Both the modified K-C and R-C models are easy to use and require limited parameter input, and both models gave...

  18. Effects of temperature and thermally-induced microstructure change on hydraulic conductivity of Boom Clay

    Directory of Open Access Journals (Sweden)

    W.Z. Chen

    2017-06-01

    Full Text Available Boom Clay is one of the potential host rocks for deep geological disposal of high-level radioactive nuclear waste in Belgium. In order to investigate the mechanism of hydraulic conductivity variation under complex thermo-mechanical coupling conditions and to better understand the thermo-hydro-mechanical (THM coupling behaviour of Boom Clay, a series of permeability tests using temperature-controlled triaxial cell has been carried out on the Boom Clay samples taken from Belgian underground research laboratory (URL HADES. Due to its sedimentary nature, Boom Clay presents across-anisotropy with respect to its sub-horizontal bedding plane. Direct measurements of the vertical (Kv and horizontal (Kh hydraulic conductivities show that the hydraulic conductivity at 80 °C is about 2.4 times larger than that at room temperature (23 °C, and the hydraulic conductivity variation with temperature is basically reversible during heating–cooling cycle. The anisotropic property of Boom Clay is studied by scanning electron microscope (SEM tests, which highlight the transversely isotropic characteristics of intact Boom Clay. It is shown that the sub-horizontal bedding feature accounts for the horizontal permeability higher than the vertical one. The measured increment in hydraulic conductivity with temperature is lower than the calculated one when merely considering the changes in water kinematic viscosity and density with temperature. The nuclear magnetic resonance (NMR tests have also been carried out to investigate the impact of microstructure variation on the THM properties of clay. The results show that heating under unconstrained boundary condition will produce larger size of pores and weaken the microstructure. The discrepancy between the hydraulic conductivity experimentally measured and predicted (considering water viscosity and density changes with temperature can be attributed to the microstructural weakening effect on the thermal volume change

  19. ENERGY EFFICIENCY OF DIESEL LOCOMOTIVE HYDRAULIC TRANSMISSION TESTS AT LOCOMOTIVE REPAIR PLANT

    Directory of Open Access Journals (Sweden)

    B. E. Bodnar

    2015-10-01

    Full Text Available Purpose. In difficult economic conditions, cost reduction of electricity consumption for the needs of production is an urgent task for the country’s industrial enterprises. Technical specifications of enterprises, which repair diesel locomotive hydraulic transmission, recommend conducting a certain amount of evaluation and regulatory tests to monitor their condition after repair. Experience shows that a significant portion of hydraulic transmission defects is revealed by bench tests. The advantages of bench tests include the ability to detect defects after repair, ease of maintenance of the hydraulic transmission and relatively low labour intensity for eliminating defects. The quality of these tests results in the transmission resource and its efficiency. Improvement of the technology of plant post-repairs hydraulic tests in order to reduce electricity consumption while testing. Methodology. The possible options for hydraulic transmission test bench improvement were analysed. There was proposed an energy efficiency method for diesel locomotive hydraulic transmission testing in locomotive repair plant environment. This is achieved by installing additional drive motor which receives power from the load generator. Findings. Based on the conducted analysis the necessity of improving the plant stand testing of hydraulic transmission was proved. The variants of the stand modernization were examined. The test stand modernization analysis was conducted. Originality. The possibility of using electric power load generator to power the stand electric drive motor or the additional drive motor was theoretically substantiated. Practical value. A variant of hydraulic transmission test stand based on the mutual load method was proposed. Using this method increases the hydraulic transmission load range and power consumption by stand remains unchanged. The additional drive motor will increase the speed of the input shaft that in its turn wil allow testing in

  20. Reduction of saltwater intrusion by modifying hydraulic conductivity

    Science.gov (United States)

    Strack, O. D. L.; Stoeckl, L.; Damm, K.; Houben, G.; Ausk, B. K.; de Lange, W. J.

    2016-09-01

    We present an approach for reducing saltwater intrusion in coastal aquifers by artificially reducing the hydraulic conductivity in the upper part of selected areas by using a precipitate. We apply a previously presented analytical approach to develop formulas useful for the design of artificial barriers. Equations for the location of the tip of the saltwater wedge are presented and verified through a sand-tank experiment. The analysis is capable of computing discharges exactly, but requires the Dupuit-Forchheimer approximation to compute points of the interface between flowing fresh and stationary saltwater. We consider a vertical coastline and boundaries in the freshwater zone of either given discharge or given head. We demonstrate in the paper that reduction of the hydraulic conductivity in the upper part of a coastal aquifer will result in a decrease of saltwater intrusion, and present analytic expressions that can be used for design purposes. The previously presented analytical approach can be applied to design systems to reduce saltwater intrusion caused by pumping inland from the zone that contains saline groundwater.

  1. Effects of the hydraulic conductivity microstructure on macrodispersivity

    Science.gov (United States)

    Di Dato, Mariaines; de Barros, Felipe P. J.; Fiori, Aldo; Bellin, Alberto

    2016-09-01

    Heterogeneity of the hydraulic properties is one of the main causes of the seemingly random distribution of solute concentration observed in contaminated aquifers, with macrodispersivity providing a global measure of spreading. Earlier studies on transport of solutes in heterogeneous formations, either theoretical or numerical, expressed dispersivity as a function of the geostatistical properties of the hydraulic conductivity K. In most cases, K follows a second-order statistical characterization, which may not be adequate when heterogeneity is high. In this work, we adopt the Multi-Indicator Model-Self Consistent Approach (MIMSCA) to compute the longitudinal and transverse macrodispersivity. This methodology enables to model the K field by using geological inclusions of different shapes and orientation (defined here as the microstructure), while replicating the heterogeneous macrostructure obtained by the second-order statistics. The above scheme attempts to reproduce the effect on macrodispersion of different distribution and orientation of local facies, and for instance it may represent the orientation and spatial features of the layers that are often observed in aquifers. The relevant impact of the microstructure on effective conductivity, longitudinal and transverse macrodispersivities is analyzed and discussed, for both binary and lognormally distributed K fields.

  2. Dentin permeability: effects of temperature on hydraulic conductance.

    Science.gov (United States)

    Pashley, D H; Thompson, S M; Stewart, F P

    1983-09-01

    The rates of fluid movement across dentin discs, in vitro, were measured at 10, 20, 30, 40, and 50 degrees C in unetched and acid-etched dentin. Increasing the temperature 40 degrees (i.e., from 10 to 50 degrees C) resulted in a 1.8-fold increase in fluid flow in unetched dentin, which was of a magnitude similar to the decrease in viscosity that occurred over the same temperature range. In acid-etched dentin, the 40 degrees C temperature change produced more than a four-fold increase in fluid conductance, more than double that which could be accounted for by changes in viscosity. Analysis of the data suggests that this additional increment in hydraulic conductance is due to thermal expansion-induced increases in tubular diameter.

  3. Effects Of Evaporation Rate of Some Common Organic Contaminants on Hydraulic Conductivity of Aquifer Sand

    Science.gov (United States)

    Saud, Q. J.; Hasan, S. E.

    2014-12-01

    As part of a larger study to investigate potential effects of hydrocarbons on the geotechnical properties of aquifer solids, a series of laboratory experiments were carried out to ascertain the influence of evaporation rate of some common and widespread organic contaminants on the hydraulic conductivity of aquifer sand. Gasoline and its constituent chemicals-benzene, toluene, ethylbenzene, xylene (BTEX), isooctane- and trichloroethylene (TCE) were used to contaminate sand samples collected from the aquifer and vadose zone, at varying concentrations for extended periods of time. The goal was to study any change in the chemical makeup of the contaminants and its control on hydraulic conductivity of the sand. It was found that: (a) gasoline breaks down into constituent compounds when subjected to evaporation, e.g. during oil spills and leaks; and (b) lighter compounds volatilize faster and in the following order: TCE> benzene > isooctane > toluene > gasoline> ethylbenzene > xylene. In addition, these contaminants also caused a decrease in hydraulic conductivity of sand by up to 60% as compared to the uncontaminated sand. The inherent differences in the chemical structure of contaminating chemicals influenced hydraulic conductivity such that the observed decrease was greater for aliphatic than aromatic and chlorinated hydrocarbons. The presentation includes details of the experimental set up; evaporation rate, and geotechnical tests; X-ray diffraction and scanning electron microscope studies; and data analyses and interpretation. Rate of evaporation test indicates that residual LNAPLs will occupy a certain portion of the pores in the soil either as liquid or vapor phase in the vadose zone, and will create a coating on the adjacent solid mineral grains in the aquifer. Replacement of air by the LNAPLs along with grain coatings and the intramolecular forces would impede groundwater movement, thus affecting overall permeability of contaminated aquifers. Keywords: aquifer

  4. Thermal Hydraulic Tests for Reactor Core Safety

    Energy Technology Data Exchange (ETDEWEB)

    Moon, S. K.; Baek, W. P.; Chun, S. Y. (and others)

    2007-06-15

    The main objectives of the present project are to resolve the current issues of reactor core thermal hydraulics, to develop an advanced measurement and analytical techniques, and to perform reactor core safety verification tests. 6x6 reflood experiments, various heat transfer experiments using Freon, and experiments on the spacer grids effects on the post-dryout are carried out using spacer grids developed in Korea in order to resolve the current issues of the reactor core thermal hydraulics. In order to develop a reflood heat transfer model, the detailed reflood phenomena are visualized and measured using round tube and 2x2 rod bundle. A detailed turbulent mixing phenomenon for subchannels is measured using advanced measurement techniques such as LDV and PIV. MARS and MATRA codes developed in Korea are assessed, verified and improved using the obtained experimental data. Finally, a systematic quality assurance program and experimental data generation system has been constructed in order to increase the reliability of the experimental data.

  5. Design of a laboratory hydraulic device for testing of hydraulic pumps

    Directory of Open Access Journals (Sweden)

    Pavel Máchal

    2013-01-01

    Full Text Available The present contribution deals with solves problem of research of testing device to monitor of hydrostatic pumps durability about dynamic loading under laboratory conditions. When carrying out the design of testing device are based on load characteristics of tractor hydraulic circuit, the individual characteristics of hydraulic components and performed calculations. Load characteristics on the tractors CASE IH Magnum 310, JOHN DEERE 8100, ZETOR FORTERRA 114 41 and Fendt 926 Vario were measured. Design of a hydraulic laboratory device is based on the need for testing new types of hydraulic pumps or various types of hydraulic fluids. When creating of hydraulic device we focused on testing hydraulic pumps used in agricultural and forestry tractors. Proportional pressure control valve is an active member of the hydraulic device, which provides change of a continuous control signal into relative pressure of operating fluid. The advantage of a designed hydraulic system is possibility of simulation of dynamic operating loading, which is obtained by measurement under real conditions, and thereby creates laboratory conditions as close to real conditions as possible. The laboratory device is constructed at the Department of Transport and Handling, Faculty of Engineering, Slovak University of Agriculture in Nitra.

  6. EVALUATION OF THE BENTONITE CONTENT IN SPENT FOUNDRY SANDS AS A FUNCTION OF HYDRAULIC CONDUCTIVITY COEFFICIENT

    Directory of Open Access Journals (Sweden)

    Schirlene Chegatti

    2013-06-01

    Full Text Available This study evaluates the relationship of the bentonite content and hydraulic conductivity coefficient (k of waste foundry sands in tests of hydraulic conductivity in a flexible wall permeameter. The test samples had concentrations of activated sodium bentonite and natural sodium bentonite between 4% and 15%. It was also analyzed chemically the liquid leachate (aluminum, barium, chromium, cadmium, lead, phenols, iron, fluoride, and manganese, following de standard tests of Standard Methods 3111 B e D for the determination of this components in liquid samples. The experiments were supplemented with cation exchange capacity analysis. The results indicate that the values of are is related to the content of bentonite in waste foundry sand and the percolation from this waste disposal.

  7. Research on hydraulic-powered roof supports test problems

    Institute of Scientific and Technical Information of China (English)

    SUN Hong-bo; JIANG Jin-qiu; MA Qiang

    2011-01-01

    The load-bearing characters of hydraulic-powered roof support with dual telescopic legs were analyzed. With a specific type hydraulic-powered roof support with dual telescopic legs for research object, the inside load test problems in factories was analyzed, and the correct test methods were given, which can enhance the test efficiency and make the factories away from the error design of hydraulic-powered roof supports and legs.

  8. Interstitial hydraulic conductivity and interstitial fluid pressure for avascular or poorly vascularized tumors.

    Science.gov (United States)

    Liu, L J; Schlesinger, M

    2015-09-07

    A correct description of the hydraulic conductivity is essential for determining the actual tumor interstitial fluid pressure (TIFP) distribution. Traditionally, it has been assumed that the hydraulic conductivities both in a tumor and normal tissue are constant, and that a tumor has a much larger interstitial hydraulic conductivity than normal tissue. The abrupt transition of the hydraulic conductivity at the tumor surface leads to non-physical results (the hydraulic conductivity and the slope of the TIFP are not continuous at tumor surface). For the sake of simplicity and the need to represent reality, we focus our analysis on avascular or poorly vascularized tumors, which have a necrosis that is mostly in the center and vascularization that is mostly on the periphery. We suggest that there is an intermediary region between the tumor surface and normal tissue. Through this region, the interstitium (including the structure and composition of solid components and interstitial fluid) transitions from tumor to normal tissue. This process also causes the hydraulic conductivity to do the same. We introduce a continuous variation of the hydraulic conductivity, and show that the interstitial hydraulic conductivity in the intermediary region should be monotonically increasing up to the value of hydraulic conductivity in the normal tissue in order for the model to correspond to the actual TIFP distribution. The value of the hydraulic conductivity at the tumor surface should be the lowest in value.

  9. Combining 3D Hydraulic Tomography with Tracer Tests for Improved Transport Characterization.

    Science.gov (United States)

    Sanchez-León, E; Leven, C; Haslauer, C P; Cirpka, O A

    2016-07-01

    Hydraulic tomography (HT) is a method for resolving the spatial distribution of hydraulic parameters to some extent, but many details important for solute transport usually remain unresolved. We present a methodology to improve solute transport predictions by combining data from HT with the breakthrough curve (BTC) of a single forced-gradient tracer test. We estimated the three dimensional (3D) hydraulic-conductivity field in an alluvial aquifer by inverting tomographic pumping tests performed at the Hydrogeological Research Site Lauswiesen close to Tübingen, Germany, using a regularized pilot-point method. We compared the estimated parameter field to available profiles of hydraulic-conductivity variations from direct-push injection logging (DPIL), and validated the hydraulic-conductivity field with hydraulic-head measurements of tests not used in the inversion. After validation, spatially uniform parameters for dual-domain transport were estimated by fitting tracer data collected during a forced-gradient tracer test. The dual-domain assumption was used to parameterize effects of the unresolved heterogeneity of the aquifer and deemed necessary to fit the shape of the BTC using reasonable parameter values. The estimated hydraulic-conductivity field and transport parameters were subsequently used to successfully predict a second independent tracer test. Our work provides an efficient and practical approach to predict solute transport in heterogeneous aquifers without performing elaborate field tracer tests with a tomographic layout.

  10. Test program element II blanket and shield thermal-hydraulic and thermomechanical testing, experimental facility survey

    Energy Technology Data Exchange (ETDEWEB)

    Ware, A.G.; Longhurst, G.R.

    1981-12-01

    This report presents results of a survey conducted by EG and G Idaho to determine facilities available to conduct thermal-hydraulic and thermomechanical testing for the Department of Energy Office of Fusion Energy First Wall/Blanket/Shield Engineering Test Program. In response to EG and G queries, twelve organizations (in addition to EG and G and General Atomic) expressed interest in providing experimental facilities. A variety of methods of supplying heat is available.

  11. Predicting saturated hydraulic conductivity using soil morphological properties

    Directory of Open Access Journals (Sweden)

    Gülay Karahan

    2016-01-01

    Full Text Available Many studies have been conducted to predict soil saturated hydraulic conductivity (Ks by parametric soil properties such as bulk density and particle-size distribution. Although soil morphological properties have a strong effect on Ks, studies predicting Ks by soil morphological properties such as type, size, and strength of soil structure; type, orientation and quantity of soil pores and roots and consistency are rare. This study aimed at evaluating soil morphological properties to predict Ks. Undisturbed soil samples (15 cm length and 8.0 cm id. were collected from topsoil (0-15 cm and subsoil (15-30 cm (120 samples with a tractor operated soil sampler at sixty randomly selected sampling sites on a paddy field and an adjecent grassland in Central Anatolia (Cankırı, Turkey. Synchronized disturbed soil samples were taken from the same sampling sites and sampling depths for basic soil analyses. Saturated hydraulic conductivity was measured on the soil columns using a constant-head permeameter. Following the Ks measurements, the upper part of soil columns were covered to prevent evaporation and colums were left to drain in the laboratory. When the water flow through the column was stopped, a subsample were taken for bulk density and then soil columns were disturbed for describing the soil morphological properties. In addition, soil texture, bulk density, pH, field capacity, wilting point, cation exchange capacity, specific surface area, aggregate stability, organic matter, and calcium carbonate were measured on the synchronized disturbed soil samples. The data were divided into training (80 data values and validation (40 data values sets. Measured values of Ks ranged from 0.0036 to 2.14 cmh-1 with a mean of 0.86 cmh-1. The Ks was predicted from the soil morphological and parametric properties by stepwise multiple linear regression analysis. Soil structure class, stickiness, pore-size, root-size, and pore-quantity contributed to the Ks prediction

  12. Hydraulic conductance and water potential gradients in squash leaves showing mycorrhiza-induced increases in stomatal conductance.

    Science.gov (United States)

    Augé, Robert M; Toler, Heather D; Sams, Carl E; Nasim, Ghazala

    2008-03-01

    Stomatal conductance (gs) and transpiration rates vary widely across plant species. Leaf hydraulic conductance (k leaf) tends to change with g (s), to maintain hydraulic homeostasis and prevent wide and potentially harmful fluctuations in transpiration-induced water potential gradients across the leaf (Delta Psi leaf). Because arbuscular mycorrhizal (AM) symbiosis often increases gs in the plant host, we tested whether the symbiosis affects leaf hydraulic homeostasis. Specifically, we tested whether k leaf changes with gs to maintain Delta Psi leaf or whether Delta Psi leaf differs when gs differs in AM and non-AM plants. Colonization of squash plants with Glomus intraradices resulted in increased gs relative to non-AM controls, by an average of 27% under amply watered, unstressed conditions. Stomatal conductance was similar in AM and non-AM plants with exposure to NaCl stress. Across all AM and NaCl treatments, k leaf did change in synchrony with gs (positive correlation of gs and k leaf), corroborating leaf tendency toward hydraulic homeostasis under varying rates of transpirational water loss. However, k leaf did not increase in AM plants to compensate for the higher gs of unstressed AM plants relative to non-AM plants. Consequently, Delta Psi leaf did tend to be higher in AM leaves. A trend toward slightly higher Delta Psi leaf has been observed recently in more highly evolved plant taxa having higher productivity. Higher Delta Psi leaf in leaves of mycorrhizal plants would therefore be consistent with the higher rates of gas exchange that often accompany mycorrhizal symbiosis and that are presumed to be necessary to supply the carbon needs of the fungal symbiont.

  13. Effects of distance from the pulp and thickness on the hydraulic conductance of human radicular dentin.

    Science.gov (United States)

    Fogel, H M; Marshall, F J; Pashley, D H

    1988-11-01

    The purposes of this study were: (1) to measure the effect of distance from the pulp on the hydraulic conductance of human radicular dentin; (2) to determine the influence of dentin thickness on the rates of fluid flow; and (3) to attempt to correlate dentinal tubule densities and diameters with root dentin hydraulic conductance. Dentin slabs prepared from extracted, unerupted, human third molar teeth were placed in a split-chamber device to permit quantitation of fluid filtration rate (hydraulic conductance). In the SEM portion of the study, dentinal tubule numbers and diameters were recorded. The results indicated that radicular dentin hydraulic conductance decreased with distance from the pulp and with increasing dentin thickness. Tubule density and diameter correlated well with the measured hydraulic conductances. The relatively low hydraulic conductance of outer root dentin makes it a significant barrier to fluid movement across root structure.

  14. Polyacrylamide effect on hydraulic conductivity of hardsetting soils in Northeast of Brazil

    Science.gov (United States)

    Silva, Laércio; Almeida, Brivaldo; Melo, Diego; Marques, Karina; Almeida, Ceres

    2013-04-01

    Among soil hydro-physical properties, hydraulic conductivity is more sensitive to changes in soil structure. Hydraulic conductivity describes the ease with which a fluid (usually water) can move through pore spaces or fractures. It depends on the intrinsic permeability of the material and on the degree of saturation, and on the density and viscosity of the fluid. Hardsetting soils present very low hydraulic conductivity values. When dry, these soils show high penetration resistance and consistency extremely hard, but change to friable when moist. In this condition are poorly structured, slaking when moist, limit agricultural machinery use and it may reduce the growth of the root system. In Brazil, these soils occur throughout of coastal zone in flat areas called "coastal tableland". Chemical ameliorant, such as polymers based on anionic polyacrylamide (PAM), improve hydraulic conductivity of soil in hardsetting soils. The primary functions of polyacrylamide soil conditioners are to increase soil tilth, aeration, and porosity and reduce compaction and water run-off. PAM effect is attributed to its ability to expand when placed in water, storing it in soil pore space, releasing it gradually to the plants. This process occurs by reducing the water flow through the pores of the soil, due to water molecules can be absorbed by PAM, providing water gradually. Thus, this study tested the hypothesis that PAM reduces the soil hardsetting character. The area is located in coastal zone in Goiana city, Pernambuco, northeastern of Brazil. This soil is typical hardsetting soil. Intact soil cores were collected from four horizons until 70cm depth. In the laboratory, the soil cores were saturated with different PAM concentrations (0.01, 0.005, 0.00125%) and H2O (control). Saturated hydraulic conductivity (Ksat) was determined using a constant head method, according to Klute and Dirksen (1986). Four replicates were used for each horizon and Tukey test at 5% probability was used by

  15. Beneficial impact of polymer treatment of Ca-bentonites on long term hydraulic conductivity

    OpenAIRE

    Di Emidio, Gemmina; De Camillis, Michela; Bezuijen, Adam; Verastegui Flores, R.D.

    2014-01-01

    The hydraulic conductivity of geosynthetic clay liners for the confinement of waste disposal facilities mainly depends on the hydraulic conductivity of the core bentonite clay encased between the two geotextiles. Bentonite clay is the most common material for geosynthetic clay liners. Even thought, sodium bentonite has the lowest hydraulic conductivity to water, calcium bentonite is widely used because of low cost and availability. This research concerns the evaluation of the treatment of cal...

  16. Sand box experiments with bioclogging of porous media: Hydraulic conductivity reductions

    DEFF Research Database (Denmark)

    Seifert, Dorte; Engesgaard, Peter

    2012-01-01

    Tracer experiments during clogging and de-clogging experiments in a 2D sand box were via an image analysis used to establish a data set on the relation between changes in hydraulic conductivity (K) and relative porosity (β). Clogging appears to create a finger-like tracer transport, which could...... and closer to the substrate source during the experiments suggesting that the zone of clogging moved upstream. Three clogging models, K(β), from the literature were tested for their ability to describe the temporal changes in clogging at the scale of the sand box; the model of Clement et al. (1996......) that makes no assumption on biomass distribution, the plug formation model of Thullner et al. (2002a), and the biofilm-plug formation model of Vandevivere (1995). The plug formation and biofilm-plug formation models both match the observed changes between the hydraulic conductivity of the sand box...

  17. Determining the unsaturated hydraulic conductivity of a compacted sand-bentonite mixture under constant volume and free-swell conditions

    CERN Document Server

    Cui, Yu-Jun; Loiseau, Cyril; Delage, Pierre; 10.1016/j.pce.2008.10.017

    2008-01-01

    Highly compacted sand-bentonite mixtures are often considered as possible engineered barriers in deep high-level radioactive waste disposals. In-situ, the saturation of these barriers from their initially unsaturated state is a complex hydro-mechanical coupled process in which temperature effects also play a role. The key parameter of this process is the unsaturated hydraulic conductivity of the barrier. In this paper, isothermal infiltration experiments were conducted to determine the unsaturated hydraulic conductivity according to the instantaneous profile method. To do so, total suction changes were monitored at different locations along the soil specimen by using resistivity relative humidity probes. Three constant volume infiltration tests were conducted showing, unexpectedly, a decrease of the hydraulic conductivity during infiltration. One test performed under free-swell conditions showed the opposite and standard trend. These observations were interpreted in terms of microstructure changes during wett...

  18. Investigating the relationship between unsaturated hydraulic conductivity curve and confined compression curve

    Science.gov (United States)

    Bayat, Hossein; Sedaghat, Azadeh; Safari Sinegani, Ali Akbar; Gregory, Andrew S.

    2015-03-01

    This study was conducted to estimate the soil unsaturated hydraulic conductivity through the van Genuchten model using easy to measure soil properties by regression and artificial neural networks methods. In this study, 148 soil samples were taken from five provinces of Iran. Basic soil properties (clay, silt/sand and bulk density) and other soil properties were measured. Soil water retention curve was measured to obtain the unsaturated hydraulic conductivity curve using the van Genuchten-Mualem model. Confined compression curve was measured and the modified model of van Genuchten was fitted on its data. Two-thirds and one-third of the data were used for the training and testing steps, respectively. Confined compression curve parameters and other soil properties were used as predictors to estimate unsaturated hydraulic conductivity curve. Pedotransfer functions (PTFs) were developed in two separate parts: in 5 and 6 PTFs basic soil properties were or were not used as predictors, respectively. The artificial neural networks (ANNs) performed better than the regression methods. Among the ANN-developed PTFs which have not used basic soil properties as predictors, PTFa3, with the inputs of the parameters of confined compression curve (n∗, α∗ and e0), performed better than the others. Also, among the ANN-developed PTFs that used basic soil properties as predictors along with the other input variables, PTFb5 that used the σmc (stress at the maximum curvature) and σi (stress at the inflection point) as inputs along with basic soil properties, performed better than the other PTFs. The results showed a successful prediction of the hydraulic conductivity curve using confined compression curve.

  19. Flowing fluid electrical conductivity logging of a deep borehole during and following drilling: estimation of transmissivity, water salinity and hydraulic head of conductive zones

    Science.gov (United States)

    Doughty, Christine; Tsang, Chin-Fu; Rosberg, Jan-Erik; Juhlin, Christopher; Dobson, Patrick F.; Birkholzer, Jens T.

    2016-11-01

    Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Åre, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them.

  20. Flowing fluid electrical conductivity logging of a deep borehole during and following drilling: estimation of transmissivity, water salinity and hydraulic head of conductive zones

    Science.gov (United States)

    Doughty, Christine; Tsang, Chin-Fu; Rosberg, Jan-Erik; Juhlin, Christopher; Dobson, Patrick F.; Birkholzer, Jens T.

    2017-03-01

    Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Åre, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them.

  1. Borehole Heat Exchanger Systems: Hydraulic Conductivity and Frost-Resistance of Backfill Materials

    Science.gov (United States)

    Anbergen, Hauke; Sass, Ingo

    2016-04-01

    Ground source heat pump (GSHP) systems are economic solutions for both, domestic heating energy supply, as well as underground thermal energy storage (UTES). Over the past decades the technology developed to complex, advanced and highly efficient systems. For an efficient operation of the most common type of UTES, borehole heat exchanger (BHE) systems, it is necessary to design the system for a wide range of carrier fluid temperatures. During heat extraction, a cooled carrier fluid is heated up by geothermal energy. This collected thermal energy is energetically used by the heat pump. Thereby the carrier fluid temperature must have a lower temperature than the surrounding underground in order to collect heat energy. The steeper the thermal gradient, the more energy is transferred to the carrier fluid. The heat injection case works vice versa. For fast and sufficient heat extraction, even over long periods of heating (winter), it might become necessary to run the BHE with fluid temperatures below 0°C. As the heat pump runs periodically, a cyclic freezing of the pore water and corresponding ice-lens growth in the nearfield of the BHE pipes becomes possible. These so called freeze-thaw-cycles (FTC) are a critical state for the backfill material, as the sealing effect eventually decreases. From a hydrogeological point of view the vertical sealing of the BHE needs to be secured at any time (e.g. VDI 4640-2, Draft 2015). The vertical hydraulic conductivity of the BHE is influenced not only by the permeability of the grouting material itself, but by the contact area between BHE pipes and grout. In order to assess the sealing capacity of grouting materials a laboratory testing procedure was developed that measures the vertical hydraulic conductivity of the system BHE pipe and grout. The key features of the procedure are: • assessment of the systeḿs hydraulic conductivity • assessment of the systeḿs hydraulic conductivity after simulation of freeze-thaw-cycle

  2. Estimation of hydraulic conductivity of a coastal aquifer using satellite imagery

    Science.gov (United States)

    Rebolledo-Vieyra, M.; Iglesias-Prieto, R.; Marino-Tapia, I.

    2012-12-01

    The northern Yucatan Peninsula is characterized by a young and dynamic karstic system that yields very high secondary porosity and permeability. However, we have little, if none, knowledge about the hydraulic conductivity and the amount of groundwater being discharged in to ocean. Here we present and estimation of the hydraulic conductivity and quantity of groundwater being discharged by the northern Yucatan Peninsula coastal aquifer into the Gulf of Mexico, using the Sea Surface Temperature (SST) Images offshore the Yucatan coast, where we have detected a thermal anomaly that appears few hours after heavy rainfall in northern Yucatan. We associated these thermal anomalies of the SST to the groundwater being discharged into the ocean. To test our hypothesis we conducted a review of extreme rainfall events in the last 10 years; in parallel we used data from pressure and flow direction gauges installed in a known submarine groundwater discharge (SGD) to estimate the hydraulic conductivity and the quantity of groundwater being discharged. The satellite imagery and the rainfall data, allowed us to estimate the time lag between the rainfall and the SGD beginning, along with the hydraulic data from the gauges we have estimated the hydrogeological parameters of the coastal aquifer. This data is very important to contribute to the understanding the hydrogeological setting of the Yucatan coastal aquifer and its implications of the impact of human activities on the water quality. July 29th, 2005, NOAA's Sea Surface Temperature (SST) image of the Gulf of Mexico taken a week after hurricane Emily (2005). A thermal low is present offshore northern Yucatan.

  3. Transport of heavy metals and chemical compatibility of hydraulic conductivity of a compacted sand-bentonite mixture

    Directory of Open Access Journals (Sweden)

    Nanthanit Charoenthaisong

    2008-03-01

    Full Text Available Clayey soils are usually used as barrier material in landfill liners because of its low hydraulic conductivity and high sorption capacity. Bentonite, which consists mainly of montmorillonite, has a high cation exchange capacity resulting in a high retention capacity of heavy metals. Sand is a permeable material but its hydraulic conductivity decreases significantly when mixed with bentonite. However, using a sand-bentonite mixture as landfill liners is questionable, because the hydraulic conductivity of the sand-bentonite mixture may increase when permeated with heavy metal solutions, which are normally found in landfill leachates. In this paper, transport of heavy metals through a compacted sand-bentonite mixture and its chemical compatibility were studied through the batch adsorption test, the column test, and the hydraulic conductivity test.Experimental results indicate that the sorption capacity of the bentonite, ranked in descending order, was Cr3+, Pb2+, Cd2+, Zn2+, and Ni2+, respectively. The diffusion coefficients of the sand-bentonite mixture were in the order of 10-5 cm2/s and the retardation factors were 130, 115, 111, and 90 for Pb2+, Ni2+, Zn2+, and Cd2+, respectively. The hydraulic conductivity of thesand-bentonite mixture was only compatible with a chromium solution having a concentration not greater than 0.001 M.

  4. Hydraulic conductance of Acacia phyllodes (foliage) is driven by primary nerve (vein) conductance and density.

    Science.gov (United States)

    Sommerville, Katy E; Sack, Lawren; Ball, Marilyn C

    2012-01-01

    We determined effects of venation traits on hydraulic conductance of phyllodes (foliage), using an array of Acacia s.str. species with diverse phyllode morphologies as the source of variation. Measurements were made on phyllodes from 44 species, grown in common gardens but originating from different positions along a precipitation gradient. K(phyllode) varied 18-fold and was positively correlated with primary nerve hydraulic conductance, and with primary nerve (vein) density but not with minor nerve density, in contrast with previous studies of true leaves in other dicotyledons. Phyllodes with higher primary nerve density also had greater mass per area (PMA) and larger bundle sheath extensions (BSEs) from their minor nerves. We suggest that higher primary nerve conductivity and density may decrease the distance travelled in the high-resistance extra-xylem pathways of the phyllode. Further, larger BSEs may increase the area available for dispersion of water from the xylem to the extra-xylem tissue. High PMA phyllodes were more common in acacias from areas receiving lower annual precipitation. Maximizing efficient water movement through phyllodes may be more important where rainfall is meagre and infrequent, explaining relationships between nerve patterns and the climates of origin in Australian phyllodinous Acacia.

  5. Hydraulics.

    Science.gov (United States)

    Decker, Robert L.; Kirby, Klane

    This curriculum guide contains a course in hydraulics to train entry-level workers for automotive mechanics and other fields that utilize hydraulics. The module contains 14 instructional units that cover the following topics: (1) introduction to hydraulics; (2) fundamentals of hydraulics; (3) reservoirs; (4) lines, fittings, and couplers; (5)…

  6. MEASURING VERTICAL PROFILES OF HYDRAULIC CONDUCTIVITY WITH IN SITU DIRECT-PUSH METHODS

    Science.gov (United States)

    U.S. EPA (Environmental Protection Agency) staff developed a field procedure to measure hydraulic conductivity using a direct-push system to obtain vertical profiles of hydraulic conductivity. Vertical profiles were obtained using an in situ field device-composed of a Geopr...

  7. New empirical relationship between grain size distribution and hydraulic conductivity for ephemeral streambed sediments

    KAUST Repository

    Rosas, Jorge

    2014-07-19

    Grain size distribution, porosity, and hydraulic conductivity were determined for 39 sediment samples collected from ephemeral streams (wadis) in western Saudi Arabia. The measured hydraulic conductivity values were then compared to values calculated using 20 different empirical equations commonly used to estimate hydraulic conductivity from grain size analyses. It was found that most of the hydraulic conductivity values estimated from the empirical equations correlated very poorly with the measured hydraulic conductivity values. Modifications of the empirical equations, including changes to special coefficients and statistical offsets, were made to produce modified equations that considerably improved the hydraulic conductivity estimates from grain size data for wadi sediments. The Chapuis, Hazen, Kozeny, Slichter, Terzaghi, and Barr equations produced the best correlations, but still had relatively high predictive errors. The Chapius equation was modified for wadi sediments by incorporating mud percentage and the standard deviation (in phi units) into a new equation that reduced the predicted hydraulic conductivity error to ±14.1 m/day. The equation is best applied to ephemeral stream samples that have hydraulic conductive values greater than 2 m/day.

  8. Saturated hydraulic conductivity and porosity within macroaggregates modified by tillage

    Energy Technology Data Exchange (ETDEWEB)

    Park, E.J.; Smucker, A.J.M. (MSU)

    2010-07-20

    Greater knowledge of intraaggregate porosity modifications by tillage conveys new information for identifying additional hydrologic, ion retention, and aggregate stability responses to specific management practices. Macroaggregates, 2 to 4, 4 to 6.3, and 6.3 to 9.5 mm across, were separated into multiple concentric layers and their porosities were determined. Saturated hydraulic conductivity (K{sub s}) of multiple aggregate fractions from two soil types subjected to conventional tillage (CT), no tillage (NT), and native forest (NF) soils were measured individually to identify the effects of tillage on aggregate structure, porosity, and K{sub s}. Intraaggregate porosities were the highest in NF aggregates. Greater porosities were identified in exterior layers of soil aggregates from all treatments. Lowest intraaggregate porosities were observed in the central regions of CT aggregates. Soil aggregates, 6.3 to 9.5 mm across, had the greatest total porosities, averaging 37.5% for both soil types. Long-term CT reduced intraaggregate porosities and K, within macroaggregates, of the same size fraction, from both the Hoytville silty clay loam and Wooster silt loam soil types. Values for K, of NF aggregates, 5.0 x 10{sup -5} cm s{sup -1}, were reduced 50-fold by long-term CT treatments of the Hoytville series. The K, values through Wooster aggregates from NF, 16.0 x 10{sup -5} cm s{sup -1}, were reduced 80-fold by long-term CT treatments. The K{sub s} values through NF and NT aggregates were positively correlated with their intraaggregate porosities (R{sup 2} = 0.84 for NF and R{sup 2} = 0.45 for NT at P < 0.005). Additional studies are needed to identify rates at which pore geometries within macroaggregates are degraded by CT or improved by NT.

  9. Leaf hydraulic conductance for a tank bromeliad: axial and radial pathways for moving and conserving water.

    Science.gov (United States)

    North, Gretchen B; Lynch, Frank H; Maharaj, Franklin D R; Phillips, Carly A; Woodside, Walter T

    2013-01-01

    Epiphytic plants in the Bromeliaceae known as tank bromeliads essentially lack stems and absorptive roots and instead take up water from reservoirs formed by their overlapping leaf bases. For such plants, leaf hydraulic conductance is plant hydraulic conductance. Their simple strap-shaped leaves and parallel venation make them suitable for modeling leaf hydraulic conductance based on vasculature and other anatomical and morphological traits. Plants of the tank bromeliad Guzmania lingulata were investigated in a lowland tropical forest in Costa Rica and a shaded glasshouse in Los Angeles, CA, USA. Stomatal conductance to water vapor and leaf anatomical variables related to hydraulic conductance were measured for both groups. Tracheid diameters and numbers of vascular bundles (veins) were used with the Hagen-Poiseuille equation to calculate axial hydraulic conductance. Measurements of leaf hydraulic conductance using the evaporative flux method were also made for glasshouse plants. Values for axial conductance and leaf hydraulic conductance were used in a model based on leaky cable theory to estimate the conductance of the radial pathway from the vein to the leaf surface and to assess the relative contributions of both axial and radial pathways. In keeping with low stomatal conductance, low stomatal density, low vein density, and narrow tracheid diameters, leaf hydraulic conductance for G. lingulata was quite low in comparison with most other angiosperms. Using the predicted axial conductance in the leaky cable model, the radial resistance across the leaf mesophyll was predicted to predominate; lower, more realistic values of axial conductance resulted in predicted radial resistances that were closer to axial resistance in their impact on total leaf resistance. Tracer dyes suggested that water uptake through the tank region of the leaf was not limiting. Both dye movement and the leaky cable model indicated that the leaf blade of G. lingulata was structurally and

  10. IN-SERVICE HYDRAULIC CONDUCTIVITY OF GCLS IN LANDFILL COVERS - LABORATORY AND FIELD STUDIES

    Science.gov (United States)

    Laboratory experiments using multi-species inorganic solutions (containing calcium and sodium) were conducted on specimens of a new geosynthetic clay liner (GCL) containing sodium bentonite to determine how cation exchange and desiccation affected the hydraulic conductivity. Calc...

  11. Determination of Material Strengths by Hydraulic Bulge Test

    Directory of Open Access Journals (Sweden)

    Hankui Wang

    2016-12-01

    Full Text Available The hydraulic bulge test (HBT method is proposed to determine material tensile strengths. The basic idea of HBT is similar to the small punch test (SPT, but inspired by the manufacturing process of rupture discs—high-pressure hydraulic oil is used instead of punch to cause specimen deformation. Compared with SPT method, the HBT method can avoid some of influence factors, such as punch dimension, punch material, and the friction between punch and specimen. A calculation procedure that is entirely based on theoretical derivation is proposed for estimate yield strength and ultimate tensile strength. Both conventional tensile tests and hydraulic bulge tests were carried out for several ferrous alloys, and the results showed that hydraulic bulge test results are reliable and accurate.

  12. Determination of Material Strengths by Hydraulic Bulge Test.

    Science.gov (United States)

    Wang, Hankui; Xu, Tong; Shou, Binan

    2016-12-30

    The hydraulic bulge test (HBT) method is proposed to determine material tensile strengths. The basic idea of HBT is similar to the small punch test (SPT), but inspired by the manufacturing process of rupture discs-high-pressure hydraulic oil is used instead of punch to cause specimen deformation. Compared with SPT method, the HBT method can avoid some of influence factors, such as punch dimension, punch material, and the friction between punch and specimen. A calculation procedure that is entirely based on theoretical derivation is proposed for estimate yield strength and ultimate tensile strength. Both conventional tensile tests and hydraulic bulge tests were carried out for several ferrous alloys, and the results showed that hydraulic bulge test results are reliable and accurate.

  13. MEASUREMENT OF HYDRAULIC CONDUCTIVITY DISTRIBUTIONS: A MANUAL OF PRACTICE

    Science.gov (United States)

    The ability of hydrologists to perform field measurements of aquifer hydraulic properties must be enhanced in order to significantly improve the capacity to solve groundwater contamination problems at Superfund and other sites. The primary purpose of this manual is to provide ne...

  14. Near-saturated hydraulic conductivity: database development, meta-analysis and pedotransfer functions

    Science.gov (United States)

    Jarvis, Nicholas; Koestel, John; Messing, Ingmar; Lindahl, Anna

    2013-04-01

    Near-saturated hydraulic conductivity exerts a critical control on water flow and solute transport through the vadose zone, yet very little is known concerning how it is influenced by various soil properties and site factors and attributes. Starting from the 1980's, tension infiltrometers or disc permeameters have become an increasingly popular method to measure near-saturated hydraulic conductivity in undisturbed soil. In this presentation, we describe the development and organization of a large database of tension infiltrometer measurements (n>700) collated from the published literature. The raw datasets were standardized and summarized using a modified Kozeny-Carman model of near-saturated hydraulic conductivity (Jarvis, N.J. 2008. Near-saturated hydraulic properties of macroporous soils. Vadose Zone Journal, 7, 1302-1310). This model was found to accurately describe near-saturated conductivity for this large dataset (92% of cases had R2 values larger than 0.9). We will show the results of some initial analyses of the dataset, which show how hydraulic conductivity at pressure heads of -1 and -10 cm, as well as the slope of the near-saturated conductivity function, are affected by: i.) the choice of method to convert unconfined 3D infiltration to hydraulic conductivity, and ii.) interactions between soil properties such as texture and bulk density and site attributes such as land use and climate. We will also present some initial attempts to develop pedotransfer functions for parameters describing near-saturated hydraulic conductivity using the technique of random forests.

  15. Improved estimation of hydraulic conductivity by combining stochastically simulated hydrofacies with geophysical data.

    Science.gov (United States)

    Zhu, Lin; Gong, Huili; Chen, Yun; Li, Xiaojuan; Chang, Xiang; Cui, Yijiao

    2016-03-01

    Hydraulic conductivity is a major parameter affecting the output accuracy of groundwater flow and transport models. The most commonly used semi-empirical formula for estimating conductivity is Kozeny-Carman equation. However, this method alone does not work well with heterogeneous strata. Two important parameters, grain size and porosity, often show spatial variations at different scales. This study proposes a method for estimating conductivity distributions by combining a stochastic hydrofacies model with geophysical methods. The Markov chain model with transition probability matrix was adopted to re-construct structures of hydrofacies for deriving spatial deposit information. The geophysical and hydro-chemical data were used to estimate the porosity distribution through the Archie's law. Results show that the stochastic simulated hydrofacies model reflects the sedimentary features with an average model accuracy of 78% in comparison with borehole log data in the Chaobai alluvial fan. The estimated conductivity is reasonable and of the same order of magnitude of the outcomes of the pumping tests. The conductivity distribution is consistent with the sedimentary distributions. This study provides more reliable spatial distributions of the hydraulic parameters for further numerical modeling.

  16. The influence of topology on hydraulic conductivity in a sand-and-gravel aquifer

    Science.gov (United States)

    Morin, R.H.; LeBlanc, D.R.; Troutman, B.M.

    2010-01-01

    A field experiment consisting of geophysical logging and tracer testing was conducted in a single well that penetrated a sand-and-gravel aquifer at the U.S. Geological Survey Toxic Substances Hydrology research site on Cape Cod, Massachusetts. Geophysical logs and flowmeter/pumping measurements were obtained to estimate vertical profiles of porosity ??, hydraulic conductivity K, temperature, and bulk electrical conductivity under background, freshwater conditions. Saline-tracer fluid was then injected into the well for 2 h and its radial migration into the surrounding deposits was monitored by recording an electromagnetic-induction log every 10 min. The field data are analyzed and interpreted primarily through the use of Archie's (1942) law to investigate the role of topological factors such as pore geometry and connectivity, and grain size and packing configuration in regulating fluid flow through these coarse-grained materials. The logs reveal no significant correlation between K and ??, and imply that groundwater models that link these two properties may not be useful at this site. Rather, it is the distribution and connectivity of the fluid phase as defined by formation factor F, cementation index m, and tortuosity ?? that primarily control the hydraulic conductivity. Results show that F correlates well with K, thereby indicating that induction logs provide qualitative information on the distribution of hydraulic conductivity. A comparison of ??, which incorporates porosity data, with K produces only a slightly better correlation and further emphasizes the weak influence of the bulk value of ?? on K. Copyright ?? 2009 The Author(s) are Federal Government Employees. Journal compilation ?? 2009 National Ground Water Association.

  17. A Self-Consistent Approach for Calculating the Effective Hydraulic Conductivity of a Bimodal, Heterogeneous Medium

    Energy Technology Data Exchange (ETDEWEB)

    Pozdniakov, Sergey; Tsang, Chin-Fu

    2004-01-02

    In this paper, we consider an approach for estimating the effective hydraulic conductivity of a 3D medium with a binary distribution of local hydraulic conductivities. The medium heterogeneity is represented by a combination of matrix medium conductivity with spatially distributed sets of inclusions. Estimation of effective conductivity is based on a self-consistent approach introduced by Shvidler (1985). The tensor of effective hydraulic conductivity is calculated numerically by using a simple system of equations for the main diagonal elements. Verification of the method is done by comparison with theoretical results for special cases and numerical results of Desbarats (1987) and our own numerical modeling. The method was applied to estimating the effective hydraulic conductivity of a 2D and 3D fractured porous medium. The medium heterogeneity is represented by a combination of matrix conductivity and a spatially distributed set of highly conductive fractures. The tensor of effective hydraulic conductivity is calculated for parallel- and random-oriented sets of fractures. The obtained effective conductivity values coincide with Romm's (1966) and Snow's (1969) theories for infinite fracture length. These values are also physically acceptable for the sparsely-fractured-medium case with low fracture spatial density and finite fracture length. Verification of the effective hydraulic conductivity obtained for a fractured porous medium is done by comparison with our own numerical modeling for a 3D case and with Malkovsky and Pek's (1995) results for a 2D case.

  18. Determination of hydraulic conductivity from grain-size distribution for different depositional environments.

    Science.gov (United States)

    Rosas, Jorge; Lopez, Oliver; Missimer, Thomas M; Coulibaly, Kapo M; Dehwah, Abdullah H A; Sesler, Kathryn; Lujan, Luis R; Mantilla, David

    2014-01-01

    Over 400 unlithified sediment samples were collected from four different depositional environments in global locations and the grain-size distribution, porosity, and hydraulic conductivity were measured using standard methods. The measured hydraulic conductivity values were then compared to values calculated using 20 different empirical equations (e.g., Hazen, Carman-Kozeny) commonly used to estimate hydraulic conductivity from grain-size distribution. It was found that most of the hydraulic conductivity values estimated from the empirical equations correlated very poorly to the measured hydraulic conductivity values with errors ranging to over 500%. To improve the empirical estimation methodology, the samples were grouped by depositional environment and subdivided into subgroups based on lithology and mud percentage. The empirical methods were then analyzed to assess which methods best estimated the measured values. Modifications of the empirical equations, including changes to special coefficients and addition of offsets, were made to produce modified equations that considerably improve the hydraulic conductivity estimates from grain size data for beach, dune, offshore marine, and river sediments. Estimated hydraulic conductivity errors were reduced to 6 to 7.1 m/day for the beach subgroups, 3.4 to 7.1 m/day for dune subgroups, and 2.2 to 11 m/day for offshore sediments subgroups. Improvements were made for river environments, but still produced high errors between 13 and 23 m/day.

  19. Determination of hydraulic conductivity from grain-size distribution for different depositional environments

    KAUST Repository

    Rosas, Jorge

    2013-06-06

    Over 400 unlithified sediment samples were collected from four different depositional environments in global locations and the grain-size distribution, porosity, and hydraulic conductivity were measured using standard methods. The measured hydraulic conductivity values were then compared to values calculated using 20 different empirical equations (e.g., Hazen, Carman-Kozeny) commonly used to estimate hydraulic conductivity from grain-size distribution. It was found that most of the hydraulic conductivity values estimated from the empirical equations correlated very poorly to the measured hydraulic conductivity values with errors ranging to over 500%. To improve the empirical estimation methodology, the samples were grouped by depositional environment and subdivided into subgroups based on lithology and mud percentage. The empirical methods were then analyzed to assess which methods best estimated the measured values. Modifications of the empirical equations, including changes to special coefficients and addition of offsets, were made to produce modified equations that considerably improve the hydraulic conductivity estimates from grain size data for beach, dune, offshore marine, and river sediments. Estimated hydraulic conductivity errors were reduced to 6 to 7.1m/day for the beach subgroups, 3.4 to 7.1m/day for dune subgroups, and 2.2 to 11m/day for offshore sediments subgroups. Improvements were made for river environments, but still produced high errors between 13 and 23m/day. © 2013, National Ground Water Association.

  20. Geologic Controls of Hydraulic Conductivity in the Snake River Plain Aquifer At and Near the Idaho National Engineering and Environmental Laboratory, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    S. R. Anderson; M. A. Kuntz; L. C. Davis

    1999-02-01

    The effective hydraulic conductivity of basalt and interbedded sediment that compose the Snake River Plain aquifer at and near the Idaho National Engineering and Environmental Laboratory (INEEL) ranges from about 1.0x10 -2 to 3.2x10 4 feet per day (ft/d). This six-order-of-magnitude range of hydraulic conductivity was estimated from single-well aquifer tests in 114 wells, and is attributed mainly to the physical characteristics and distribution of basalt flows and dikes. Hydraulic conductivity is greatest in thin pahoehoe flows and near-vent volcanic deposits. Hydraulic conductivity is least in flows and deposits cut by dikes. Estimates of hydraulic conductivity at and near the INEEL are similar to those measured in similar volcanic settings in Hawaii. The largest variety of rock types and the greatest range of hydraulic conductivity are in volcanic rift zones, which are characterized by numerous aligned volcanic vents and fissures related to underlying dikes. Three broad categories of hydraulic conductivity corresponding to six general types of geologic controls can be inferred from the distribution of wells and vent corridors. Hydraulic conductivity of basalt flows probably is increased by localized fissures and coarse mixtures of interbedded sediment, scoria, and basalt rubble. Hydraulic conductivity of basalt flows is decreased locally by abundant alteration minerals of probable hydrothermal origin. Hydraulic conductivity varies as much as six orders of magnitude in a single vent corridor and varies from three to five orders of magnitude within distances of 500 to 1,000 feet. Abrupt changes in hydraulic conductivity over short distances suggest the presence of preferential pathways and local barriers that may greatly affect the movement of ground water and the dispersion of radioactive and chemical wastes downgradient from points of waste disposal.

  1. Influence of the heterogeneity on the hydraulic conductivity of a real aquifer

    Science.gov (United States)

    Carmine, Fallico; Aldo Pedro, Ferrante; Chiara, Vita Maria; Bartolo Samuele, De

    2010-05-01

    Many factors influence the flux in the porous media therefore the values of the representative parameters of the aquifer such as the hydraulic conductivity (k). A lot of studies have shown that this parameter increases with the portion of the aquifer tested. The main cause of this behaviour is the heterogeneity in the aquifer (Sànchez-Vila et al., 1996). It was also verified that the scale dependence of hydraulic conductivity does not depend on the specific method of measurement (Schulze-Makuch and Cherkauer, 1998). An experimental approach to study this phenomenon is based on sets of measurements carried out at different scales. However, one should consider that for the lower scale values k can be determined by direct measurements, performed in the laboratory using samples of different dimensions; whyle, for the large scales the measurement of the hydraulic conductivity requires indirect methods (Johnson and Sen, 1988; Katz and Thompson, 1986; Bernabé and Revil, 1995). In this study the confined aquifer of Montalto Uffugo test field was examined. This aquifer has the geological characteristics of a recently formed valley, with conglomeratic and sandy alluvial deposits; specifically the layer of sands and conglomerates, with a significant percentage of silt at various levels, lies about 55-60 m below the ground surface, where there is a heavy clay formation. Moreover in the test field, for the considered confined aquifer, there are one completely penetrating well, five partially penetrating wells and two completely penetrating piezometers. Along two vertical lines a series of cylindrical samples (6.4 cm of diameter and 15 cm of head) were extracted and for each one of them the k value was measured in laboratory by direct methods, based on the use of flux cells. Also indirect methods were used; in fact, a series of slug tests was carried out, determining the corresponding k values and the radius of influence (R). Moreover another series of pumping tests was

  2. Saturated hydraulic conductivity of US soils grouped according textural class and bulk density

    Science.gov (United States)

    Importance of the saturated hydraulic conductivity as soil hydraulic property led to the development of multiple pedotransfer functions for estimating it. One approach to estimating Ksat was using textural classes rather than specific textural fraction contents as pedotransfer inputs. The objective...

  3. Saturated hydraulic conductivity of US soils grouped according to textural class and bulk density

    Science.gov (United States)

    Importance of the saturated hydraulic conductivity as soil hydraulic property led to the development of multiple pedotransfer functions for estimating it. One approach to estimating Ksat was using textural classes rather than specific textural fraction contents as pedotransfer inputs. The objective...

  4. Sample dimensions effect on prediction of soil water retention curve and saturated hydraulic conductivity

    Science.gov (United States)

    Soil water retention curve (SWRC) and saturated hydraulic conductivity (SHC) are key hydraulic properties for unsaturated zone hydrology and groundwater. Not only are the SWRC and SHC measurements time-consuming, their results are scale dependent. Although prediction of the SWRC and SHC from availab...

  5. Prediction of spatially variable unsaturated hydraulic conductivity using scaled particle-size distribution functions

    NARCIS (Netherlands)

    Nasta, P.; Romano, N.; Assouline, S; Vrugt, J.A.; Hopmans, J.W.

    2013-01-01

    Simultaneous scaling of soil water retention and hydraulic conductivity functions provides an effective means to characterize the heterogeneity and spatial variability of soil hydraulic properties in a given study area. The statistical significance of this approach largely depends on the number of s

  6. Method development for determining the hydraulic conductivity of fractured porous media

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Kenneth L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2013-09-30

    Plausible, but unvalidated, theoretical model constructs for unsaturated hydraulic conductivity of fractured porous media are currently used in Performance Assessment (PA) modeling for cracked saltstone and concrete (Flach 2011). The Nuclear Regulatory Commission (NRC) has expressed concern about the lack of model support for these assumed Moisture Characteristic Curves (MCC) data, as noted in Requests for Additional Information (RAIs) PA-8 and SP-4 (Savannah River Remediation, LLC, 2011). The objective of this task was to advance PA model support by developing an experimental method for determining the hydraulic conductivity of fractured cementitious materials under unsaturated conditions, and to demonstrate the technique on fractured saltstone samples. The task was requested through Task Technical Request (TTR) HLW-SSF-TTR-2012-0016 and conducted in accordance with Task Technical & Quality Assurance Plan (TTQAP) SRNL-TR-2012-00090. Preliminary method development previously conducted by Kohn et al. (2012) identified transient outflow extraction as the most promising method for characterizing the unsaturated properties of fractured porous media. While the research conducted by Kohn et al. (2012) focused on fractured media analogs such as stacked glass slides, the current task focused directly on fractured saltstone. For this task, four sample types with differing fracture geometries were considered: 1) intact saltstone, 2) intact saltstone with a single saw cut, smooth surface fracture, 3) micro-fractured saltstone (induced by oven drying), and 4) micro-fractured saltstone with a single, fully-penetrating, rough-surface fracture. Each sample type was tested initially for saturated hydraulic conductivity following method ASTM D 5084 using a flexible wall permeameter. Samples were subsequently tested using the transient outflow extraction method to determine cumulative outflow as a function of time and applied pressure. Of the four sample types tested, two yielded

  7. Interrelations among the soil-water retention, hydraulic conductivity, and suction-stress characteristic curves

    Science.gov (United States)

    Lu, Ning; Kaya, Murat; Godt, Jonathan W.

    2014-01-01

    The three fundamental constitutive relations that describe fluid flow, strength, and deformation behavior of variably saturated soils are the soil-water retention curve (SWRC), hydraulic conductivity function (HCF), and suction-stress characteristic curve (SSCC). Until recently, the interrelations among the SWRC, HCF, and SSCC have not been well established. This work sought experimental confirmation of interrelations among these three constitutive functions. Results taken from the literature for six soils and those obtained for 11 different soils were used. Using newly established analytical relations among the SWRC, HCF, and SSCC and these test results, the authors showed that these three constitutive relations can be defined by a common set of hydromechanical parameters. The coefficient of determination for air-entry pressures determined independently using hydraulic and mechanical methods is >0.99, >0.98 for the pore size parameter, and 0.94 for the residual degree of saturation. One practical implication is that one of any of the four experiments (axis-translation, hydraulic, shear-strength, or deformation) is sufficient to quantify all three constitutive relations.

  8. Thermal Hydraulic Integral Effect Tests for Pressurized Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Baek, W. P.; Song, C. H.; Kim, Y. S. and others

    2005-02-15

    The objectives of the project are to construct a thermal-hydraulic integral effect test facility and to perform various integral effect tests for design, operation, and safety regulation of pressurized water reactors. During the first phase of this project (1997.8{approx}2002.3), the basic technology for thermal-hydraulic integral effect tests was established and the basic design of the test facility was accomplished: a full-height, 1/300-volume-scaled full pressure facility for APR1400, an evolutionary pressurized water reactor that was developed by Korean industry. Main objectives of the present phase (2002.4{approx}2005.2), was to optimize the facility design and to construct the experimental facility. We have performed following researches: 1) Optimization of the basic design of the thermal-hydraulic integral effect test facility for PWRs - ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation) - Reduced height design for APR1400 (+ specific design features of KSNP safety injection systems) - Thermal-hydraulic scaling based on three-level scaling methodology by Ishii et al. 2) Construction of the ATLAS facility - Detailed design of the test facility - Manufacturing and procurement of components - Installation of the facility 3) Development of supporting technology for integral effect tests - Development and application of advanced instrumentation technology - Preliminary analysis of test scenarios - Development of experimental procedures - Establishment and implementation of QA system/procedure.

  9. Laboratory tests of hydraulic fracturing and swell healing

    DEFF Research Database (Denmark)

    Thunbo, Christensen Claes; Foged, Christensen Helle; Foged, Niels

    1998-01-01

    New laboratory test set-ups and test procedures are described - for testing the formation of hydraulically induced fractures as well as the potential for subsequent fracture closurefrom the relase of a swelling potential. The main purpose with the tests is to provide information on fracturing...

  10. Method of Relating Grain Size Distribution to Hydraulic Conductivity in Dune Sands to Assist in Assessing Managed Aquifer Recharge Projects: Wadi Khulays Dune Field, Western Saudi Arabia

    KAUST Repository

    Lopez Valencia, Oliver M.

    2015-11-12

    Planning for use of a dune field aquifer for managed aquifer recharge (MAR) requires that hydraulic properties need to be estimated over a large geographic area. Saturated hydraulic conductivity of dune sands is commonly estimated from grain size distribution data by employing some type of empirical equation. Over 50 samples from the Wadi Khulays dune field in Western Saudi Arabia were collected and the grain size distribution, porosity, and hydraulic conductivity were measured. An evaluation of 20 existing empirical equations showed a generally high degree of error in the predicted compared to the measured hydraulic conductivity values of these samples. Statistical analyses comparing estimated versus measured hydraulic conductivity demonstrated that there is a significant relationship between hydraulic conductivity and mud percentage (and skewness). The modified Beyer equation, which showed a generally low prediction error, was modified by adding a second term fitting parameter related to the mud concentration based on 25 of the 50 samples analyzed. An inverse optimization process was conducted to quantify the fitting parameter and a new empirical equation was developed. This equation was tested against the remaining 25 samples analyzed and produced an estimated saturated hydraulic conductivity with the lowest error of any empirical equation. This methodology can be used for large dune field hydraulic conductivity estimation and reduce planning costs for MAR systems.

  11. Method of Relating Grain Size Distribution to Hydraulic Conductivity in Dune Sands to Assist in Assessing Managed Aquifer Recharge Projects: Wadi Khulays Dune Field, Western Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Oliver M. Lopez

    2015-11-01

    Full Text Available Planning for use of a dune field aquifer for managed aquifer recharge (MAR requires that hydraulic properties need to be estimated over a large geographic area. Saturated hydraulic conductivity of dune sands is commonly estimated from grain size distribution data by employing some type of empirical equation. Over 50 samples from the Wadi Khulays dune field in Western Saudi Arabia were collected and the grain size distribution, porosity, and hydraulic conductivity were measured. An evaluation of 20 existing empirical equations showed a generally high degree of error in the predicted compared to the measured hydraulic conductivity values of these samples. Statistical analyses comparing estimated versus measured hydraulic conductivity demonstrated that there is a significant relationship between hydraulic conductivity and mud percentage (and skewness. The modified Beyer equation, which showed a generally low prediction error, was modified by adding a second term fitting parameter related to the mud concentration based on 25 of the 50 samples analyzed. An inverse optimization process was conducted to quantify the fitting parameter and a new empirical equation was developed. This equation was tested against the remaining 25 samples analyzed and produced an estimated saturated hydraulic conductivity with the lowest error of any empirical equation. This methodology can be used for large dune field hydraulic conductivity estimation and reduce planning costs for MAR systems.

  12. Hamiltonian Monte Carlo algorithm for the characterization of hydraulic conductivity from the heat tracing data

    Science.gov (United States)

    Djibrilla Saley, A.; Jardani, A.; Soueid Ahmed, A.; Raphael, A.; Dupont, J. P.

    2016-11-01

    Estimating spatial distributions of the hydraulic conductivity in heterogeneous aquifers has always been an important and challenging task in hydrology. Generally, the hydraulic conductivity field is determined from hydraulic head or pressure measurements. In the present study, we propose to use temperature data as source of information for characterizing the spatial distributions of the hydraulic conductivity field. In this way, we performed a laboratory sandbox experiment with the aim of imaging the heterogeneities of the hydraulic conductivity field from thermal monitoring. During the laboratory experiment, we injected a hot water pulse, which induces a heat plume motion into the sandbox. The induced plume was followed by a set of thermocouples placed in the sandbox. After the temperature data acquisition, we performed a hydraulic tomography using the stochastic Hybrid Monte Carlo approach, also called the Hamiltonian Monte Carlo (HMC) algorithm to invert the temperature data. This algorithm is based on a combination of the Metropolis Monte Carlo method and the Hamiltonian dynamics approach. The parameterization of the inverse problem was done with the Karhunen-Loève (KL) expansion to reduce the dimensionality of the unknown parameters. Our approach has provided successful reconstruction of the hydraulic conductivity field with low computational effort.

  13. Hydraulic Hybrid Parcel Delivery Truck Deployment, Testing & Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Gallo, Jean-Baptiste [Calstart Incorporated, Pasadena, CA (United States)

    2014-03-07

    Although hydraulic hybrid systems have shown promise over the last few years, commercial deployment of these systems has primarily been limited to Class 8 refuse trucks. In 2005, the Hybrid Truck Users Forum initiated the Parcel Delivery Working Group including the largest parcel delivery fleets in North America. The goal of the working group was to evaluate and accelerate commercialization of hydraulic hybrid technology for parcel delivery vehicles. FedEx Ground, Purolator and United Parcel Service (UPS) took delivery of the world’s first commercially available hydraulic hybrid parcel delivery trucks in early 2012. The vehicle chassis includes a Parker Hannifin hydraulic hybrid drive system, integrated and assembled by Freightliner Custom Chassis Corp., with a body installed by Morgan Olson. With funding from the U.S. Department of Energy, CALSTART and its project partners assessed the performance, reliability, maintainability and fleet acceptance of three pre-production Class 6 hydraulic hybrid parcel delivery vehicles using information and data from in-use data collection and on-road testing. This document reports on the deployment of these vehicles operated by FedEx Ground, Purolator and UPS. The results presented provide a comprehensive overview of the performance of commercial hydraulic hybrid vehicles in parcel delivery applications. This project also informs fleets and manufacturers on the overall performance of hydraulic hybrid vehicles, provides insights on how the technology can be both improved and more effectively used. The key findings and recommendations of this project fall into four major categories: -Performance, -Fleet deployment, -Maintenance, -Business case. Hydraulic hybrid technology is relatively new to the market, as commercial vehicles have been introduced only in the past few years in refuse and parcel delivery applications. Successful demonstration could pave the way for additional purchases of hydraulic hybrid vehicles throughout the

  14. Oscillatory Flow Testing in a Sandbox - Towards Oscillatory Hydraulic Tomography

    Science.gov (United States)

    Zhou, Y.; Lim, D.; Cupola, F.; Cardiff, M. A.

    2014-12-01

    Detailed knowledge of subsurface hydraulic properties is important for predicting groundwater flow and contaminant transport. The spatial variation of hydraulic properties in the shallow subsurface has been extensively studied in the past two decades. A recent approach to characterize subsurface properties is hydraulic tomography, in which pressure data from multiple constant-rate pumping tests is inverted using a numerical model. Many laboratory sandbox studies have explored the performance of hydraulic tomography under different controlled conditions and shown that detailed heterogeneity information can be extracted (Liu et al., 2002, Illman et al., 2007, 2008, 2010a, 2010b, Liu et al., 2007, 2008, Xiang et al., 2009, Yin and Illman, 2009, Liu and Kitanidis, 2011, Berg and Illman, 2011a). Recently, Cardiff et al. (2013) proposed a modified approach of Oscillatory Hydraulic Tomography (OHT) - in which periodic pumping signals of different frequencies are used for aquifer stimulation - to characterize aquifer properties. The potential advantages of OHT over traditional hydraulic tomography include: 1) no net injection or extraction of water; 2) little movement of existing contamination; 3) minimal impact of model boundary conditions; and 4) robust extraction of oscillatory signals from noisy data. To evaluate the premise of OHT, we built a highly-instrumented 2-D laboratory sandbox and record pressure responses to periodic pumping tests. In our setup, the laboratory sandbox is filled with sand of known hydraulic properties, and we measure aquifer responses at a variety of testing frequencies. The signals recorded are processed using Fourier-domain analysis, and compared against expected results under linear (Darcian) theory. The responses are analyzed using analytical and numerical models, which provide key insights as to: 1) how "effective" hydraulic properties estimated using homogeneous models are associated with aquifer heterogeneity; and 2) how OHT is able to

  15. Sensitivity study on hydraulic well testing inversion using simulated annealing

    Energy Technology Data Exchange (ETDEWEB)

    Nakao, Shinsuke; Najita, J.; Karasaki, Kenzi

    1997-11-01

    For environmental remediation, management of nuclear waste disposal, or geothermal reservoir engineering, it is very important to evaluate the permeabilities, spacing, and sizes of the subsurface fractures which control ground water flow. Cluster variable aperture (CVA) simulated annealing has been used as an inversion technique to construct fluid flow models of fractured formations based on transient pressure data from hydraulic tests. A two-dimensional fracture network system is represented as a filled regular lattice of fracture elements. The algorithm iteratively changes an aperture of cluster of fracture elements, which are chosen randomly from a list of discrete apertures, to improve the match to observed pressure transients. The size of the clusters is held constant throughout the iterations. Sensitivity studies using simple fracture models with eight wells show that, in general, it is necessary to conduct interference tests using at least three different wells as pumping well in order to reconstruct the fracture network with a transmissivity contrast of one order of magnitude, particularly when the cluster size is not known a priori. Because hydraulic inversion is inherently non-unique, it is important to utilize additional information. The authors investigated the relationship between the scale of heterogeneity and the optimum cluster size (and its shape) to enhance the reliability and convergence of the inversion. It appears that the cluster size corresponding to about 20--40 % of the practical range of the spatial correlation is optimal. Inversion results of the Raymond test site data are also presented and the practical range of spatial correlation is evaluated to be about 5--10 m from the optimal cluster size in the inversion.

  16. Is inversion based high resolution characterization of spatially heterogeneous river bed hydraulic conductivity needed and possible?

    Directory of Open Access Journals (Sweden)

    W. Kurtz

    2013-05-01

    Full Text Available River-aquifer exchange fluxes influence local and regional water balances and affect groundwater and river water quality and quantity. Unfortunately, river-aquifer exchange fluxes tend to be strongly spatially variable and it is an open research question to which degree river bed heterogeneity has to be represented in a~model in order to achieve reliable estimates of river-aquifer exchange fluxes. This research question is addressed in this paper with help of synthetic simulation experiments, which mimic the Limmat aquifer in Zurich (Switzerland, where river-aquifer exchange fluxes and groundwater management activities play an important role. The solution of the unsaturated-saturated subsurface hydrological flow problem including river-aquifer interaction is calculated for ten different synthetic realities where the strongly heterogeneous river bed hydraulic conductivities (L are perfectly known. Hydraulic head data (100 in the default scenario are sampled from the synthetic realities. In subsequent data assimilation experiments, where L is unknown now, the hydraulic head data are used as conditioning information, with help of the Ensemble Kalman Filter (EnKF. For each of the ten synthetic realities, four different ensembles of L are tested in the experiments with EnKF; one ensemble estimates high resolution L-fields with different L values for each element, and the other three ensembles estimate effective L values for 5, 3 or 2 zones. The calibration of higher resolution L-fields (i.e., fully heterogeneous or 5 zones gives better results than the calibration of L for only 3 or 2 zones in terms of reproduction of states, stream-aquifer exchange fluxes and parameters. Effective L for a limited number of zones cannot always reproduce the true states and fluxes well and results in biased estimates of net exchange fluxes between aquifer and stream. Also in case only 10 head data are used for conditioning, the high resolution L-fields outperform the

  17. Hydraulic testing of Salado Formation evaporites at the Waste Isolation Pilot Plant site: Second interpretive report

    Energy Technology Data Exchange (ETDEWEB)

    Beauheim, R.L. [Sandia National Labs., Albuquerque, NM (United States); Roberts, R.M.; Dale, T.F.; Fort, M.D.; Stensrud, W.A. [INTERA, Inc., Austin, TX (United States)

    1993-12-01

    Pressure-pulse, constant-pressure flow, and pressure-buildup tests have been performed in bedded evaporites of the Salado Formation at the Waste Isolation Pilot Plant (WIPP) site to evaluate the hydraulic properties controlling brine flow through the Salado. Transmissivities have been interpreted from six sequences of tests conducted on five stratigraphic intervals within 15 m of the WIPP underground excavations.

  18. Verification of combined thermal-hydraulic and heat conduction analysis code FLOWNET/TRUMP

    Science.gov (United States)

    Maruyama, Soh; Fujimoto, Nozomu; Kiso, Yoshihiro; Murakami, Tomoyuki; Sudo, Yukio

    1988-09-01

    This report presents the verification results of the combined thermal-hydraulic and heat conduction analysis code, FLOWNET/TRUMP which has been utilized for the core thermal hydraulic design, especially for the analysis of flow distribution among fuel block coolant channels, the determination of thermal boundary conditions for fuel block stress analysis and the estimation of fuel temperature in the case of fuel block coolant channel blockage accident in the design of the High Temperature Engineering Test Reactor(HTTR), which the Japan Atomic Energy Research Institute has been planning to construct in order to establish basic technologies for future advanced very high temperature gas-cooled reactors and to be served as an irradiation test reactor for promotion of innovative high temperature new frontier technologies. The verification of the code was done through the comparison between the analytical results and experimental results of the Helium Engineering Demonstration Loop Multi-channel Test Section(HENDEL T(sub 1-M)) with simulated fuel rods and fuel blocks.

  19. Effect of the method of estimation of soil saturated hydraulic conductivity with regards to the design of stormwater infiltration trenches

    Science.gov (United States)

    Paiva coutinho, Artur; Predelus, Dieuseul; Lassabatere, Laurent; Ben Slimene, Erij; Celso Dantas Antonino, Antonio; Winiarski, Thierry; Joaquim da Silva Pereira Cabral, Jaime; Angulo-Jaramillo, Rafael

    2014-05-01

    Best management practices are based on the infiltration of stormwater (e.g. infiltration into basins or trenches) to reduce the risk of flooding of urban areas. Proper estimations of saturated hydraulic conductivity of the vadose zone are required to avoid inappropriate design of infiltration devices. This article aims at assessing (i) the method-dependency of the estimation of soils saturated hydraulic conductivity and (ii) the consequences of such dependency on the design of infiltration trenches. This is illustrated for the specific case of an infiltration trench to be constructed to receive stormwater from a specific parking surface, 250 m2 in area, in Recife (Brazil). Water infiltration experiments were conducted according to the Beerkan Method, i.e. application of a zero water pressure head through a disc source (D=15 cm) and measures of the amount of infiltrated water with time. Saturated hydraulic conductivity estimates are derived from the analysis of these infiltration tests using several different conceptual approaches: one-dimensional models of Horton(1933) and Philip(1957), three-dimensional methods recently developed (Lassabatere et al., 2006, Wu et al., 1999, and Bagarello et al., 2013) and direct 3-dimensional numerical inversion. The estimations for saturated hydraulic conductivity ranged between 65.5 mm/h and 94 mm/h for one-dimensional methods, whereas using three-dimensional methods saturated hydraulic conductivity ranged between 15.6 mm/h and 50 mm/h. These results shows the need for accounting for 3D geometry, and more generally, the physics of water infiltration in soils, if a proper characterization of soil saturated hydraulic conductivity is targeted. In a second step, each estimate of the saturated hydraulic conductivity was used to calculate the stormwater to be stored in the studied trench for several rainfall events of recurrence intervals of 2 to 25 years. The calculation of these volumes showed a great sensitivity with regards to the

  20. HYDRAULIC CONDUCTIVITY OF SALTSTONE FORMULATED USING 1Q11, 2Q11 AND 3Q11 TANK 50 SLURRY SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Reigel, M.; Nichols, R.

    2012-06-27

    As part of the Saltstone formulation work requested by Waste Solidification Engineering (WSE), Savannah River National Laboratory (SRNL) was tasked with preparing Saltstone samples for fresh property analysis and hydraulic conductivity measurements using actual Tank 50 salt solution rather than simulated salt solution. Samples of low level waste salt solution collected from Tank 50H during the first, second, and third quarters of 2011 were used to formulate the Saltstone samples. The salt solution was mixed with premix (45 wt % slag, 45 wt % fly ash, and 10 wt % cement), in a ratio consistent with facility operating conditions during the quarter of interest. The fresh properties (gel, set, bleed) of each mix were evaluated and compared to the recommended acceptance criteria for the Saltstone Production Facility. ASTM D5084-03, Method C was used to measure the hydraulic conductivity of the Saltstone samples. The hydraulic conductivity of Saltstone samples prepared from 1Q11 and 2Q11 samples of Tank 50H is 4.2E-9 cm/sec and 2.6E-9 cm/sec, respectively. Two additional 2Q11 and one 3Q11 sample were not successfully tested due to the inability to achieve stable readings during saturation and testing. The hydraulic conductivity of the samples made from Tank 50H salt solution compare well to samples prepared with simulated salt solution and cured under similar conditions (1.4E-9 - 4.9E-8 cm/sec).

  1. Sand box experiments with bioclogging of porous media: hydraulic conductivity reductions.

    Science.gov (United States)

    Seifert, Dorte; Engesgaard, Peter

    2012-08-01

    Tracer experiments during clogging and de-clogging experiments in a 2D sand box were via an image analysis used to establish a data set on the relation between changes in hydraulic conductivity (K) and relative porosity (β). Clogging appears to create a finger-like tracer transport, which could be caused by an initial heterogeneous distribution of biomass in the sand box. De-clogging occurs at a slower rate possibly due to the presence of inert biomass that is not affected by the starvation conditions by sudden removal of the substrate source. The tracer front was observed to get disturbed closer and closer to the substrate source during the experiments suggesting that the zone of clogging moved upstream. Three clogging models, K(β), from the literature were tested for their ability to describe the temporal changes in clogging at the scale of the sand box; the model of Clement et al. (1996) that makes no assumption on biomass distribution, the plug formation model of Thullner et al. (2002a), and the biofilm-plug formation model of Vandevivere (1995). The plug formation and biofilm-plug formation models both match the observed changes between the hydraulic conductivity of the sand box and the relative porosity. Unfortunately our experiments did not reach low relative porosities where the two models predict different behaviors. The model by Clement et al. (1996) underestimates clogging.

  2. State of the art hydraulic turbine model test

    Science.gov (United States)

    Fabre, Violaine; Duparchy, Alexandre; Andre, Francois; Larroze, Pierre-Yves

    2016-11-01

    Model tests are essential in hydraulic turbine development and related fields. The methods and technologies used to perform these tests show constant progress and provide access to further information. In addition, due to its contractual nature, the test demand evolves continuously in terms of quantity and accuracy. Keeping in mind that the principal aim of model testing is the transposition of the model measurements to the real machine, the measurements should be performed accurately, and a critical analysis of the model test results is required to distinguish the transposable hydraulic phenomena from the test rig interactions. Although the resonances’ effects are known and described in the IEC standard, their identification is difficult. Leaning on a strong experience of model testing, we will illustrate with a few examples of how to identify the potential problems induced by the test rig. This paper contains some of our best practices to obtain the most accurate, relevant, and independent test-rig measurements.

  3. Mapping of Soil Saturated Hydraulic Conductivity in Navroud-Assalem Watershed in Guilan Province

    Directory of Open Access Journals (Sweden)

    M.R. Khaledian

    2016-02-01

    Full Text Available Introduction: With increasing awareness of human beings towards the environment, researchers pay more attention to process and redistribution of water flow and solute transport in the soil and groundwater. Moreover, determination of soil hydraulic conductivity is necessary to determine the runoff from basins. Water movement within the unsaturated zone is often described by the formulae proposed by Richards. To solve this equation, initial and boundary conditions of the hydraulic conductivity and the soil water pressure should be determined as functions of soil water content. Beerkan method was developed to identify retention and hydraulic conductivity curves. In this method, van Gunechten with Burdine condition and Brooks and Corey equations were used to describe water retention and hydraulic conductivity curves. Recognition of the spatial pattern of studied parameter using semivariogram and then preparing zoning map with interpolation methods such as IDW and kriging can help us in relevant watershed management. The aim of this study was to spatial analyze of saturated hydraulic conductivity from 50 infiltration tests at watershed scale using Beerkan method and then preparing zoning map for the Navroud watershed. Materials and Methods: Navroud-Assalem watershed with an area of about 307 km2 is located in the west part of Guilan province, within the city of Talesh. Of the total watershed area of Navroud, about 41 km2 is plains and the rest of it is about 266 km2, corresponding to the mountainous area. The study area includes an area with a height above 130 m. In order to complete the database of the studied watershed the present study was designed to assess soil saturated hydraulic conductivity. In this study, a 2×2 km network was designed in Navroud watershed with a surface area of 307 km2, and then infiltration tests were carried out in each node using single ring of Beerkan. Beerkan method derives shape parameters from particle

  4. Effects of leachate infiltration and desiccation cracks on hydraulic conductivity of compacted clay

    Directory of Open Access Journals (Sweden)

    Jun HE

    2015-04-01

    Full Text Available Both cracks in clay liner and the complex composition of landfill leachate might have effects on the hydraulic conductivity of a compacted clay liner. In this study, the hydraulic conductivities of natural clay and bentonite-modified clay with and without desiccation cracks were measured, respectively, using three types of liquids as permeating liquid: 2 500 mg/L acetic acid solution, 0.5 mol/L CaCl2 solution, and tap water. When tap water was adopted as the permeating liquid, desiccation cracks resulted in increases in the average value of hydraulic conductivity: a 25-fold increase for the natural clay and a 5.7-fold increase for the bentonite-modified clay. It was also found out that the strong self-healing capability of bentonite helped to reduce the adverse impact of cracks on hydraulic performance. In contrast to tap water, simulated leachates (acetic acid and CaCl2 solutions show no adverse effect on the hydraulic conductivities of natural and bentonite-modified clays. It is concluded that desiccation cracks and bentonite have more significant effects on hydraulic performance than simulated leachates.

  5. Analysis of Grain Size Distribution and Hydraulic Conductivity for a Variety of Sediment Types with Application to Wadi Sediments

    KAUST Repository

    Rosas Aguilar, Jorge

    2013-05-01

    Grain size distribution, porosity, and hydraulic conductivity from over 400 unlithified sediment samples were analized. The measured hydraulic conductivity values were then compared to values calculated using 20 different empirical equations commonly used to estimate hydraulic conductivity from grain size analyses. It was found that most of the hydraulic conductivity values estimated from the empirical equations correlated very poorly to the measured hydraulic conductivity values. Modifications of the empirical equations, including changes to special coefficients and statistical off sets, were made to produce modified equations that considerably improve the hydraulic conductivity estimates from grain size data for beach, dune, off shore marine, and wadi sediments. Expected hydraulic conductivity estimation errors were reduced. Correction factors were proposed for wadi sediments, taking mud percentage and the standard deviation (in phi units) into account.

  6. Integrating hydraulic conductivity with biogeochemical gradients and microbial activity along river-groundwater exchange zones in a subtropical stream

    Science.gov (United States)

    Claret, Cécile; Boulton, Andrew J.

    2009-02-01

    The pervious lateral bars (parafluvial zone) and beds (hyporheic zone), where stream water and groundwater exchange, are dynamic sites of hydrological and biological retention. The significance of these biogeochemical ‘hotspots’ to stream and groundwater metabolism is largely controlled by filtration capacity, defined as the extent to which subsurface flowpaths and matrix hydraulic conductivity modify water characteristics. Where hydraulic conductivity is high, gradients in biogeochemistry and microbial activity along subsurface flowpaths were hypothesized to be less marked than where hydraulic conductivity is low. This hypothesis was tested in two riffles and gravel bars in an Australian subtropical stream. At one site, gradients in chemical and microbial variables along flowpaths were associated with reduced hydraulic conductivity, longer water residence time and reduced filtration capacity compared with the second site where filtration capacity was greater and longitudinal biogeochemical trends were dampened. These results imply that factors affecting the sediment matrix in this subtropical stream can alter filtration capacity, interstitial microbial activity and biogeochemical gradients along subsurface flowpaths. This hydroecological approach also indicates potential for a simple field technique to estimate filtration capacity and predict the prevailing hyporheic gradients in microbial activity and biogeochemical processing efficiency, with significant implications for stream ecosystem function.

  7. Regional characterization of hydraulic properties of rock using well test data

    Energy Technology Data Exchange (ETDEWEB)

    Wladis, D.; Joensson, P.; Wallroth, T. [Chalmers Univ. of Technology., Goeteborg (Sweden). Dept. of Geology

    1997-11-01

    This study was aimed at investigating the possible use of data from the SGU well archive for characterization of the hydraulic properties of the crystalline basement of Sweden at a regional scale. Two areas studied as possible candidates for a radioactive waste repository were selected. The SGU well data and the hydraulic conductivity data evaluated from packer tests in boreholes at the sites were characterized statistically also considering possible spatial dependence. The two types of data were compared and the correlation between the data sets was investigated. This part of the study considered the uppermost 100 m of the packer test data, which is the approximate depth range covered by the SGU data. In a second part of the work the packer test data from the two study areas were analyzed in terms of possible depth trends. The exploratory statistical analyses suggested that the SGU data are useful for estimations of hydrogeological parameters for areas of different geologic settings. The geostatistical analysis provided further understanding of the spatial behaviour of the studied parameters. The analysis of depth dependence indicates that at both sites there is a layer of higher hydraulic conductivity close to the surface. Within these layers, about 200 and 280 m thick, resp., the conductivity decreases with increasing depth. At larger depths however, the decrease with depth is very slow or negligible. It was found that the scatter in the measured hydraulic conductivity data is very large compared to differences between the depth functions tested 33 refs, 21 figs, 6 tabs

  8. Using boosted regression trees to predict the near-saturated hydraulic conductivity of undisturbed soils

    Science.gov (United States)

    Koestel, John; Bechtold, Michel; Jorda, Helena; Jarvis, Nicholas

    2015-04-01

    The saturated and near-saturated hydraulic conductivity of soil is of key importance for modelling water and solute fluxes in the vadose zone. Hydraulic conductivity measurements are cumbersome at the Darcy scale and practically impossible at larger scales where water and solute transport models are mostly applied. Hydraulic conductivity must therefore be estimated from proxy variables. Such pedotransfer functions are known to work decently well for e.g. water retention curves but rather poorly for near-saturated and saturated hydraulic conductivities. Recently, Weynants et al. (2009, Revisiting Vereecken pedotransfer functions: Introducing a closed-form hydraulic model. Vadose Zone Journal, 8, 86-95) reported a coefficients of determination of 0.25 (validation with an independent data set) for the saturated hydraulic conductivity from lab-measurements of Belgian soil samples. In our study, we trained boosted regression trees on a global meta-database containing tension-disk infiltrometer data (see Jarvis et al. 2013. Influence of soil, land use and climatic factors on the hydraulic conductivity of soil. Hydrology & Earth System Sciences, 17, 5185-5195) to predict the saturated hydraulic conductivity (Ks) and the conductivity at a tension of 10 cm (K10). We found coefficients of determination of 0.39 and 0.62 under a simple 10-fold cross-validation for Ks and K10. When carrying out the validation folded over the data-sources, i.e. the source publications, we found that the corresponding coefficients of determination reduced to 0.15 and 0.36, respectively. We conclude that the stricter source-wise cross-validation should be applied in future pedotransfer studies to prevent overly optimistic validation results. The boosted regression trees also allowed for an investigation of relevant predictors for estimating the near-saturated hydraulic conductivity. We found that land use and bulk density were most important to predict Ks. We also observed that Ks is large in fine

  9. Solid Rocket Booster Hydraulic Pump Port Cap Joint Load Testing

    Science.gov (United States)

    Gamwell, W. R.; Murphy, N. C.

    2004-01-01

    The solid rocket booster uses hydraulic pumps fabricated from cast C355 aluminum alloy, with 17-4 PH stainless steel pump port caps. Corrosion-resistant steel, MS51830 CA204L self-locking screw thread inserts are installed into C355 pump housings, with A286 stainless steel fasteners installed into the insert to secure the pump port cap to the housing. In the past, pump port cap fasteners were installed to a torque of 33 Nm (300 in-lb). However, the structural analyses used a significantly higher nut factor than indicated during tests conducted by Boeing Space Systems. When the torque values were reassessed using Boeing's nut factor, the fastener preload had a factor of safety of less than 1, with potential for overloading the joint. This paper describes how behavior was determined for a preloaded joint with a steel bolt threaded into steel inserts in aluminum parts. Finite element models were compared with test results. For all initial bolt preloads, bolt loads increased as external applied loads increased. For higher initial bolt preloads, less load was transferred into the bolt, due to external applied loading. Lower torque limits were established for pump port cap fasteners and additional limits were placed on insert axial deformation under operating conditions after seating the insert with an initial preload.

  10. Aerenchyma Formed Under Phosphorus Deficiency Contributes to the Reduced Root Hydraulic Conductivity in Maize Roots

    Institute of Scientific and Technical Information of China (English)

    Mingshou Fan; Ruiqin Bai; Xuefeng Zhao; Jianhua Zhang

    2007-01-01

    Root hydraulic conductivity has been shown to decrease under phosphorus (P) deficiency. This study investigated how the formation of aerenchyma is related to this change. Root anatomy, as well as root hydraulic conductivity was studied in maize (Zea mays L.) roots under different phosphorus nutrition conditions. Plant roots under P stress showed enhanced degradation of cortical cells and the aerenchyma formation was associated with their reduced root hydraulic conductivity, supporting our hypothesis that air spaces that form in the cortex of phosphorusstressed roots impede the radial transport of water in a root cylinder. Further evidence came from the variation in aerenchyma formation due to genotypic differences. Five maize inbred lines with different porosity in their root cortex showed a significant negative correlation with their root hydraulic conductivity. Shoot relative water content was also found lower in P-deficient maize plants than that in P-sufficient ones when such treatment was prolonged enough, suggesting a limitation of water transport due to lowered root hydraulic conductivity of P-deficient piants.

  11. Hydraulic Model Tests on Modified Wave Dragon

    DEFF Research Database (Denmark)

    Hald, Tue; Lynggaard, Jakob

    A floating model of the Wave Dragon (WD) was built in autumn 1998 by the Danish Maritime Institute in scale 1:50, see Sørensen and Friis-Madsen (1999) for reference. This model was subjected to a series of model tests and subsequent modifications at Aalborg University and in the following...... are found in Hald and Lynggaard (2001). Model tests and reconstruction are carried out during the phase 3 project: ”Wave Dragon. Reconstruction of an existing model in scale 1:50 and sequentiel tests of changes to the model geometry and mass distribution parameters” sponsored by the Danish Energy Agency...

  12. Is high-resolution inverse characterization of heterogeneous river bed hydraulic conductivities needed and possible?

    Directory of Open Access Journals (Sweden)

    W. Kurtz

    2013-10-01

    Full Text Available River–aquifer exchange fluxes influence local and regional water balances and affect groundwater and river water quality and quantity. Unfortunately, river–aquifer exchange fluxes tend to be strongly spatially variable, and it is an open research question to which degree river bed heterogeneity has to be represented in a model in order to achieve reliable estimates of river–aquifer exchange fluxes. This research question is addressed in this paper with the help of synthetic simulation experiments, which mimic the Limmat aquifer in Zurich (Switzerland, where river–aquifer exchange fluxes and groundwater management activities play an important role. The solution of the unsaturated–saturated subsurface hydrological flow problem including river–aquifer interaction is calculated for ten different synthetic realities where the strongly heterogeneous river bed hydraulic conductivities (L are perfectly known. Hydraulic head data (100 in the default scenario are sampled from the synthetic realities. In subsequent data assimilation experiments, where L is unknown now, the hydraulic head data are used as conditioning information, with the help of the ensemble Kalman filter (EnKF. For each of the ten synthetic realities, four different ensembles of L are tested in the experiments with EnKF; one ensemble estimates high-resolution L fields with different L values for each element, and the other three ensembles estimate effective L values for 5, 3 or 2 zones. The calibration of higher-resolution L fields (i.e. fully heterogeneous or 5 zones gives better results than the calibration of L for only 3 or 2 zones in terms of reproduction of states, stream–aquifer exchange fluxes and parameters. Effective L for a limited number of zones cannot always reproduce the true states and fluxes well and results in biased estimates of net exchange fluxes between aquifer and stream. Also in case only 10 head data are used for conditioning, the high

  13. Treated wastewater irrigation effects on soil hydraulic conductivity and aggregate stability of loamy soils in Israel

    Directory of Open Access Journals (Sweden)

    Schacht Karsten

    2015-03-01

    Full Text Available The use of treated wastewater (TWW for agricultural irrigation becomes increasingly important in water stressed regions like the Middle East for substituting fresh water (FW resources. Due to elevated salt concentrations and organic compounds in TWW this practice has potential adverse effects on soil quality, such as the reduction of hydraulic conductivity (HC and soil aggregate stability (SAS. To assess the impact of TWW irrigation in comparison to FW irrigation on HC, in-situ infiltration measurements using mini disk infiltrometer were deployed in four different long-term experimental orchard test sites in Israel. Topsoil samples (0-10 cm were collected for analyzing SAS and determination of selected soil chemical and physical characteristics.

  14. The role of water channel proteins in facilitating recovery of leaf hydraulic conductance from water stress in Populus trichocarpa.

    Directory of Open Access Journals (Sweden)

    Joan Laur

    Full Text Available Gas exchange is constrained by the whole-plant hydraulic conductance (Kplant. Leaves account for an important fraction of Kplant and may therefore represent a major determinant of plant productivity. Leaf hydraulic conductance (Kleaf decreases with increasing water stress, which is due to xylem embolism in leaf veins and/or the properties of the extra-xylary pathway. Water flow through living tissues is facilitated and regulated by water channel proteins called aquaporins (AQPs. Here we assessed changes in the hydraulic conductance of Populus trichocarpa leaves during a dehydration-rewatering episode. While leaves were highly sensitive to drought, Kleaf recovered only 2 hours after plants were rewatered. Recovery of Kleaf was absent when excised leaves were bench-dried and subsequently xylem-perfused with a solution containing AQP inhibitors. We examined the expression patterns of 12 highly expressed AQP genes during a dehydration-rehydration episode to identify isoforms that may be involved in leaf hydraulic adjustments. Among the AQPs tested, several genes encoding tonoplast intrinsic proteins (TIPs showed large increases in expression in rehydrated leaves, suggesting that TIPs contribute to reversing drought-induced reductions in Kleaf. TIPs were localized in xylem parenchyma, consistent with a role in facilitating water exchange between xylem vessels and adjacent living cells. Dye uptake experiments suggested that reversible embolism formation in minor leaf veins contributed to the observed changes in Kleaf.

  15. STOCHASTIC ANALYSIS OF UNSATURATED FLOW WITH THE NORMAL DISTRIBUTION OF SOIL HYDRAULIC CONDUCTIVITY

    Institute of Scientific and Technical Information of China (English)

    Huang Guan-hua; Zhang Ren-duo

    2003-01-01

    Stochastic approaches are useful to quantitatively describe transport behavior over large temporal and spatial scales while accounting for the influence of small-scale variabilities. Numerous solutions have been developed for unsaturated soil water flow based on the lognormal distribution of soil hydraulic conductivity. To our knowledge, no available stochastic solutions for unsaturated flow have been derived on the basis of the normal distribution of hydraulic conductivity. In this paper, stochastic solutions were developed for unsaturated flow by assuming the normal distribution of saturated hydraulic conductivity (Ks). Under the assumption that soil hydraulic properties are second-order stationary, analytical expressions for capillary tension head variance (σ2h) and effective hydraulic conductivity (K*ii) in stratified soils were derived using the perturbation method. The dependence of σ2h and K*ii on soil variability and mean flow variables (the mean capillary tension head and its temporal and spatial gradients) and mean flow conditions (wetting and drying) were systematically analyzed. The calculated variance of capillary tension head with the analytical solution derived in this paper was compared with field experimental data. The good agreement indicates that the analytical solution is applicable to evaluate the variance of capillary tension head of field soils with moderate variability.

  16. Scaling of material properties for Yucca Mountain: literature review and numerical experiments on saturated hydraulic conductivity

    Energy Technology Data Exchange (ETDEWEB)

    McKenna, S.A.; Rautman, C.A.

    1996-08-01

    A review of pertinent literature reveals techniques which may be practical for upscaling saturated hydraulic conductivity at Yucca Mountain: geometric mean, spatial averaging, inverse numerical modeling, renormalization, and a perturbation technique. Isotropic realizations of log hydraulic conductivity exhibiting various spatial correlation lengths are scaled from the point values to five discrete scales through these techniques. For the variances in log{sub 10} saturated hydraulic conductivity examined here, geometric mean, numerical inverse and renormalization adequately reproduce point scale fluxes across the modeled domains. Fastest particle velocities and dispersion measured on the point scale are not reproduced by the upscaled fields. Additional numerical experiments examine the utility of power law averaging on a geostatistical realization of a cross-section similar to the cross-sections that will be used in the 1995 groundwater travel time calculations. A literature review on scaling techniques for thermal and mechanical properties is included. 153 refs., 29 figs., 6 tabs.

  17. Method for estimating spatially variable seepage loss and hydraulic conductivity in intermittent and ephemeral streams

    Science.gov (United States)

    Niswonger, R.G.; Prudic, D.E.; Fogg, G.E.; Stonestrom, D.A.; Buckland, E.M.

    2008-01-01

    A method is presented for estimating seepage loss and streambed hydraulic conductivity along intermittent and ephemeral streams using streamflow front velocities in initially dry channels. The method uses the kinematic wave equation for routing streamflow in channels coupled to Philip's equation for infiltration. The coupled model considers variations in seepage loss both across and along the channel. Water redistribution in the unsaturated zone is also represented in the model. Sensitivity of the streamflow front velocity to parameters used for calculating seepage loss and for routing streamflow shows that the streambed hydraulic conductivity has the greatest sensitivity for moderate to large seepage loss rates. Channel roughness, geometry, and slope are most important for low seepage loss rates; however, streambed hydraulic conductivity is still important for values greater than 0.008 m/d. Two example applications are presented to demonstrate the utility of the method. Copyright 2008 by the American Geophysical Union.

  18. Gas diffusion-derived tortuosity governs saturated hydraulic conductivity in sandy soils

    DEFF Research Database (Denmark)

    Masis Melendez, Federico; Deepagoda Thuduwe Kankanamge Kelum, Chamindu; de Jonge, Lis Wollesen

    2014-01-01

    Accurate prediction of saturated hydraulic conductivity (Ksat) is essential for the development of better distributed hydrological models and area-differentiated risk assessment of chemical leaching. The saturated hydraulic conductivity is often estimated from basic soil properties such as particle...... size distribution or, more recently, soil-air permeability. However, similar links to soil gas diffusivity (Dp/Do) have not been fully explored even though gas diffusivity is a direct measure of connectivity and tortuosity of the soil pore network. Based on measurements for a coarse sandy soil....../Do model to measured data, and subsequently linked to the cementation exponent of the wellestablished Revil and Cathles predictive model for saturated hydraulic conductivity. Furthermore, a two-parameter model, analogue to the Kozeny-Carman equation, was developed for the Ksat - Dp/Do relationships. All 44...

  19. Hydraulic conductivity in response to exchangeable sodium percentage and solution salt concentration

    Directory of Open Access Journals (Sweden)

    Jefferson Luiz de Aguiar Paes

    2014-10-01

    Full Text Available Hydraulic conductivity is determined in laboratory assays to estimate the flow of water in saturated soils. However, the results of this analysis, when using distilled or deionized water, may not correspond to field conditions in soils with high concentrations of soluble salts. This study therefore set out to determine the hydraulic conductivity in laboratory conditions using solutions of different electrical conductivities in six soils representative of the State of Pernambuco, with the exchangeable sodium percentage adjusted in the range of 5-30%. The results showed an increase in hydraulic conductivity with both decreasing exchangeable sodium percentage and increasing electrical conductivity in the solution. The response to the treatments was more pronounced in soils with higher proportion of more active clays. Determination of hydraulic conductivity in laboratory is routinely performed with deionized or distilled water. However, in salt affected soils, these determinations should be carried out using solutions of electrical conductivity different from 0 dS m-1, with values close to those determined in the saturation extracts.

  20. In-Plant Testing of High-Efficiency Hydraulic Separators

    Energy Technology Data Exchange (ETDEWEB)

    G. H. Luttrell; R. Q. Honaker; R. C. Bratton; T. C. Westerfield; J. N. Kohmuench

    2004-07-20

    The mineral processing industry has commonly utilized hydraulic separators throughout history for classification and gravity concentration of various minerals. More commonly referred to as hindered-bed or fluidized-bed separators, these units make use of differential particle settling rates to segregate particles according to shape, size, and/or density. As with any equipment, there are inefficiencies associated with its operation, which prompted an industry driven research program to further evaluate two novel high-efficiency hindered bed separators. These units, which are commercially called the CrossFlow separator and HydroFloat separator, have the potential to improve performance (separation efficiency and throughput) and reduce operating costs (power consumption, water and reagent usage). This report describes the results of Phase I activities (laboratory and pilot-scale tests) conducted with the CrossFlow and HydroFloat separators at several locations in the minerals and coal industries. Details of the testing programs (equipment setup, shakedown testing and detailed testing) associated with four coal plants and two phosphate plants are summarized in this work. In most of these applications, the high-efficiency units proved to provide a higher quality product at reduced costs when compared against the performance of conventional separators. Based on promising results obtained from Phase I, full-scale prototypes will be purchased by several mining companies for use in Phase II of this project. Two of the prototype units, which will be constructed by Eriez Manufacturing, are expected to be installed by a major U.S. phosphate producer and a large eastern U.S. coal company. Negotiations are also underway to purchase and install additional prototype units by a mineral sands producer and a second phosphate producer. The data obtained from the full-scale evaluations will be used to further promote commercialization and industrial applications of these innovative

  1. Steady state method to determine unsaturated hydraulic conductivity at the ambient water potential

    Science.gov (United States)

    HUbbell, Joel M.

    2014-08-19

    The present invention relates to a new laboratory apparatus for measuring the unsaturated hydraulic conductivity at a single water potential. One or more embodiments of the invented apparatus can be used over a wide range of water potential values within the tensiometric range, requires minimal laboratory preparation, and operates unattended for extended periods with minimal supervision. The present invention relates to a new laboratory apparatus for measuring the unsaturated hydraulic conductivity at a single water potential. One or more embodiments of the invented apparatus can be used over a wide range of water potential values within the tensiometric range, requires minimal laboratory preparation, and operates unattended for extended periods with minimal supervision.

  2. Field experiments in a fractured clay till. 1. Hydraulic conductivity and fracture aperture

    Science.gov (United States)

    McKay, Larry D.; Cherry, John A.; Gillham, Robert W.

    1993-04-01

    Field values of horizontal hydraulic conductivity measured in the upper 1.5-5.5 m of a weathered and fractured clay-rich till were strongly influenced by smearing around piezometer intakes, which occurs during augering, and by the physical scale of the measuring device. Values measured in conventional augered piezometers were typically 1-2 orders of magnitude lower than those measured in piezometers designed to reduce smearing. Measurements of hydraulic conductivity in small-scale seepage collectors or piezometers, which typically intersect fewer than 10 fractures, vary over a much greater range, 10-10 to 10-6 m/s, than large-scale values based on infiltration into 5.5-m-deep trenches which intersect thousands of fractures (range 10-7 to 3×10-7 m/s). Values of hydraulic fracture aperture, 1-43 μm, and fracture porosity, 3×10-5 to 2×10-3, were calculated using the cubic law with fracture orientation/distribution measurements and the small-scale hydraulic conductivity measurements. This paper provides the first reliable determination of the magnitude and spatial distribution of hydraulically derived fracture parameters in a clay deposit. The absence of such data has, until now, severely limited the application of quantitative groundwater flow and contaminant transport models in this type of deposit.

  3. VISTA : thermal-hydraulic integral test facility for SMART reactor

    Energy Technology Data Exchange (ETDEWEB)

    Choi, K. Y.; Park, H. S.; Cho, S.; Park, C. K.; Lee, S. J.; Song, C. H.; Chung, M. K. [KAERI, Taejon (Korea, Republic of)

    2003-07-01

    Preliminary performance tests were carried out using the thermal-hydraulic integral test facility, VISTA (Experimental Verification by Integral Simulation of Transients and Accidents), which has been constructed to simulate the SMART-P. The VISTA facility is an integral test facility including the primary and secondary systems as well as safety-related Passive Residual Heat Removal (PRHR) systems. Its scaled ratio with respect to the SMART-P is 1/1 in height and 1/96 in volume and heater power. Several steady states and power changing tests have been carried out to verify the overall thermal hydraulic primary and secondary characteristics in the range of 10% to 100% power operation. As for the preliminary results, the steady state conditions were found to coincide with the expected design values of the SMART-P. But the major thermal hydraulic parameters are greatly affected by the initial water level and the nitrogen pressure in the reactor's upper annular cavity. The power step/ramp changing tests are successfully carried out and the system responses are observed. The primary natural circulation operation is achieved, but advanced control logics need to be developed to reach the natural circulation mode without pressure excursion. In the PRHR transient tests, the natural circulation flow rate through the PRHR system was found to be about 10 percent in the early phases of PRHR operation.

  4. PILOT-SCALE HYDRAULIC TESTING OF RESORCINOL FORMALDEHYDE ION EXCHANGE RESIN

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D.

    2009-05-28

    Savannah River National Laboratory (SRNL) performed pilot-scale hydraulic/chemical testing of spherical resorcinol formaldehyde (RF) ion exchange (IX) resin for the River Protection Project-Hanford Tank Waste Treatment & Immobilization Plant (WTP) Project. The RF resin hydraulic cycle testing was conducted in two pilot-scale IX columns, 1/4 and 1/2 scale. A total of twenty-three hydraulic/chemical cycles were successfully completed on the spherical RF resin. Sixteen of these cycles were completed in the 24-inch IX Column (1/2 scale column). Hydraulic testing showed that the permeability of the RF resin remained essentially constant, with no observed trend in the reduction of the permeability as the number of cycles increased. The permeability during the pilot-scale testing was 3 times better than the design requirements of the WTP full-scale IX system. The RF resin bed showed no tendency to form fissures or pack more densely as the number of cycles increased. Particle size measurements of the RF resin showed no indication of particle size change (for a given chemical) with cycles and essentially no fines formation. The permeability of the resin bed was uniform with respect to changes in bed depth. Upflow Regeneration and Simulant Introduction in the IX columns revealed another RF resin benefit; negligible radial pressures to the column walls from the swelling of resin beads. The hydraulic and chemical performance of the spherical RF resin during cycle testing was found to be superior to all other tested IX resins. The pilot-scale testing indicates that the RF resin is durable and should hold up to many hydraulic cycles in actual radioactive Cesium (Cs) separation.

  5. Light response of hydraulic conductance in bur oak (Quercus macrocarpa) leaves.

    Science.gov (United States)

    Voicu, Mihaela C; Zwiazek, Janusz J; Tyree, Melvin T

    2008-07-01

    A four- to seven-fold enhancement of leaf hydraulic conductance by light has been reported in three temperate tree species. The enhancement occurs in the liquid-flow pathway between the petiole and the site of water evaporation. The enhancement occurs within 1 h, and dissipates in darkness over a period of 1 to 10 h depending on species. Here we report light-induced enhancement of leaf hydraulic conductance in a fourth species, bur oak (Quercus macrocarpa Michx.), the dependence of the effect on light flux and color, its absence in leaves of seedlings, and the impact on the response of leaf vein severance and several metabolic inhibitors. The light response of leaf hydraulic conductance approached saturation at a photosynthetic photon flux of 150 mumol m(-2) s(-1). Hydraulic enhancement was greater in response to blue and green light than to visible radiation of longer wavelengths, although at the same irradiance, the response to white light was greater than to light of any single color. Atrazine (a photosystem II inhibitor), fusicoccin (which stimulates plasma membrane-bound H(+)-ATPase) and HgCl(2) (an aquaporin blocker) reduced the light response of leaf lamina hydraulic conductance. When 2-mercaptoethanol was added following mercury treatment, the light response was totally suppressed. Our results are consistent with the notion that the effect of light on leaf lamina hydraulic conductance is controlled by factors acting outside the leaf veins, possibly through light-induced changes in membrane permeability of either mesophyll or bundle sheath cells, or both.

  6. Averaging hydraulic head, pressure head, and gravitational head in subsurface hydrology, and implications for averaged fluxes, and hydraulic conductivity

    Directory of Open Access Journals (Sweden)

    G. H. de Rooij

    2009-07-01

    Full Text Available Current theories for water flow in porous media are valid for scales much smaller than those at which problem of public interest manifest themselves. This provides a drive for upscaled flow equations with their associated upscaled parameters. Upscaling is often achieved through volume averaging, but the solution to the resulting closure problem imposes severe restrictions to the flow conditions that limit the practical applicability. Here, the derivation of a closed expression of the effective hydraulic conductivity is forfeited to circumvent the closure problem. Thus, more limited but practical results can be derived. At the Representative Elementary Volume scale and larger scales, the gravitational potential and fluid pressure are treated as additive potentials. The necessary requirement that the superposition be maintained across scales is combined with conservation of energy during volume integration to establish consistent upscaling equations for the various heads. The power of these upscaling equations is demonstrated by the derivation of upscaled water content-matric head relationships and the resolution of an apparent paradox reported in the literature that is shown to have arisen from a violation of the superposition principle. Applying the upscaling procedure to Darcy's Law leads to the general definition of an upscaled hydraulic conductivity. By examining this definition in detail for porous media with different degrees of heterogeneity, a series of criteria is derived that must be satisfied for Darcy's Law to remain valid at a larger scale.

  7. Acceptance test report for the Westinghouse 100 ton hydraulic trailer

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, R.A.

    1995-03-06

    The SY-101 Equipment Removal System 100 Ton Hydraulic Trailer was designed and built by KAMP Systems, Inc. Performance of the Acceptance Test Procedure at KAMP`s facility in Ontario, California (termed Phase 1 in this report) was interrupted by discrepancies noted with the main hydraulic cylinder. The main cylinder was removed and sent to REMCO for repair while the trailer was sent to Lampson`s facility in Pasco, Washington. The Acceptance Test Procedure was modified and performance resumed at Lampson (termed Phase 2 in this report) after receipt of the repaired cylinder. At the successful conclusion of Phase 2 testing the trailer was accepted as meeting all the performance criteria specified.

  8. A semi-analytical generalized Hvorslev formula for estimating riverbed hydraulic conductivity with an open-ended standpipe permeameter

    Science.gov (United States)

    Pozdniakov, Sergey P.; Wang, Ping; Lekhov, Mikhail V.

    2016-09-01

    The well-known Hvorslev (1951) formula was developed to estimate soil permeability using single-well slug tests and has been widely applied to determine riverbed hydraulic conductivity using in situ standpipe permeameter tests. Here, we further develop a general solution of the Hvorslev (1951) formula that accounts for flow in a bounded medium and assumes that the bottom of the river is a prescribed head boundary. The superposition of real and imaginary disk sources is used to obtain a semi-analytical expression of the total hydraulic resistance of the flow in and out of the pipe. As a result, we obtained a simple semi-analytical expression for the resistance, which represents a generalization of the Hvorslev (1951). The obtained expression is benchmarked against a finite-element numerical model of 2-D flow (in r-z coordinates) in an anisotropic medium. The results exhibit good agreement between the simulated and estimated riverbed hydraulic conductivity values. Furthermore, a set of simulations for layered, stochastically heterogeneous riverbed sediments was conducted and processed using the proposed expression to demonstrate the potential associated with measuring vertical heterogeneity in bottom sediments using a series of standpipe permeameter tests with different lengths of pipe inserted into the riverbed sediments.

  9. Comparison of instream methods for measuring hydraulic conductivity in sandy streambeds.

    Science.gov (United States)

    Landon, M K; Rus, D L; Harvey, F E

    2001-01-01

    Streambed hydraulic conductivity (K) values were determined at seven stream transects in the Platte River Basin in Nebraska using different instream measurement techniques. Values were compared to determine the most appropriate technique(s) for use in sandy streambeds. Values of K determined from field falling- and constant-head permeameter tests analyzed using the Darcy equation decreased as permeameter diameter increased. Seepage meters coupled with hydraulic gradient measurements failed to yield K values in 40% of the trials. Consequently, Darcy permeameter and seepage meter tests were not preferred approaches. In the upper 0.25 m of the streambed, field falling- and constant-head permeameter tests analyzed with the Hvorslev solution generally had similar K values that were significantly greater than those determined using the Hazen grain-size, Bouwer and Rice slug test for anisotropic and isotropic conditions, and Alyamani and Sen grain-size methods; median differences between these tests and the Hvorslev falling-head 60 cm diameter permeameter were about 8, 9, 17, and 35 m/day, respectively. The Hvorslev falling-head permeameter test is considered the most robust method for measuring K of the upper 0.25 m of the streambed because of the inherent limitations of the empirical grain-size methods and less sediment disturbance for permeameter than slug tests. However, lateral variability in K along transects on the Platte, North Platte, and Wood Rivers was greater than variability in K between valid permeameter, grain-size, or slug tests, indicating that the method used may matter less than making enough measurements to characterize spatial variability adequately. At the Platte River tributary sites, the upper 0.3 m of the streambed typically had greater K than sediment located 0.3 to 2.5 m below the streambed surface, indicating that deposits below the streambed may limit ground water/surface water fluxes. The Hvorslev permeameter tests are not a practical

  10. A wilty mutant of rice has impaired hydraulic conductance.

    Science.gov (United States)

    Koizumi, Koji; Ookawa, Taiichiro; Satoh, Hikaru; Hirasawa, Tadashi

    2007-08-01

    The rice CM2088 mutant is the wilty phenotype and wilts markedly under well-watered sunny conditions. The leaf water potential and epidermal (mainly stomatal) conductance of CM2088 plants decreased significantly under conditions that induced intense transpiration, as compared with those of wild-type plants, revealing that the wilty phenotype was not the result of abnormal stomatal behavior but was due to an increase in resistance to water transport. The resistance to water transport was dramatically elevated in the node and the sheath and blade of a leaf of the mutant, but not in the root or stem. The diameter of xylem vessels in the large vascular bundles of the leaf sheath and the internode tended to be small, and the numbers of vessel elements with narrowed or scalariform perforation plates in the leaf blade and sheath were greater in the mutant than in the wild type. Most xylem vessels were occluded, with air bubbles in the leaf sheath of the mutant during the midday hours under intense transpiration conditions, while no bubbles were observed in plants that were barely transpiring, revealing that the significant increase in resistance to water transport was a result of the cavitation. The additive effects of cavitation in xylem vessels and the decreased diameter and deformed plates of vessel elements might be responsible for the wilty phenotype of CM2088.

  11. Evaluating temporal changes in hydraulic conductivities near karst-terrain dams: Dokan Dam (Kurdistan-Iraq)

    Science.gov (United States)

    Dafny, Elad; Tawfeeq, Kochar Jamal; Ghabraie, Kazem

    2015-10-01

    Dam sites provide an outstanding opportunity to explore dynamic changes in the groundwater flow regime because of the high hydraulic gradient rapidly induced in their surroundings. This paper investigates the temporal changes of the hydraulic conductivities of the rocks and engineered structures via a thorough analysis of hydrological data collected at the Dokam Dam, Iraq, and a numerical model that simulates the Darcian component of the seepage. Analysis of the data indicates increased seepage with time and suggests that the hydraulic conductivity of the rocks increased as the conductivity of the grout curtain decreased. Conductivity changes on the order of 10-8 m/s, in a 20-yr period were quantified using the numerical analysis. It is postulated that the changes in hydraulic properties in the vicinity of Dokan Dam are due to suspension of fine materials, interbedded in small fissures in the rocks, and re-settlement of these materials along the curtain. Consequently, the importance of the grout curtain to minimize the downstream seepage, not only as a result of the conductivity contrast with the rocks, but also as a barrier to suspended clay sediments, is demonstrated. The numerical analysis also helped us to estimate the proportion of the disconnected karstic conduit flow to the overall flow.

  12. Improving prediction of hydraulic conductivity by constraining capillary bundle models to a maximum pore size

    Science.gov (United States)

    Iden, Sascha C.; Peters, Andre; Durner, Wolfgang

    2015-11-01

    The prediction of unsaturated hydraulic conductivity from the soil water retention curve by pore-bundle models is a cost-effective and widely applied technique. One problem for conductivity predictions from retention functions with continuous derivatives, i.e. continuous water capacity functions, is that the hydraulic conductivity curve exhibits a sharp drop close to water saturation if the pore-size distribution is wide. So far this artifact has been ignored or removed by introducing an explicit air-entry value into the capillary saturation function. However, this correction leads to a retention function which is not continuously differentiable. We present a new parameterization of the hydraulic properties which uses the original saturation function (e.g. of van Genuchten) and introduces a maximum pore radius only in the pore-bundle model. In contrast to models using an explicit air entry, the resulting conductivity function is smooth and increases monotonically close to saturation. The model concept can easily be applied to any combination of retention curve and pore-bundle model. We derive closed-form expressions for the unimodal and multimodal van Genuchten-Mualem models and apply the model concept to curve fitting and inverse modeling of a transient outflow experiment. Since the new model retains the smoothness and continuous differentiability of the retention model and eliminates the sharp drop in conductivity close to saturation, the resulting hydraulic functions are physically more reasonable and ideal for numerical simulations with the Richards equation or multiphase flow models.

  13. ESTIMATION OF HYDRAULIC CONDUCTIVITY AND CONTENT OF FINES FROM EXPERIMENTAL LAWS THAT CORELATE HYDRAULIC AND ELECTRIC PARAMETERS

    Directory of Open Access Journals (Sweden)

    Héctor José Peinado-Guevara

    2010-09-01

    Full Text Available Hydraulic conductivity is a basic element in the advancement of knowledge of a geological environment in both the flow and transport processes of pollutants for conservation projects, managementand environmental management and also for the development of public policies for protection of ecosystems, among others. The aim of this paper is to obtain the hydraulic conductivity (K and the finescontent (C of saturated granular half using two empirical laws. One correlates the electrical conductivity of saturated granular media σo and water saturated σw which depends on the formation factor(F, cation exchange capacity (CEC and the fines content in the saturated soil. Using data obtained from materials of 18 samples from 6 wells the relationships between F-C and CEC-C were obtained,so the equation reduces to a σo function in terms of σw and C, with a correlation coefficient of R = 0.97. A second experimental law is the one that results from the experimental relationship between K and C,being 1.4054 K 0.1804.C with a correlation coefficient of R = 0.96. From both experimental expressions relationships between K and C, a and C,and C are created so from every pair knowing one of them you get to know the other one. Under the scheme outlined electrical conductivity sections for the saturated medium and fines content are obtained,finding that the groundwater in the study area consists of a thin top layer and beneath it there is a predominantly sandy environment.

  14. Flammability Tests on Hot Surface for Several Hydraulic Fluids

    Directory of Open Access Journals (Sweden)

    L. Deleanu

    2011-09-01

    Full Text Available Industrial equipment using hydraulic fluids are design to accept higher load and speed, implicitly higher temperatures, including for fluids. Leakages from enclosures like gear boxes or hydraulic systems could increase the risk of fluid reaching hot surfaces, thus producing fires hard to be controlled and isolated. The designer have to evaluate the flammability of fluids and they should select several solutions for a particular application in order to estimate the costs of different solutions and to mitigate the risk of having accidental fires due to a specific fluid grade. The tests were done with the help of an original equipment allowing a dedicated soft assistance in order to protect the operator and to sustain reproducibility, according to the standard SR EN ISO 20823:2004 Petroleum and related products. The determination of the flammability characteristics of fluids in contact with hot surfaces - Manifold ignition test, There were tested the following grades of hydraulic oil HLP 68 X-Oil, HFC Prista, MHE 40 Prista (100% oil, a rapeseed oil (obtained after a dewaxing process and an emulsion oil-in-water (5% vol. MHE 40 Prista. There were identified distinct behaviours of these fluids under the test conditions

  15. Testing the suitability of geologic frameworks for extrapolating hydraulic properties across regional scales

    Science.gov (United States)

    Mirus, Benjamin B.; Halford, Keith; Sweetkind, Don; Fenelon, Joe

    2016-08-01

    The suitability of geologic frameworks for extrapolating hydraulic conductivity ( K) to length scales commensurate with hydraulic data is difficult to assess. A novel method is presented for evaluating assumed relations between K and geologic interpretations for regional-scale groundwater modeling. The approach relies on simultaneous interpretation of multiple aquifer tests using alternative geologic frameworks of variable complexity, where each framework is incorporated as prior information that assumes homogeneous K within each model unit. This approach is tested at Pahute Mesa within the Nevada National Security Site (USA), where observed drawdowns from eight aquifer tests in complex, highly faulted volcanic rocks provide the necessary hydraulic constraints. The investigated volume encompasses 40 mi3 (167 km3) where drawdowns traversed major fault structures and were detected more than 2 mi (3.2 km) from pumping wells. Complexity of the five frameworks assessed ranges from an undifferentiated mass of rock with a single unit to 14 distinct geologic units. Results show that only four geologic units can be justified as hydraulically unique for this location. The approach qualitatively evaluates the consistency of hydraulic property estimates within extents of investigation and effects of geologic frameworks on extrapolation. Distributions of transmissivity are similar within the investigated extents irrespective of the geologic framework. In contrast, the extrapolation of hydraulic properties beyond the volume investigated with interfering aquifer tests is strongly affected by the complexity of a given framework. Testing at Pahute Mesa illustrates how this method can be employed to determine the appropriate level of geologic complexity for large-scale groundwater modeling.

  16. Testing the suitability of geologic frameworks for extrapolating hydraulic properties across regional scales

    Science.gov (United States)

    Mirus, Benjamin B.; Halford, Keith J.; Sweetkind, Donald; Fenelon, Joseph M.

    2016-01-01

    The suitability of geologic frameworks for extrapolating hydraulic conductivity (K) to length scales commensurate with hydraulic data is difficult to assess. A novel method is presented for evaluating assumed relations between K and geologic interpretations for regional-scale groundwater modeling. The approach relies on simultaneous interpretation of multiple aquifer tests using alternative geologic frameworks of variable complexity, where each framework is incorporated as prior information that assumes homogeneous K within each model unit. This approach is tested at Pahute Mesa within the Nevada National Security Site (USA), where observed drawdowns from eight aquifer tests in complex, highly faulted volcanic rocks provide the necessary hydraulic constraints. The investigated volume encompasses 40 mi3 (167 km3) where drawdowns traversed major fault structures and were detected more than 2 mi (3.2 km) from pumping wells. Complexity of the five frameworks assessed ranges from an undifferentiated mass of rock with a single unit to 14 distinct geologic units. Results show that only four geologic units can be justified as hydraulically unique for this location. The approach qualitatively evaluates the consistency of hydraulic property estimates within extents of investigation and effects of geologic frameworks on extrapolation. Distributions of transmissivity are similar within the investigated extents irrespective of the geologic framework. In contrast, the extrapolation of hydraulic properties beyond the volume investigated with interfering aquifer tests is strongly affected by the complexity of a given framework. Testing at Pahute Mesa illustrates how this method can be employed to determine the appropriate level of geologic complexity for large-scale groundwater modeling.

  17. Workgroup for Hydraulic laboratory Testing and Verification of Hydroacoustic Instrumentation

    Science.gov (United States)

    Fulford, Janice M.; Armstrong, Brandy N.; Thibodeaux, Kirk G.

    2015-01-01

    An international workgroup was recently formed for hydraulic laboratory testing and verification of hydroacoustic instrumentation used for water velocity measurements. The activities of the workgroup have included one face to face meeting, conference calls and an inter-laboratory exchange of two acoustic meters among participating laboratories. Good agreement was found among four laboratories at higher tow speeds and poorer agreement at the lowest tow speed.

  18. The effect of mineral-ion interactions on soil hydraulic conductivity

    Science.gov (United States)

    The reuse of winery wastewater (WW) for irrigation could provide an alternative water source for wine production. The shift of many wineries and other food processing industries to K+-based cleaners requires studies on the effects of K+ on soil hydraulic conductivity (HC). Soils of contrasting mine...

  19. Evaluation of two methods for measuring saturated hydraulic conductivity of soils under two vegetation covers

    Energy Technology Data Exchange (ETDEWEB)

    Rubio, C.M.; Josa, R.; Poyatos, R.; Llorens, P.; Gallart, F.; Latron, J.; Ferrer, F.

    2009-07-01

    The main goal of this work is to determine and to evaluate the saturated hydraulic conductivity for a silt loam soil in field and laboratory conditions. the experimental area was located in the Vallcebre research catchment, in headwaters of the Llobregat River (NE Spain). Hydraulic conductivity was measured in the field using the Guelph permeameter and field saturated hydraulic conductivity (K{sub f}s) based on Elrick equation was calculated. The Guelph permeameter measures were made in two conditions (dry and wet) and in profiles below two vegetation covers (meadows and forest). To determine the saturated hydraulic conductivity at the laboratory (K{sub s}) the constant head permeameter was used. The average K{sub f}s values for the wet period was about 2 cm.h{sup -}1. During the dry period, both soil profiles presented higher values, about 7.5 cm.h{sup -}1. Under laboratory conditions, means observed K{sub s} values were between 12 and 25 cm.h{sup -}1. The relationship K{sub f}s/k{sub s} was of 0.1 cm.h{sup -}1 in wet conditions and about 0.4 cm.h{sup -}1 in dry conditions. The results indicated significant differences between both methods and between both seasons. differences can be explained by the anisotropy of soils as a consequence of vegetation root system that promotes preferential flows paths. (Author) 10 refs.

  20. Measurement of residual CO2 saturation at a geological storage site using hydraulic tests

    Science.gov (United States)

    Rötting, T. S.; Martinez-Landa, L.; Carrera, J.; Russian, A.; Dentz, M.; Cubillo, B.

    2012-12-01

    Estimating long term capillary trapping of CO2 in aquifers remains a key challenge for CO2 storage. Zhang et al. (2011) proposed a combination of thermal, tracer, and hydraulic experiments to estimate the amount of CO2 trapped in the formation after a CO2 push and pull test. Of these three types of experiments, hydraulic tests are the simplest to perform and possibly the most informative. However, their potential has not yet been fully exploited. Here, a methodology is presented to interpret these tests and analyze which parameters can be estimated. Numerical and analytical solutions are used to simulate a continuous injection in a porous medium where residual CO2 has caused a reduction in hydraulic conductivity and an increase in storativity over a finite thickness (a few meters) skin around the injection well. The model results are interpreted using conventional pressure build-up and diagnostic plots (a plot of the drawdown s and the logarithmic derivative d s / d ln t of the drawdown as a function of time). The methodology is applied using the hydraulic parameters estimated for the Hontomin site (Northern Spain) where a Technology Demonstration Plant (TDP) for geological CO2 storage is planned to be set up. The reduction of hydraulic conductivity causes an increase in observed drawdowns, the increased storativity in the CO2 zone causes a delay in the drawdown curve with respect to the reference curve measured before CO2 injection. The duration (characteristic time) of these effects can be used to estimate the radius of the CO2 zone. The effects of reduced permeability and increased storativity are well separated from wellbore storage and natural formation responses, even if the CO2-brine interface is inclined (i.e. the CO2 forms a cone around the well). We find that both skin hydraulic conductivity and storativity (and thus residual CO2 saturation) can be obtained from the water injection test provided that water flow rate is carefully controlled and head build

  1. A simplified transfer function for estimating saturated hydraulic conductivity of porous drainage filters

    DEFF Research Database (Denmark)

    Canga, Eriona; Iversen, Bo Vangsø; Kjærgaard, Charlotte

    2013-01-01

    Knowledge of the saturated hydraulic conductivity (Ksat) of porous filters used in water treatment technologies is important for optimizing the retention of nutrients and pollutants. This parameter determines the hydraulic capacity, which together with the Chemical properties of the filter media......, bulk density, uniformity coefficient, particle density, and porosity of 46 porous media fractions. The fractions ranged in grain size from 0.5 to 20 mm and were obtained from seven commercial available coarse filter materials. A backward stepwise regression analysis was performed between Ksat and 10...

  2. A low cost apparatus for measuring the xylem hydraulic conductance in plants

    Directory of Open Access Journals (Sweden)

    Luciano Pereira

    2012-01-01

    Full Text Available Plant yield and resistance to drought are directly related to the efficiency of the xylem hydraulic conductance and the ability of this system to avoid interrupting the flow of water. In this paper we described in detail the assembling of an apparatus proposed by TYREE et al. (2002, and its calibration, as well as low cost adaptations that make the equipment accessible for everyone working in this research area. The apparatus allows measuring the conductance in parts of roots or shoots (root ramifications or branches, or in the whole system, in the case of small plants or seedlings. The apparatus can also be used to measure the reduction of conductance by embolism of the xylem vessels. Data on the hydraulic conductance of eucalyptus seedlings obtained here and other reports in the literature confirm the applicability of the apparatus in physiological studies on the relationship between productivity and water stress.

  3. Contrasting xylem vessel constraints on hydraulic conductivity between native and non-native woody understory species

    Directory of Open Access Journals (Sweden)

    Maria S Smith

    2013-11-01

    Full Text Available We examined the hydraulic properties of 82 native and non-native woody species common to forests of Eastern North America, including several congeneric groups, representing a range of anatomical wood types. We observed smaller conduit diameters with greater frequency in non-native species, corresponding to lower calculated potential vulnerability to cavitation index. Non-native species exhibited higher vessel-grouping in metaxylem compared with native species, however, solitary vessels were more prevalent in secondary xylem. Higher frequency of solitary vessels in secondary xylem was related to a lower potential vulnerability index. We found no relationship between anatomical characteristics of xylem, origin of species and hydraulic conductivity, indicating that non-native species did not exhibit advantageous hydraulic efficiency over native species. Our results confer anatomical advantages for non-native species under the potential for cavitation due to freezing, perhaps permitting extended growing seasons.

  4. Inferring the heterogeneity, transmissivity and hydraulic conductivity of crystalline aquifers from a detailed water-table map

    Science.gov (United States)

    Dewandel, Benoît; Jeanpert, Julie; Ladouche, Bernard; Join, Jean-Lambert; Maréchal, Jean-Christophe

    2017-07-01

    Estimating the transmissivity or hydraulic conductivity field to characterize the heterogeneity of a crystalline aquifer is particularly difficult because of the wide variations of the parameters. We developed a new approach based on the analysis of a dense network of water-table data. It is based on the concept that large-scale variations in hydraulic head may give information on large-scale aquifer parameters. The method assumes that flux into the aquifer is mainly sub-horizontal and that the water table is mostly controlled by topography, rather than recharge. It is based on an empirical statistical relationship between field data on transmissivity and the inverse slope values of a topography-reduced water-table map. This relationship is used to compute a transmissivity map that must be validated with field measurements. The proposed approach can provide a general pattern of transmissivity, or hydraulic conductivity, but cannot correctly reproduce strong variations at very local scale (less than10 m), and will face of some uncertainties where vertical flows cannot be neglected. The method was tested on a peridotite (ultramafic rock) aquifer of 3.5 km2 in area located in New Caledonia. The resulting map shows transmissivity variations over about 5 orders of magnitude (average LogT: -5.2 ± 0.7). Comparison with a map based on measured water-level data (n = 475) shows that the comparison between LogT-computed values and LogT data deduced from 28 hydraulic tests is estimated with an error less than 20% in 71% of cases (LogT ± 0.4), and with an error less than 10% (LogT ± 0.2 on average) in 39% of cases. From this map a hydraulic-conductivity map has been computed showing values ranging over 8 orders of magnitude. The repeatability of the approach was tested on a second data set of hydraulic-head measurements (n = 543); the mean deviation between both LogT maps is about 11%. These encouraging results show that the method can give valuable parameter estimates, and

  5. Regional groundwater characteristics and hydraulic conductivity based on geological units in Korean peninsula

    Science.gov (United States)

    Kim, Y.; Suk, H.

    2011-12-01

    In this study, about 2,000 deep observation wells, stream and/or river distribution, and river's density were analyzed to identify regional groundwater flow trend, based on the regional groundwater survey of four major river watersheds including Geum river, Han river, Youngsan-Seomjin river, and Nakdong river in Korea. Hydrogeologial data were collected to analyze regional groundwater flow characteristics according to geological units. Additionally, hydrological soil type data were collected to estimate direct runoff through SCS-CN method. Temperature and precipitation data were used to quantify infiltration rate. The temperature and precipitation data were also used to quantify evaporation by Thornthwaite method and to evaluate groundwater recharge, respectively. Understanding the regional groundwater characteristics requires the database of groundwater flow parameters, but most hydrogeological data include limited information such as groundwater level and well configuration. In this study, therefore, groundwater flow parameters such as hydraulic conductivities or transmissivities were estimated using observed groundwater level by inverse model, namely PEST (Non-linear Parameter ESTimation). Since groundwater modeling studies have some uncertainties in data collection, conceptualization, and model results, model calibration should be performed. The calibration may be manually performed by changing parameters step by step, or various parameters are simultaneously changed by automatic procedure using PEST program. In this study, both manual and automatic procedures were employed to calibrate and estimate hydraulic parameter distributions. In summary, regional groundwater survey data obtained from four major river watersheds and various data of hydrology, meteorology, geology, soil, and topography in Korea were used to estimate hydraulic conductivities using PEST program. Especially, in order to estimate hydraulic conductivity effectively, it is important to perform

  6. Natural Attenuation of Fuel Hydrocarbon Contaminants:Correlation of Biodegradation with Hydraulic Conductivity in a Field Case Study

    Institute of Scientific and Technical Information of China (English)

    LU Guo-ping; ZHENG Chun-miao

    2004-01-01

    Two biodegradation models are developed to represent natural attenuation of fuel-hydrocarbon contaminants as observed in a comprehensive natural-gradient tracer test in a heterogeneous aquifer on the Columbus Air Force Base in Mississippi, USA. The first, a first-order mass loss model, describes the irreversible losses of BTEX and its individual components, i.e., benzene (B), toluene (T), ethyl benzene (E), and xylene (X). The second, a reactive pathway model, describes sequential degradation pathways for BTEX utilizing multiple electron acceptors, including oxygen, nitrate, iron and sulfate, and via methanogenesis. The heterogeneous aquifer is represented by multiple hydraulic conductivity (K) zones delineated on the basis of numerous flowmeter K measurements. A direct propagation artificial neural network (DPN) is used as an inverse modeling tool to estimate the biodegradation rate constants associated with each of the K zones. In both the mass loss model and the reactive pathway model, the biodegradation rate constants show an increasing trend with the hydraulic conductivity. The finding of correlation between biodegradation kinetics and hydraulic conductivity distributions is of general interest and relevance to characterization and modeling of natural attenuation of hydrocarbons in other petroleum-product contaminated sites.

  7. Application of a new hydraulic conductivity model to simulate rapid groundwater fluctuations in the Eel River watershed in Northern California

    Science.gov (United States)

    Vrettas, M. D.; Fung, I. Y.

    2015-12-01

    High-frequency multi-year observations of the water table at several wells in the Angelo Coast Range Reserve in the Eel River Watershed in northern California show rapid fluctuations, where the water table, some 10-15 meters below the surface, rises by as much as 1 meter in a day or two after the first storms of the rain season. The observations highlight preferential flow through weathered bedrock, which can store as much as 30% of the moisture in the column ("rock moisture"). This rapid transfer of moisture and storage at depth could have a significant impact on ecosystem dynamics and the water and energy budgets of the atmosphere on various time scales. Despite its high importance, preferential flow through weather bedrock is not routinely captured in most climate models. This work presents a new hydraulic conductivity parameterization that captures the preferential flow, with straightforward implementation into current global climate models. The hydraulic conductivity is represented as a product of the effective saturation (normalized water content) and a background hydraulic conductivity Kbkg, drawn from a depth dependent lognormal distribution. A unique feature of the parameterization is that the variance of hydraulic conductivity is large when there is little rock moisture, and decreases with increasing saturation, mimicking flow through fractures. The new method is applied to seven wells locations on a steep (35 degrees) hill-slope in the Eel River watershed in Northern California, for the duration of six years and estimates of the model parameters are provided by assimilating, into Richards' equation, measurements of precipitation [mm] and water table depths [m] at 30-minute time intervals. The simulation results show that the new approach yields a good agreement of the rapid rise of the observed water table at the tested well locations. Furthermore, the water stored in the weathered bedrock is estimated to be in the range between 32% and 41%, which could

  8. Mind the bubbles: achieving stable measurements of maximum hydraulic conductivity through woody plant samples.

    Science.gov (United States)

    Espino, Susana; Schenk, H Jochen

    2011-01-01

    The maximum specific hydraulic conductivity (k(max)) of a plant sample is a measure of the ability of a plants' vascular system to transport water and dissolved nutrients under optimum conditions. Precise measurements of k(max) are needed in comparative studies of hydraulic conductivity, as well as for measuring the formation and repair of xylem embolisms. Unstable measurements of k(max) are a common problem when measuring woody plant samples and it is commonly observed that k(max) declines from initially high values, especially when positive water pressure is used to flush out embolisms. This study was designed to test five hypotheses that could potentially explain declines in k(max) under positive pressure: (i) non-steady-state flow; (ii) swelling of pectin hydrogels in inter-vessel pit membranes; (iii) nucleation and coalescence of bubbles at constrictions in the xylem; (iv) physiological wounding responses; and (v) passive wounding responses, such as clogging of the xylem by debris. Prehydrated woody stems from Laurus nobilis (Lauraceae) and Encelia farinosa (Asteraceae) collected from plants grown in the Fullerton Arboretum in Southern California, were used to test these hypotheses using a xylem embolism meter (XYL'EM). Treatments included simultaneous measurements of stem inflow and outflow, enzyme inhibitors, stem-debarking, low water temperatures, different water degassing techniques, and varied concentrations of calcium, potassium, magnesium, and copper salts in aqueous measurement solutions. Stable measurements of k(max) were observed at concentrations of calcium, potassium, and magnesium salts high enough to suppress bubble coalescence, as well as with deionized water that was degassed using a membrane contactor under strong vacuum. Bubble formation and coalescence under positive pressure in the xylem therefore appear to be the main cause for declining k(max) values. Our findings suggest that degassing of water is essential for achieving stable and

  9. Models for Unsaturated Hydraulic Conductivity Based on Truncated Lognormal Pore-size Distributions

    CERN Document Server

    Malama, Bwalya

    2013-01-01

    We develop a closed-form three-parameter model for unsaturated hydraulic conductivity associated with a three-parameter lognormal model of moisture retention, which is based on lognormal grainsize distribution. The derivation of the model is made possible by a slight modification to the theory of Mualem. We extend the three-parameter lognormal distribution to a four-parameter model that also truncates the pore size distribution at a minimum pore radius. We then develop the corresponding four-parameter model for moisture retention and the associated closed-form expression for unsaturated hydraulic conductivity. The four-parameter model is fitted to experimental data, similar to the models of Kosugi and van Genuchten. The proposed four-parameter model retains the physical basis of Kosugi's model, while improving fit to observed data especially when simultaneously fitting pressure-saturation and pressure-conductivity data.

  10. CFX Analysis of the CANDU Moderator Thermal-Hydraulics in the Stern Lab. Test Facility

    Science.gov (United States)

    Kim, Hyoung Tae

    2014-06-01

    A numerical calculation with the commercial CFD code CFX is conducted for a test facility simulating the CANDU moderator thermal-hydraulics. Two kinds of moderator thermal-hydraulic tests at Stern Laboratories Inc. were performed in the full geometric configuration of the CANDU moderator circulating vessel, which is called a Calandria, housing a matrix of horizontal rod bundles simulating the Calandria tubes. The first of these tests is the pressure drop measurement of a cross flow in the horizontal rod bundles. The other is the local temperature measurement on the cross section of the horizontal cylinder vessel simulating the Calandria. In the present study the full geometric details of the Calandria are incorporated in the grid generation of the computational domain to which the boundary conditions for each experiment are applied. The numerical solutions are reviewed and compared with the available test data.

  11. Sample dimensions effect on prediction of soil water retention curve and saturated hydraulic conductivity

    Science.gov (United States)

    Ghanbarian, Behzad; Taslimitehrani, Vahid; Dong, Guozhu; Pachepsky, Yakov A.

    2015-09-01

    Soil water retention curve (SWRC) and saturated hydraulic conductivity (SHC) are key hydraulic properties for unsaturated zone hydrology and groundwater. Not only the SWRC and SHC measurements are time-consuming, but also their results are scale dependent. Although prediction of the SWRC and SHC from available parameters, such as textural data, organic matter, and bulk density have been under investigation for decades, up to now no research has focused on the effect of sample dimensions on the soil hydraulic properties pedotransfer functions development. The main purpose here is investigating sample internal diameter and height (or length) effects on the prediction of the soil water retention curve and the saturated hydraulic conductivity. We, therefore, develop pedotransfer functions using a novel approach called contrast pattern aided regression (CPXR) and consider the sample dimensions as input variables. Two datasets including 210 and 213 soil samples with known sample dimensions were extracted from the UNSODA database to develop and evaluate pedotransfer functions for the SWRC and SHC, respectively. The 10-fold cross-validation method is applied to evaluate the accuracy and reliability of the proposed regression-based models. Our results show that including sample dimensions, such as sample internal diameter and height (or length) could substantially improve the accuracy of the SWRC and SHC pedotransfer functions developed using the CPXR method.

  12. Comparison of Measured and Modelled Hydraulic Conductivities of Fractured Sandstone Cores

    Science.gov (United States)

    Baraka-Lokmane, S.; Liedl, R.; Teutsch, G.

    - A new method for characterising the detailed fracture geometry in sandstone cores is presented. This method is based on the impregnation of samples with coloured resin, without significant disturbance of the fractures. The fractures are made clearly visible by the resin, thus allowing the fracture geometry to be examined digitally. In order to model the bulk hydraulic conductivity, the samples are sectioned serially perpendicular to the flow direction. The hydraulic conductivity of individual sections is estimated by summing the contribution of the matrix and each fracture from the digital data. Finally, the hydraulic conductivity of the bulk sample is estimated by a harmonic average in series along the flow path. Results of this geometrical method are compared with actual physical conductivity values measured from fluid experiments carried out prior to sectioning. The predicted conductivity from the fracture geometry parameters (e.g., fracture aperture, fracture width, fracture length and fracture relative roughness all measured using an optical method) is in good agreement with the independent physical measurements, thereby validating the approach.

  13. Comparison of laboratory, in situ, and rock mass measurements of the hydraulic conductivity of metamorphic rock at the Savannah River Plant near Aiken, South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Marine, I W

    1980-01-01

    In situ testing of exploratory wells in metamorphic rock indicates that two types of fracturing occur in the rock mass. Rock containing small openings that permit only extremely slow movement of water is termed virtually impermeable rock. Rock containing openings of sufficient size to permit transmission of water at a significantly faster rate is termed hydraulically transmissive rock. Laboratory methods are unsuitable for measuring hydraulic conductivity in hydraulically transmissive rock; however, for the virtually impermeable rock, values comparable to the in situ tests are obtained. The hydraulic conductivity of the rock mass over a large region is calculated by using the hydraulic gradient, porosity, and regional velocity. This velocity is determined by dividing the inferred travel distance by the age of water which is determined by the helium content of the water. This rock mass hydraulic conductivity value is between the values measured for the two types of fractures, but is closer to the measured value for the virtually impermeable rock. This relationship is attributed to the control of the regional flow rate by the virtually impermeable rock where the discrete fractures do not form a continuous open connection through the entire rock mass. Thus, laboratory methods of measuring permeability in metamorphic rock are of value if they are properly applied.

  14. Comparison of Laboratory, in Situ, and Rock Mass Measurements of the Hydraulic Conductivity of Metamorphic Rock at the Savannah River Plant Near Aiken, South Carolina

    Science.gov (United States)

    Marine, I. Wendell

    1981-06-01

    In situ testing of exploratory wells in metamorphic rock indicates that two types of fracturing occur in the rock mass. Rock containing small openings that permit only extremely slow movement of water is termed virtually impermeable rock. Rock containing openings of sufficient size to permit transmission of water at a significantly faster rate is termed hydraulically transmissive rock. Laboratory methods are unsuitable for measuring hydraulic conductivity in hydraulically transmissive rock; however, for the virtually impermeable rock, values comparable to those of the in situ tests are obtained. The hydraulic conductivity of the rock mass over a large region is calculated by using the hydraulic gradient, porosity, and regional velocity. This velocity is determined by dividing the inferred travel distance by the age of water, which is determined by the helium content of the water. This rock mass hydraulic conductivity value is between the values measured for the two types of fractures but is closer to the measured value for the virtually impermeable rock. This relationship is attributed to the control of the regional flow rate by the virtually impermeable rock where the discrete fractures do not form a continuous open connection through the entire rock mass. Thus laboratory methods of measuring permeability in metamorphic rock are of value if they are properly applied.

  15. Characterisation of river-aquifer exchange fluxes: The role of spatial patterns of riverbed hydraulic conductivities

    Science.gov (United States)

    Tang, Q.; Kurtz, W.; Brunner, P.; Vereecken, H.; Hendricks Franssen, H.-J.

    2015-12-01

    Interactions between surface water and groundwater play an essential role in hydrology, hydrogeology, ecology, and water resources management. A proper characterisation of riverbed structures might be important for estimating river-aquifer exchange fluxes. The ensemble Kalman filter (EnKF) is commonly used in subsurface flow and transport modelling for estimating states and parameters. However, EnKF only performs optimally for MultiGaussian distributed parameter fields, but the spatial distribution of streambed hydraulic conductivities often shows non-MultiGaussian patterns, which are related to flow velocity dependent sedimentation and erosion processes. In this synthetic study, we assumed a riverbed with non-MultiGaussian channel-distributed hydraulic parameters as a virtual reference. The synthetic study was carried out for a 3-D river-aquifer model with a river in hydraulic connection to a homogeneous aquifer. Next, in a series of data assimilation experiments three different groups of scenarios were studied. In the first and second group of scenarios, stochastic realisations of non-MultiGaussian distributed riverbeds were inversely conditioned to state information, using EnKF and the normal score ensemble Kalman filter (NS-EnKF). The riverbed hydraulic conductivity was oriented in the form of channels (first group of scenarios) or, with the same bimodal histogram, without channelling (second group of scenarios). In the third group of scenarios, the stochastic realisations of riverbeds have MultiGaussian distributed hydraulic parameters and are conditioned to state information with EnKF. It was found that the best results were achieved for channel-distributed non-MultiGaussian stochastic realisations and with parameter updating. However, differences between the simulations were small and non-MultiGaussian riverbed properties seem to be of less importance for subsurface flow than non-MultiGaussian aquifer properties. In addition, it was concluded that both En

  16. Determination of hydraulic conductivities of low permeability materials in the Sierra Ladrones Formation, Albuquerque basin

    Energy Technology Data Exchange (ETDEWEB)

    Planert, C.S.

    1995-06-01

    Low permeability materials in the Sierra Ladrones Formation were sampled and analyzed to determine their hydraulic conductivities using the falling head centrifugation method (fc) as described by Nimmo et al. (1991). The method is similar to the traditional falling head method, only it uses greatly increased centrifugal forces, allowing measurements to make in a relatively short amount of time. Using these measurements, variations in saturated hydraulic conductivities between different sediment types were analyzed using Analysis of Variance (ANOVA). Sampling resulted in useable data chiefly from the clay and silt facies of the formation. The range of conductivities determined are representative of brown and red clays, and silts which make up the overbank deposits of this region. Hydraulic conductivities for these overbank fines were found to range from approximately log K = {minus}9 m/s to log K = {minus}7 m/s. The upper measurement limit of the centrifuge apparatus was determined to be approximately 1.43 {times} 10{sup {minus}7} m/s and the lower limit was approximately 7.6 {times} 10{sup {minus}12} m/s.

  17. Joint inversion of hydraulic head and self-potential data associated with harmonic pumping tests

    Science.gov (United States)

    Soueid Ahmed, A.; Jardani, A.; Revil, A.; Dupont, J. P.

    2016-09-01

    Harmonic pumping tests consist in stimulating an aquifer by the means of hydraulic stimulations at some discrete frequencies. The inverse problem consisting in retrieving the hydraulic properties is inherently ill posed and is usually underdetermined when considering the number of well head data available in field conditions. To better constrain this inverse problem, we add self-potential data recorded at the ground surface to the head data. The self-potential method is a passive geophysical method. Its signals are generated by the groundwater flow through an electrokinetic coupling. We showed using a 3-D saturated unconfined synthetic aquifer that the self-potential method significantly improves the results of the harmonic hydraulic tomography. The hydroelectric forward problem is obtained by solving first the Richards equation, describing the groundwater flow, and then using the result in an electrical Poisson equation describing the self-potential problem. The joint inversion problem is solved using a reduction model based on the principal component geostatistical approach. In this method, the large prior covariance matrix is truncated and replaced by its low-rank approximation, allowing thus for notable computational time and storage savings. Three test cases are studied, to assess the validity of our approach. In the first test, we show that when the number of harmonic stimulations is low, combining the harmonic hydraulic and self-potential data does not improve the inversion results. In the second test where enough harmonic stimulations are performed, a significant improvement of the hydraulic parameters is observed. In the last synthetic test, we show that the electrical conductivity field required to invert the self-potential data can be determined with enough accuracy using an electrical resistivity tomography survey using the same electrodes configuration as used for the self-potential investigation.

  18. Avoidance of harvesting and sampling artefacts in hydraulic analyses: a protocol tested on Malus domestica.

    Science.gov (United States)

    Beikircher, Barbara; Mayr, Stefan

    2016-06-01

    A prerequisite for reliable hydraulic measurements is an accurate collection of the plant material. Thereby, the native hydraulic state of the sample has to be preserved during harvesting (i.e., cutting the plant or plant parts) and preparation (i.e., excising the target section). This is particularly difficult when harvesting has to be done under transpiring conditions. In this article, we present a harvesting and sampling protocol designed for hydraulic measurements on Malus domestica Borkh. and checked for possible sampling artefacts. To test for artefacts, we analysed the percentage loss of hydraulic conductivity, maximum specific conductivity and water contents of bark and wood of branches, taking into account conduit length, time of day of harvesting, different shoot ages and seasonal effects. Our results prove that use of appropriate protocols can avoid artefactual embolization or refilling even when the xylem is under tension at harvest. The presented protocol was developed for Malus but may also be applied for other angiosperms with similar anatomy and refilling characteristics.

  19. Influence of hydroponic culture method on morphology and hydraulic conductivity of roots of honey locust.

    Science.gov (United States)

    Graves, W R

    1992-09-01

    The morphology and hydraulic conductivity of root systems of Gleditsia triacanthos L. var. inermis Willd. (honey locust) grown hydroponically in sand and solution cultures were compared. Total root system length was similar in the two cultures. However, root systems grown in solution had longer primary roots, fewer lateral roots and root hairs, and a greater distance between the tip of the primary root and the junction of the youngest secondary root and the primary root than root systems grown in sand. Hydraulic conductivities of root systems grown hydroponically for 21 or 35 days in sand or solution culture were similar. These findings show that different methods of hydroponic culture can affect root morphology without altering root resistance to water transport.

  20. Estimating Saturated Hydraulic Conductivity from Surface Ground-Penetrating Radar Monitoring of Infiltration

    CERN Document Server

    Léger, Emmanuel; Coquet, Yves

    2013-01-01

    In this study we used Hydrus-1D to simulate water infiltration from a ring infiltrometer. We generated water content profiles at each time step of infiltration, based on a particular value of the saturated hydraulic conductivity while knowing the other van Genuchten parameters. Water content profiles were converted to dielectric permittivity profiles using the Complex Refractive Index Method relation. We then used the GprMax suite of programs to generate radargrams and to follow the wetting front using arrival time of electromagnetic waves recorded by a Ground-Penetrating Radar (GPR). Theoretically, the depth of the inflection point of the water content profile simulated at any infiltration time step is related to the peak of the reflected amplitude recorded in the corresponding trace in the radargram. We used this relationship to invert the saturated hydraulic conductivity for constant and falling head infiltrations. We present our method on synthetic examples and on two experiments carried out on sand. We f...

  1. Estimating saturated hydraulic conductivity and air permeability from soil physical properties using state-space analysis

    DEFF Research Database (Denmark)

    Poulsen, Tjalfe; Møldrup, Per; Nielsen, Don

    2003-01-01

    field were used. Multiple regression and ARIMA models yielded similar prediction accuracy, whereas state-space models generally gave significantly higher accuracy. State-space modeling suggested K-S at a given location could be predicted using nearby values of K-S, k(a100) and air-filled porosity......Estimates of soil hydraulic conductivity (K) and air permeability (k(a)) at given soil-water potentials are often used as reference points in constitutive models for K and k(a) as functions of moisture content and are, therefore, a prerequisite for predicting migration of water, air, and dissolved...... and gaseous chemicals in the vadose zone. In this study, three modeling approaches were used to identify the dependence of saturated hydraulic conductivity (K-S) and air permeability at -100 cm H2O soil-water potential (k(a100)) on soil physical properties in undisturbed soil: (i) Multiple regression, (ii...

  2. ROOT HYDRAULIC CONDUCTIVITY AND PHOTOSYNTHETIC CAPACITY OF EUCALYPT CLONAL CUTTINGS WITH ROOT MALFORMATION INDUCTIONS

    Directory of Open Access Journals (Sweden)

    Fábio Afonso Mazzei Moura de Assis Figueiredo

    2014-06-01

    Full Text Available http://dx.doi.org/10.5902/1980509814566The gain reduction of wood biomass in trees has been assigned to root deformations even in the nursery phase. The objective of this work was the evaluation of the root system hydraulic conductivity, gas exchanges and photochemical efficiency of eucalypt clonal cuttings with and without root deformation inductions. The treatments were: 1 operational cuttings without root malformation inductions (grown according to the used methodology of Fibria Cellulose S.A.; 2 root deformation inductions. These inductions did not promote decrease in the root volume. However, the deformations brought reduction of the root system hydraulic conductivity. Lower photosynthetic rates were also observed along the day in the cuttings in the root deformed cuttings. This decreasing rate is connected to stomatal and non stomatal factors.

  3. The chemical identity of intervessel pit membranes in Acer challenges hydrogel control of xylem hydraulic conductivity

    Science.gov (United States)

    Klepsch, Matthias M.; Schmitt, Marco; Paul Knox, J.; Jansen, Steven

    2016-01-01

    Ion-mediated enhancement of the hydraulic conductivity of xylem tissue (i.e. the ionic effect) has been reported for various angiosperm species. One explanation of the ionic effect is that it is caused by the swelling and shrinking of intervessel pit membranes due to the presence of pectins and/or other cell-wall matrix polymers such as heteroxylans or arabinogalactan–proteins (AGPs) that may contain acidic sugars. Here, we examined the ionic effect for six Acer species and their pit membrane chemistry using immunocytochemistry, including antibodies against glycoproteins. Moreover, anatomical features related to the bordered pit morphology and vessel dimensions were investigated using light and electron microscopy. The ionic effect varied from 18 % (± 9) to 32 % (± 13). Epitopes of homogalacturonan (LM18) and xylan (LM11) were not detected in intervessel pit membranes. Negative results were also obtained for glycoproteins (extensin: LM1, JIM20; AGP glycan: LM2), although AGP (JIM13)-related epitopes were detected in parenchyma cells. The mean vessel length was significantly correlated with the magnitude of the ionic effect, unlike other pit or vessel-related characteristics. Our results suggest that intervessel pit membranes of Acer are unlikely to contain pectic or other acidic polysaccharides. Therefore, alternative explanations should be tested to clarify the ionic effect. PMID:27354661

  4. Spectral induced polarization measurements for predicting the hydraulic conductivity in sandy aquifers

    Directory of Open Access Journals (Sweden)

    M. Attwa

    2013-10-01

    Full Text Available Field and laboratory spectral induced polarization (SIP measurements are integrated to characterize the hydrogeological conditions at the Schillerslage test site in Germany. The phase images are capable of monitoring thin peat layers within the sandy aquifers. However, the field results show limitations of decreasing resolution with depth. In comparison with the field inversion results, the SIP laboratory measurements show a certain shift in SIP response due to different compaction and sorting of the samples. The SIP data are analyzed to derive an empirical relationship for predicting the hydraulic conductivity (K. In particular, two significant but weak correlations between individual real resistivities (ρ' and relaxation times (τ, based on a Debye decomposition (DD model, with measured K are found for the upper groundwater aquifer. The maximum relaxation time (τmax and logarithmically weighted average relaxation time (τlw show a better relation with K values than the median value τ50. A combined power law relation between individual ρ' and τ with K is developed with an expression of A · (ρ'B · (τlwC, where A, B and C are determined using a least-squares fit between the measured and predicted K. The suggested approach with the calculated coefficients of the first aquifer is applied for the second. Results show good correlation with the measured K indicating that the derived relationship is superior to single phase angle models as Börner or Slater models.

  5. Reassessing the MADE direct-push hydraulic conductivity data using a revised calibration procedure

    Science.gov (United States)

    Bohling, Geoffrey C.; Liu, Gaisheng; Dietrich, Peter; Butler, James J.

    2016-11-01

    In earlier work, we presented a geostatistical assessment of high-resolution hydraulic conductivity (K) profiles obtained at the MADE site using direct-push (DP) methods. The profiles are derived from direct-push injection logger (DPIL) measurements that provide a relative indicator of vertical variations in K with a sample spacing of 1.5 cm. The DPIL profiles are converted to K profiles by calibrating to the results of direct-push permeameter (DPP) tests performed at selected depths in some of the profiles. Our original calibration used a linear transform that failed to adequately account for an upper limit on DPIL responses in high-K zones and noise in the DPIL data. Here we present a revised calibration procedure that accounts for the upper limit and noise, leading to DPIL K values that display a somewhat different univariate distribution and a lower lnK variance (5.9 ± 1.5) than the original calibration values (6.9 ± 1.8), although each variance estimate falls within the other's 95% confidence interval. Despite the change in the univariate distribution, the autocorrelation structure and large-scale patterns exhibited by the revised DPIL K values still agree well with those exhibited by the flowmeter data from the site. We provide the DPIL and DPP data, along with our calibrated DPIL K values, in the Supporting Information.

  6. Rapid measurement of field-saturated hydraulic conductivity for areal characterization

    Science.gov (United States)

    Nimmo, J.R.; Schmidt, K.M.; Perkins, K.S.; Stock, J.D.

    2009-01-01

    To provide an improved methodology for characterizing the field-saturated hydraulic conductivity (Kfs) over broad areas with extreme spatial variability and ordinary limitations of time and resources, we developed and tested a simplified apparatus and procedure, correcting mathematically for the major deficiencies of the simplified implementation. The methodology includes use of a portable, falling-head, small-diameter (???20 cm) single-ring infiltrometer and an analytical formula for Kfs that compensates both for nonconstant falling head and for the subsurface radial spreading that unavoidably occurs with small ring size. We applied this method to alluvial fan deposits varying in degree of pedogenic maturity in the arid Mojave National Preserve, California. The measurements are consistent with a more rigorous and time-consuming Kfs measurement method, produce the expected systematic trends in Kfs when compared among soils of contrasting degrees of pedogenic development, and relate in expected ways to results of widely accepted methods. ?? Soil Science Society of America. All rights reserved.

  7. Integration of Fuzzy and Probabilistic Information in the Description of Hydraulic Conductivity

    Science.gov (United States)

    Druschel, B.; Ozbek, M.; Pinder, G.

    2004-12-01

    Evaluation of the heterogeneity of hydraulic conductivity, K, is a well-known problem in groundwater hydrology. The open question is how to fully represent a given highly heterogeneous K field and its inherent uncertainty at least cost. Today, most K fields are analyzed using field test data and probability theory. Uncertainty is usually reported in the spatial covariance. In an attempt to develop a more cost effective method which still provides an accurate approximation of a K field, we propose using an evidence theory framework to merge probabilistic and fuzzy (or possibilistic) information in an effort to improve our ability to fully define a K field. The tool chosen to fuse probabilistic information obtained via experiment and subjective information provided by the groundwater professional is Dempster's Rule of Combination. In using this theory we must create mass assignments for our subject of interest, describing the degree of evidence that supports the presence of our subject in a particular set. These mass assignments can be created directly from the probabilistic information and, in the case of the subjective information, from feedback we obtain from an expert. The fusion of these two types of information provides a better description of uncertainty than would typically be available with just probability theory alone.

  8. The effect of the shape parameters of a sample on the hydraulic conductivity

    Science.gov (United States)

    Kucza, Jarosław; Ilek, Anna

    2016-03-01

    The present study is a complement to the research investigating a laboratory method for measuring the saturated hydraulic conductivity of mountain forest soils, the results of which were presented in a paper by Ilek and Kucza (2014). The aim of the study is to analyse the influence of variation of particular cross-sections of samples and their enlarged side surface on the hydraulic conductivity measurement. The results show that a narrowing in the upper section of the sample results in an approximately twice lower disturbance of the laminar water flow than the narrowing occurring inside the sample. For that reason, the extent of the effect of the cross-section narrowing on the hydraulic conductivity measurement error is dependent on the location of the narrowing. An enlarged side surface of a sample, as described by the coefficient of side surface development, is on average 30% larger than the surface of a sample having the same volume and the same average cross-sectional area but a regular shape. The values of the coefficient of side surface development for a given sample were adopted in the range of 1.10-1.56. Among the shape parameters of the analysed irregular soil samples, the greatest impact on the measurement error is exerted by their enlarged lateral surface, which almost entirely explains the whole error of hydraulic conductivity measurement. The variability of successive cross-sectional areas of samples appears to be of marginal importance for the occurrence of this error, whose mean value was 1.15%.

  9. Bayesian Model Averaging of Artificial Intelligence Models for Hydraulic Conductivity Estimation

    Science.gov (United States)

    Nadiri, A.; Chitsazan, N.; Tsai, F. T.; Asghari Moghaddam, A.

    2012-12-01

    This research presents a Bayesian artificial intelligence model averaging (BAIMA) method that incorporates multiple artificial intelligence (AI) models to estimate hydraulic conductivity and evaluate estimation uncertainties. Uncertainty in the AI model outputs stems from error in model input as well as non-uniqueness in selecting different AI methods. Using one single AI model tends to bias the estimation and underestimate uncertainty. BAIMA employs Bayesian model averaging (BMA) technique to address the issue of using one single AI model for estimation. BAIMA estimates hydraulic conductivity by averaging the outputs of AI models according to their model weights. In this study, the model weights were determined using the Bayesian information criterion (BIC) that follows the parsimony principle. BAIMA calculates the within-model variances to account for uncertainty propagation from input data to AI model output. Between-model variances are evaluated to account for uncertainty due to model non-uniqueness. We employed Takagi-Sugeno fuzzy logic (TS-FL), artificial neural network (ANN) and neurofuzzy (NF) to estimate hydraulic conductivity for the Tasuj plain aquifer, Iran. BAIMA combined three AI models and produced better fitting than individual models. While NF was expected to be the best AI model owing to its utilization of both TS-FL and ANN models, the NF model is nearly discarded by the parsimony principle. The TS-FL model and the ANN model showed equal importance although their hydraulic conductivity estimates were quite different. This resulted in significant between-model variances that are normally ignored by using one AI model.

  10. Silicon Enhances Water Stress Tolerance by Improving Root Hydraulic Conductance in Solanum lycopersicum L.

    Science.gov (United States)

    Shi, Yu; Zhang, Yi; Han, Weihua; Feng, Ru; Hu, Yanhong; Guo, Jia; Gong, Haijun

    2016-01-01

    Silicon (Si) can improve drought tolerance in plants, but the mechanism is still not fully understood. Previous research has been concentrating on Si's role in leaf water maintenance in Si accumulators, while little information is available on its role in water uptake and in less Si-accumulating plants. Here, we investigated the effects of Si on root water uptake and its role in decreasing oxidative damage in relation to root hydraulic conductance in tomato (Solanum lycopersicum 'Zhongza No.9') under water stress. Tomato seedlings were subjected to water stress induced by 10% (w/v) polyethylene glycol-6000 in the absence or presence of 2.5 mM added silicate. The results showed that Si addition ameliorated the inhibition in tomato growth and photosynthesis, and improved water status under water stress. The root hydraulic conductance of tomato plants was decreased under water stress, and it was significantly increased by added Si. There was no significant contribution of osmotic adjustment in Si-enhanced root water uptake under water stress. The transcriptions of plasma membrane aquaporin genes were not obviously changed by Si under water stress. Water stress increased the production of reactive oxygen species and induced oxidative damage, while added Si reversed these. In addition, Si addition increased the activities of superoxide dismutase and catalase and the levels of ascorbic acid and glutathione in the roots under stress. It is concluded that Si enhances the water stress tolerance via enhancing root hydraulic conductance and water uptake in tomato plants. Si-mediated decrease in membrane oxidative damage may have contributed to the enhanced root hydraulic conductance.

  11. Silicon enhances water stress tolerance by improving root hydraulic conductance in Solanum lycopersicum L.

    Directory of Open Access Journals (Sweden)

    Yu eShi

    2016-02-01

    Full Text Available Silicon (Si can improve drought tolerance in plants, but the mechanism is still not fully understood. Previous research has been concentrating on Si’s role in leaf water maintenance in Si accumulators, while little information is available on its role in water uptake and in less Si-accumulating plants. Here, we investigated the effects of Si on root water uptake and its role in decreasing oxidative damage in relation to root hydraulic conductance in tomato (Solanum lycopersicum ‘Zhongza No.9’ under water stress. Tomato seedlings were subjected to water stress induced by 10% (w/v polyethylene glycol-6000 in the absence or presence of 2.5 mM added silicate. The results showed that Si addition ameliorated the inhibition in tomato growth and photosynthesis, and improved water status under water stress. The root hydraulic conductance of tomato plants was decreased under water stress, and it was significantly increased by added Si. There was no significant contribution of osmotic adjustment in Si-enhanced root water uptake under water stress. The transcriptions of plasma membrane aquaporin genes were not obviously changed by Si under water stress. Water stress increased the production of reactive oxygen species and induced oxidative damage, while added Si reversed these. In addition, Si addition increased the activities of superoxide dismutase and catalase and the levels of ascorbic acid and glutathione in the roots under stress. It is concluded that Si enhances the water stress tolerance via enhancing root hydraulic conductance and water uptake in tomato plants. Si-mediated decrease in membrane oxidative damage may have contributed to the enhanced root hydraulic conductance.

  12. Study on test and preparation of load spectrum of hydraulic excavator

    Science.gov (United States)

    Zhang, Hong; Feng, Guodi; Zhang, Haijun; Wang, Xiaofeng; Zhang, Yingzhi

    2017-01-01

    Due to harsh working conditions, the components of hydraulic excavator are subject to large amount of alternating load and random load during the operation and they are seriously damaged. The test of load signal and preparation of load spectrum for the hydraulic excavator are studied in this paper. In the first place, pretreatment of filtering and noise reduction for load signal is conducted based on experimental test on site and experimental working condition analysis. After the load signal is processed in sections, distribution fitting is performed for information like mean amplitude after rain flow counting with the approach of probability statistics to get the probability distribution function for mean value and amplitude value. Finally the two dimensional load spectrum for mean amplitude is obtained and program spectrum loading solution of fatigue experiment is given. The study of load signal test and load spectrum preparation method for hydraulic excavator conducted in this paper is of great significance for clarification of load distribution of excavator and further reliability test of excavator.

  13. Characterizing hydraulic fractures in shale gas reservoirs using transient pressure tests

    Directory of Open Access Journals (Sweden)

    Cong Wang

    2015-06-01

    This work presents an unconventional gas reservoir simulator and its application to quantify hydraulic fractures in shale gas reservoirs using transient pressure data. The numerical model incorporates most known physical processes for gas production from unconventional reservoirs, including two-phase flow of liquid and gas, Klinkenberg effect, non-Darcy flow, and nonlinear adsorption. In addition, the model is able to handle various types and scales of fractures or heterogeneity using continuum, discrete or hybrid modeling approaches under different well production conditions of varying rate or pressure. Our modeling studies indicate that the most sensitive parameter of hydraulic fractures to early transient gas flow through extremely low permeability rock is actually the fracture-matrix contacting area, generated by fracturing stimulation. Based on this observation, it is possible to use transient pressure testing data to estimate the area of fractures generated from fracturing operations. We will conduct a series of modeling studies and present a methodology using typical transient pressure responses, simulated by the numerical model, to estimate fracture areas created or to quantity hydraulic fractures with traditional well testing technology. The type curves of pressure transients from this study can be used to quantify hydraulic fractures in field application.

  14. The perceptual trap: Experimental and modelling examples of soil moisture, hydraulic conductivity and response units in complex subsurface settings.

    Science.gov (United States)

    Jackisch, Conrad; Demand, Dominic; Allroggen, Niklas; Loritz, Ralf; Zehe, Erwin

    2017-04-01

    In order to discuss hypothesis testing in hydrology, the question of the solid foundation of such tests has to be answered. But how certain are we about our measurements of the components of the water balance and the states and dynamics of the complex systems? What implicit assumptions or bias are already embedded in our perception of the processes? How can we find light in the darkness of heterogeneity? We will contribute examples from experimental findings, modelling approaches and landscape analysis to the discussion. Example soil moisture and the soil continuum: The definition of soil moisture as fraction of water in the porous medium assumes locally well-mixed conditions. Moreover, a unique relation of soil water retention presumes instant local thermodynamic equilibrium in the pore water arrangement. We will show findings from soil moisture responses to precipitation events, from irrigation experiments, and from a model study of initial infiltration velocities. The results highlight, that the implicit assumption relating soil moisture state dynamics with actual soil water flow is biased towards the slow end of the actual velocity distribution and rather blind for preferential flow acting in a very small proportion of the pore space. Moreover, we highlight the assumption of a well-defined continuum during the extrapolation of point-scale measurements and why spatially and temporally continuous observation techniques of soil water states are essential for advancing our understanding and development of subsurface process theories. Example hydraulic conductivity: Hydraulic conductivity lies at the heart of hydrological research and modelling. Its values can range across several orders of magnitude at a single site alone. Yet, we often consider it a crisp, effective parameter. We have conducted measurements of soil hydraulic conductivity in the lab and in the field. Moreover, we assessed infiltration capacity and conducted plot-scale irrigation experiments to

  15. Influence of soil, land use and climatic factors on the hydraulic conductivity of soil

    Science.gov (United States)

    Jarvis, N.; Koestel, J.; Messing, I.; Moeys, J.; Lindahl, A.

    2013-12-01

    Due to inadequate data support, existing algorithms used to estimate soil hydraulic conductivity, K, in (eco)hydrological models ignore the effects of key site factors such as land use and climate and underplay the significant effects of soil structure on water flow at and near saturation. These limitations may introduce serious bias and error into predictions of terrestrial water balances and soil moisture status, and thus plant growth and rates of biogeochemical processes. To resolve these issues, we collated a new global database of hydraulic conductivity measured by tension infiltrometer under field conditions. The results of our analyses on this data set contrast markedly with those of existing algorithms used to estimate K. For example, saturated hydraulic conductivity, Ks, in the topsoil (< 0.3 m depth) was found to be only weakly related to texture. Instead, the data suggests that Ks depends more strongly on bulk density, organic carbon content and land use. In this respect, organic carbon was negatively correlated with Ks, presumably due to water repellency, while Ks at arable sites was, on average, ca. 2-3 times smaller than under natural vegetation, forests and perennial agriculture. The data also clearly demonstrates that clay soils have smaller K in the soil matrix and thus a larger contribution of soil macropores to K at and near saturation.

  16. Effect of formation characteristics on hydraulic conductivity in unconfined bed in Etchie, rivers state of Nigeria

    Directory of Open Access Journals (Sweden)

    Solomon Ndubuisi Eluozo

    2013-01-01

    Full Text Available Formation characteristics determine the hydraulic conductivity of the soil, the major parameter that determine the rate of hydraulic conductivity of the soil in study location are void ratio and permeability of the soil, degree of void ratio and permeability where determine to evaluate the rate of hydraulic conductivity and storage coefficient,the results from these two parameters  shows the variation deposition of void ratio and permeability in the study location. Ground water hydrogeological data where found to be unavailable in the study area this condition has resulted to a lots of abortive well, this has also cause a lot of abandoned ground water project done by government, this type of economic waste is a serious concern and need to be addressed., the study is imperative because it will improve the result of ground water exploration in the study area, the result from this study will definitely serve as baseline for professional to apply in   the development of ground water system in the study area .

  17. The effect of subsurface military detonations on vadose zone hydraulic conductivity, contaminant transport and aquifer recharge

    Science.gov (United States)

    Lewis, Jeffrey; Burman, Jan; Edlund, Christina; Simonsson, Louise; Berglind, Rune; Leffler, Per; Qvarfort, Ulf; Thiboutot, Sonia; Ampleman, Guy; Meuken, Denise; Duvalois, Willem; Martel, Richard; Sjöström, Jan

    2013-03-01

    Live fire military training involves the detonation of explosive warheads on training ranges. The purpose of this experiment is to evaluate the hydrogeological changes to the vadose zone caused by military training with high explosive ammunition. In particular, this study investigates artillery ammunition which penetrates underground prior to exploding, either by design or by defective fuze mechanisms. A 105 mm artillery round was detonated 2.6 m underground, and hydraulic conductivity measurements were taken before and after the explosion. A total of 114 hydraulic conductivity measurements were obtained within a radius of 3 m from the detonation point, at four different depths and at three different time periods separated by 18 months. This data was used to produce a three dimensional numerical model of the soil affected by the exploding artillery round. This model was then used to investigate potential changes to aquifer recharge and contaminant transport caused by the detonating round. The results indicate that an exploding artillery round can strongly affect the hydraulic conductivity in the vadose zone, increasing it locally by over an order of magnitude. These variations, however, appear to cause relatively small changes to both local groundwater recharge and contaminant transport.

  18. Turbine efficiency test on a large hydraulic turbine unit

    Institute of Scientific and Technical Information of China (English)

    YAN ZongGuo; ZHOU LingJiu; WANG ZhengWei

    2012-01-01

    The flow rate measurements are the most difficult part of efficiency tests on prototype hydraulic turbines.Among the numerous flow rate measurement methods,the Winter Kennedy method is preferred for measuring turbine flow rates,since it is convenient,practical and economical.This paper describes efficiency tests on a large 300 MW Francis turbine,with the flow rate measured using the Winter Kennedy method and the Winter Kennedy flow rate coefficient calibrated using the Gibson method.The measured turbine efficiency curve is then compared with the curve provided by the manufacturer.The CFD calculations including the spiral case are then used to analyze the influence with the coefficient K and index n in the Winter Kennedy flow rate formula on the flow rate measurement.The uncertainty values of n and K are a key reason for the differences between the curves obtained from the efficiency test and the curves provided by the manufacturer.

  19. A multiscale approach to determine hydraulic conductivity in thick claystone aquitards using field, laboratory, and numerical modeling methods

    Science.gov (United States)

    Smith, L. A.; Barbour, S. L.; Hendry, M. J.; Novakowski, K.; van der Kamp, G.

    2016-07-01

    Characterizing the hydraulic conductivity (K) of aquitards is difficult due to technical and logistical difficulties associated with field-based methods as well as the cost and challenge of collecting representative and competent core samples for laboratory analysis. The objective of this study was to produce a multiscale comparison of vertical and horizontal hydraulic conductivity (Kv and Kh, respectively) of a regionally extensive Cretaceous clay-rich aquitard in southern Saskatchewan. Ten vibrating wire pressure transducers were lowered into place at depths between 25 and 325 m, then the annular was space was filled with a cement-bentonite grout. The in situ Kh was estimated at the location of each transducer by simulating the early-time pore pressure measurements following setting of the grout using a 2-D axisymmetric, finite element, numerical model. Core samples were collected during drilling for conventional laboratory testing for Kv to compare with the transducer-determined in situ Kh. Results highlight the importance of scale and consideration of the presence of possible secondary features (e.g., fractures) in the aquitard. The proximity of the transducers to an active potash mine (˜1 km) where depressurization of an underlying aquifer resulted in drawdown through the aquitard provided a unique opportunity to model the current hydraulic head profile using both the Kh and Kv estimates. Results indicate that the transducer-determined Kh estimates would allow for the development of the current hydraulic head distribution, and that simulating the pore pressure recovery can be used to estimate moderately low in situ Kh (<10-11 m s-1).

  20. Indirect measurements of field-scale hydraulic conductivity of waste from two landfill sites.

    Science.gov (United States)

    Fleming, I R

    2011-12-01

    Management and prediction of the movement and distribution of fluids in large landfills is important for various reasons. Bioreactor landfill technology shows promise, but in arid or semi-arid regions, the natural content of landfilled waste may be low, thus requiring addition of significant volumes of water. In more humid locations, landfills can become saturated, flooding gas collection systems and causing sideslope leachate seeps or other undesirable occurrences. This paper compares results from two different approaches to monitoring water in waste. At the Brock West Landfill in eastern Canada, positive pore pressures were measured at various depths in saturated waste. The downward seepage flux through the waste is known, thus the vertical saturated hydraulic conductivity of the waste at this landfill was determined to be 3 × 10(-7)cm/s. By comparison, the Spadina Landfill in western Canada is predominantly unsaturated. The infiltration of moisture into the waste was measured using moisture sensors installed in boreholes which determined arrival time for moisture fronts resulting from major precipitation events as well as longer-term change in moisture content resulting from unsaturated drainage during winter when frozen ground prevented infiltration. The unsaturated hydraulic conductivity calculated from these data ranged from approximately 10(-6)cm/s for the slow winter drainage in the absence of significant recharge to 10(-2)cm/s or higher for shallow waste subject to high infiltration through apparent preferential pathways. These two very different approaches to field-scale measurements of vertical hydraulic conductivity provide insight into the nature of fluid movement in saturated and unsaturated waste masses. It is suggested that the principles of unsaturated seepage apply reasonably well for landfilled waste and that the hydraulic behavior of waste is profoundly influenced by the nature and size of voids and by the degree of saturation prevailing in the

  1. In-Plant Testing of High-Efficiency Hydraulic Separators

    Energy Technology Data Exchange (ETDEWEB)

    G. H. Luttrell; R. Q. Honaker; R. C. Bratton; T. C. Westerfield; J. N. Kohmuench

    2006-06-30

    Hydraulic separators are commonly used for particle size classification and gravity concentration of minerals and coal. Unfortunately, the efficiency of these processes can be quite low due to poor equipment design and variations in feed consistency. To help alleviate these problems, an industry-driven R&D program has been undertaken to develop a new generation of hydraulic separators that are more efficient and less costly to operate and maintain. These units, which are commercially called the CrossFlow separator and HydroFloat separator, have the potential to improve performance (separation efficiency and throughput) and reduce operating costs (power consumption, water and reagent usage). In Phase I of this project, laboratory and pilot-scale test units were evaluated at various industrial sites in both the coal and mineral industries. Based on promising results obtained from Phase I, full-scale prototypes were purchased and installed by a major U.S. phosphate producer and a large eastern U.S. coal company. The test data obtained from these sites demonstrate that significant performance improvements can be realized through the application of these high-efficiency separators.

  2. IN-PLANT TESTING OF HIGH-EFFICIENCY HYDRAULIC SEPARATORS

    Energy Technology Data Exchange (ETDEWEB)

    G.H. Luttrell; R.Q. Honaker; R.C. Bratton; T.C. Westerfield; J.N. Kohmuench

    2006-05-22

    Hydraulic separators are commonly used for particle size classification and gravity concentration of minerals and coal. Unfortunately, the efficiency of these processes can be quite low due to poor equipment design and variations in feed consistency. To help alleviate these problems, an industry-driven R&D program has been undertaken to develop a new generation of hydraulic separators that are more efficient and less costly to operate and maintain. These units, which are commercially called the CrossFlow separator and HydroFloat separator, have the potential to improve performance (separation efficiency and throughput) and reduce operating costs (power consumption, water and reagent usage). In Phase I of this project, laboratory and pilot-scale test units were evaluated at various industrial sites in both the coal and mineral industries. Based on promising results obtained from Phase I, full-scale prototypes were purchased and installed by a major U.S. phosphate producer and a large eastern U.S. coal company. The test data obtained from these sites demonstrate that significant performance improvements can be realized through the application of these high-efficiency separators.

  3. Impact of root growth and root hydraulic conductance on water availability of young walnut trees

    Science.gov (United States)

    Jerszurki, Daniela; Couvreur, Valentin; Hopmans, Jan W.; Silva, Lucas C. R.; Shackel, Kenneth A.; de Souza, Jorge L. M.

    2015-04-01

    Walnut (Juglans regia L.) is a tree species of high economic importance in the Central Valley of California. This crop has particularly high water requirements, which makes it highly dependent on irrigation. The context of decreasing water availability in the state calls for efficient water management practices, which requires improving our understanding of the relationship between water application and walnut water availability. In addition to the soil's hydraulic conductivity, two plant properties are thought to control the supply of water from the bulk soil to the canopy: (i) root distribution and (ii) plant hydraulic conductance. Even though these properties are clearly linked to crop water requirements, their quantitative relation remains unclear. The aim of this study is to quantitatively explain walnut water requirements under water deficit from continuous measurements of its water consumption, soil and stem water potential, root growth and root system hydraulic conductance. For that purpose, a greenhouse experiment was conducted for a two month period. Young walnut trees were planted in transparent cylindrical pots, equipped with: (i) rhizotron tubes, which allowed for non-invasive monitoring of root growth, (ii) pressure transducer tensiometers for soil water potential, (iii) psychrometers attached to non-transpiring leaves for stem water potential, and (iv) weighing scales for plant transpiration. Treatments consisted of different irrigation rates: 100%, 75% and 50% of potential crop evapotranspiration. Plant responses were compared to predictions from three simple process-based soil-plant-atmosphere models of water flow: (i) a hydraulic model of stomatal regulation based on stem water potential and vapor pressure deficit, (ii) a model of plant hydraulics predicting stem water potential from soil-root interfaces water potential, and (iii) a model of soil water depletion predicting the water potential drop between the bulk soil and soil-root interfaces

  4. Hydraulic Testing of Salado Formation Evaporites at the Waste Isolation Pilot Plant Site: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Beauheim, Richard L.; Domski, Paul S.; Roberts, Randall M.

    1999-07-01

    This report presents interpretations of hydraulic tests conducted in bedded evaporates of the Salado Formation from May 1992 through May 1995 at the Waste Isolation Pilot Plant (WIPP) site in southeastern New Mexico. The WIPP is a US Department of Energy research and development facility designed to demonstrate safe disposal of transuranic wastes from the nation's defense programs. The WIPP disposal horizon is located in the lower portion of the Permian Salado Formation. The hydraulic tests discussed in this report were performed in the WIPP underground facility by INTERA inc. (now Duke Engineering and Services, Inc.), Austin, Texas, following the Field Operations Plan and Addendum prepared by Saulnier (1988, 1991 ) under the technical direction of Sandia National Laboratories, Albuquerque, New Mexico.

  5. The hydraulic conductivity of the xylem in conifer needles (Picea abies and Pinus mugo).

    Science.gov (United States)

    Charra-Vaskou, Katline; Mayr, Stefan

    2011-08-01

    Main resistances of the plant water transport system are situated in leaves. In contrast to angiosperm leaves, knowledge of conifer needle hydraulics and of the partitioning of resistances within needles is poor. A new technique was developed which enabled flow-meter measurements through needles embedded in paraffin and thus quantification of the specific hydraulic conductivity (K(s)) of the needle xylem. In Picea abies, xylem K(s) of needle and axes as well as in needles of different age were compared. In Pinus mugo, resistance partitioning within needles was estimated by measurements of xylem K(s) and leaf conductance (K(leaf), measured via 'rehydration kinetics'). Mean K(s) in P. abies needles was 3.5×10(-4) m(2) s(-1) MPa(-1) with a decrease in older needles, and over all similar to K(s) of corresponding axes xylem. In needles of P. mugo, K(s) was 0.9×10(-4) m(2) s(-1) MPa(-1), and 24% of total needle resistance was situated in the xylem. The results indicate species-specific differences in the hydraulic efficiency of conifer needle xylem. The vascular section of the water transport system is a minor but relevant resistance in needles.

  6. Hydraulic Conductivity Measurements with HTU at Eurajoki, Olkiluoto, Borehole OL-KR15 and OL-KR15B, Year 2004

    Energy Technology Data Exchange (ETDEWEB)

    Haemaelaeinen, H.

    2005-07-01

    As a part of the site investigations for the disposal of spent nuclear fuel, hydraulic conductivity measurements were carried out in borehole OL-KR15 at Eurajoki, Olkiluoto. The objective was to investigate the distribution of the hydraulic conductivity in the surrounding bedrock volume. Measurements were carried out during 2003-2004 in two phases. The total length of the borehole OL-KR15 is 518,85 m and 158 45,14 m. Of the 471 ,5 m + 44,5 m total measurable length 414 m was covered with 237 standard tests with 2 m packer separation as specified in the research plan, partly with 1 m overlaps. 259 tests were initiated, but some of them ended to hardware or software errors or unsuitable parameter values. Double-packer constant-head method was used throughout with nominal 200 kPa overpressure. Injection stage lasted normally 20 minutes and fall-off stage 10 minutes. The tests were often shortened if there were clear indications that the hydraulic conductivity is below the measuring range of the system. The pressure in the test section was let to stabilise at least 5 min before injection. In some test sections the stabilisation or injection stage lasted several hours. Two transient (Horner and 1/Q) interpretations and one stationary-state (Moye) interpretation were made in-situ immediately after the test. The Hydraulic Testing Unit (HTU-system) is owned by Posiva Oy and it was operated by Geopros Oy. (orig.)

  7. A complete soil hydraulic model accounting for capillary and adsorptive water retention, capillary and film conductivity, and hysteresis

    NARCIS (Netherlands)

    Sakai, Masaru; Van Genuchten, Martinus Th; Alazba, A. A.; Setiawan, Budi Indra; Minasny, Budiman

    2015-01-01

    A soil hydraulic model that considers capillary hysteretic and adsorptive water retention as well as capillary and film conductivity covering the complete soil moisture range is presented. The model was obtained by incorporating the capillary hysteresis model of Parker and Lenhard into the hydraulic

  8. Soil hydraulic properties and REV study using X-ray microtomography and pore-scale modelling: saturated hydraulic conductivity

    Science.gov (United States)

    Gerke, Kirill; Khirevich, Siarhei; Sizonenko, Timofey; Karsanina, Marina; Umarova, Aminat; Korost, Dmitry; Matthai, Stephan; Mallants, Dirk

    2016-04-01

    To verify pore-scale modelling approach for determination of soil saturated hydraulic conductivity properties we scanned three cylindrical soil samples taken from A, Ah and B horizons using X-ray microtomography method. Resulting 3D soil images with resolutions of 15.25-20.96 μm were segmented into pores and solids and their maximum inscribed cube subvolumes were used as input data for three major pore-scale modelling methods to simulate saturated flow - lattice-Boltzmann method, finite-difference solution of the Stokes problem, and pore-network model. Provided that imaging resolution is high enough to capture the backbone of effective porosity and the main conducting pores all three methods resulted in simulated soil permeabilities close to experimental values for Ah and B samples. The resolution of A sample was not enough for an accurate modelling and we concluded that this soil requires multi-scale imaging to cover all relevant heterogeneities. We demonstrate that popular SWV method to choose segmentation threshold resulted in oversegmentation and order of magnitude higher permeability values. Careful manual thresholding combined with local segmentation algorithm provided much more accurate results. Detailed analysis of water retention curves showed that air-filled porosity at relevant pressure stages cannot be used for verification of the segmentation results. Representativity analysis by simulating flow in increasing soil volume up to 2.8 cm3 revealed no representative elementary volume (REV) within Ah sample and non-uniqueness of REV for B sample. The latter was explained by soil structure non-stationarity. We further speculate that structures soil horizons can exhibit no REV at all. We discuss numerous advantages of coupled imaging and pore-scale modelling approach and show how it can become a successor of the conventional soil coring method to parametrize large scale continuum models.

  9. Using environmental tracers and transient hydraulic heads to estimate groundwater recharge and conductivity

    Science.gov (United States)

    Erdal, Daniel; Cirpka, Olaf A.

    2017-04-01

    Regional groundwater flow strongly depends on groundwater recharge and hydraulic conductivity. While conductivity is a spatially variable field, recharge can vary in both space and time. None of the two fields can be reliably observed on larger scales, and their estimation from other sparse data sets is an open topic. Further, common hydraulic-head observations may not suffice to constrain both fields simultaneously. In the current work we use the Ensemble Kalman filter to estimate spatially variable conductivity, spatiotemporally variable recharge and porosity for a synthetic phreatic aquifer. We use transient hydraulic-head and one spatially distributed set of environmental tracer observations to constrain the estimation. As environmental tracers generally reside for a long time in an aquifer, they require long simulation times and carries a long memory that makes them highly unsuitable for use in a sequential framework. Therefore, in this work we use the environmental tracer information to precondition the initial ensemble of recharge and conductivities, before starting the sequential filter. Thereby, we aim at improving the performance of the sequential filter by limiting the range of the recharge to values similar to the long-term annual recharge means and by creating an initial ensemble of conductivities that show similar pattern and values to the true field. The sequential filter is then used to further improve the parameters and to estimate the short term temporal behavior as well as the temporally evolving head field needed for short term predictions within the aquifer. For a virtual reality covering a subsection of the river Neckar it is shown that the use of environmental tracers can improve the performance of the filter. Results using the EnKF with and without this preconditioned initial ensemble are evaluated and discussed.

  10. Reduced content of homogalacturonan does not alter the ion-mediated increase in xylem hydraulic conductivity in tobacco.

    Science.gov (United States)

    Nardini, Andrea; Gascó, Antonio; Cervone, Felice; Salleo, Sebastiano

    2007-04-01

    Xylem hydraulic conductivity (K(s)) in stems of tobacco (Nicotiana tabacum) wild-type SR1 was compared to that of PG7 and PG16, two transgenic lines with increased levels of expression of the gene encoding the Aspergillus niger endopolygalacturonase (AnPGII). Activity of AnPGII removes in planta blocks of homogalacturonan (HG) with deesterified carboxyls, thus increasing the degree of neutrality of pectins. The effect of K+ was tested in increasing stem K(s) using model plants with more neutral polysaccharides in primary walls and, hence, in intervessel pit membranes. K(s) measured with deionized water was compared to that with KCl solutions at increasing concentrations (DeltaK(s), %). Plants transformed for HG degree of neutrality showed a dwarfed phenotype, but DeltaK(s) did not differ among the three experimental groups. The ion-mediated hydraulic effect saturated at a KCl concentration of 25 mm in SR1 plants. All the three tobacco lines showed DeltaK(s) of around +12.5% and +17.0% when perfused with 10 and 25 mm KCl, respectively. Because modification of HG content did not influence ion-mediated hydraulic enhancement, we suggest that pectin components other than HG, like rhamnogalacturonan-I and/or rhamnogalacturonan-II, might play important roles in the hydrogel behavior of pit membranes.

  11. A mutation that eliminates bundle sheath extensions reduces leaf hydraulic conductance, stomatal conductance and assimilation rates in tomato (Solanum lycopersicum).

    Science.gov (United States)

    Zsögön, Agustin; Negrini, Ana Clarissa Alves; Peres, Lázaro Eustáquio Pereira; Nguyen, Hoa Thi; Ball, Marilyn C

    2015-01-01

    Bundle sheath extensions (BSEs) are key features of leaf structure whose distribution differs among species and ecosystems. The genetic control of BSE development is unknown, so BSE physiological function has not yet been studied through mutant analysis. We screened a population of ethyl methanesulfonate (EMS)-induced mutants in the genetic background of the tomato (Solanum lycopersicum) model Micro-Tom and found a mutant lacking BSEs. The leaf phenotype of the mutant strongly resembled the tomato mutant obscuravenosa (obv). We confirmed that obv lacks BSEs and that it is not allelic to our induced mutant, which we named obv-2. Leaves lacking BSEs had lower leaf hydraulic conductance and operated with lower stomatal conductance and correspondingly lower assimilation rates than wild-type leaves. This lower level of function occurred despite similarities in vein density, midvein vessel diameter and number, stomatal density, and leaf area between wild-type and mutant leaves, the implication being that the lack of BSEs hindered water dispersal within mutant leaves. Our results comparing near-isogenic lines within a single species confirm the hypothesised role of BSEs in leaf hydraulic function. They further pave the way for a genetic model-based analysis of a common leaf structure with deep ecological consequences.

  12. Property-Transfer Modeling to Estimate Unsaturated Hydraulic Conductivity of Deep Sediments at the Idaho National Laboratory, Idaho

    Science.gov (United States)

    Perkins, Kim S.; Winfield, Kari A.

    2007-01-01

    The unsaturated zone at the Idaho National Laboratory is complex, comprising thick basalt flow sequences interbedded with thinner sedimentary layers. Understanding the highly nonlinear relation between water content and hydraulic conductivity within the sedimentary interbeds is one element in predicting water flow and solute transport processes in this geologically complex environment. Measurement of unsaturated hydraulic conductivity of sediments is costly and time consuming, therefore use of models that estimate this property from more easily measured bulk-physical properties is desirable. A capillary bundle model was used to estimate unsaturated hydraulic conductivity for 40 samples from sedimentary interbeds using water-retention parameters and saturated hydraulic conductivity derived from (1) laboratory measurements on core samples, and (2) site-specific property transfer regression models developed for the sedimentary interbeds. Four regression models were previously developed using bulk-physical property measurements (bulk density, the median particle diameter, and the uniformity coefficient) as the explanatory variables. The response variables, estimated from linear combinations of the bulk physical properties, included saturated hydraulic conductivity and three parameters that define the water-retention curve. The degree to which the unsaturated hydraulic conductivity curves estimated from property-transfer-modeled water-retention parameters and saturated hydraulic conductivity approximated the laboratory-measured data was evaluated using a goodness-of-fit indicator, the root-mean-square error. Because numerical models of variably saturated flow and transport require parameterized hydraulic properties as input, simulations were run to evaluate the effect of the various parameters on model results. Results show that the property transfer models based on easily measured bulk properties perform nearly as well as using curve fits to laboratory-measured water

  13. Seasonal variability of near-saturated hydraulic conductivity on cultivated soil

    Science.gov (United States)

    Klípa, Vladimír; Zumr, David; Sněhota, Michal

    2014-05-01

    The soil structure and hydraulic properties of arable soils considerably vary during the year due to the periodical tillage and fertilization activities, soil compaction, plant and root grow, climate impact etc. The knowledge of the effect of temporal soil variability is essential when assessing water regime and associated dissolved substance transport in soils. The main aim of this contribution is to describe the temporal development of unsaturated hydraulic conductivity on arable land during a year. The experimental site is located in Nucice catchment (Central Bohemia, Czech republic), where also rainfall-runoff and soil erosion processes are studied. The soil is classified as Cambisol, typical texture ranges from loam to clay loam classes. Soil is conservatively tilled till depth of approximately 17 cm, below the topsoil a compacted subsoil was observed. Tension infiltration experiments were performed repeatedly at single location in order to determine the unsaturated hydraulic conductivity of the topsoil. So far four tension infiltration campaigns were carried out under tension h0 = -3.0 cm with different field conditions: (i) young winter barley (October 2012), (ii) between postharvest stubble breaking and seeding (April 2013), (iii) full-grown oat (June 2013) and (iv) after fresh postharvest stubble breaking (October 2013). Measurements were carried out using newly introduced automated multi minidisk tension infiltrometer (Klipa et al., EGU2014-7230). All experiments were performed on the levelled soil surface after removing upper soil layer (1 to 3 cm). A thin layer of quartz sand (thickness 1 - 2 mm, grain size 0.1 - 0.6 mm) was applied to improve contact between the infiltrometer and the soil surface. Each infiltration campaign consisted of six tension infiltration experiments, the total number of 24 infiltration data sets was obtained for this study. Results show that unsaturated hydraulic conductivity was significantly smaller in April, but rather the

  14. Abrasion test of flexible protective materials on hydraulic structures

    Directory of Open Access Journals (Sweden)

    Xin WANG

    2014-01-01

    Full Text Available In this study, several kinds of flexible protective materials sprayed with polyurea elastomers (hereinafter referred to as polyurea elastomer protective material were adopted to meet the abrasion resistance requirement of hydraulic structures, and their abrasion resistances against the water flow with suspended load or bed load were studied systematically through tests. Natural basalt stones were adopted as the abrasive for simulation of the abrasion effect of the water flow with bed load, and test results indicate that the basalt stone is suitable for use in the abrasion resistance test of the flexible protective material. The wear process of the polyurea elastomer protective material is stable, and the wear loss is linear with the time of abrasion. If the wear thickness is regarded as the abrasion resistance evaluation factor, the abrasion resistance of the 351 pure polyurea is about twice those of pure polyurea with a high level of hardness and aliphatic polyurea, and over five times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with suspended load. It is also about 50 times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with bed load. Overall, the abrasion resistance of pure polyurea presented a decreasing trend with increasing hardness. Pure polyurea with a Shore hardness of D30 has the best abrasion resistance, which is 60 to 70 times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with bed load, and has been recommended, among the five kinds of pure polyurea materials with different hardness, in anti-abrasion protection of hydraulic structures.

  15. Water infiltration and hydraulic conductivity in a natural Mediterranean oak forest: impacts of hydrology-oriented silviculture on soil hydraulic properties

    Science.gov (United States)

    Di Prima, Simone; Bagarello, Vincenzo; Bautista, Inmaculada; Cerdà, Artemi; Cullotta, Sebastiano; del Campo, Antonio; González-Sanchis, María; Iovino, Massimo; Maetzke, Federico

    2016-04-01

    the practice of forest management persist for almost one century. It is therefore important to monitor managed sites over longer periods, since short-term investigations are insufficient to detect changes that may influence e.g. larger parts of watersheds (Bens et al., 2006). In addition, soil hydraulic properties exhibit strong spatial and temporal variations and a large number of determinations are required to assess the magnitude of the variation within the selected area (Logsdon and Jaynes, 1996). The use of simple and rapid field techniques is therefore important to obtain reliable data with a sustainable effort (Bagarello et al., 2014; Di Prima et al., 2016). The Beerkan Estimation of Soil Transfer (BEST) parameters procedure by Lassabatere et al. (2006) is very attractive for practical use since it allows an estimation of both the soil water retention and the hydraulic conductivity functions from cumulative infiltration collected during a ponded field experiment and a few routinely laboratory determinations. Lassabatere et al. (2006) suggested to measure the infiltration time of small volumes of water repeatedly poured on the soil surface confined by a ring inserted to a depth of about 1 cm into the soil. BEST considers a zero ponded infiltration model which was assumed to be appropriate for an infiltration run performed with small, but positive, pressure heads. This assumption was supported by numerical tests carried out by Touma et al. (2007). Recently, Di Prima (2015) developed a method to automate data collection with a compact infiltrometer under constant head conditions. The device, maintaining a small quasi-constant head of water (i.e., 2-3 mm) on the infiltration surface, is equipped with a differential pressure transducer to measure the stepwise drop of water level in the reservoir, and, in turn, to quantify cumulative infiltration into the soil. The data acquisition system has been designed with low cost components and it is based on the open source

  16. Wave Dragon. Test to evaluate hydraulic response. Report phase A

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, H.C.; Friis-Madsen, E.

    1999-02-01

    Danish Maritime Institute has in the spring 1998 built a model in scale 1:50 of the wave energy converter Wave Dragon. The scale model is based on calculations performed by the inventor Erik Friis-Madsen from the consultant Loewenmark F.R.I. The scale model is tested in the wave tank at Aalborg University, the Hydraulic and Coastal Engineering Laboratory. This report deals with the results from this test (phase A of the test program). The objective of the test series was to get a judgement of the viability of Wave Dragon in extreme sea conditions in the Danish part of the North Sea at a water depth of 30 meters. The test series had to document: The viability of the Wave Dragon in extreme sea conditions up to 100-year waves; the hydraulic response in 7 different sea conditions where forces and movements have been registered. The main findings are: Wave Dragon has the expected behavior, i.e. the converter is able to survive a 100-year storm; An adjustment of the pitch of the converter could improve the energy efficiency; The forces in the mooring system and the junction between wave reflectors and the platform are acceptable. The forces and the movements are registered at 7 different sea conditions. Video recording has been taken during the test. Five of the sea conditions correspond to 'normal' waves in which power will be produced. Two sea conditions correspond to extreme wave situations. The duration of the registration in each sea conditions was approximately 1/2 an hour, i.e. 3.5 hours in scale 1:1. The conclusion is: The planned test series to evaluate the energy performance can start up (phase B of the test program); The energy efficiency is expected to be improved by a slight modification in the geometry of the Wave Dragon. The modifications can include the geometry of the front and the stabilising wing at the rear end of the platform. Further on changes are possible in the stiffness of the junction between the wave reflectors and the platform and

  17. Spectral induced polarization measurements for environmental purposes and predicting the hydraulic conductivity in sandy aquifers

    Directory of Open Access Journals (Sweden)

    M. Attwa

    2013-04-01

    Full Text Available Low-frequency field and laboratory induced polarization measurements are carried out to characterize the hydrogeological conditions at Schillerslage test site in Germany. The laboratory spectral induced polarization (SIP data are analyzed to derive an empirical relationship for predicting the hydraulic conductivity (K in the field scale. On the other hand, the results from SIP sounding and profiling field data indicate that the method identifies the lithological layers with sufficient resolution to achieve our objectives. Two main Quaternary groundwater aquifers separated by a till layer can be well differentiated. Furthermore, the phase images are also capable of monitoring thin peat layers within the sandy groundwater aquifer. However, the field results show limitations of decreasing resolution with depth and/or low data coverage. Similarly, the SIP laboratory results show a certain shift in SIP response due to different compaction and sorting of the samples. The overall results obtained show that the integration of field and laboratory SIP measurements is an efficient tool to avoid a hydrogeological misinterpretation. In particular, two significant but weak correlations between individual real resistivities (ρ' and relaxation times (τ, based on a Debye decomposition (DD model, with measured K are found for the upper groundwater aquifer. While the maximum relaxation time (τmax and logarithmically weighted average relaxation time (τlw show a better relation with K values than the median value τ50, however, the single relationships are weak. A combined power law relation between individual ρ' and/or τ with K is developed with an expression of A · (ρ'B · (τlwC, where A, B and C are determined using a least-squares fit between the measured and predicted K. The suggested approach with the calculated coefficients of the first aquifer is applied for the second one. The results indicate a good correlation with the measured K and prove to be

  18. Effect of exchangeable Mg on saturated hydraulic conductivity, disaggregation and clay dispersion of disturbed soils

    Science.gov (United States)

    Zhang, X. C.; Norton, L. D.

    2002-03-01

    Different opinions exist regarding the specific effect of Mg on soil physical and chemical properties. We hypothesized that Mg 2+, compared with Ca 2+, reduces saturated hydraulic conductivity ( Ks) via promoting clay swelling, disaggregation, and clay dispersion. Two soils (mixed, mesic Typic Hapludalfs) in packed soil columns were leached with either Ca- or Mg-containing solutions at the successive concentrations of 250, 10, 2, 0.5, and 0 mM. Critical flocculation concentration (CFC) in either Ca or Mg systems was determined with flocculation series tests. Aggregate stability and mean weight diameter (MWD) were assessed by wet-sieving. The CFCs were higher in Mg than in Ca for both soils, indicating that Mg is more dispersive than Ca. The MWDs measured using 1-2 mm aggregates of both soils were significantly larger for Ca-soils than for Mg-soils ( P=0.05). The Ksr (normalized with initial Ks) started to decline at higher concentrations for Mg than for Ca, and the reduction was much greater in Mg than in Ca above 0.5 mM. The Ksr and percent transmittance (inversely related to turbidity) of leachate at a given eluted pore volume following 'steady state' were higher in Ca than in Mg for both soils ( P=0.1), indicating lower permeability and more clay dispersion with the Mg treatment. Swelling and disaggregation, which reduced large pores, appeared to be the dominant process causing the rapid initial decline of Ksr. Clay dispersion and subsequent pore plugging became progressively important when electrolyte concentration was reduced to below CFCs.

  19. Thermal hydraulics in the hot pool of Fast Breeder Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Padmakumar, G. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, TN 603 102 (India)], E-mail: gpk@igcar.gov.in; Pandey, G.K.; Vaidyanathan, G. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, TN 603 102 (India)

    2009-06-15

    Sodium cooled Fast Breeder Test Reactor (FBTR) of 40 MWt/13 MWe capacity is in operation at Kalpakkam, near Chennai. Presently it is operating with a core of 10.5 MWt. Knowledge of temperatures and flow pattern in the hot pool of FBTR is essential to assess the thermal stresses in the hot pool. While theoretical analysis of the hot pool has been conducted by a three-dimensional code to access the temperature profile, it involves tuning due to complex geometry, thermal stresses and vibration. With this in view, an experimental model was fabricated in 1/4 scale using acrylic material and tests were conducted in water. Initially hydraulic studies were conducted with ambient water maintaining Froude number similarity. After that thermal studies were conducted using hot and cold water maintaining Richardson similitude. In both cases Euler similarity was also maintained. Studies were conducted simulating both low and full power operating conditions. This paper discusses the model simulation, similarity criteria, the various thermal hydraulic studies that were carried out, the results obtained and the comparison with the prototype measurements.

  20. Unsaturated hydraulic conductivity of sandy soil columns packed to different bulk densities and water uptake by plantroots

    NARCIS (Netherlands)

    Rossi-Pisa, P.

    1978-01-01

    This paper describes a laboratory metbod used to determine both the soil moisture retention curve and the unsaturated hydraulic conductivity in soil columns under transient flow conditions during evaporation.

  1. Structural-hydraulic test of the liquid metal EURISOL target mock-up

    Science.gov (United States)

    Milenković, Rade Ž.; Dementjevs, Sergejs; Samec, Karel; Platacis, Ernests; Zik, Anatolij; Flerov, Aleksej; Manfrin, Enzo; Thomsen, Knud

    2009-08-01

    Structural-hydraulic tests of the European Isotope Separation On-Line (EURISOL) neutron converter target mock-up, named MErcury Target EXperiment 1 (METEX 1), have been conducted by Paul Scherrer Institut (PSI, Switzerland) in cooperation with Institute of Physics of the University of Latvia (IPUL, Latvia). PSI proceeded with extensive thermal-hydraulic and structural computational studies, followed by the target mock-up tests carried out on the mercury loop at IPUL. One of the main goals of the METEX 1 test is to investigate the hydraulic and structural behaviour of the EURISOL target mock-up for various inlet flow conditions (i.e. mass flow rates) and, in particular, for nominal operating flow rate and pressure in the system. The experimental results were analysed by advanced time-frequency methods such as Short-Time Fourier Transform in order to check the vibration characteristics of the mock-up and the resonance risk. The experimental results (obtained in METEX 1), which include inlet flow rate, pressure of the cover gas, total pressure loss, structural acceleration, sound and strain data, were jointly analysed together with numerical data obtained from Computational Fluid Dynamics (CFD).

  2. Leaf hydraulic conductance varies with vein anatomy across Arabidopsis thaliana wild-type and leaf vein mutants.

    Science.gov (United States)

    Caringella, Marissa A; Bongers, Franca J; Sack, Lawren

    2015-12-01

    Leaf venation is diverse across plant species and has practical applications from paleobotany to modern agriculture. However, the impact of vein traits on plant performance has not yet been tested in a model system such as Arabidopsis thaliana. Previous studies analysed cotyledons of A. thaliana vein mutants and identified visible differences in their vein systems from the wild type (WT). We measured leaf hydraulic conductance (Kleaf ), vein traits, and xylem and mesophyll anatomy for A. thaliana WT (Col-0) and four vein mutants (dot3-111 and dot3-134, and cvp1-3 and cvp2-1). Mutant true leaves did not possess the qualitative venation anomalies previously shown in the cotyledons, but varied quantitatively in vein traits and leaf anatomy across genotypes. The WT had significantly higher mean Kleaf . Across all genotypes, there was a strong correlation of Kleaf with traits related to hydraulic conductance across the bundle sheath, as influenced by the number and radial diameter of bundle sheath cells and vein length per area. These findings support the hypothesis that vein traits influence Kleaf , indicating the usefulness of this mutant system for testing theory that was primarily established comparatively across species, and supports a strong role for the bundle sheath in influencing Kleaf .

  3. Analysis of Responses From Hydraulic Testing of the Lower Carbonate Aquifer at Yucca Flat, Nevada Test Site, Nye County, Nevada

    Science.gov (United States)

    Bhark, E. W.; Ruskauff, G.

    2005-12-01

    The Yucca Flat corrective action unit extends over an approximately 120 square-mile basin at the Nevada Test Site (NTS), southern Nevada, and was the site for over 650 historical underground nuclear tests. The lower carbonate aquifer (LCA), roughly 1,800 feet below ground surface at Yucca Flat and with a confined thickness of several thousand feet, is the primary aquifer for much of southern Nevada and underlies the full extent of Yucca Flat. Within the last decade, long-term (multiple-day) single- and multiple-well hydraulic tests have been performed to better define aquifer properties over larger scales. The LCA is highly heterogeneous, both laterally and vertically across Yucca Flat, reflecting differences in fracturing and fault density. As such, analysis of the recent testing data requires the consideration of heterogeneous hydraulic properties at multiple spatial scales. Three individual hydraulic tests are presented that portray the marked spatial variability of hydraulic properties related to both local fracturing and basin-scale faulting across Yucca Flat. Two ten-day single-well tests (wells ER-7-1, ER-6-2) and one ninety-day multiple-well test (well cluster ER-6-1) are considered. Interpretive and numerical analyses are based upon the log-log diagnostic plots of drawdown and recovery from pumping, utilizing both the head change and derivative. Heterogeneity is considered using the flow dimension, which represents a variable formation area of flow away from the well, and proves to be a fundamental analytical tool. All hydraulic parameter estimates, including flow dimension, are complete with a measure of uncertainty. The composite interpretation of all data results in a conceptual flow model representative of two spatially continuous scales. At the larger basin (km) scale, the data indicate a fracture- or high permeability strip-dominated flow regime created by fault-related features. Ubiquitous north-south trending faults throughout Yucca Flat appear to

  4. 2D aquifer characterization and improved prediction of hydraulic conductivity using surface Nuclear Magnetic Resonance

    Science.gov (United States)

    Dlugosch, Raphael; Günther, Thomas; Müller-Petke, Mike; Yaramanci, Ugur

    2014-05-01

    We present recent studies on the characterization of shallow aquifers using Nuclear Magnetic Resonance (NMR). NMR can help to gather detailed information about the water content and pore size related NMR relaxation time, of porous and water saturated material. The field application of surface NMR uses large wire loops placed at the surface of the Earth allows imaging the subsurface down to around hundred meters. First, a sophisticated inversion scheme is presented to simultaneously determine the two-dimensional (2D) distribution of the water content and the NMR relaxation time (T2*) in the subsurface from a surface NMR survey. The outstanding features of the new inversion scheme are its robustness to noisy data and the potential to distinguish aquifers of different lithology due to their specific NMR relaxation time. The successful application of the inversion scheme is demonstrated on two field cases both characterized by channel structures in the glacial sediments of Northern Germany. Second, we revise the prediction of hydraulic conductivity from NMR measurements for coarse-grained and unconsolidated sediments, commonly found in shallow aquifers. The presented Kozeny-Godefroy model replaces the empirical factors in known relations with physical, structural, and intrinsic NMR parameters. It additionally accounts for bulk water relaxation and is not limited to fast diffusion conditions. This improves the prediction of the hydraulic conductivity for clay-free sediments with grain sizes larger than medium sand. The model is validated by laboratory measurements on glass beads and sand samples. Combining the new inversion scheme and petrophysical model allows 2D imaging of the hydraulic conductivity in the subsurface from a surface NMR survey.

  5. Role of leaf hydraulic conductance in the regulation of stomatal conductance in almond and olive in response to water stress.

    Science.gov (United States)

    Hernandez-Santana, Virginia; Rodriguez-Dominguez, Celia M; Fernández, J Enrique; Diaz-Espejo, Antonio

    2016-06-01

    The decrease of stomatal conductance (gs) is one of the prime responses to water shortage and the main determinant of yield limitation in fruit trees. Understanding the mechanisms related to stomatal closure in response to imposed water stress is crucial for correct irrigation management. The loss of leaf hydraulic functioning is considered as one of the major factors triggering stomatal closure. Thus, we conducted an experiment to quantify the dehydration response of leaf hydraulic conductance (Kleaf) and its impact on gs in two Mediterranean fruit tree species, one deciduous (almond) and one evergreen (olive). Our hypothesis was that a higher Kleaf would be associated with a higher gs and that the reduction in Kleaf would predict the reduction in gs in both species. We measured Kleaf in olive and almond during a cycle of irrigation withholding. We also compared the results of two methods to measure Kleaf: dynamic rehydration kinetics and evaporative flux methods. In addition, determined gs, leaf water potential (Ψleaf), vein density, photosynthetic capacity and turgor loss point. Results showed that gs was higher in almond than in olive and so was Kleaf (Kmax = 4.70 and 3.42 mmol s(-1) MPa(-1) m(-2), in almond and olive, respectively) for Ψleaf > -1.2 MPa. At greater water stress levels than -1.2 MPa, however, Kleaf decreased exponentially, being similar for both species, while gs was still higher in almond than in olive. We conclude that although the Kleaf decrease with increasing water stress does not drive unequivocally the gs response to water stress, Kleaf is the variable most strongly related to the gs response to water stress, especially in olive. Other variables such as the increase in abscisic acid (ABA) may be playing an important role in gs regulation, although in our study the gs-ABA relationship did not show a clear pattern.

  6. Silicon enhances water stress tolerance by improving root hydraulic conductance in Solanum lycopersicum L.

    OpenAIRE

    Yu eShi; Yi eZhang; Weihua eHan; Ru eFeng; Yanhong eHu; Jia eGuo; Haijun eGong

    2016-01-01

    Silicon (Si) can improve drought tolerance in plants, but the mechanism is still not fully understood. Previous research has been concentrating on Si’s role in leaf water maintenance in Si accumulators, while little information is available on its role in water uptake and in less Si-accumulating plants. Here, we investigated the effects of Si on root water uptake and its role in decreasing oxidative damage in relation to root hydraulic conductance in tomato (Solanum lycopersicum ‘Zhongza No.9...

  7. Silicon Enhances Water Stress Tolerance by Improving Root Hydraulic Conductance in Solanum lycopersicum L.

    OpenAIRE

    SHI, YU; Zhang, Yi; Han, Weihua; Feng, Ru; Hu, Yanhong; Guo, Jia; Gong, Haijun

    2016-01-01

    Silicon (Si) can improve drought tolerance in plants, but the mechanism is still not fully understood. Previous research has been concentrating on Si’s role in leaf water maintenance in Si accumulators, while little information is available on its role in water uptake and in less Si-accumulating plants. Here, we investigated the effects of Si on root water uptake and its role in decreasing oxidative damage in relation to root hydraulic conductance in tomato (Solanum lycopersicum ‘Zhongza No.9...

  8. Hydraulic conductance and viscous coupling of three-phase layers in angular capillaries

    Science.gov (United States)

    Dehghanpour, H.; Aminzadeh, B.; Dicarlo, D. A.

    2011-06-01

    Predicting three-phase relative permeability by network models requires reliable models for hydraulic conductance of films and layers stabilized by capillary forces at the pore level. We solve the creeping flow approximation of the Navier-Stokes equation for stable wetting and intermediate layers in the corner of angular capillaries by using a continuity boundary condition at the layer interface. We find significant coupling between the condensed phases and calculate the generalized mobilities by solving cocurrent and countercurrent flow of wetting and intermediate layers. Finally, we present a simple heuristic model for the generalized mobilities as a function of the geometry and viscosity ratio.

  9. Results of hydraulic tests in wells DOE-1, 2, 3, Salt Valley, Grand County, Utah

    Science.gov (United States)

    Rush, F. Eugene; Hart, I.M.; Whitfield, M.S.; Giles, T.F.; D'Epagnier, T. E.

    1980-01-01

    Three exploratory wells were drilled for geological, geophysical, and hydrological purposes in Salt Valley, Grand County, Utah. Cap rock, salt, and interbeds of the Paradox Member of the Hermosa Formation of Middle Pennsylvanian age were penetrated. The observed depth below land surface of the cap rock-salt interface ranges from 163 meters (m) to 191 meters. Approximately the upper 100 meters of cap rock were unsaturated by ground water. Within the saturated part of the cap rock, hydraulic heads generally decrease with depth and southwestward. Ion concentrations generally increase with depth in the saturated cap rock.Hydraulic conductivity of cap rock, as determined from pumping tests, may be on the order of 5 x 10-3 meters per day; as a result, ground-water flow rates in the cap rock are probably very low. A carbon 14 specific activity for cap rock water yielded an uncorrected "age" of greater than 36,000 years. Salt and interbeds have hydraulic conductivities probably less than 1 x 10-4 meters per day.

  10. Two and Three-Phases Fractal Models Application in Soil Saturated Hydraulic Conductivity Estimation

    Directory of Open Access Journals (Sweden)

    ELNAZ Rezaei abajelu

    2017-03-01

    Full Text Available Introduction: Soil Hydraulic conductivity is considered as one of the most important hydraulic properties in water and solutionmovement in porous media. In recent years, variousmodels as pedo-transfer functions, fractal models and scaling technique are used to estimate the soil saturated hydraulic conductivity (Ks. Fractal models with two subset of two (solid and pore and three phases (solid, pore and soil fractal (PSF are used to estimate the fractal dimension of soil particles. The PSF represents a generalization of the solid and pore mass fractal models. The PSF characterizes both the solid and pore phases of the porous material. It also exhibits self-similarity to some degree, in the sense that where local structure seems to be similar to the whole structure.PSF models can estimate interface fractal dimension using soil pore size distribution data (PSD and soil moisture retention curve (SWRC. The main objective of this study was to evaluate different fractal models to estimate the Ksparameter. Materials and Methods: The Schaapetal data was used in this study. The complex consists of sixty soil samples. Soil texture, soil bulk density, soil saturated hydraulic conductivity and soil particle size distribution curve were measured by hydrometer method, undistributed soil sample, constant head method and wet sieve method, respectively for all soil samples.Soil water retention curve were determined by using pressure plates apparatus.The Ks parameter could be estimated by Ralws model as a function of fractal dimension by seven fractal models. Fractal models included Fuentes at al. (1996, Hunt and Gee (2002, Bird et al. (2000, Huang and Zhang (2005, Tyler and Wheatcraft (1990, Kutlu et al. (2008, Sepaskhah and Tafteh (2013.Therefore The Ks parameter can be estimated as a function of the DS (fractal dimension by seven fractal models (Table 2.Sensitivity analysis of Rawls model was assessed by making changes±10%, ±20% and±30%(in input parameters

  11. Engineered Barrier Systems Thermal-Hydraulic-Chemical Column Test Report

    Energy Technology Data Exchange (ETDEWEB)

    W.E. Lowry

    2001-12-13

    The Engineered Barrier System (EBS) Thermal-Hydraulic-Chemical (THC) Column Tests provide data needed for model validation. The EBS Degradation, Flow, and Transport Process Modeling Report (PMR) will be based on supporting models for in-drift THC coupled processes, and the in-drift physical and chemical environment. These models describe the complex chemical interaction of EBS materials, including granular materials, with the thermal and hydrologic conditions that will be present in the repository emplacement drifts. Of particular interest are the coupled processes that result in mineral and salt dissolution/precipitation in the EBS environment. Test data are needed for thermal, hydrologic, and geochemical model validation and to support selection of introduced materials (CRWMS M&O 1999c). These column tests evaluated granular crushed tuff as potential invert ballast or backfill material, under accelerated thermal and hydrologic environments. The objectives of the THC column testing are to: (1) Characterize THC coupled processes that could affect performance of EBS components, particularly the magnitude of permeability reduction (increases or decreases), the nature of minerals produced, and chemical fractionation (i.e., concentrative separation of salts and minerals due to boiling-point elevation). (2) Generate data for validating THC predictive models that will support the EBS Degradation, Flow, and Transport PMR, Rev. 01.

  12. Ear Rachis Xylem Occlusion and Associated Loss in Hydraulic Conductance Coincide with the End of Grain Filling for Wheat.

    Science.gov (United States)

    Neghliz, Hayet; Cochard, Hervé; Brunel, Nicole; Martre, Pierre

    2016-01-01

    Seed dehydration is the normal terminal event in the development of orthodox seeds and is physiologically related to the cessation of grain dry mass accumulation and crop grain yield. For a better understanding of grain dehydration, we evaluated the hypothesis that hydraulic conductance of the ear decreases during the latter stages of development and that this decrease results from disruption or occlusion of xylem conduits. Whole ear, rachis, and stem nodes hydraulic conductance and percentage loss of xylem conductivity were measured from flowering to harvest-ripeness on bread wheat (Triticum aestivum L.) cv. Récital grown under controlled environments. Flag leaf transpiration, stomatal conductance, chlorophyll content and grain and ear water potentials were also measured during grain development. We show that grain dehydration was not related with whole plant physiology and leaf senescence, but closely correlated with the hydraulic properties of the xylem conduits irrigating the grains. Indeed, there was a substantial decrease in rachis hydraulic conductance at the onset of the grain dehydration phase. This hydraulic impairment was not caused by the presence of air embolism in xylem conduits of the stem internodes or rachis but by the occlusion of the xylem lumens by polysaccharides (pectins and callose). Our results demonstrate that xylem hydraulics plays a key role during grain maturation.

  13. Hydraulic conductivity of active layer soils in the McMurdo Dry Valleys, Antarctica: Geological legacy controls modern hillslope connectivity

    Science.gov (United States)

    Schmidt, Logan M.; Levy, Joseph S.

    2017-04-01

    Spatial variability in the hydraulic and physical properties of active layer soils influences shallow groundwater flow through cold-desert hydrological systems. This study measures the saturated hydraulic conductivity and grain-size distribution of 90 soil samples from the McMurdo Dry Valleys (MDV), Antarctica-primarily from Taylor Valley-to determine what processes affect the spatial distribution of saturated hydraulic conductivity in a simple, mineral-soil-dominated natural hillslope laboratory. We find that the saturated hydraulic conductivity and the grain-size distribution of soils are organized longitudinally within Taylor Valley. Soils sampled down-valley near the coast have a higher percentage of fine-sized sediments (fine sand, silt, clay) and lower saturated hydraulic conductivities than soils collected up-valley near Taylor Glacier (1.3 × 10- 2 vs. 1.2 × 10- 1 cm/s). Soils collected mid-valley have intermediate amounts of fines and saturated hydraulic conductivity values consistent with a hydrogeologic gradient spanning the valley from high inland to low near the coast. These results suggest the organization of modern soil properties within Taylor Valley is a relict signature from past glaciations that have deposited soils of decreasing age toward the mouth of the valley, modified by fluvial activity acting along temporal and microclimate gradients.

  14. Hydraulic model tests on modified Wave Dragon. Phase 3

    Energy Technology Data Exchange (ETDEWEB)

    Hald, T.; Lynggaard, J.

    2002-11-01

    The purpose of this report is to describe the model tests conducted with a new designed 2. generation WD model as well as obtained model test results. Tests are conducted as sequential reconstruction followed by physical model tests. All details concerning the reconstruction are found in Hald and Lynggaard (2001). Model tests and reconstruction are carried out during the phase 3 project: 'Wave Dragon. Reconstruction of an existing model in scale 1:50 and sequential tests of changes to the model geometry and mass distribution parameters' sponsored by the Danish Energy Agency (DEA) wave energy programme. The tests will establish a well documented basis for the development of a 1:4.5 scale prototype planned for testing Nissum Bredning, a sea inlet on the Danish West Coast. (au)

  15. Estimation of hydraulic conductivity on clay content in soil determined from resistivity data

    Energy Technology Data Exchange (ETDEWEB)

    Shevnin, Vladimir; Delgado-Rodriguez, Omar; Mousatov, Aleksandr [Mexican Petroleum Institute, Mexico, D.F. (Mexico); Ryjov, Albert [Moscow State Geological Prospecting Academy, Geophysical Faculty, Moscow (Russian Federation)

    2006-07-15

    The influence of clay content in sandy and clayey soils on hydraulic conductivity (filtration coefficient) is considered. A review of published experimental data on the relationship of hydraulic conductivity with soil lithology and grain size, as dependent on clay content is presented. Theoretical calculations include clay content. Experimental and calculated data agree, and several approximation formulas for filtration coefficient vs clay content are presented. Clay content in soil is estimated from electric resistivity data obtained from 2D VES interpretation. A two-step method is proposed, the first step including clay content calculating from soil resistivity and groundwater salinity, and the second step including filtration coefficient estimating from clay content. Two applications are presented. [Spanish] El contenido de arcilla en suelos areno-arcillosos influye sobre la permeabilidad hidraulica (coeficiente de filtracion). Se presenta una revision de datos experimentales publicados que relacionan el coeficiente de filtracion con el tipo litologico del suelo y el tamano de las particulas. A partir de calculos teoricos, se modifican las conocidas formulas que relacionan el coeficiente de filtracion con el contenido de arcilla. Se estima el contenido de arcilla a partir de los datos interpretados por el metodo SEV, y se propone un procedimiento para la estimacion del coeficiente de filtracion: (a) calculo del contenido de arcilla a partir de la resistividad del suelo y de la salinidad del agua subterranea, (b) estimacion del coeficiente de filtracion a partir del contenido de arcilla. Se presentan algunos ejemplos de la aplicacion de esta metodologia.

  16. The strength/moisture relations and hydraulic conductivity of Mexican tepetate

    Energy Technology Data Exchange (ETDEWEB)

    Nimlos, T.J. (Univ. of Montana, Missoula (USA)); Hillery P.A. (Environmental Information Center, Helena, MT (USA))

    1990-07-01

    Indurated soil material formed from volcanic-ash-flow tuff is widespread in the Pacific rim portions of Latin America. This material is called tepetate in Mexico where, in some areas, all soil overlying tepetate has been removed by erosion, leaving a barren landscape with a very slowly permeable surface that contributes to overland flow and flooding. Reclamation of this land involves ripping to break up the upper part of the tepetate or terracing to retain water so that it may infiltrate. Tepetate strength and hydraulic conductivity influence both treatments. The authors determined the change in tepetate strength with moisture. Unconfined compressive strength of eight typical samples was measured at four moisture contents. Strength declined with increasing moisture, especially in samples of high or moderate strength. These data suggest that tepetate of moderate or high strength should be reclaimed during the wet season, whereas low-strength tepetate can be reclaimed at any season. They also determined tepetate's saturated hydraulic conductivity; it varied from 1.5 {times} 10{sup {minus}7} to 36.0 {times} 10{sup {minus}7} m/s. These low values demonstrate the very slowly permeable nature of tepetate and account for the extensive erosion and flooding frequency.

  17. Control of Leaf Expansion by Nitrogen Nutrition in Sunflower Plants : ROLE OF HYDRAULIC CONDUCTIVITY AND TURGOR.

    Science.gov (United States)

    Radin, J W; Boyer, J S

    1982-04-01

    Nitrogen nutrition strongly affected the growth rate of young sunflower (Helianthus annuus L.) leaves. When plants were grown from seed on either of two levels of N availability, a 33% decrease in tissue N of expanding leaves was associated with a 75% overall inhibition of leaf growth. Almost all of the growth inhibition resulted from a depression of the daytime growth rate. Measurements of pressure-induced water flux through roots showed that N deficiency decreased root hydraulic conductivity by about half. Thus, N deficiency lowered the steady-state water potential of expanding leaves during the daytime when transpiration was occurring. As a result, N-deficient leaves were unable to maintain adequate turgor for growth in the daytime. N deficiency also decreased the hydraulic conductivity for water movement into expanding leaf cells in the absence of transpiration, but growth inhibition at night was much less than in the daytime. N nutrition had no detectable effects on plastic extensibility or the threshold turgor for growth.

  18. Root architecture and hydraulic conductance in nutrient deprived Pistacia lentiscus L. seedlings.

    Science.gov (United States)

    Trubat, Roman; Cortina, Jordi; Vilagrosa, Alberto

    2012-12-01

    Plants respond to low nutrient availability by modifying root morphology and root system topology. Root responses to nitrogen (N) and phosphorus (P) limitation may affect plant capacity to withstand water stress. But studies on the effect of nutrient availability on plant ability to uptake and transport water are scarce. In this study, we assess the effect of nitrogen and phosphorus limitation on root morphology and root system topology in Pistacia lentiscus L seedlings, a common Mediterranean shrub, and relate these changes to hydraulic conductivity of the whole root system. Nitrogen and phosphorus deprivation had no effect on root biomass, but root systems were more branched in nutrient limited seedlings. Total root length was higher in seedlings subjected to phosphorus deprivation. Root hydraulic conductance decreased in nutrient-deprived seedlings, and was related to the number of root junctions but not to other architectural traits. Our study shows that changes in nutrient availability affect seedling water use by modifying root architecture. Changes in nutrient availability should be taken into account when evaluating seedling response to drought.

  19. Comparative Analysis of Soluble Phosphate Amendments for the Remediation of Heavy Metal Contaminants: Effect on Sediment Hydraulic Conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Wellman, Dawn M.; Icenhower, Jonathan P.; Owen, Antionette T.

    2006-07-10

    A series of conventional, saturated column experiments were conducted to evaluate the effect of utilizing in situ phosphate amendments, for subsurface, metal remediation, on sediment hydraulic conductivity. Experiments were conducted under mildly alkaline/calcareous conditions representative of conditions commonly encountered at sites across the arid western United States, which have been used in weapons and fuel production and display significant subsurface contamination. Results indicate the displacement of a single pore volume of either sodium monophosphate or phytic acid amendments causes approximately a 30% decrease in the hydraulic conductivity of the sediment. Long-chain polyphosphate amendments afford no measurable reduction in hydraulic conductivity. These results demonstrate (1) the utility of long-chain polyphosphate amendments for subsurface metal sequestration and (2) the necessity of conducting column experiments to completely evaluate the effects of subsurface remediation.

  20. Xylem embolism alleviated by ion-mediated increase in hydraulic conductivity of functional xylem: insights from field measurements.

    Science.gov (United States)

    Trifilò, Patrizia; Lo Gullo, Maria A; Salleo, Sebastiano; Callea, Katia; Nardini, Andrea

    2008-10-01

    Recent studies have shown that, in some species, xylem hydraulic conductivity (K(h)) increases with increasing cation concentration of xylem sap. Evidence indicates that K(h) increases as a result of the de-swelling of pit membrane pectins caused by cation neutralization of polygalacturonanes. We tested whether this ionic effect partly compensates for the embolism-induced loss of stem hydraulic conductivity (PLC) by increasing K(h) of functioning conduits. We report changes in PLC, leaf water status and potassium concentration ([K(+)]) of xylem sap measured in April and July in two evergreens (Ceratonia siliqua L. and Phytolacca dioica L.) and one deciduous tree (Platanus orientalis L.) growing in the field in Sicily. In summer, Ceratonia siliqua and Phytolacca dioica showed similar native embolism (PLC = 30-40%) and [K(+)] of xylem sap (14 to 17 mM), and K(h) of stems perfused with 10 to 25 mM KCl increased by 15 to 18% compared with K(h) of stems perfused with a low concentration of a multi-ionic solution. In contrast, native [K(+)] of sap of Platanus orientalis was 50% of that in the two evergreens in summer, with a parallel lack of detectable changes in PLC that was below 10% in both spring and summer. The ionic effect was PLC-dependent: the enhancement of K(h) induced by 10 to 25 mM KCl changed from 15% for fully hydrated stems to 50-75% for stems with PLC = 50%. In Ceratonia siliqua, PLC was less than 10% in spring and about 40% in summer; concurrently, xylem sap [K(+)] increased from 3 to about 15 mM. This [K(+)] at the recorded PLC would cause an increase in residual K(h) of about 30%. Hence, the actual reduction in water transport capacity of Ceratonia siliqua stems in summer is about 20%. Similar calculations for Phytolacca dioica suggest that the actual loss of hydraulic conductivity in stems of this species in summer would be only about 10%, and not 30% as suggested by hydraulic measurements performed in the laboratory. We conclude that an increase in

  1. [Spatial variation characteristics of surface soil water content, bulk density and saturated hydraulic conductivity on Karst slopes].

    Science.gov (United States)

    Zhang, Chuan; Chen, Hong-Song; Zhang, Wei; Nie, Yun-Peng; Ye, Ying-Ying; Wang, Ke-Lin

    2014-06-01

    Surface soil water-physical properties play a decisive role in the dynamics of deep soil water. Knowledge of their spatial variation is helpful in understanding the processes of rainfall infiltration and runoff generation, which will contribute to the reasonable utilization of soil water resources in mountainous areas. Based on a grid sampling scheme (10 m x 10 m) and geostatistical methods, this paper aimed to study the spatial variability of surface (0-10 cm) soil water content, soil bulk density and saturated hydraulic conductivity on a typical shrub slope (90 m x 120 m, projected length) in Karst area of northwest Guangxi, southwest China. The results showed that the surface soil water content, bulk density and saturated hydraulic conductivity had different spatial dependence and spatial structure. Sample variogram of the soil water content was fitted well by Gaussian models with the nugget effect, while soil bulk density and saturated hydraulic conductivity were fitted well by exponential models with the nugget effect. Variability of soil water content showed strong spatial dependence, while the soil bulk density and saturated hydraulic conductivity showed moderate spatial dependence. The spatial ranges of the soil water content and saturated hydraulic conductivity were small, while that of the soil bulk density was much bigger. In general, the soil water content increased with the increase of altitude while it was opposite for the soil bulk densi- ty. However, the soil saturated hydraulic conductivity had a random distribution of large amounts of small patches, showing high spatial heterogeneity. Soil water content negatively (P conductivity, while there was no significant correlation between the soil bulk density and saturated hydraulic conductivity.

  2. Commissioning of the ATLAS thermal-hydraulic integral test facility

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeon-Sik [Thermal Hydraulics Safety Research Division, Korea Atomic Energy Research Institute, 1045 Daedeokdaero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)], E-mail: yskim3@kaeri.re.kr; Choi, Ki-Yong; Park, Hyeon-Sik; Cho, Seok; Kim, Bok-Deug; Choi, Nam-Hyeon; Baek, Won-Pil [Thermal Hydraulics Safety Research Division, Korea Atomic Energy Research Institute, 1045 Daedeokdaero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2008-10-15

    KAERI recently constructed a new thermal-hydraulic integral test facility for advanced pressurized water reactors (PWRs) - ATLAS. The ATLAS facility has the following characteristics: (a) 1/2-height and length, 1/288-volume, and full pressure simulation of APR1400, (b) maintaining a geometrical similarity with APR1400 including 2(hot legs) x 4(cold legs) reactor coolant loops, direct vessel injection (DVI) of emergency core cooling water, integrated annular downcomer, etc., (c) incorporation of specific design characteristics of OPR1000 such as cold leg injection and low-pressure safety injection pumps, (d) maximum 10% of the scaled nominal core power. The ATLAS will mainly be used to simulate various accident and transient scenarios for evolutionary PWRs, OPR1000 and APR1400: the simulation capability of broad scenarios including the reflood phase of a large-break loss-of-coolant accident (LOCA), small-break LOCA scenarios including DVI line breaks, a steam generator tube rupture, a main steam line break, a feed line break, a mid-loop operation, etc. The ATLAS is now in operation after an extensive series of commissioning tests in 2006.

  3. Hydraulic conductivity measurements with HTU at Eurajoki, Olkiluoto, drillholes OL-KR52 and OL-KR47 in 2013 and 2014

    Energy Technology Data Exchange (ETDEWEB)

    Hurmerinta, E. [Poeyry Finland Oy, Vantaa (Finland)

    2014-09-15

    As a part of the site investigations for the disposal of spent nuclear fuel, hydraulic conductivity measurements were carried out with the HTU-equipment in drillholes OL KR52 and OL KR47 on the Olkiluoto investigation site. The objective was to investigate the distribution of the hydraulic conductivity in the surrounding bedrock volume. In OL-KR52 measurements were carried out between February 2013 and April 2013 and in OL-KR47 between October 2013 and February 2014. The total length of the drillhole OL-KR52 is 427.35 m, 376.00 m of which was covered by 188 standard tests with 2 m packer separation as specified in the measurement plan. Respectively, OL-KR47 is 1008.76 m long and 312 similar tests were conducted in it covering 624.00 m of the drillhole. These numbers include one equipment test measurement near the surface in OL-KR47. Double-packer constant-head method was used throughout with nominal 200 kPa overpressure. Injection stage lasted normally 20 minutes and fall-off stage 10 minutes. The tests were often shortened if there were clear indications that the hydraulic conductivity is below the measuring range of the system. The pressure in the test section was let to stabilise at least 5 min before injection. In some test sections the test stage times were extended if longer times were needed to obtain correct results or when suited to the working schedule. Two transient (Horner and 1/Q) interpretations and one stationary-state (Moye) interpretation were made in-situ immediately after the test. The Hydraulic Testing Unit (HTU-system) is owned by Posiva Oy and it was operated by Poeyry Finland Oy in co-operation with Geopros Oy. (orig.)

  4. KJRR-FAI Hydraulic Flow Testing Input Package

    Energy Technology Data Exchange (ETDEWEB)

    N.E. Woolstenhulme; R.B. Nielson; D.B. Chapman

    2013-12-01

    The INL, in cooperation with the KAERI via Cooperative Research And Development Agreement (CRADA), undertook an effort in the latter half of calendar year 2013 to produce a conceptual design for the KJRR-FAI campaign. The outcomes of this effort are documented in further detail elsewhere [5]. The KJRR-FAI was designed to be cooled by the ATR’s Primary Coolant System (PCS) with no provision for in-pile measurement or control of the hydraulic conditions in the irradiation assembly. The irradiation assembly was designed to achieve the target hydraulic conditions via engineered hydraulic losses in a throttling orifice at the outlet of the irradiation vehicle.

  5. Interaction between soil mineralogy and the application of crop residues on aggregate stability and hydraulic conductivity of the soil

    Science.gov (United States)

    Lado, M.; Kiptoon, R.; Bar-Tal, A.; Wakindiki, I. I. C.; Ben-Hur, M.

    2012-04-01

    One of the main goals of modern agriculture is to achieve sustainability by maintaining crop productivity while avoiding soil degradation. Intensive cultivation could lead to a reduction in soil organic matter that could affect the structure stability and hydraulic conductivity of the soil. Moreover, crops extract nutrients from the soil that are taken away from the field when harvested, and as a consequence, the addition of fertilizers to the soil is necessary to maintain crop productivity. One way to deal with these problems is to incorporate crop residues into the soil after harvest. Crop residues are a source of organic matter that could improve soil physical properties, such as aggregate stability and soil hydraulic conductivity. However, this effect could vary according to other soil properties, such as clay content, clay mineralogy, and the presence of other cementing materials in the soil (mainly carbonates and aluminum and iron oxides). In the present work, the interaction between the addition of chickpea crop residues to the soil and clay mineralogy on aggregate stability and saturated hydraulic conductivity were studied. Chickpea plant residues were added at a rate of 0.5% (w/w) to smectitic, kaolinitic, illitic and non-phyllosilicate soils from different regions. The soils without (control) and with chickpea residues were incubated for 0, 3, 7 and 30 days, and the saturated hydraulic conductivity of the soils was measured in columns after each incubation time. The response of hydraulic conductivity to the addition of residues and incubation time was different in the soils with various mineralogies, although in general, the addition of chickpea residues increased the saturated hydraulic conductivity as compared with the control soils. This positive effect of crop residues on hydraulic conductivity was mainly a result of improved aggregate stability and resistance to slaking during wetting.

  6. Thermo-hydraulic analysis of the cool-down of the EDIPO test facility

    Science.gov (United States)

    Lewandowska, Monika; Bagnasco, Maurizio

    2011-09-01

    The first cool-down of the EDIPO (European DIPOle) test facility is foreseen to take place in 2011 by means of the existing 1.2 kW cryoplant at EPFL-CRPP Villigen. In this work, the thermo-hydraulic analysis of the EDIPO cool-down is performed in order both to assess the its duration and to optimize the procedure. The cool-down is driven by the helium flowing in both the outer cooling channel and in the windings connected hydraulically in parallel. We take into account limitations due to the pressure drop in the cooling circuit and the refrigerator capacity as well as heat conduction in the iron yoke. Two schemes of the hydraulic cooling circuit in the EDIPO windings are studied (coils connected in series and coils connected in parallel). The analysis is performed by means of an analytical model complemented by and numerical model. The results indicate that the cool-down to 5 K can be achieved in about 12 days.

  7. Stochastic fusion of dynamic hydrological and geophysical data for estimating hydraulic conductivities: insights and observations (Invited)

    Science.gov (United States)

    Irving, J. D.; Singha, K.

    2010-12-01

    Traditionally, hydrological measurements have been used to estimate subsurface properties controlling groundwater flow and contaminant transport. However, such measurements are limited by their support volume and expense. A considerable benefit of geophysical measurements is that they provide a degree of spatial coverage and resolution that are unattainable with other methods, and the data can be acquired in a cost-effective manner. In particular, dynamic geophysical data allow us to indirectly observe changes in hydrological state variables as flow and transport processes occur, and can thus provide a link to hydrological properties when coupled with a process-based model. Stochastic fusion of these two data types offers the potential to provide not only estimates of subsurface hydrological properties, but also a quantification of their uncertainty. This information is critical when considering the end use of the data, which may be for groundwater remediation and management decision making. Here, we examine a number of key issues in the stochastic fusion of dynamic hydrogeophysical data. We focus our attention on the specific problem of integrating time-lapse crosshole electrical resistivity measurements and saline tracer-test concentration data in order to estimate the spatial distribution of hydraulic conductivity (K). To assimilate the geophysical and hydrological measurements in a stochastic manner, we use a Bayesian Markov-chain-Monte-Carlo (McMC) methodology. This provides multiple realizations of the subsurface K field that are consistent with the measured data and assumptions regarding model structure and data errors. To account for incomplete petrophysical knowledge, the geophysical and hydrological forward models are linked through an uncertain relationship between electrical resistivity and concentration following the general form of Archie’s law. To make the spatially distributed, fully stochastic inverse problem computationally tractable, we take

  8. Measurement of hydraulic conductivity and water retention curves for different methods and prediction of soil physical properties by kriging

    OpenAIRE

    Eurileny Lucas de Almeida

    2013-01-01

    Knowledge of the physical and hydraulic properties of the soil and its spatial dependence is important because it allows you to perform the zoning of the area in plots that receive differentiated management. This work was divided into three chapters whose general objective is to measure the hydraulic conductivity and water retention curve in soil by different methods and by using the Kriging, draw maps of soil physical attributes of the Irrigation Perimeter Baixo AcaraÃ. To obtain the water r...

  9. Determination of the saturated film conductivity to improve the EMFX model in describing the soil hydraulic properties over the entire moisture range

    Science.gov (United States)

    Wang, Yunquan; Ma, Jinzhu; Guan, Huade; Zhu, Gaofeng

    2017-06-01

    Difficulty in measuring hydraulic conductivity, particularly under dry conditions, calls for methods of predicting the conductivity from easily obtained soil properties. As a complement to the recently published EMFX model, a method based on two specific suction conditions is proposed to estimate saturated film conductivity from the soil water retention curve. This method reduces one fitting parameter in the previous EMFX model, making it possible to predict the hydraulic conductivity from the soil water retention curve over the complete moisture range. Model performance is evaluated with published data of soils in a broad texture range from sand to clay. The testing results indicate that 1) the modified EMFX model (namely the EMFX-K model), incorporating both capillary and adsorption forces, provides good agreement with the conductivity data over the entire moisture range; 2) a value of 0.5 for the tortuosity factor in the EMFX-K model as that in the Mualem's model gives comparable estimation of the relative conductivity associated with the capillary force; and 3) a value of -1.0 × 10-20 J for the Hamaker constant, rather than the commonly used value of -6.0 × 10-20 J, appears to be more appropriate to represent solely the effect of the van der Waals forces and to predict the film conductivity. In comparison with the commonly used van Genuchten-Mualem model, the EMFX-K model significantly improves the prediction of hydraulic conductivity under dry conditions. The sensitivity analysis result suggests that the uncertainty in the film thickness estimation is important in explaining the model underestimation of hydraulic conductivity for the soils with fine texture, in addition to the uncertainties from the measurements and the model structure. High quality data that cover the complete moisture range for a variety of soil textures are required to further test the method.

  10. Use of NMR logging to obtain estimates of hydraulic conductivity in the High Plains aquifer, Nebraska, USA

    Science.gov (United States)

    Dlubac, Katherine; Knight, Rosemary; Song, Yi-Qiao; Bachman, Nate; Grau, Ben; Cannia, Jim; Williams, John

    2013-01-01

    Hydraulic conductivity (K) is one of the most important parameters of interest in groundwater applications because it quantifies the ease with which water can flow through an aquifer material. Hydraulic conductivity is typically measured by conducting aquifer tests or wellbore flow (WBF) logging. Of interest in our research is the use of proton nuclear magnetic resonance (NMR) logging to obtain information about water-filled porosity and pore space geometry, the combination of which can be used to estimate K. In this study, we acquired a suite of advanced geophysical logs, aquifer tests, WBF logs, and sidewall cores at the field site in Lexington, Nebraska, which is underlain by the High Plains aquifer. We first used two empirical equations developed for petroleum applications to predict K from NMR logging data: the Schlumberger Doll Research equation (KSDR) and the Timur-Coates equation (KT-C), with the standard empirical constants determined for consolidated materials. We upscaled our NMR-derived K estimates to the scale of the WBF-logging K(KWBF-logging) estimates for comparison. All the upscaled KT-C estimates were within an order of magnitude of KWBF-logging and all of the upscaled KSDR estimates were within 2 orders of magnitude of KWBF-logging. We optimized the fit between the upscaled NMR-derived K and KWBF-logging estimates to determine a set of site-specific empirical constants for the unconsolidated materials at our field site. We conclude that reliable estimates of K can be obtained from NMR logging data, thus providing an alternate method for obtaining estimates of K at high levels of vertical resolution.

  11. Deep rooting plants influence on soil hydraulic properties and air conductivity over time

    Science.gov (United States)

    Uteau, Daniel; Peth, Stephan; Diercks, Charlotte; Pagenkemper, Sebastian; Horn, Rainer

    2014-05-01

    Crop sequences are commonly suggested as an alternative to improve subsoil structure. A well structured soil can be characterized by enhanced transport properties. Our main hypothesis was, that different root systems can modify the soil's macro/mesopore network if enough cultivation time is given. We analyzed the influence of three crops with either shallower roots (Festuca arundinacea, fescue) or taproots (Cichorium intybus, chicory and Medicago sativa, alfalfa). The crops where cultivated on a Haplic Luvisol near Bonn (Germany) for one, two or three years. Undisturbed soil cores were taken for measurement of unsaturated hydraulic conductivity and air permeability. The unsaturated conductivity was measured using the evaporation method, monitoring the water content and tension at two depths of each undisturbed soil core. The van Genuchten-Mualem model (1991) was fitted to the measured data. Air permeability was measured in a permeameter with constant flow at low pressure gradient. The measurements were repeated at -1, -3, -6, -15, -30 and -50 kPa matric tension and the model of Ball et al. (1988) was used to describe permeability as function of matric tension. Furthermore, the cores equilibrated at -15 kPa matric tension were scanned with X-Ray computer tomography. By means of 3D image analysis, geometrical features as pore size distribution, tortuosity and connectivity of the pore network was analyzed. The measurements showed an increased unsaturated hydraulic conductivity associated to coarser pores at the taprooted cultivations. A enhanced pore system (related to shrink-swell processes) under alfalfa was observed in both transport measurements and was confirmed by the 3D image analysis. This highly functional pore system (consisting mainly of root paths, earthworm channels and shrinking cracks) was clearly visible below the 75 cm of depth and differentiated significantly from the other two treatments only after three years of cultivation, which shows the time

  12. Evolution of neural networks for the prediction of hydraulic conductivity as a function of borehole geophysical logs: Shobasama site, Japan.

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, Paul C.; McKenna, Sean Andrew

    2004-06-01

    This report describes the methodology and results of a project to develop a neural network for the prediction of the measured hydraulic conductivity or transmissivity in a series of boreholes at the Tono, Japan study site. Geophysical measurements were used as the input to EL feed-forward neural network. A simple genetic algorithm was used to evolve the architecture and parameters of the neural network in conjunction with an optimal subset of geophysical measurements for the prediction of hydraulic conductivity. The first attempt was focused on the estimation of the class of the hydraulic conductivity, high, medium or low, from the geophysical logs. This estimation was done while using the genetic algorithm to simultaneously determine which geophysical logs were the most important and optimizing the architecture of the neural network. Initial results showed that certain geophysical logs provided more information than others- most notably the 'short-normal', micro-resistivity, porosity and sonic logs provided the most information on hydraulic conductivity. The neural network produced excellent training results with accuracy of 90 percent or greater, but was unable to produce accurate predictions of the hydraulic conductivity class. The second attempt at prediction was done using a new methodology and a modified data set. The new methodology builds on the results of the first attempts at prediction by limiting the choices of geophysical logs to only those that provide significant information. Additionally, this second attempt uses a modified data set and predicts transmissivity instead of hydraulic conductivity. Results of these simulations indicate that the most informative geophysical measurements for the prediction of transmissivity are depth and sonic log. The long normal resistivity and self potential borehole logs are moderately informative. In addition, it was found that porosity and crack counts (clear, open, or hairline) do not inform predictions

  13. Hydraulic conductivity measurements with HTU at Eurajoki, Olkiluoto, drillholes OL-KR19, OL-KR45 and OL-KR46 in 2009 and 2010

    Energy Technology Data Exchange (ETDEWEB)

    Haemaelaeinen, H. [Geopros Oy, Helsinki (Finland)

    2011-10-15

    As a part of the site investigations for the disposal of spent nuclear fuel, hydraulic conductivity measurements were carried out with HTU-equipment in drillholes OL-KR19, OL-KR45 and OL-KR46 at Eurajoki, Olkiluoto. The objective was to investigate the distribution of the hydraulic conductivity in the surrounding bedrock volume. Measurements were carried out during 2009 and 2010. The total length of the borehole OL-KR19 is 544,34 m, 241,80 m of which was covered by 121 standard tests with 2 m packer separation as specified in the measurement plan. Respectively, OL-KR45 is 1023,30 m long and 63 similar tests were made in it covering 126,00 m of the hole and OL-KR46 600,10 m long, 151 tests made covering 301,35 m. The measured sections are around the depths of the planned repository. Double-packer constant-head method was used throughout with nominal 200 kPa overpressure. Injection stage lasted normally 20 minutes and fall-off stage 10 minutes. The tests were often shortened if there were clear indications that the hydraulic conductivity is below the measuring range of the system. The pressure in the test section was let to stabilise at least 5 min before injection. In some test sections the test stage times were extended. Two transient (Horner and 1/Q) interpretations and one stationary- state (Moye) interpretation were made in-situ immediately after the test. The Hydraulic Testing Unit (HTU-system) is owned by Posiva Oy and it was operated by Geopros Oy. (orig.)

  14. Wood anatomy reveals high theoretical hydraulic conductivity and low resistance to vessel implosion in a Cretaceous fossil forest from northern Mexico.

    Science.gov (United States)

    Martínez-Cabrera, Hugo I; Estrada-Ruiz, Emilio

    2014-01-01

    The Olmos Formation (upper Campanian), with over 60 angiosperm leaf morphotypes, is Mexico's richest Cretaceous flora. Paleoclimate leaf physiognomy estimates indicate that the Olmos paleoforest grew under wet and warm conditions, similar to those present in modern tropical rainforests. Leaf surface area, tree size and climate reconstructions suggest that this was a highly productive system. Efficient carbon fixation requires hydraulic efficiency to meet the evaporative demands of the photosynthetic surface, but it comes at the expense of increased risk of drought-induced cavitation. Here we tested the hypothesis that the Olmos paleoforest had high hydraulic efficiency, but was prone to cavitation. We characterized the hydraulic properties of the Olmos paleoforest using theoretical conductivity (Ks), vessel composition (S) and vessel fraction (F), and measured drought resistance using vessel implosion resistance (t/b)h(2) and the water potential at which there is 50% loss of hydraulic conductivity (P50). We found that the Olmos paleoforest had high hydraulic efficiency, similar to that present in several extant tropical-wet or semi-deciduous forest communities. Remarkably, the fossil flora had the lowest (t/b)h(2), which, together with low median P50 (-1.9 MPa), indicate that the Olmos paleoforest species were extremely vulnerable to drought-induced cavitation. Our findings support paleoclimate inferences from leaf physiognomy and paleoclimatic models suggesting it represented a highly productive wet tropical rainforest. Our results also indicate that the Olmos Formation plants had a large range of water conduction strategies, but more restricted variation in cavitation resistance. These straightforward methods for measuring hydraulic properties, used herein for the first time, can provide useful information on the ecological strategies of paleofloras and on temporal shifts in ecological function of fossil forests chronosequences.

  15. Detection of QTL for exudation rate at ripening stage in rice and its contribution to hydraulic conductance.

    Science.gov (United States)

    Yamamoto, Toshio; Suzuki, Tadafumi; Suzuki, Kenji; Adachi, Shunsuke; Sun, Jian; Yano, Masahiro; Ookawa, Taiichiro; Hirasawa, Tadashi

    2016-01-01

    Dry matter production of crops is determined by how much light they intercept and how efficiently they use it for carbon fixation; i.e., photosynthesis. The high-yielding rice cultivar, Akenohoshi, maintains a high photosynthetic rate in the middle of the day owing to its high hydraulic conductance in comparison with the elite commercial rice cultivar, Koshihikari. We developed 94 recombinant inbred lines derived from Akenohoshi and Koshihikari and measured their exudation rate to calculate hydraulic conductance to osmotic water transport in a paddy field. A quantitative trait locus (QTL) for exudation rate was detected on the long arm of chromosome 2 at the heading and ripening stages. We developed chromosome segment substitution lines which carried Akenohoshi segments in the Koshihikari genetic background, and measured hydraulic conductance to both osmotic and passive water transport. The QTL was confirmed to be located within a region of about 4.2Mbp on the distal end of long arm of chromosome 2. The Akenohoshi allele increased root surface area and hydraulic conductance, but didn't increase hydraulic conductivity of a plant.

  16. A Numerical Method for the Estimation of Distributed Hydraulic Conductivity Using Richards Equation

    Science.gov (United States)

    Cockett, R.; Haber, E.

    2013-12-01

    Characterizing groundwater flow in the vadose zone has many important and practical applications in near surface hydrogeology. The spatial estimation of the hydraulic conductivity function, which is the regulator of unsaturated groundwater flow, is an critical step in any hydrogeologic site characterization. However, this estimation is difficult and simplifications are consistently used to avert these conceptual and computational difficulties. Comprehensive time-lapse data of in situ saturations, or proxies of saturation from geophysical methods, are increasingly available. Using these large data sets appropriately, and maximizing the utility of the data to recover estimates of heterogeneous hydraulic conductivity, requires innovative numerical methods. This inverse problem has been approached in many different ways in the literature from stochastic methods to various gradient based methods. However, the way in which the computational complexity of the inverse method scales becomes important as problem size increases; as computational memory and time often become the bottleneck of solving the inverse problem when the problem is solved for heterogeneous hydraulic conductivity in two- and particularly in three-dimensions. For the inverse problem involving Richards equation, some version of a Gauss-Newton method (e.g. Levenberg-Marquardt) with a direct calculation of the sensitivity matrix is commonly used. However, while these approaches allow to deal with moderate scale problems they have one major drawback: the sensitivity matrix is a large dense matrix and its computation requires dense linear algebra and, for large scale problems, a non-trivial amount of storage. Furthermore, previous work use either numerical or automatic differentiation in order to compute the sensitivity matrix and this can generate inaccuracies in its computation and tarry convergence of the optimization algorithm. We suggest a modern numerical method that allows for the solution of the

  17. Modeling Flow Rate to Estimate Hydraulic Conductivity in a Parabolic Ceramic Water Filter

    Directory of Open Access Journals (Sweden)

    Ileana Wald

    2012-01-01

    Full Text Available In this project we model volumetric flow rate through a parabolic ceramic water filter (CWF to determine how quickly it can process water while still improving its quality. The volumetric flow rate is dependent upon the pore size of the filter, the surface area, and the height of water in the filter (hydraulic head. We derive differential equations governing this flow from the conservation of mass principle and Darcy's Law and find the flow rate with respect to time. We then use methods of calculus to find optimal specifications for the filter. This work is related to the research conducted in Dr. James R. Mihelcic's Civil and Environmental Engineering Lab at USF.

  18. A test of the hydraulic vulnerability segmentation hypothesis in angiosperm and conifer tree species.

    Science.gov (United States)

    Johnson, Daniel M; Wortemann, Remi; McCulloh, Katherine A; Jordan-Meille, Lionel; Ward, Eric; Warren, Jeffrey M; Palmroth, Sari; Domec, Jean-Christophe

    2016-08-01

    Water transport from soils to the atmosphere is critical for plant growth and survival. However, we have a limited understanding about many portions of the whole-tree hydraulic pathway, because the vast majority of published information is on terminal branches. Our understanding of mature tree trunk hydraulic physiology, in particular, is limited. The hydraulic vulnerability segmentation hypothesis (HVSH) stipulates that distal portions of the plant (leaves, branches and roots) should be more vulnerable to embolism than trunks, which are nonredundant organs that require a massive carbon investment. In the current study, we compared vulnerability to loss of hydraulic function, leaf and xylem water potentials and the resulting hydraulic safety margins (in relation to the water potential causing 50% loss of hydraulic conductivity) in leaves, branches, trunks and roots of four angiosperms and four conifer tree species. Across all species, our results supported strongly the HVSH as leaves and roots were less resistant to embolism than branches or trunks. However, branches were consistently more resistant to embolism than any other portion of the plant, including trunks. Also, calculated whole-tree vulnerability to hydraulic dysfunction was much greater than vulnerability in branches. This was due to hydraulic dysfunction in roots and leaves at less negative water potentials than those causing branch or trunk dysfunction. Leaves and roots had narrow or negative hydraulic safety margins, but trunks and branches maintained positive safety margins. By using branch-based hydraulic information as a proxy for entire plants, much research has potentially overestimated embolism resistance, and possibly drought tolerance, for many species. This study highlights the necessity to reconsider past conclusions made about plant resistance to drought based on branch xylem only. This study also highlights the necessity for more research of whole-plant hydraulic physiology to better

  19. Scale-dependency of effective hydraulic conductivity on fire-affected hillslopes

    Science.gov (United States)

    Langhans, Christoph; Lane, Patrick N. J.; Nyman, Petter; Noske, Philip J.; Cawson, Jane G.; Oono, Akiko; Sheridan, Gary J.

    2016-07-01

    Effective hydraulic conductivity (Ke) for Hortonian overland flow modeling has been defined as a function of rainfall intensity and runon infiltration assuming a distribution of saturated hydraulic conductivities (Ks). But surface boundary condition during infiltration and its interactions with the distribution of Ks are not well represented in models. As a result, the mean value of the Ks distribution (KS¯), which is the central parameter for Ke, varies between scales. Here we quantify this discrepancy with a large infiltration data set comprising four different methods and scales from fire-affected hillslopes in SE Australia using a relatively simple yet widely used conceptual model of Ke. Ponded disk (0.002 m2) and ring infiltrometers (0.07 m2) were used at the small scales and rainfall simulations (3 m2) and small catchments (ca 3000 m2) at the larger scales. We compared KS¯ between methods measured at the same time and place. Disk and ring infiltrometer measurements had on average 4.8 times higher values of KS¯ than rainfall simulations and catchment-scale estimates. Furthermore, the distribution of Ks was not clearly log-normal and scale-independent, as supposed in the conceptual model. In our interpretation, water repellency and preferential flow paths increase the variance of the measured distribution of Ks and bias ponding toward areas of very low Ks during rainfall simulations and small catchment runoff events while areas with high preferential flow capacity remain water supply-limited more than the conceptual model of Ke predicts. The study highlights problems in the current theory of scaling runoff generation.

  20. FRACTAL SCALING OF PARTICLE AND PORE SIZE DISTRIBUTIONS AND ITS RELATION TO SOIL HYDRAULIC CONDUCTIVITY

    Directory of Open Access Journals (Sweden)

    BACCHI O.O.S.

    1996-01-01

    Full Text Available Fractal scaling has been applied to soils, both for void and solid phases, as an approach to characterize the porous arrangement, attempting to relate particle-size distribution to soil water retention and soil water dynamic properties. One important point of such an analysis is the assumption that the void space geometry of soils reflects its solid phase geometry, taking into account that soil pores are lined by the full range of particles, and that their fractal dimension, which expresses their tortuosity, could be evaluated by the fractal scaling of particle-size distribution. Other authors already concluded that although fractal scaling plays an important role in soil water retention and porosity, particle-size distribution alone is not sufficient to evaluate the fractal structure of porosity. It is also recommended to examine the relationship between fractal properties of solids and of voids, and in some special cases, look for an equivalence of both fractal dimensions. In the present paper data of 42 soil samples were analyzed in order to compare fractal dimensions of pore-size distribution, evaluated by soil water retention curves (SWRC of soils, with fractal dimensions of soil particle-size distributions (PSD, taking the hydraulic conductivity as a standard variable for the comparison, due to its relation to tortuosity. A new procedure is proposed to evaluate the fractal dimension of pore-size distribution. Results indicate a better correlation between fractal dimensions of pore-size distribution and the hydraulic conductivity for this set of soils, showing that for most of the soils analyzed there is no equivalence of both fractal dimensions. For most of these soils the fractal dimension of particle-size distribution does not indicate properly the pore trace tortuosity. A better equivalence of both fractal dimensions was found for sandy soils.

  1. Gamma ray transmission for hydraulic conductivity measurement of undisturbed soil columns

    Directory of Open Access Journals (Sweden)

    Anderson Camargo Moreira

    2007-03-01

    Full Text Available This work had the objective to determine the Hydraulic Conductivity K(theta function for different depth levels z, of columns of undisturbed soil, using the gamma ray transmission technique applied to the Sisson method. The results indicated a growing behavior for K(theta and a homogeneous soil density, both in relation to the increase of the depth. The methodology of gamma ray transmission showed satisfactory results on the determination of the hydraulic conductivity in columns of undisturbed soil, besides being very reliable and a nondestructive method.O estudo da condutividade hidráulica para solos não saturados é essencial quando aplicado às situações relacionadas à irrigação, drenagem e transporte de nutrientes no solo, é uma importante propriedade para desenvolvimentos de culturas agrícolas. Este trabalho tem o objetivo de determinar a função Condutividade Hidráulica K(teta, em diferentes níveis z de profundidade, em colunas de solo indeformado, utilizando a transmissão de raios gama aplicada ao método de Sisson. Os resultados indicam um comportamento crescente para K(teta e uma densidade de solo homogênea, ambos em relação ao aumento da profundidade. A metodologia de transmissão de raios gama mostrou resultados bastante satisfatórios na determinação da condutividade hidráulica em colunas de solo indeformado, além de ser muito confiável e não destrutivo.

  2. A global data set of soil hydraulic properties and sub-grid variability of soil water retention and hydraulic conductivity curves

    Science.gov (United States)

    Montzka, Carsten; Herbst, Michael; Weihermüller, Lutz; Verhoef, Anne; Vereecken, Harry

    2017-07-01

    Agroecosystem models, regional and global climate models, and numerical weather prediction models require adequate parameterization of soil hydraulic properties. These properties are fundamental for describing and predicting water and energy exchange processes at the transition zone between solid earth and atmosphere, and regulate evapotranspiration, infiltration and runoff generation. Hydraulic parameters describing the soil water retention (WRC) and hydraulic conductivity (HCC) curves are typically derived from soil texture via pedotransfer functions (PTFs). Resampling of those parameters for specific model grids is typically performed by different aggregation approaches such a spatial averaging and the use of dominant textural properties or soil classes. These aggregation approaches introduce uncertainty, bias and parameter inconsistencies throughout spatial scales due to nonlinear relationships between hydraulic parameters and soil texture. Therefore, we present a method to scale hydraulic parameters to individual model grids and provide a global data set that overcomes the mentioned problems. The approach is based on Miller-Miller scaling in the relaxed form by Warrick, that fits the parameters of the WRC through all sub-grid WRCs to provide an effective parameterization for the grid cell at model resolution; at the same time it preserves the information of sub-grid variability of the water retention curve by deriving local scaling parameters. Based on the Mualem-van Genuchten approach we also derive the unsaturated hydraulic conductivity from the water retention functions, thereby assuming that the local parameters are also valid for this function. In addition, via the Warrick scaling parameter λ, information on global sub-grid scaling variance is given that enables modellers to improve dynamical downscaling of (regional) climate models or to perturb hydraulic parameters for model ensemble output generation. The present analysis is based on the ROSETTA PTF

  3. A global data set of soil hydraulic properties and sub-grid variability of soil water retention and hydraulic conductivity curves

    Directory of Open Access Journals (Sweden)

    C. Montzka

    2017-07-01

    Full Text Available Agroecosystem models, regional and global climate models, and numerical weather prediction models require adequate parameterization of soil hydraulic properties. These properties are fundamental for describing and predicting water and energy exchange processes at the transition zone between solid earth and atmosphere, and regulate evapotranspiration, infiltration and runoff generation. Hydraulic parameters describing the soil water retention (WRC and hydraulic conductivity (HCC curves are typically derived from soil texture via pedotransfer functions (PTFs. Resampling of those parameters for specific model grids is typically performed by different aggregation approaches such a spatial averaging and the use of dominant textural properties or soil classes. These aggregation approaches introduce uncertainty, bias and parameter inconsistencies throughout spatial scales due to nonlinear relationships between hydraulic parameters and soil texture. Therefore, we present a method to scale hydraulic parameters to individual model grids and provide a global data set that overcomes the mentioned problems. The approach is based on Miller–Miller scaling in the relaxed form by Warrick, that fits the parameters of the WRC through all sub-grid WRCs to provide an effective parameterization for the grid cell at model resolution; at the same time it preserves the information of sub-grid variability of the water retention curve by deriving local scaling parameters. Based on the Mualem–van Genuchten approach we also derive the unsaturated hydraulic conductivity from the water retention functions, thereby assuming that the local parameters are also valid for this function. In addition, via the Warrick scaling parameter λ, information on global sub-grid scaling variance is given that enables modellers to improve dynamical downscaling of (regional climate models or to perturb hydraulic parameters for model ensemble output generation. The present analysis is based

  4. Saturated hydraulic conductivity determined by on ground mono-offset Ground-Penetrating Radar inside a single ring infiltrometer

    CERN Document Server

    Léger, Emmanuel; Coquet, Yves

    2013-01-01

    In this study we show how to use GPR data acquired along the infiltration of water inside a single ring infiltrometer to inverse the saturated hydraulic conductivity. We used Hydrus-1D to simulate the water infiltration. We generated water content profiles at each time step of infiltration, based on a particular value of the saturated hydraulic conductivity, knowing the other van Genuchten parameters. Water content profiles were converted to dielectric permittivity profiles using the Complex Refractive Index Method relation. We then used the GprMax suite of programs to generate radargrams and to follow the wetting front using arrival time of electromagnetic waves recorded by a Ground-Penetrating Radar (GPR). Theoretically, the 1D time convolution between reflectivity and GPR signal at any infiltration time step is related to the peak of the reflected amplitude recorded in the corresponding trace in the radargram. We used this relation ship to invert the saturated hydraulic conductivity for constant and fallin...

  5. HYDRAULIC CONDUCTIVITY IN ENVIRONMENTAL LINERS PRODUCED WITH SANDY SOIL, CHEMICALLY STABILIZED = CONDUTIVIDADE HIDRÁULICA DE BARREIRAS DE PROTEÇÃO PRODUZIDAS COM SOLO ARENOSO ESTABILIZADO QUIMICAMENTE

    Directory of Open Access Journals (Sweden)

    José Augusto de Lollo

    2004-01-01

    Full Text Available Hydraulic conductivity of barriers produced with sandy soil (65% sand and 27% clay stabilized with lime and cement was tested. Specimens produced with compacted mixtures and tested using variable charges and total surface tests in order to determine hydraulic conductivity. Some factors vary during the tests, like the kind of aditive (lime and cement, the amount of lime and cement, cure time and exposition condition. Obtained hydraulic conductivity values were smaller than 10-9 m/s, showing values fully compatible with the intended purpose. Is also proposed a sistematic procedure to aply this techinque in simmilar situations. = Foi testada a condutividade hidráulica de barreiras de proteção ambiental produzidas com solo arenoso (65% de areia e 27% de argila estabilizado quimicamente com cal e cimento. Foram ensaiados corpos de prova das misturas compactadas usando as técnicas de ensaio de permeabilidade a carga variável e em área plena considerando os fatores tipo de estabilizante, teor de estabilizante, tempo de cura e condição de exposição. Os resultados dos ensaios de permeabilidade mostraram valores de condutividade hidráulica inferiores a 10-9 m/s, portanto compatíveis com a finalidade pretendida. É proposta uma seqüência de procedimentos a ser adotada em situações similares nas quais se pretenda aplicar esta técnica.

  6. Oscillatory hydraulic testing as a strategy for NAPL source zone monitoring: Laboratory experiments

    Science.gov (United States)

    Zhou, YaoQuan; Cardiff, Michael

    2017-05-01

    Non-aqueous phase liquids (NAPLs) have a complex mode of transport in heterogeneous aquifers, which can result in pools and lenses of NAPLs (the ;source zone;) that are difficult to detect and can cause long-term contamination via slow dissolution into groundwater (the ;dissolved plume;). Characterizing the extent and evolution of NAPL contamination within the source zone is a useful strategy for designing and adapting appropriate remedial actions at many contaminated sites. As a NAPL flows into a given aquifer volume, the effective hydraulic conductivity (K) and specific storage (Ss) of the volume changes associated with the viscosity and compressibility of the impinging fluid, meaning that NAPL movement may be detectable with hydraulic testing. Recently, the use of oscillatory pumping tests - in which sinusoidal pumping variations are implemented and oscillatory pressure changes are detected at monitoring locations - has been suggested as a low-impact hydraulic testing strategy for characterizing aquifer properties (Cardiff et al., 2013; Zhou et al., 2016). Here, we investigate this strategy in an experimental laboratory sandbox where dyed vegetable oil is injected and allowed to migrate as a NAPL. Initial qualitative analyses demonstrate that measurable changes in pressure signal amplitude and phase provide clear evidence for NAPL plume emplacement and migration. Using the approach developed in Zhou et al. (2016), we then apply tomographic analyses to estimate the location of effective K changes (representing fluid changes) and their movement throughout time. This approach provides a method for monitoring ongoing NAPL movement without net extraction or injection of fluid, making it advantageous in field remediation applications.

  7. Estimating the saturated soil hydraulic conductivity by the near steady-state phase of a beerkan infiltration run

    Science.gov (United States)

    Di Prima, Simone; Bagarello, Vincenzo; Iovino, Massimo

    2017-04-01

    Simple infiltration experiments carried out in the field allow an easy and inexpensive way of characterizing soil hydraulic behavior, maintaining the functional connection of the sampled soil volume with the surrounding soil. The beerkan method consists of a three-dimensional (3D) infiltration experiment at zero pressure head (Haverkamp et al., 1996). It uses a simple annular ring inserted to a depth of about 0.01 m to avoid lateral loss of the ponded water. Soil disturbance is minimized by the limited ring insertion depth. Infiltration time of small volumes of water repeatedly poured on the confined soil are measured to determine the cumulative infiltration. Different algorithms based on this methodology (the so-called BEST family of algorithms) were developed for the determination of soil hydraulic characteristic parameters (Bagarello et al., 2014a; Lassabatere et al., 2006; Yilmaz et al., 2010). Recently, Bagarello et al. (2014b) developed a Simplified method based on a Beerkan Infiltration run (SBI method) to determine saturated soil hydraulic conductivity, Ks, by only the transient phase of a beerkan infiltration run and an estimate of the α* parameter, expressing the relative importance of gravity and capillary forces during an infiltration process (Reynolds and Elrick, 1990). However, several problems yet arise with the existing BEST-algorithms and the SBI method, including (i) the need of supplementary field and laboratory measurements (Bagarello et al., 2013); (ii) the difficulty to detect a linear relationship between I / √t and √t in the early stage of the infiltration process (Bagarello et al., 2014b); (iii) estimation of negative Ks values for hydrophobic soils (Di Prima et al., 2016). In this investigation, a new Simplified method based on the analysis of the Steady-state Beerkan Infiltration run (SSBI method) was proposed and tested. In particular, analytical data were generated to simulate beerkan infiltration experiments for six contrasting

  8. Biochar-Induced Changes in Soil Hydraulic Conductivity and Dissolved Nutrient Fluxes Constrained by Laboratory Experiments

    Science.gov (United States)

    Barnes, Rebecca T.; Gallagher, Morgan E.; Masiello, Caroline A.; Liu, Zuolin; Dugan, Brandon

    2014-01-01

    The addition of charcoal (or biochar) to soil has significant carbon sequestration and agronomic potential, making it important to determine how this potentially large anthropogenic carbon influx will alter ecosystem functions. We used column experiments to quantify how hydrologic and nutrient-retention characteristics of three soil materials differed with biochar amendment. We compared three homogeneous soil materials (sand, organic-rich topsoil, and clay-rich Hapludert) to provide a basic understanding of biochar-soil-water interactions. On average, biochar amendment decreased saturated hydraulic conductivity (K) by 92% in sand and 67% in organic soil, but increased K by 328% in clay-rich soil. The change in K for sand was not predicted by the accompanying physical changes to the soil mixture; the sand-biochar mixture was less dense and more porous than sand without biochar. We propose two hydrologic pathways that are potential drivers for this behavior: one through the interstitial biochar-sand space and a second through pores within the biochar grains themselves. This second pathway adds to the porosity of the soil mixture; however, it likely does not add to the effective soil K due to its tortuosity and smaller pore size. Therefore, the addition of biochar can increase or decrease soil drainage, and suggests that any potential improvement of water delivery to plants is dependent on soil type, biochar amendment rate, and biochar properties. Changes in dissolved carbon (C) and nitrogen (N) fluxes also differed; with biochar increasing the C flux from organic-poor sand, decreasing it from organic-rich soils, and retaining small amounts of soil-derived N. The aromaticity of C lost from sand and clay increased, suggesting lost C was biochar-derived; though the loss accounts for only 0.05% of added biochar-C. Thus, the direction and magnitude of hydraulic, C, and N changes associated with biochar amendments are soil type (composition and particle size) dependent

  9. Determination of hydraulic conductivity of fractured rock masses:A case study for a rock cavern project in Singapore

    Institute of Scientific and Technical Information of China (English)

    Zhipeng Xu; Zhiye Zhao; Jianping Sun; Ming Lu

    2015-01-01

    In order to reduce the risk associated with water seepage in an underground rock cavern project in Singapore, a reliable hydro-geological model should be established based on the in situ investigation data. The key challenging issue in the hydro-geological model building is how to integrate limited geological and hydro-geological data to determine the hydraulic conductivity of the fractured rock masses. Based on the data obtained from different stages (feasibility investigation stage, construction stage, and post-construction stage), suitable models and methods are proposed to determine the hy-draulic conductivities at different locations and depths, which will be used at other locations in the future.

  10. Research on the improvement of nuclear safety -Thermal hydraulic tests for reactor safety system-

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Moon Kee; Park, Choon Kyung; Yang, Sun Kyoo; Chun, Se Yung; Song, Chul Hwa; Jun, Hyung Kil; Jung, Heung Joon; Won, Soon Yun; Cho, Yung Roh; Min, Kyung Hoh; Jung, Jang Hwan; Jang, Suk Kyoo; Kim, Bok Deuk; Kim, Wooi Kyung; Huh, Jin; Kim, Sook Kwan; Moon, Sang Kee; Lee, Sang Il [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-06-01

    The present research aims at the development of the thermal hydraulic verification test technology for the safety system of the conventional and advanced nuclear power plant and the development of the advanced thermal hydraulic measuring techniques. In this research, test facilities simulating the primary coolant system and safety system are being constructed for the design verification tests of the existing and advanced nuclear power plant. 97 figs, 14 tabs, 65 refs. (Author).

  11. Impact of treated wastewater on growth, respiration and hydraulic conductivity of citrus root systems in light and heavy soils.

    Science.gov (United States)

    Paudel, Indira; Cohen, Shabtai; Shaviv, Avi; Bar-Tal, Asher; Bernstein, Nirit; Heuer, Bruria; Ephrath, Jhonathan

    2016-06-01

    Roots interact with soil properties and irrigation water quality leading to changes in root growth, structure and function. We studied these interactions in an orchard and in lysimeters with clay and sandy loam soils. Minirhizotron imaging and manual sampling showed that root growth was three times lower in the clay relative to sandy loam soil. Treated wastewater (TWW) led to a large reduction in root growth with clay (45-55%) but not with sandy loam soil (hydraulic conductivity was severely reduced in clay soil. Treated wastewater increased respiration rate and reduced hydraulic conductivity of all root orders in clay but only of the lower root orders in sandy loam soil. Loss of hydraulic conductivity increased with root order in clay and clay irrigated with TWW. Respiration and hydraulic properties of all root orders were significantly affected by sodium-amended TWW in sandy loam soil. These changes in root order morphology, anatomy, physiology and hydraulic properties indicate rapid and major modifications of root systems in response to differences in soil type and water quality.

  12. Development of realistic thermal-hydraulic system analysis codes ; development of thermal hydraulic test requirements for multidimensional flow modeling

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Kune Yull; Yoon, Sang Hyuk; Noh, Sang Woo; Lee, Il Suk [Seoul National University, Seoul (Korea)

    2002-03-01

    This study is concerned with developing a multidimensional flow model required for the system analysis code MARS to more mechanistically simulate a variety of thermal hydraulic phenomena in the nuclear stem supply system. The capability of the MARS code as a thermal hydraulic analysis tool for optimized system design can be expanded by improving the current calculational methods and adding new models. In this study the relevant literature was surveyed on the multidimensional flow models that may potentially be applied to the multidimensional analysis code. Research items were critically reviewed and suggested to better predict the multidimensional thermal hydraulic behavior and to identify test requirements. A small-scale preliminary test was performed in the downcomer formed by two vertical plates to analyze multidimensional flow pattern in a simple geometry. The experimental result may be applied to the code for analysis of the fluid impingement to the reactor downcomer wall. Also, data were collected to find out the controlling parameters for the one-dimensional and multidimensional flow behavior. 22 refs., 40 figs., 7 tabs. (Author)

  13. Design and Experiment of Electronic-hydraulic Loading Test-bed Based on Tractor’s Hydraulic Steering By-wire

    Institute of Scientific and Technical Information of China (English)

    Yue JIN; Yang LU; Jiahui GONG; Zhixiong LU; Wenming LI; Jungan WU

    2015-01-01

    An Electro-hydraulic loading system is designed based on a test-bed of tractor’s hydraulic steering by-wire. To simulate the steering resistance driving tractor in many kinds of soils and roads,the loading force is controlled to make proportional and continuous variable by an electro-hydraulic proportional relief valve. A steering resistance loading test-bed is built to test three kinds of steering resistance including constant,step and sine style. Tire lateral resistance is also tested under different steering conditions. The result shows that the electro-hydraulic loading system has high stability and following performance. Besides,the system’s steady state error is lower than 3. 1%,and it meets the test requirement of tractor’s hydraulic steering by-wire.

  14. Steady-state discharge into tunnels in formations with random variability and depth-decaying trend of hydraulic conductivity

    Science.gov (United States)

    Jiang, Xiao-Wei; Wan, Li; Yeh, Tian-Chyi Jim; Wang, Xu-Sheng; Xu, Liang

    2010-06-01

    SummaryMulti-scale heterogeneity of geological formations is a rule, which consists of random (local-scale) and systematic (large-scale) variability of hydraulic conductivity. The random variability and depth-decaying trend, a systematic variability, have different effects on subsurface flow, thus on groundwater discharge into tunnels. Little research has examined this problem in the past. Using Monte Carlo simulation and information of statistics of heterogeneity, we evaluate the most likely (ensemble average) discharge rate into a tunnel in geologic media with the multi-scale heterogeneity and uncertainty associated with this estimate. We find that the ensemble average discharge rate is larger than the discharge rate predicted by geometric mean of hydraulic conductivity, and smaller than the discharge rate predicted by arithmetic mean of hydraulic conductivity. Moreover, the ensemble average discharge rate decreases with the decay exponent of the depth-decaying trend, and increases with the standard deviation as well as the correlation scale of the stationary log-conductivity fields. We also find that the discharge rate of a tunnel is highly influenced by the hydraulic conductivity near the tunnel. Furthermore, deviation of the true discharge rate from the ensemble average can be large and increases with the decay exponent, standard deviation and correlation scale of log-conductivity fields. The largest uncertainty of discharge rate prediction in the shallow subsurface is controlled by the variability of conductivity fields and the uncertainty at the deep subsurface is by the depth-decaying trend of hydraulic conductivity. Therefore, accurate prediction of groundwater discharge into tunnels requires detailed characterization of multi-scale heterogeneity.

  15. Hydraulic Conductivity Measurements with HTU at Eurajoki, Olkiluoto, Boreholes OL-KR16, 16B, 17, 17B, 18 and 18B, Year 2004

    Energy Technology Data Exchange (ETDEWEB)

    Haemaelaeinen, H.

    2005-07-01

    As a part of the site investigations for the disposal of spent nuclear fuel, hydraulic con- ductivity measurements were carried out in boreholes OL-KR16, 16B, 17, 17 B, 18 and 18B at Eurajoki, Olkiluoto. The objective was to investigate the distribution of the hydraulic conductivity in the surrounding bedrock volume. Measurements were carried out during spring-summer 2004. The total lengths of the boreholes are: OL-KR16 170,20 m, OL-KR17 157,13 m and OL-KR18 125,49 m. Corresponding B-holes are around 45 m deep, parallel and adjacent to their 'parent' holes so representing the cased sections of them. The conbined measurable length of the holes is about 453,57 m, of which 429,15 m was covered with 217 standard tests at 2 m packer separation as specified in the research plan. 246 tests were initiated, but some had to be cancelled due to errors or unsuitable control parameters. Double-packer constant-head method was used throughout with nominal 200 kPa overpressure. Injection stage lasted normally 20 minutes and fall-off stage 10 minutes. The tests were often shortened if there were clear indications that the hydraulic conductivity is below the measuring range of the system. The pressure in the test section was let to stabilise at least 5 min before injection. In some test sections the stabilisation, injection or fall-off stage lasted several hours. Two transient (Horner and 1/Q) interpretations and one stationary-state (Moye) interpretation were made in-situ immediately after the test. The Hydraulic Testing Unit (HTU-system) is owned by Posiva Oy and it was operated by Geopros Oy. (orig.)

  16. Analysis of 6-year fluid electric conductivity logs to evaluate the hydraulic structure of the deep drill hole at Outokumpu, Finland

    Science.gov (United States)

    Sharma, Prabhakar; Tsang, Chin-Fu; Kukkonen, Ilmo T.; Niemi, Auli

    2016-07-01

    Over the last two decades, the flowing fluid electric conductivity (FFEC) logging method has been applied in boreholes in the well-testing mode to evaluate the transmissivity, hydraulic head, and formation water electrical conductivity as a function of depth with a resolution of about 10-20 cm. FFEC profiles along the borehole are obtained under both shut-in and pumping conditions in a logging procedure that lasts only 3 or 4 days. A method for analyzing these FFEC logs has been developed and successfully employed to obtain formation parameters in a number of field studies. The present paper concerns the analysis of a unique set of FFEC logs that were taken from a deep borehole reaching down to 2.5 km at Outokumpu, Finland, over a 6-year time period. The borehole intersects paleoproterozoic metasedimentary, granitoid, and ophiolite-derived rocks. After the well was drilled, completed, and cleaned up, FFEC logs were obtained after 7, 433, 597, 948, and 2036 days. In analyzing these five profiles, we discovered the need to account for salinity diffusion from water in the formation to the borehole. Analysis results include the identification of 15 hydraulically conducting zones along the borehole, the calculation of flow rates associated with these 15 zones, as well as the estimation of the variation of formation water electrical conductivity as a function of depth. The calculated flow rates were used to obtain the tentative hydraulic conductivity values at these 15 depth levels.

  17. Feedback from uncertainties propagation research projects conducted in different hydraulic fields: outcomes for engineering projects and nuclear safety assessment.

    Science.gov (United States)

    Bacchi, Vito; Duluc, Claire-Marie; Bertrand, Nathalie; Bardet, Lise

    2017-04-01

    In recent years, in the context of hydraulic risk assessment, much effort has been put into the development of sophisticated numerical model systems able reproducing surface flow field. These numerical models are based on a deterministic approach and the results are presented in terms of measurable quantities (water depths, flow velocities, etc…). However, the modelling of surface flows involves numerous uncertainties associated both to the numerical structure of the model, to the knowledge of the physical parameters which force the system and to the randomness inherent to natural phenomena. As a consequence, dealing with uncertainties can be a difficult task for both modelers and decision-makers [Ioss, 2011]. In the context of nuclear safety, IRSN assesses studies conducted by operators for different reference flood situations (local rain, small or large watershed flooding, sea levels, etc…), that are defined in the guide ASN N°13 [ASN, 2013]. The guide provides some recommendations to deal with uncertainties, by proposing a specific conservative approach to cover hydraulic modelling uncertainties. Depending of the situation, the influencing parameter might be the Strickler coefficient, levee behavior, simplified topographic assumptions, etc. Obviously, identifying the most influencing parameter and giving it a penalizing value is challenging and usually questionable. In this context, IRSN conducted cooperative (Compagnie Nationale du Rhone, I-CiTy laboratory of Polytech'Nice, Atomic Energy Commission, Bureau de Recherches Géologiques et Minières) research activities since 2011 in order to investigate feasibility and benefits of Uncertainties Analysis (UA) and Global Sensitivity Analysis (GSA) when applied to hydraulic modelling. A specific methodology was tested by using the computational environment Promethee, developed by IRSN, which allows carrying out uncertainties propagation study. This methodology was applied with various numerical models and in

  18. Hydraulic bridges in unsaturated coarse granular media: Influence of bridge size and conductivity on flow through clasts

    Science.gov (United States)

    Jayakody, Jeevan A.; Nicholl, Michael J.

    2016-10-01

    Unsaturated flow in coarse granular media must pass through hydraulic bridges (e.g., pendular water, porous connections) that form a physical connection between adjoining clasts. Previous studies suggest that volumetric flow through a porous clast (Q) will be linearly dependent on the cross-sectional area of the hydraulic bridges, and understate the importance of bridge conductivity. Numerical simulations were performed to explore steady-state flow through a spherical clast with identical bridges located at the top and bottom. The cross-sectional area of the bridges relative to that of the clast (Ar) was varied across six orders of magnitude. The ratio of hydraulic conductivity between bridges and clasts (Kb/Kc) was varied across 12 orders of magnitude to consider resistive, neutral, and conductive bridges. Results show that hydraulic bridges place a primary control on both Q and flux distribution within the clast. For neutral and conductive bridges (Kb/Kc ≥1), Ar is the dominant factor in determining Q, while Kb/Kc is the primary control for resistive bridges (Kb/Kc < 1). For all bridges, Q shows a non-linear dependency on both Ar and Kb/Kc. The intra-clast flow distribution shifts outwards as Ar increases. Conductive bridges promote this process and resistive bridges impede it.

  19. The Hydraulic Test Procedure for Non-instrumented Irradiation Test Rig of Annular Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae Ho; Lee, Kang Hee; Shin, Chang Hwan; Park, Chan Kook

    2008-08-15

    This report presents the procedure of pressure drop test, vibration test and endurance test for the non-instrumented rig using the irradiation test in HANARO of advanced PWR annular fuel which were designed and fabricated by KAERI. From the out-pile thermal hydraulic tests, confirm the flow rate at the 200 kPa pressure drop and measure the RMS displacement at this time. And the endurance test is confirmed the wear and the integrity of the non-instrumented rig at the 110% design flow rate. This out-pile test perform the Flow-Induced Vibration and Pressure Drop Experimental Tester(FIVPET) facility. The instruments in FIVPET facility was calibrated in KAERI and the pump and the thermocouple were certified by manufacturer.

  20. Design of hydraulic active stabilizer bar test platform based on dSPACE

    Directory of Open Access Journals (Sweden)

    Shan CHEN

    2016-12-01

    Full Text Available For the study of the influence of hydraulic active stabilizer bar to vehicle lateral stability under high speed steering maneuver, the hydraulic active stabilizer bar HIL test platform is implemented. The HIL test platform is designed with single/double axles universal test bench to experiment on single or double axles active stabilizer bar, using MC9S12DG128 microcontroller as the core controller and running vehicle dynamics model in the dSPACE. This HIL platform is used to study the effect of the hydraulic active stabilizer bar on the vehicle roll stability under different types of the road and typical steering maneuvers. The experiment results illustrate that the hydraulic active stabilizer bar HIL test platform can simulate the experiment environment and provide a powerful support for the development of active stabilizer bar system.

  1. Mechanical testing of hydraulic fluids II; Mechanische Pruefung von Hydraulikfluessigkeiten II

    Energy Technology Data Exchange (ETDEWEB)

    Kessler, M.; Feldmann, D.G.; Laukart, V.

    2001-09-01

    Since May 1996 the Institute for Mechanical Engineering Design 1 of Technical University of Hamburg-Harburg is working on the topic of ''Mechanical Testing of Hydraulic fluids''. The first project lasting 2 1/2 years was completed in 1999, the results are published as the DGMK report 514. Within these project a testing principle for the ''mechanical testing'' of hydraulic fluids has been derived, a prototype of a test rig was designed and set in operation at the authors' institute. This DGMK-report 514-1 describes the results of the second project, which investigates the operating behaviour of the test-rig more in detail. Several test-runs with a total number of 11 different hydraulic fluids show the dependence of the different lubricating behaviour of the tested fluids and their friction and wear behaviour during the tests in a reproducible way. The aim of the project was to derive a testing principle including the design of a suitable test-rig for the mechanical testing of hydraulic fluids. Based on the described results it can be stated that with the developed test it is possible to test the lubricity of hydraulic fluids reproducible and in correlation to field experiences within a relatively short time, so the target was reached. (orig.)

  2. Does the soil's effective hydraulic conductivity adapt in order to obey the Maximum Entropy Production principle? A lab experiment

    Science.gov (United States)

    Westhoff, Martijn; Zehe, Erwin; Erpicum, Sébastien; Archambeau, Pierre; Pirotton, Michel; Dewals, Benjamin

    2015-04-01

    The Maximum Entropy Production (MEP) principle is a conjecture assuming that a medium is organized in such a way that maximum power is subtracted from a gradient driving a flux (with power being a flux times its driving gradient). This maximum power is also known as the Carnot limit. It has already been shown that the atmosphere operates close to this Carnot limit when it comes to heat transport from the Equator to the poles, or vertically, from the surface to the atmospheric boundary layer. To reach this state close to the Carnot limit, the effective thermal conductivity of the atmosphere is adapted by the creation of convection cells (e.g. wind). The aim of this study is to test if the soil's effective hydraulic conductivity also adapts itself in such a way that it operates close to the Carnot limit. The big difference between atmosphere and soil is the way of adaptation of its resistance. The soil's hydraulic conductivity is either changed by weathering processes, which is a very slow process, or by creation of preferential flow paths. In this study the latter process is simulated in a lab experiment, where we focus on the preferential flow paths created by piping. Piping is the process of backwards erosion of sand particles subject to a large pressure gradient. Since this is a relatively fast process, it is suitable for being tested in the lab. In the lab setup a horizontal sand bed connects two reservoirs that both drain freely at a level high enough to keep the sand bed always saturated. By adding water to only one reservoir, a horizontal pressure gradient is maintained. If the flow resistance is small, a large gradient develops, leading to the effect of piping. When pipes are being formed, the effective flow resistance decreases; the flow through the sand bed increases and the pressure gradient decreases. At a certain point, the flow velocity is small enough to stop the pipes from growing any further. In this steady state, the effective flow resistance of

  3. Simulation of a spatial, servo-hydraulic test facility for space structures

    Science.gov (United States)

    Leimbach, K.-D.; Hahn, H.

    1994-01-01

    In this paper different control concepts for servo-hydraulic test facilities are derived using exact linearization techniques. Based on different linear and nonlinear models of the test table and the actuator dynamics several nonlinear controllers of different complexity are derived. The closed loop system performance of the controlled servo-hydraulic test facility is tested in various computer simulations using both, standard test signals and large test signals as system inputs. The simulation results turn out, that in case of standard input signals the test facility controller must include a linear test table mechanics model and a nonlinear servo-hydraulic actuator model. Additional simulations demonstrate the robustness of the control concept selected for standard test signals with respect to variations of plant parameters.

  4. The effects of sustained forest use on hillslope soil hydraulic conductivity in the Middle Mountains of Central Nepal

    NARCIS (Netherlands)

    Ghimire, C.P.; Bruijnzeel, L. Adrian; Bonell, Mike; Coles, Neil A.; Lubczynski, M.; Gilmour, Don A.

    2013-01-01

    This work investigated the multi-decadal changes in field saturated hydraulic conductivity, Kfs, beneath severely degraded pasture, natural forest and two mature planted Pinus roxburghii stands between two sets of measurements made in 1986 and 2011 at the same locations in the Middle Mountains of

  5. Evaluation of clogging in planted and unplanted horizontal subsurface flow constructed wetlands: solids accumulation and hydraulic conductivity reduction.

    Science.gov (United States)

    De Paoli, André Cordeiro; von Sperling, Marcos

    2013-01-01

    This study aimed to evaluate the behaviour of two horizontal subsurface flow constructed wetland units regarding solids build up and clogging of the filter medium. In order to analyse the causes of this process, which is considered the major operational problem of constructed wetlands, studies were carried out to characterize accumulated solids and hydraulic conductivity at specific points of the beds of two wetlands (planted with Typha latifolia and unplanted units) receiving effluent from an upflow anaerobic sludge blanket reactor treating sanitary sewage (population equivalent of 50 inhabitants each unit). The experiments were performed after the units were operating for 2 years and 4 months. This study presents comparative results related to the quantification and characterization of accumulated solids and hydraulic conductivity along the length and width of the filter beds. Approximately 80% of the solids found were inorganic (fixed). Near the inlet end, the rate interstitial solids/attached solids was 5.0, while in the outlet end it was reduced to 1.5. Hydraulic conductivity was lower near the inlet of the units (as expected) and, by comparing the planted wetland with the unplanted, the hydraulic conductivity was lower in the former, resulting in larger undesired surface flow.

  6. Root hydraulic conductivity and xylem sap levels of zeatin riboside and abscisic acid in ectomycorrhizal Douglas fir seedlings

    Science.gov (United States)

    Mark D. Coleman; Caroline S. Bledsoe; Barbara A. Smit

    1990-01-01

    Mechanistic hypotheses to explain mycorrhizal enhancement of root hydraulic conductivity (Lp) suggest that phosphorus (P) nutrition, plant growth substances and/or altered morphology may be responsible. Such ideas are based on work with VA (vesicular-arbuscular) mycorrhizas. Since VA mycorrhizas and ectomycorrhizas differ in many respects, they...

  7. Do quantitative vessel and pit characters account for ion-mediated changes in the hydraulic conductance of angiosperm xylem?

    NARCIS (Netherlands)

    Jansen, S.; Gortan, E.; Lens, F.; Assunta Lo Gullo, M.; Salleo, S.; Scholtz, A.; Stein, A.; Trifilò, P.; Nardini, A.

    2011-01-01

    • The hydraulic conductance of angiosperm xylem has been suggested to vary with changes in sap solute concentrations because of intervessel pit properties. • The magnitude of the ‘ionic effect’ was linked with vessel and pit dimensions in 20 angiosperm species covering 13 families including six Laur

  8. Hydraulic conductivity how subsidy in evaluation of the contaminated area in the petrochemical industry; Condutividade hidraulica como subsidio na avaliacao de area contaminada em industria petroquimica

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Julia Brazil; Polivanov, Helena; Moraes, Patricia [Universidade Federal do Rio de Janeiro, RJ (Brazil)]. E-mail: juliabrazilsousa@yahoo.com

    2003-07-01

    The activities here described were undertaken in the scope of the Environmental Management System (EMS) of Petroflex Ind. e Com. S.A., done in cooperation with the Geosciences Institute (Instituto de Geociencias) of the UFRJ. In order to determine the hydraulic conductivity of the media in the lab, and to estimate the influence of this property on the retention of a contamination plume resulted from unsuitable disposal of industrial residues, five undisturbed samples of marine organic clay were tested. The hydraulic conductivity values obtained in laboratory vary from 10{sup -5} to 10{sup -7} cm/s. Slug tests done by the company personnel yielded results with a magnitude of 10{sup -8} cm/s. The small values of hydraulic conductivity, associated to chemical and mineralogical properties from the material, lead to the conclusion that the possibly existing contamination plume would hardly pass through the organic clay layer without having its concentration modified, since many factors provide interaction between soil and contaminant, reducing the substance concentration in fluid (water) and providing good conditions to remediation measures. (author)

  9. Using automatic calibration method for optimizing the performance of Pedotransfer functions of saturated hydraulic conductivity

    Directory of Open Access Journals (Sweden)

    Ahmed M. Abdelbaki

    2016-06-01

    Full Text Available Pedotransfer functions (PTFs are an easy way to predict saturated hydraulic conductivity (Ksat without measurements. This study aims to auto calibrate 22 PTFs. The PTFs were divided into three groups according to its input requirements and the shuffled complex evolution algorithm was used in calibration. The results showed great modification in the performance of the functions compared to the original published functions. For group 1 PTFs, the geometric mean error ratio (GMER and the geometric standard deviation of error ratio (GSDER values were modified from range (1.27–6.09, (5.2–7.01 to (0.91–1.15, (4.88–5.85 respectively. For group 2 PTFs, the GMER and the GSDER values were modified from (0.3–1.55, (5.9–12.38 to (1.00–1.03, (5.5–5.9 respectively. For group 3 PTFs, the GMER and the GSDER values were modified from (0.11–2.06, (5.55–16.42 to (0.82–1.01, (5.1–6.17 respectively. The result showed that the automatic calibration is an efficient and accurate method to enhance the performance of the PTFs.

  10. Effect of pH on saturated hydraulic conductivity and soil dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Suarez, D.L.; Roades, J.D.; Lavado, R.; Grieve, C.M.

    The adverse effects of exchangeable sodium on soil hydraulic conductivity (K) are well known, but at present only sodicity and total electrolyte concentration are used in evaluating irrigation water suitability. In arid areas, high sodicity is often associatd with high dissolved carbonate and thus high pH, but in humid areas high sodicity may be associated with low pH. To evaluate the effect of pH (as an independent variable) on K, solutions with the same SAR and electrolyte level were prepared at pH 6, 7, 8, and 9. Saturated K values were determined at constant flux in columns packed at a bulk density of 1.5 Mg m/sup -3/. At pH 9, saturated K values were lower than at pH 6 for a montmorillonitic and kaolinitic soil. For a vermiculitic soil with lower organic carbon and higher silt content, pH changes did not cause large K differences. Decreases in K were not reversible on application of waters with higher electrolyte levels. The results from the K experiments were generally consistent with optical transmission measurements of dispersion. Although anion adsorption was at or below detection limits and cation exchange capacity (CEC) was only slightly dependent on pH, differences in pH effects on K among soils are likely due to differences in quantities of variable-charge minerals and organic matter.

  11. Arbuscular mycorrhizal symbiosis and methyl jasmonate avoid the inhibition of root hydraulic conductivity caused by drought.

    Science.gov (United States)

    Sánchez-Romera, Beatriz; Ruiz-Lozano, Juan Manuel; Zamarreño, Ángel María; García-Mina, José María; Aroca, Ricardo

    2016-02-01

    Hormonal regulation and symbiotic relationships provide benefits for plants to overcome stress conditions. The aim of this study was to elucidate the effects of exogenous methyl jasmonate (MeJA) application on root hydraulic conductivity (L) of Phaseolus vulgaris plants which established arbuscular mycorrhizal (AM) symbiosis under two water regimes (well-watered and drought conditions). The variation in endogenous contents of several hormones (MeJA, JA, abscisic acid (ABA), indol-3-acetic acid (IAA), salicylic acid (SA)) and the changes in aquaporin gene expression, protein abundance and phosphorylation state were analyzed. AM symbiosis decreased L under well-watered conditions, which was partially reverted by the MeJA treatment, apparently by a drop in root IAA contents. Also, AM symbiosis and MeJA prevented inhibition of L under drought conditions, most probably by a reduction in root SA contents. Additionally, the gene expression of two fungal aquaporins was upregulated under drought conditions, independently of the MeJA treatment. Plant aquaporin gene expression could not explain the behaviour of L. Conversely, evidence was found for the control of L by phosphorylation of aquaporins. Hence, MeJA addition modified the response of L to both AM symbiosis and drought, presumably by regulating the root contents of IAA and SA and the phosphorylation state of aquaporins.

  12. Estimation of soil saturated hydraulic conductivity by artificial neural networks ensemble in smectitic soils

    Science.gov (United States)

    Sedaghat, A.; Bayat, H.; Safari Sinegani, A. A.

    2016-03-01

    The saturated hydraulic conductivity ( K s ) of the soil is one of the main soil physical properties. Indirect estimation of this parameter using pedo-transfer functions (PTFs) has received considerable attention. The Purpose of this study was to improve the estimation of K s using fractal parameters of particle and micro-aggregate size distributions in smectitic soils. In this study 260 disturbed and undisturbed soil samples were collected from Guilan province, the north of Iran. The fractal model of Bird and Perrier was used to compute the fractal parameters of particle and micro-aggregate size distributions. The PTFs were developed by artificial neural networks (ANNs) ensemble to estimate K s by using available soil data and fractal parameters. There were found significant correlations between K s and fractal parameters of particles and microaggregates. Estimation of K s was improved significantly by using fractal parameters of soil micro-aggregates as predictors. But using geometric mean and geometric standard deviation of particles diameter did not improve K s estimations significantly. Using fractal parameters of particles and micro-aggregates simultaneously, had the most effect in the estimation of K s . Generally, fractal parameters can be successfully used as input parameters to improve the estimation of K s in the PTFs in smectitic soils. As a result, ANNs ensemble successfully correlated the fractal parameters of particles and micro-aggregates to K s .

  13. Spatial Variability of Soil Saturated Hydraulic Conductivity in a Small Watershed of Loess Hilly Region,China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Saturated hydraulic conductivity (Ks) is an important soil hydraulic parameter for charactering the rate of water flow across the soils and is mainly related to its high spatial variability. In a small watershed with the area of 0.27 km2 in the Loess Plateau, Ks of 197 soil samples under different vegetations and landforms were measured. Ks had a moderate variability for total samples. The forestland had high Ks with low coefficient of variation (CV), but the grassland in the watershed bottom had low Ks wit...

  14. Reflection seismic imaging of a hydraulically conductive fracture zone in a high noise area, Forsmark, Sweden

    Science.gov (United States)

    Juhlin, C.; Stephens, M. B.; Cosma, C.

    2007-05-01

    borehole shows that the reflection corresponds to a hydraulically conductive fracture zone that was intersected at about 320 m depth.

  15. Development and industrial tests of the first LNG hydraulic turbine system in China

    Directory of Open Access Journals (Sweden)

    Jie Chen

    2016-10-01

    Full Text Available The cryogenic hydraulic turbine can be used to replace the conventional J–T valve for LNG or mixed refrigerant throttling and depressurization in a natural gas liquefaction plant. This advanced technology is not only to enhance the efficiency of the liquefaction plant, but to usher a new trend in the development of global liquefaction technologies. China has over 136 liquefaction plants, but the cryogenic hydraulic turbines have not been deployed in industrial utilization. In addition, these turbines cannot be manufactured domestically. In this circumstance, through working on the key technologies for LNG hydraulic turbine process & control system development, hydraulic model optimization design, structure design and manufacturing, the first domestic cryogenic hydraulic turbine with a flow rate of 40 m3/h was developed to recover the pressure energy from the LNG of cold box. The turbine was installed in the CNOOC Zhuhai Natural Gas Liquefaction Plant for industrial tests under multiple working conditions, including start-stop, variable flow rates and variable rotation speeds. Test results show that the domestic LNG cryogenic hydraulic turbine has satisfactory mechanical and operational performances at low temperatures as specified in design. In addition, the process & control system and frequency-conversion power-generation system of the turbine system are designed properly to automatically and smoothly replace the existing LNG J–T valve. As a result, the domestic LNG cryogenic hydraulic turbine system can improve LNG production by an average of 2% and generate power of 8.3 kW.

  16. Characterization of a rice variety with high hydraulic conductance and identification of the chromosome region responsible using chromosome segment substitution lines.

    Science.gov (United States)

    Adachi, Shunsuke; Tsuru, Yukiko; Kondo, Motohiko; Yamamoto, Toshio; Arai-Sanoh, Yumiko; Ando, Tsuyu; Ookawa, Taiichiro; Yano, Masahiro; Hirasawa, Tadashi

    2010-11-01

    The rate of photosynthesis in paddy rice often decreases at noon on sunny days because of water stress, even under submerged conditions. Maintenance of higher rates of photosynthesis during the day might improve both yield and dry matter production in paddy rice. A high-yielding indica variety, 'Habataki', maintains a high rate of leaf photosynthesis during the daytime because of the higher hydraulic conductance from roots to leaves than in the standard japonica variety 'Sasanishiki'. This research was conducted to characterize the trait responsible for the higher hydraulic conductance in 'Habataki' and identified a chromosome region for the high hydraulic conductance. Hydraulic conductance to passive water transport and to osmotic water transport was determined for plants under intense transpiration and for plants without transpiration, respectively. The varietal difference in hydraulic conductance was examined with respect to root surface area and hydraulic conductivity (hydraulic conductance per root surface area, L(p)). To identify the chromosome region responsible for higher hydraulic conductance, chromosome segment substitution lines (CSSLs) derived from a cross between 'Sasanishiki' and 'Habataki' were used. The significantly higher hydraulic conductance resulted from the larger root surface area not from L(p) in 'Habataki'. A chromosome region associated with the elevated hydraulic conductance was detected between RM3916 and RM2431 on the long arm of chromosome 4. The CSSL, in which this region was substituted with the 'Habataki' chromosome segment in the 'Sasanishiki' background, had a larger root mass than 'Sasanishiki'. The trait for increasing plant hydraulic conductance and, therefore, maintaining the higher rate of leaf photosynthesis under the conditions of intense transpiration in 'Habataki' was identified, and it was estimated that there is at least one chromosome region for the trait located on chromosome 4.

  17. Saturated hydraulic conductivity model computed from bimodal water retention curves for a range of New Zealand soils

    Directory of Open Access Journals (Sweden)

    J. A. P. Pollacco

    2017-06-01

    Full Text Available Descriptions of soil hydraulic properties, such as the soil moisture retention curve, θ(h, and saturated hydraulic conductivities, Ks, are a prerequisite for hydrological models. Since the measurement of Ks is expensive, it is frequently derived from statistical pedotransfer functions (PTFs. Because it is usually more difficult to describe Ks than θ(h from pedotransfer functions, Pollacco et al. (2013 developed a physical unimodal model to compute Ks solely from hydraulic parameters derived from the Kosugi θ(h. This unimodal Ks model, which is based on a unimodal Kosugi soil pore-size distribution, was developed by combining the approach of Hagen–Poiseuille with Darcy's law and by introducing three tortuosity parameters. We report here on (1 the suitability of the Pollacco unimodal Ks model to predict Ks for a range of New Zealand soils from the New Zealand soil database (S-map and (2 further adaptations to this model to adapt it to dual-porosity structured soils by computing the soil water flux through a continuous function of an improved bimodal pore-size distribution. The improved bimodal Ks model was tested with a New Zealand data set derived from historical measurements of Ks and θ(h for a range of soils derived from sandstone and siltstone. The Ks data were collected using a small core size of 10 cm diameter, causing large uncertainty in replicate measurements. Predictions of Ks were further improved by distinguishing topsoils from subsoil. Nevertheless, as expected, stratifying the data with soil texture only slightly improved the predictions of the physical Ks models because the Ks model is based on pore-size distribution and the calibrated parameters were obtained within the physically feasible range. The improvements made to the unimodal Ks model by using the new bimodal Ks model are modest when compared to the unimodal model, which is explained by the poor accuracy of measured total porosity. Nevertheless, the new bimodal

  18. Saturated hydraulic conductivity model computed from bimodal water retention curves for a range of New Zealand soils

    Science.gov (United States)

    Pollacco, Joseph Alexander Paul; Webb, Trevor; McNeill, Stephen; Hu, Wei; Carrick, Sam; Hewitt, Allan; Lilburne, Linda

    2017-06-01

    Descriptions of soil hydraulic properties, such as the soil moisture retention curve, θ(h), and saturated hydraulic conductivities, Ks, are a prerequisite for hydrological models. Since the measurement of Ks is expensive, it is frequently derived from statistical pedotransfer functions (PTFs). Because it is usually more difficult to describe Ks than θ(h) from pedotransfer functions, Pollacco et al. (2013) developed a physical unimodal model to compute Ks solely from hydraulic parameters derived from the Kosugi θ(h). This unimodal Ks model, which is based on a unimodal Kosugi soil pore-size distribution, was developed by combining the approach of Hagen-Poiseuille with Darcy's law and by introducing three tortuosity parameters. We report here on (1) the suitability of the Pollacco unimodal Ks model to predict Ks for a range of New Zealand soils from the New Zealand soil database (S-map) and (2) further adaptations to this model to adapt it to dual-porosity structured soils by computing the soil water flux through a continuous function of an improved bimodal pore-size distribution. The improved bimodal Ks model was tested with a New Zealand data set derived from historical measurements of Ks and θ(h) for a range of soils derived from sandstone and siltstone. The Ks data were collected using a small core size of 10 cm diameter, causing large uncertainty in replicate measurements. Predictions of Ks were further improved by distinguishing topsoils from subsoil. Nevertheless, as expected, stratifying the data with soil texture only slightly improved the predictions of the physical Ks models because the Ks model is based on pore-size distribution and the calibrated parameters were obtained within the physically feasible range. The improvements made to the unimodal Ks model by using the new bimodal Ks model are modest when compared to the unimodal model, which is explained by the poor accuracy of measured total porosity. Nevertheless, the new bimodal model provides an

  19. In-situ stress from hydraulic fracture measurements in G Tunnel, Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C.; Vollendorf, W. C.; Warren, W. E.

    1981-04-01

    Hydraulic fracture work in G Tunnel, Nevada Test Site, performed to obtain the in-situ stress state is discussed. Field equipment and procedures are described; analysis is developed to relate the hydraulic fracture pressures to the in-situ stress state. Pressure data are analyzed to provide estimates of the stress state at a number of locations in the tunnel complex. A unique feature of the work is the mineback - a mining process in which the rock is cut away to reveal the actual plane of the fracture. Advantages, limitations, and problem areas associated with extracting in-situ stress fields from hydraulic fracture pressure records are discussed in detail.

  20. The contribution of vascular and extra-vascular water pathways to drought-induced decline of leaf hydraulic conductance.

    Science.gov (United States)

    Trifiló, Patrizia; Raimondo, Fabio; Savi, Tadeja; Lo Gullo, Maria A; Nardini, Andrea

    2016-09-01

    Drought stress can impair leaf hydraulic conductance (Kleaf), but the relative contribution of changes in the efficiency of the vein xylem water pathway and in the mesophyll route outside the xylem in driving the decline of Kleaf is still debated. We report direct measurements of dehydration-induced changes in the hydraulic resistance (R=1/K) of whole leaf (Rleaf), as well as of the leaf xylem (Rx) and extra-vascular pathways (Rox) in four Angiosperm species. Rleaf, Rx, and Rox were measured using the vacuum chamber method (VCM). Rleaf values during progressive leaf dehydration were also validated with measurements performed using the rehydration kinetic method (RKM). We analysed correlations between changes in Rx or Rox and Rleaf, as well as between morpho-anatomical traits (including dehydration-induced leaf shrinkage), vulnerability to embolism, and leaf water relation parameters. Measurements revealed that the relative contribution of vascular and extra-vascular hydraulic properties in driving Kleaf decline during dehydration is species-specific. Whilst in two study species the progressive impairment of both vascular and extra-vascular pathways contributed to leaf hydraulic vulnerability, in the other two species the vascular pathway remained substantially unaltered during leaf dehydration, and Kleaf decline was apparently caused only by changes in the hydraulic properties of the extra-vascular compartment.

  1. Changes in root hydraulic conductivity facilitate the overall hydraulic response of rice (Oryza sativa L.) cultivars to salt and osmotic stress.

    Science.gov (United States)

    Meng, Delong; Fricke, Wieland

    2017-04-01

    The aim of the present work was to assess the significance of changes in root AQP gene expression and hydraulic conductivity (Lp) in the regulation of water balance in two hydroponically-grown rice cultivars (Azucena, Bala) which differ in root morphology, stomatal regulation and aquaporin (AQP) isoform expression. Plants were exposed to NaCl (25 mM, 50 mM) and osmotic stress (5%, 10% PEG6000). Root Lp was determined for exuding root systems (osmotic forces driving water uptake; 'exudation Lp') and transpiring plants (hydrostatic forces dominating; 'transpiration-Lp'). Gene expression was analysed by qPCR. Stress treatments caused a consistent and significant decrease in plant growth, transpirational water loss, stomatal conductance, shoot-to-root surface area ratio and root Lp. Comparison of exudation-with transpiration-Lp supported a significant contribution of AQP-facilitated water flow to root water uptake. Changes in root Lp in response to treatments were correlated much stronger with root morphological characteristics, such as the number of main and lateral roots, surface area ratio of root to shoot and plant transpiration rate than with AQP gene expression. Changes in root Lp, involving AQP function, form an integral part of the plant hydraulic response to stress and facilitate changes in the root-to-shoot surface area ratio, transpiration and stomatal conductance.

  2. Influence of leaf vein density and thickness on hydraulic conductance and photosynthesis in rice (Oryza sativa L.) during water stress

    OpenAIRE

    2016-01-01

    The leaf venation architecture is an ideal, highly structured and efficient irrigation system in plant leaves. Leaf vein density (LVD) and vein thickness are the two major properties of this system. Leaf laminae carry out photosynthesis to harvest the maximum biological yield. It is still unknown whether the LVD and/or leaf vein thickness determines the plant hydraulic conductance (K plant) and leaf photosynthetic rate (A). To investigate this topic, the current study was conducted with two v...

  3. Hydraulic Tomography and High-Resolution Slug Testing to Determine Hydraulic Conductivity Distributions - Year 3

    Science.gov (United States)

    2007-12-01

    comparison of phase values from a numerical model, two homogeneous analytical solutions, and the spatially weighted raytrace average for three...investigating involves the spatially weighted raytracing method. For a given set of raypaths the path lengths through each zone must be computed only once

  4. Thermal hydraulic studies in steam generator test facility

    Energy Technology Data Exchange (ETDEWEB)

    Vinod, V.; Suresh Kumar, V.A.; Noushad, I.B.; Ellappan, T.R.; Rajan, K.K.; Rajan, M.; Vaidyanathan, G. [Engineering Development Group Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India)

    2005-07-01

    Full text of publication follows: A 500 MWe fast breeder reactor is being constructed at Kalpakkam, India. This is a sodium cooled reactor with two primary and two secondary sodium loops with total 8 steam generators. The typical advantage of fast breeder plants is the high operating temperature of steam cycles and the high plant efficiency. To produce this high pressure and high temperature steam, once through straight tube vertical sodium heated steam generators are used. The steam is generated from the heat produced in the reactor core and being transported through primary and secondary sodium circuits. The steam generator is a 25 m high middle supported steam generator with expansion bend and 23 m heat transfer length. Steam Generator Test Facility (SGTF) constructed at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam aims at performing various tests on a 5.5 MWt steam generator. This vertically simulated test article is similar in all respects to the proposed 157 MWt steam generator module for the Prototype Fast Breeder Reactor (PFBR), with reduced number of tubes. Heat transfer performance tests are done with this 19 tube steam generator at various load conditions. Sodium circuit for the SGTF is equipped with oil fired heater as heat source and centrifugal sodium pump, to pump sodium at 105 m{sup 3}/hr flow rate. Other typical components like sodium to air heat exchanger, sodium purification system and hydrogen leak detection system is also present in the sodium circuit. High pressure steam produced in the steam generator is dumped in a condenser and recycled. Important tests planned in SGTF are the heat transfer performance test, stability test, endurance test and performance test of steam generator under various transients. The controlled operation of steam generator will be studied with possible control schemes. A steady state simulation of the steam generator is done with a mathematical model. This paper gives the details of heat transfer

  5. Hazards and Safeguards of High Pressure Hydraulic Fatigue Testing

    Science.gov (United States)

    1990-07-01

    rew e I&64aN neem mde tliF by block mumber) The creation and transfer of hydraulic pressure at the 690-MPa (100,000-psi) level is in itself hazardous...than alloy steel, we have found that it is more notch sensitive to fatigue and drastically degrades with small constituent variations. To avoid this...I ATTN: SMCWV-PP DIRECTOR, PRODUCT ASSURANCE DIRECTORATE 1 ATTN: SMCWV-QA NOTE: PLEASE NOTIFY DIRECTOR, BENET LABORATORIES, ATTN: SMCAR-CCB-TL, OF ANY

  6. INFLUENCE OF CYCLIC FREEZING AND THAWING ON THE HYDRAULIC CONDUCTIVITY OF SELECTED AGGREGATES USED IN THE CONSTRUCTION OF GREEN ROOFS

    Directory of Open Access Journals (Sweden)

    Karolina Gwóżdź

    2016-09-01

    Full Text Available The construction of a green roof requires drainage which ought to be characterized by adequate hydraulic conductivity and be resistant to changing meteorological conditions during the winter period. A properly functioning drainage system guarantees the reliability of the entire green roof system. The article presents studies on the freeze-thaw durability and hydraulic conductivity of selected aggregates applied for constructing green roof drainage systems. The aggregates were subjected to a cyclic freezing and thawing process in 30 and 70 cycles. The obtained results indicate that the conductivity of aggregates studied using the constant head method decreases along with an increase in the number of freeze-thaw cycles they were subjected to. This means that the indicator of freeze-thaw durability can have an indicative nature in the assessment of the usefulness of selected aggregates for constructing drainage layers. The conducted studies indicate that the deciding parameter when selecting an aggregate ought to be its hydraulic conductivity, determined accounting for the changes taking place in the freeze-thaw cycles. The equations of changes in the conductivity of aggregates indicated by the authors make it possible to assess them for practical purposes.

  7. FY 1993 progress report on the ANS thermal-hydraulic test loop operation and results

    Energy Technology Data Exchange (ETDEWEB)

    Siman-Tov, M.; Felde, D.K.; Farquharson, G. [and others

    1994-07-01

    The Thermal-Hydraulic Test Loop (THTL) is an experimental facility constructed to support the development of the Advanced Neutron Source Reactor (ANSR) at Oak Ridge National Laboratory (ORNL). Highly subcooled heavy-water coolant flows vertically upward at a very high mass flux of almost 27 MG/m{sup 2}-s. In a parallel fuel plate configuration as in the ANSR, the flow is subject to a potential excursive static-flow instability that can very rapidly lead to flow starvation and departure from nucleate boiling (DNB) in the ``hot channel``. The current correlations and experimental data bases for flow excursion (FE) and critical heat flux (CHF) seldom evaluate the specific combination of ANSR operating parameters. The THTL facility was designed and built to provide known thermal-hydraulic (T/H) conditions for a simulated full-length coolant subchannel of the ANS reactor core, thus facilitating experimental determination of FE and CHF thermal limits under expected ANSR T/H conditions. A series of FE tests with water flowing vertically upward was completed over a nominal heat flux range of 6 to 17 MW/m{sup 2}, a mass flux range of 8 to 28 Mg/m{sup 2}-s, an exit pressure range of 1.4 to 2.1 MPa, and an inlet temperature range of 40 to 50 C. FE experiments were also conducted using as ``soft`` a system as possible to secure a true FE phenomena (actual secondary burnout). True DNB experiments under similar conditions were also conducted. To the author`s knowledge, no other FE data have been reported in the literature to date that dover such a combination of conditions of high mass flux, high heat flux, and moderately high pressure.

  8. Hydraulic Conductivity Functions in Relation to Some Chemical Properties in a Cultivated Oxisols of a Humid Region, Delta State, Nigeria

    Directory of Open Access Journals (Sweden)

    Egbuchua, C. N.

    2014-04-01

    Full Text Available The study was conducted to evaluate hydraulic conductivity functions in relation to some soil chemical properties in an oxisols of the tropics. Field and laboratory studies were carried out and data collected, subjected to statistical analytical procedure for computing coefficient of variability and correlation among soil properties. Results of the study showed that hydraulic conductivity functions varied spatially and temporarily across the experimental points with a moderate mean value of 0.0026 cm/h and a coefficient o variation of 31.45% soil chemical properties showed that the soils were acidic with a mean pH value of 5.12. Organic carbon, total nitrogen and available phosphorus were low with mean values of 1.29%, 0.68% and 4.43 mgkg-1. Coefficient of variability among soil properties indicated less to moderately variable. Soil pH had negative correlation with all the soil properties evaluated.

  9. Towards improved estimation of the unsaturated soil hydraulic conductivity in the near saturated range by a fully automated, pressure controlled unit gradient experiment.

    Science.gov (United States)

    Werisch, Stefan; Müller, Marius

    2017-04-01

    Determination of soil hydraulic properties has always been an important part of soil physical research and model applications. While several experiments are available to measure the water retention of soil samples, the determination of the unsaturated hydraulic conductivity is often more complicated, bound to strong assumption and time consuming. Although, the application of unit gradient experiments is recommended since the middle of the last century, as one method towards a (assumption free) direct measurement of the unsaturated hydraulic conductivity, data from unit gradient experiments is seldom to never reported in literature. We developed and build a fully automated, pressure controlled, unit gradient experiment, which allows a precise determination of the unsaturated soil hydraulic conductivity K(h) and water retention VWC(h), especially in the highly dynamic near saturated range. The measurement apparatus applies the concept of hanging water columns and imposes the required soil water pressure by dual porous plates. This concepts allows the simultaneous and direct measurement of water retention and hydraulic conductivity. Moreover, this approach results in a technically less demanding experiment than related flux controlled experiments, and virtually any flux can be measured. Thus, both soil properties can be measured in mm resolution, for wetting and drying processes, between saturation and field capacity for all soil types. Our results show, that it is important to establish separate measurements of the unsaturated hydraulic conductivity in the near saturated range, as the shape of the retention function and hydraulic conductivity curve do not necessarily match. Consequently, the prediction of the hydraulic conductivity curve from measurements of the water retention behavior in combination with a value for the saturated hydraulic conductivity can be misleading. Thus, separate parameterizations of the individual functions might be necessary and are

  10. A tale of two plasticities: leaf hydraulic conductances and related traits diverge for two tropical epiphytes from contrasting light environments.

    Science.gov (United States)

    North, Gretchen B; Browne, Marvin G; Fukui, Kyle; Maharaj, Franklin D R; Phillips, Carly A; Woodside, Walter T

    2016-07-01

    We compared the effects of different light environments on leaf hydraulic conductance (Kleaf ) for two congeneric epiphytes, the tank bromeliads Guzmania lingulata (L.) Mez and Guzmania monostachia (L.) Rusby ex Mez. They occur sympatrically at the study site, although G. monostachia is both wider ranging and typically found in higher light. We collected plants from two levels of irradiance and measured Kleaf as well as related morphological and anatomical traits. Leaf xylem conductance (Kxy ) was estimated from tracheid dimensions, and leaf conductance outside the xylem (Kox ) was derived from a leaky cable model. For G. monostachia, but not for G. lingulata, Kleaf and Kxy were significantly higher in high light conditions. Under both light conditions, Kxy and Kox were co-limiting for the two species, and all conductances were in the low range for angiosperms. With respect to hydraulic conductances and a number of related anatomical traits, G. monostachia exhibited greater plasticity than did G. lingulata, which responded to high light chiefly by reducing leaf size. The positive plasticity of leaf hydraulic traits in varying light environments in G. monostachia contrasted with negative plasticity in leaf size for G. lingulata, suggesting that G. monostachia may be better able to respond to forest conditions that are likely to be warmer and more disturbed in the future.

  11. Ozone and simulated acid rain effects on growth root hydraulic conductivity, and photosynthesis of red spruce

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W.S.; Chevone, B.I.; Seiler, J.R.

    1987-04-01

    Three-year-old red spruce seedlings were exposed to ozone (O/sub 3/) at 0.00 (control) or 0.10 ppm, 4 hr/d, 3 d/wk in combination with simulated rain (pH 3.0 or 5.6, 1 hr/d, 2 d/wk at 0.75 cm/hr) for 10 wks. All seedlings were submitted to two drought cycles after the 10-wk-treatment. O/sub 3/ significantly decreased root hydraulic conductivity (Lp) by 21% after 10 wks across all rain pHs. The reduction of Lp in seedlings treated with O/sub 3/ was enhanced by drought stress. Rain pH alone did not affect Lp during the 10-wks-exposure and drought cycles. However, the O/sub 3/ effect on Lp was more severe at pH 5.6 than at pH 3.0. Rain at pH 3.0 stimulated shoot height growth by 31% compared with pH 5.6 across all O/sub 3/ treatments. However, root, shoot, and total dry weight of seedlings were not changed by any treatments. Neither O/sub 3/ nor rain pH affected net photosynthetic (P/sub i/) response to branch water potential in plants subjected to one or two drought cycles. However, P/sub i/ was less sensitive to water potential after two drought cycles, indicating physiological adjustment to drought stress.

  12. Effect of urban waste compost application on soil near-saturated hydraulic conductivity.

    Science.gov (United States)

    Schneider, S; Coquet, Y; Vachier, P; Labat, C; Roger-Estrade, J; Benoit, P; Pot, V; Houot, S

    2009-01-01

    Compost application tends to increase soil fertility and is likely to modify soil hydrodynamic properties by acting on soil structural porosity. Two composts, a municipal solid waste compost (MSW) and a co-compost of green wastes and sewage sludge (SGW), have been applied every other year for 6 yr to cultivated plots located on a silt loam soil in the Parisian Basin, France. Four soil zones were defined in the topsoil after plowing: the plowpan located at the base of the plowed layer, compacted (Delta) or noncompacted (Gamma) zones located within the plowed layer, and interfurrows created by plowing and containing a large quantity of crop residues together with the recently-applied compost. To assess the effect of compost application on the near-saturated soil hydraulic conductivity, infiltration rates were measured using a tension disc infiltrometer at three water pressure potentials -0.6, -0.2, and -0.05 kPa in the various zones of the soil profile. Compost addition decreased K((sat)) in the interfurrows after plowing by almost one order of magnitude with average values of 5.6 x 10(-5) m.s(-1) in the MSW plot and 4.1 x 10(-5) m.s(-1) in the SGW plot, against 2.2 x 10(-4) m.s(-1) in the control plot. This effect had disappeared 6 mo after plowing when the average K((sat)) in the control plot had decreased to 1.9 x 10(-5) m.s(-1) while that in the compost-amended plots remained stable.

  13. Simulating soil-water movement through loess-veneered landscapes using nonconsilient saturated hydraulic conductivity measurements

    Science.gov (United States)

    Williamson, Tanja N.; Lee, Brad D.; Schoeneberger, Philip J.; McCauley, W. M.; Indorante, Samuel J.; Owens, Phillip R.

    2014-01-01

    Soil Survey Geographic Database (SSURGO) data are available for the entire United States, so are incorporated in many regional and national models of hydrology and environmental management. However, SSURGO does not provide an understanding of spatial variability and only includes saturated hydraulic conductivity (Ksat) values estimated from particle size analysis (PSA). This study showed model sensitivity to the substitution of SSURGO data with locally described soil properties or alternate methods of measuring Ksat. Incorporation of these different soil data sets significantly changed the results of hydrologic modeling as a consequence of the amount of space available to store soil water and how this soil water is moved downslope. Locally described soil profiles indicated a difference in Ksat when measured in the field vs. being estimated from PSA. This, in turn, caused a difference in which soil layers were incorporated in the hydrologic simulations using TOPMODEL, ultimately affecting how soil water storage was simulated. Simulations of free-flowing soil water, the amount of water traveling through pores too large to retain water against gravity, were compared with field observations of water in wells at five slope positions along a catena. Comparison of the simulated data with the observed data showed that the ability to model the range of conditions observed in the field varied as a function of three soil data sets (SSURGO and local field descriptions using PSA-derived Ksat or field-measured Ksat) and that comparison of absolute values of soil water storage are not valid if different characterizations of soil properties are used.

  14. Hydraulic laboratory testing of Sontek-IQ Plus

    Science.gov (United States)

    Fulford, Janice M.; Kimball, Scott

    2015-11-10

    The SonTek-IQ Plus (IQ Plus) is a bottom-mounted Doppler instrument used for the measurement of water depth and velocity. Evaluation testing of the IQ Plus was performed to assess the accuracy of water depth, discharge, and velocity measurements. The IQ Plus met the manufacturer’s specifications and the U.S. Geological Survey (USGS) standard for depth accuracy measurement when the unit was installed, according to the manufacturer’s instructions, at 0 degrees pitch and roll. However, because of the limited depth testing conducted, the depth measurement is not recommended as a primary stage measurement. The IQ Plus was tested in a large indoor tilting flume in a 5-foot (ft) wide, approximately 2.3-ft deep section with mean velocities of 0.5, 1, 2, and 3 ft per second. Four IQ Plus instruments using firmware 1.52 tested for water-discharge accuracy using SonTek’s “theoretical” discharge method had a negative bias of -2.4 to -11.6 percent when compared with discharge measured with a SonTek FlowTracker and the midsection discharge method. The IQ Pluses with firmware 1.52 did not meet the manufacturer’s specification of +/-1 percent for measuring velocity. Three IQ Pluses using firmware 1.60 and SonTek’s “theoretical” method had a difference of -1.6 to -7.9 percent when compared with discharge measured with a SonTek FlowTracker and the midsection method. Mean-velocity measurements with firmware 1.60 met the manufacturer’s specification and Price Type AA meter accuracy requirements when compared with FlowTracker measurements. Because of the instrument’s velocity accuracy, the SonTek-IQ Plus with firmware 1.60 is considered acceptable for use as an index velocity instrument for the USGS. The discharge computed by the SonTek-IQ Plus during the tests had a substantial negative bias and will not be as accurate as a discharge computed with the index velocity method. The USGS does not recommend the use of undocumented computation methods, such as Son

  15. ORNL rod-bundle heat-transfer test data. Volume 6. Thermal-hydraulic test facility experimental data report for test 3. 05. 5B - double-ended cold-leg break simulation

    Energy Technology Data Exchange (ETDEWEB)

    Mullins, C.B.; Felde, D.K.; Sutton, A.G.; Gould, S.S.; Morris, D.G.; Robinson, J.J.; Schwinkendorf, K.N.

    1982-05-18

    Thermal-Hydraulic Test Facility (THTF) Test 3.05.5B was conducted by members of the ORNL PWR Blowdown Heat Transfer Separate-Effects Program on July 3, 1980. The objective of the program is to investigate heat transfer phenomena believed to occur in PWRs during accidents, including small and large break loss-of-coolant accidents. Test 3.05.5B was designed to provide transient thermal-hydraulics data in rod bundle geometry under reactor accident-type conditions. Reduced instrument responses are presented. Also included are uncertainties in the instrument responses, calculated mass flows, and calculated rod powers.

  16. Measuring the initial earth pressure of granite using hydraulic fracturing test; Goseong and Yuseong areas

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byoung Yoon; Bae, Dae Seok; Kim, Chun Soo; Kim, Kyung Su; Koh, Young Kwon; Won, Kyung Sik [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-02-01

    This report provides the initial earth pressure of granitic rocks obtained from Deep Core Drilling Program which is carried out as part of the assessment of deep geological environmental condition. These data are obtained by hydraulic fracturing test in three boreholes drilled up to 350{approx}500 m depth at the Yuseong and Goseong sites. These sites were selected based on the result of preliminary site evaluation study. The boreholes are NX-size (76 mm) and vertical. The procedure of hydraulic fracturing test is as follows: - Selecting the testing positions by preliminary investigation using BHTV logging. - Performing the hydraulic fracturing test at each selected position with depth.- Estimating the shut-in pressure by the bilinear pressure-decay-rate method. - Estimating the fracture reopening pressure from the pressure-time curves.- Estimating the horizontal principal stresses and the direction of principal stresses. 65 refs., 39 figs., 12 tabs. (Author)

  17. Practical estimates of field-saturated hydraulic conductivity of bedrock outcrops using a modified bottomless bucket method

    Science.gov (United States)

    Mirus, Benjamin B.; Perkins, Kim S.

    2012-01-01

    The bottomless bucket (BB) approach (Nimmo et al., 2009a) is a cost-effective method for rapidly characterizing field-saturated hydraulic conductivity Kfs of soils and alluvial deposits. This practical approach is of particular value for quantifying infiltration rates in remote areas with limited accessibility. A similar approach for bedrock outcrops is also of great value for improving quantitative understanding of infiltration and recharge in rugged terrain. We develop a simple modification to the BB method for application to bedrock outcrops, which uses a non-toxic, quick-drying silicone gel to seal the BB to the bedrock. These modifications to the field method require only minor changes to the analytical solution for calculating Kfs on soils. We investigate the reproducibility of the method with laboratory experiments on a previously studied calcarenite rock and conduct a sensitivity analysis to quantify uncertainty in our predictions. We apply the BB method on both bedrock and soil for sites on Pahute Mesa, which is located in a remote area of the Nevada National Security Site. The bedrock BB tests may require monitoring over several hours to days, depending on infiltration rates, which necessitates a cover to prevent evaporative losses. Our field and laboratory results compare well to Kfs values inferred from independent reports, which suggests the modified BB method can provide useful estimates and facilitate simple hypothesis testing. The ease with which the bedrock BB method can be deployed should facilitate more rapid in-situ data collection than is possible with alternative methods for quantitative characterization of infiltration into bedrock.

  18. Gas exchange recovery following natural drought is rapid unless limited by loss of leaf hydraulic conductance: evidence from an evergreen woodland.

    Science.gov (United States)

    Skelton, Robert P; Brodribb, Timothy J; McAdam, Scott A M; Mitchell, Patrick J

    2017-09-01

    Drought can cause major damage to plant communities, but species damage thresholds and postdrought recovery of forest productivity are not yet predictable. We used an El Niño drought event as a natural experiment to test whether postdrought recovery of gas exchange could be predicted by properties of the water transport system, or if metabolism, primarily high abscisic acid concentration, might delay recovery. We monitored detailed physiological responses, including shoot sapflow, leaf gas exchange, leaf water potential and foliar abscisic acid (ABA), during drought and through the subsequent rehydration period for a sample of eight canopy and understory species. Severe drought caused major declines in leaf water potential, elevated foliar ABA concentrations and reduced stomatal conductance and assimilation rates in our eight sample species. Leaf water potential surpassed levels associated with incipient loss of leaf hydraulic conductance in four species. Following heavy rainfall gas exchange in all species, except those trees predicted to have suffered hydraulic impairment, recovered to prestressed rates within 1 d. Recovery of plant gas exchange was rapid and could be predicted by the hydraulic safety margin, providing strong support for leaf vulnerability to water deficit as an index of damage under natural drought conditions. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  19. Test and application of hydraulic expansion bolts in a roadway under goaf with ultra-close separation

    Institute of Scientific and Technical Information of China (English)

    Wang Xiangyu; Bai Jianbiao; Guo Guanlong; Yu Yang

    2014-01-01

    The roof of a roadway under goaf with ultra-close separation consists of thin rock strata and rocks caving in upper goaf. Influenced by the mining of the upper coal seam, the roof is loose and broken, and its integ-rity is poor. Resin anchored bolts cannot provide an effective anchoring force in such roof conditions. By conducting free expansion tests and field pull-out tests on a hydraulic expansion bolt, this study has ana-lyzed the influencing factors and laws of radial expansion and anchoring force changes in the rod body. This has revealed the anchoring mechanism of such bolts, and has obtained reasonable water injection pressures and suitable drilling diameters (which are 20–25 MPa and 32–35 mm respectively) for the hydraulic expansion bolt (u28 mm) used in these tests. Based on pull-out tests at different interlayer spacing, the applicability of hydraulic expansion bolts had been verified for controlling the roof of road-ways under goaf with ultra-close distance. Combined with the deformation and failure characteristics of the test roadway roof, this paper proposes a united roof-control technology based on the use of hydraulic expansion bolts and advancing intubation for the roof. Engineering practice indicated that the roof of the test roadway did not generate leaking and caving phenomenon, and the amount of roof deformation was controlled to within 150 mm. Maintenance of the roadway roof has been improved significantly, which ensures safe mining in coal seams with ultra-close separation.

  20. A maximum likelihood estimator for bedrock fracture transmissivities and its application to the analysis and design of borehole hydraulic tests

    Science.gov (United States)

    West, Anthony C. F.; Novakowski, Kent S.; Gazor, Saeed

    2006-06-01

    We propose a new method to estimate the transmissivities of bedrock fractures from transmissivities measured in intervals of fixed length along a borehole. We define the scale of a fracture set by the inverse of the density of the Poisson point process assumed to represent their locations along the borehole wall, and we assume a lognormal distribution for their transmissivities. The parameters of the latter distribution are estimated by maximizing the likelihood of a left-censored subset of the data where the degree of censorship depends on the scale of the considered fracture set. We applied the method to sets of interval transmissivities simulated by summing random fracture transmissivities drawn from a specified population. We found the estimated distributions compared well to the transmissivity distributions of similarly scaled subsets of the most transmissive fractures from among the specified population. Estimation accuracy was most sensitive to the variance in the transmissivities of the fracture population. Using the proposed method, we estimated the transmissivities of fractures at increasing scale from hydraulic test data collected at a fixed scale in Smithville, Ontario, Canada. This is an important advancement since the resultant curves of transmissivity parameters versus fracture set scale would only previously have been obtainable from hydraulic tests conducted with increasing test interval length and with degrading equipment precision. Finally, on the basis of the properties of the proposed method, we propose guidelines for the design of fixed interval length hydraulic testing programs that require minimal prior knowledge of the rock.

  1. Geologically based model of heterogeneous hydraulic conductivity in an alluvial setting

    Science.gov (United States)

    Fogg, Graham E.; Noyes, Charles D.; Carle, Steven F.

    Information on sediment texture and spatial continuity are inherent to sedimentary depositional facies descriptions, which are therefore potentially good predictors of spatially varying hydraulic conductivity (K). Analysis of complex alluvial heterogeneity in Livermore Valley, California, USA, using relatively abundant core descriptions and field pumping-test data, demonstrates a depositional-facies approach to characterization of subsurface heterogeneity. Conventional textural classifications of the core show a poor correlation with K; however, further refinement of the textural classifications into channel, levee, debris-flow, and flood-plain depositional facies reveals a systematic framework for spatial modeling of K. This geologic framework shows that most of the system is composed of very low-K flood-plain materials, and that the K measurements predominantly represent the other, higher-K facies. Joint interpretation of both the K and geologic data shows that spatial distribution of K in this system could not be adequately modeled without geologic data and analysis. Furthermore, it appears that K should not be assumed to be log-normally distributed, except perhaps within each facies. Markov chain modeling of transition probability, representing spatial correlation within and among the facies, captures the relevant geologic features while highlighting a new approach for statistical characterization of hydrofacies spatial variability. The presence of fining-upward facies sequences, cross correlation between facies, as well as other geologic attributes captured by the Markov chains provoke questions about the suitability of conventional geostatistical approaches based on variograms or covariances for modeling geologic heterogeneity. Résumé Les informations sur la texture des sédiments et leur continuité spatiale font partie des descriptions de faciès sédimentaires de dépôt. Par conséquent, ces descriptions sont d'excellents prédicteurs potentiels des

  2. Conductive surge testing of circuits and systems

    Science.gov (United States)

    Richman, P.

    1980-01-01

    Techniques are given for conductive surge testing of powered electronic equipment. The correct definitions of common and normal mode are presented. Testing requires not only spike-surge generators with a suitable range of open-circuit voltage and short-circuit current waveshapes, but also appropriate means, termed couplers, for connecting test surges to the equipment under test. Key among coupler design considerations is minimization of fail positives resulting from reduction in delivered surge energy due to the coupler. Back-filters and the lines on which they are necessary, are considered as well as ground-fault and ground potential rise. A method for monitoring delivered and resulting surge waves is mentioned.

  3. Advanced Testing Method for Ground Thermal Conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaobing [ORNL; Clemenzi, Rick [Geothermal Design Center Inc.; Liu, Su [University of Tennessee (UT)

    2017-04-01

    A new method is developed that can quickly and more accurately determine the effective ground thermal conductivity (GTC) based on thermal response test (TRT) results. Ground thermal conductivity is an important parameter for sizing ground heat exchangers (GHEXs) used by geothermal heat pump systems. The conventional GTC test method usually requires a TRT for 48 hours with a very stable electric power supply throughout the entire test. In contrast, the new method reduces the required test time by 40%–60% or more, and it can determine GTC even with an unstable or intermittent power supply. Consequently, it can significantly reduce the cost of GTC testing and increase its use, which will enable optimal design of geothermal heat pump systems. Further, this new method provides more information about the thermal properties of the GHEX and the ground than previous techniques. It can verify the installation quality of GHEXs and has the potential, if developed, to characterize the heterogeneous thermal properties of the ground formation surrounding the GHEXs.

  4. Spatial Estimation of Saturated Hydraulic Conductivity from Terrain Attributes Using Regression, Kriging, and Artificial Neural Networks*1

    Institute of Scientific and Technical Information of China (English)

    H. R. MOTAGHIAN; J. MOHAMMADI

    2011-01-01

    Several methods, including stepwise regression, ordinary kriging, cokriging, kriging with external drift, kriging with varying local means, regression-kriging, ordinary artificial neural networks, and kriging combined with artificial neural networks, were compared to predict spatial variation of saturated hydraulic conductivity from environmental covariates. All methods except ordinary kriging allow for inclusion of secondary variables. The secondary spatial information used was terrain attributes including elevation, slope gradient,slope aspect, profile curvature and contour curvature. A multiple jackknifing procedure was used as a validation method. Root mean square error (RMSE) and mean absolute error (MAE) were used as the validation indices, with the mean RMSE and mean MAE used to judge the prediction quality. Prediction performance by ordinary kriging was poor, indicating that prediction of saturated hydraulic conductivity can be improved by incorporating ancillary data such as terrain variables. Kriging combined with artificial neural networks performed best. These prediction models made better use of ancillary information in predicting saturated hydraulic conductivity compared with the competing models. The combination of geostatistical predictors with neural computing techniques offers more capability for incorporating ancillary information in predictive soil mapping. There is great potential for further research and development of hybrid methods for digital soil mapping.

  5. Effects of variations in hydraulic conductivity and flow conditions on groundwater flow and solute transport in peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Kellner, Erik [Dept. of Forest Ecology, Univ. of Helsinki (Finland)

    2007-02-15

    In this report it is examined to what extent the variation in hydraulic conductivity within a peatland and adjoining sediments would affect the flow patterns within it under some certain hydraulic-head gradients and other certain border conditions. The first part of the report contains a short review of organic and mineral-soil sediment types and characteristics and what we know about present peatlands and underlying sediments in the SKB investigation areas today. In the next part, a 2-dimensional model is used to simulate flows and transports in different settings of a peatland, with the objective of studying the effects of some particular factors: 1. The magnitude of the hydraulic conductivity of the peat and of underlying layers. 2. Presence and positions of cracks in underlying clay layers. 3. Anisotropy and heterogeneity in peat hydraulic conductivity. 4. The size of the water recharge at the peatland surface. 5. The seasonal variation of the water recharge. The modelling results show that the importance of flow direction decreases with decreasing hydraulic conductivity in the peatland. This occurs as the convective flux is slowed down and the transport is taken over by the diffusive flux. Because the lowest hydraulic conductivity layer to large extent determines the size of the flow, presence of a low-conductivity layer, such as a layer of clay, is an important factor. Presence of cracks in such tight layers can increase the transport of solutes into the peat. The highest inflow rates are reached when such cracks occur in discharge areas with strong upward flow. On the other hand, a conservative solute can spread efficiently if there is a crack in low-flow locations. The effect of anisotropy is found to be small, partly because the horizontal gradients become smaller as distances are larger. The effect of layers with high or low permeability varies depending on the location and the prevailing gradients. One tight layer has a strong effect on the flow pattern

  6. Effects of the hydraulic conductivity of the matrix/macropore interface on cumulative infiltrations into dual-permeability media

    Science.gov (United States)

    Lassabatere, L.; Peyrard, X.; Angulo-Jaramillo, R.; Simunek, J.

    2009-12-01

    Modeling of water infiltration into the vadose zone is important for better understanding of movement of water-transported contaminants. There is a great need to take into account the soil heterogeneity and, in particular, the presence of macropores or cracks that could generate preferential flow. Several mathematical models have been proposed to describe unsaturated flow through heterogeneous soils. The dual-permeability model (referred to as the 2K model) assumes that flow is governed by Richards equation in both porous regions (matrix and macropores). Water can be exchanged between the two regions following a first-order rate law. Although several studies have dealt with such modeling, no study has evaluated the influence of the hydraulic conductivity of the matrix/macropore interface on water cumulative infiltration. And this is the focus of this study. An analytical scaling method reveals the role of the following main parameters for given boundary and initial conditions: the saturated hydraulic conductivity ratio (R_Ks), the water pressure scale parameter ratio (R_hg), the saturated volumetric water content ratio (R_θs), and the shape parameters of the water retention and hydraulic conductivity functions. The last essential parameter is related to the interfacial hydraulic conductivity (Ka) between the macropore and matrix regions. The scaled 2K flow equations were solved using HYDRUS-1D 4.09 for the specific case of water infiltrating into an initially uniform soil profile and a zero pressure head at the soil surface. A sensitivity of water infiltration was studied for different sets of scale parameters (R_Ks, R_hg, R_θs, and shape parameters) and the scaled interfacial conductivity (Ka). Numerical results illustrate two extreme behaviors. When the interfacial conductivity is zero (i.e., no water exchange), water infiltrates separately into matrix and macropore regions, producing a much deeper moisture front in the macropore domain. In the opposite case

  7. Implementing ground surface deformation tools to characterize field-scale properties of a fractured aquifer during a short hydraulic test

    Science.gov (United States)

    Schuite, Jonathan; Longuevergne, Laurent; Bour, Olivier; Boudin, Frédérick; Durand, Stéphane

    2016-04-01

    In naturally fractured reservoirs, fluid flow is governed by the structural and hydromechanical properties of fracture networks or conductive fault zones. In order to ensure a sustained exploitation of resources or to assess the safety of underground storage, it is necessary to evaluate these properties. As they generally form highly heterogeneous and anisotropic reservoirs, fractured media may be well characterized by means of several complementary experimental methods or sounding techniques. In this framework, the observation of ground deformation has been proved useful to gain insight of a fractured reservoir's geometry and hydraulic properties. Commonly, large conductive structures like faults can be studied from surface deformation from satellite methods at monthly time scales, whereas meter scale fractures have to be examined under short-term in situ experiments using high accuracy intruments like tiltmeters or extensometers installed in boreholes or at the ground's surface. To the best of our knowledge, the feasability of a field scale (~ 100 m) characterization of a fractured reservoir with geodetic tools in a short term experiment has not yet been addressed. In the present study, we implement two complementary ground surface geodetic tools, namely tiltmetry and optical leveling, to monitor the deformation induced by a hydraulic recovery test at the Ploemeur hydrological observatory (France). Employing a simple purely elastic modeling approach, we show that the joint use of time constraining data (tilt) and spatially constraining data (vertical displacement) makes it possible to evaluate the geometry (dip, root depth and lateral extent) and the storativity of a hydraulically active fault zone, in good agreement with previous studies. Hence we demonstrate that the adequate use of two complementary ground surface deformation methods offer a rich insight of large conductive structure's properties using a single short term hydraulic load. Ground surface

  8. The hydraulic conductance of Fraxinus ornus leaves is constrained by soil water availability and coordinated with gas exchange rates.

    Science.gov (United States)

    Gortan, Emmanuelle; Nardini, Andrea; Gascó, Antonio; Salleo, Sebastiano

    2009-04-01

    Leaf hydraulic conductance (Kleaf) is known to be an important determinant of plant gas exchange and photosynthesis. Little is known about the long-term impact of different environmental factors on the hydraulic construction of leaves and its eventual consequences on leaf gas exchange. In this study, we investigate the impact of soil water availability on Kleaf of Fraxinus ornus L. as well as the influence of Kleaf on gas exchange rates and plant water status. With this aim, Kleaf, leaf conductance to water vapour (gL), leaf water potential (Psileaf) and leaf mass per area (LMA) were measured in F. ornus trees, growing in 21 different sites with contrasting water availability. Plants growing in arid sites had lower Kleaf, gL and Psileaf than those growing in sites with higher water availability. On the contrary, LMA was similar in the two groups. The Kleaf values recorded in sites with two different levels of soil water availability were constantly different from each other regardless of the amount of precipitation recorded over 20 days before measurements. Moreover, Kleaf was correlated with gL values. Our data suggest that down-regulation of Kleaf is a component of adaptation of plants to drought-prone habitats. Low Kleaf implies reduced gas exchange which may, in turn, influence the climatic conditions on a local/regional scale. It is concluded that leaf hydraulics and its changes in response to resource availability should receive greater attention in studies aimed at modelling biosphere-atmosphere interactions.

  9. Bundle-sheath aquaporins play a role in controlling Arabidopsis leaf hydraulic conductivity.

    Science.gov (United States)

    Sade, Nir; Shatil-Cohen, Arava; Moshelion, Menachem

    2015-01-01

    The role of molecular mechanisms in the regulation of leaf hydraulics (K(leaf)) is still not well understood. We hypothesized that aquaporins (AQPs) in the bundle sheath may regulate K(leaf). To examine this hypothesis, AQP genes were constitutively silenced using artificial microRNAs and recovery was achieved by targeting the expression of the tobacco AQP (NtAQP1) to bundle-sheath cells in the silenced plants. Constitutively silenced PIP1 plants exhibited decreased PIP1 transcript levels and decreased K(leaf). However, once the plants were recovered with NtAQP1, their K(leaf) values were almost the same as those of WT plants. We also demonstrate the important role of ABA, acting via AQP, in that recovery and K(leaf) regulation. These results support our previously raised hypothesis concerning the role of bundle-sheath AQPs in the regulation of leaf hydraulics.

  10. Testing and Performance Evaluation of Tractor Mounted Hydraulic Elevator for Mango Orchard

    Directory of Open Access Journals (Sweden)

    Kishor P. Kolhe

    2011-01-01

    Full Text Available Problem statement: The harvesting and pruning of horticultural crops is quite difficult due to their tallness. There are small hand tools available for harvesting and pruning. But these tools of harvesting and pruning are restricted due tree height, unavailability of trained labours for climbing and cost of operation etc. The mechanized machines are available; these are heavy and costly and are not suitable for low land holding, Indian marginal famers. Harvesting and pruning of horticultural crops with the available hand tool is very difficult. The labor has to climb on the tree by carrying these hand tools, which requires skill too. To overcome the above problems a Tractor Mounted Hydraulic Elevator (TMHE powered by tractor PTO, was tested for the mechanical harvesting and pruning of mango orchards using digital load cell, digital Vibration meter and digital Techometer for elevator stability study and pruner engine RPM measurements while in branch cutting respectively. The field performance of the above machine was carried out on plane mango plot, at Dr. Balasaheb Sawant Konkan Krishi Vidyapeeth, Dapoli, Dist: -Ratnagiri (Maharashtra, India. The machine was tested for the better stability at maximum reach position for harvesting and pruning of various mango varieties, like Alphanso, Totapuri etc. Approach: To reduce the harvesting /pruning cost, increase the harvesting/pruning efficiency and enhance the overall productivity of mango orchards. Also to use the traditional mechanized/ manual pruning tools with the developed tractor mounted hydraulic elevator. To develop and refine the power operated mechanism for marginal farmers. This stability study was carried out, by using strain gauge load cell (S-beam, having capacity of 2000 kg. The load cell guiding device was designed and fabricated for conducting the above experiments following standard material specifications of American society of testing material. The reaction on

  11. Determination of hydraulic conductivity in three dimensions and its relation to dispersivity: Chapter D in Ground-water contamination by crude oil at the Bemidji, Minnesota, research site; US Geological Survey Toxic Waste--ground-water contamination study

    Science.gov (United States)

    1984-01-01

    Recent investigations suggest that dispersion in aquifers is scale dependent and a function of the heterogeneity of aquifer materials. Theoretical stochastic studies indicate that determining hydraulic-conductivity variability in three dimensions is important in analyzing the dispersion process. Even though field methods are available to approximate hydraulic conductivity in three dimensions, the methods are not generally used because of high cost of field equipment and because measurement and analysis techniques are cumbersome and time consuming. The hypothesis of this study is that field-determined values of dispersivity are scale dependent and that they may be described as a function of hydraulic conductivity in three dimensions. The objectives of the study at the Bemidji research site are to (1) determine hydraulic conductivity of the porous media in three dimensions, (2) determine field values of dispersivity and its scale dependence on hydraulic conductivity, and (3) develop and apply a computerized data-collection, storage, and analysis system for field use in comprehensive determination of hydraulic conductivity and dispersivity. Plans for this investigation involve a variety of methods of analysis. Hydraulic conductivity will be determined separately in the horizontal and vertical planes of the hydraulic-conductivity ellipsoid. Field values of dispersivity will be determined by single-well and doublet-well injection or withdrawal tests with tracers. A computerized data-collection, storage, and analysis system to measure pressure, flow rate, tracer concentrations, and temperature will be designed for field testing. Real-time computer programs will be used to analyze field data. The initial methods of analysis will be utilized to meet the objectives of the study. Preliminary field data indicate the aquifer underlying the Bemidji site is vertically heterogeneous, cross-bedded outwash. Preliminary analysis of the flow field around a hypothetical doublet

  12. 不同土壤转换函数预测砂土非饱和导水率的对比分析%Estimating unsaturated hydraulic conductivity of sandy soils using different pedotransfer functions

    Institute of Scientific and Technical Information of China (English)

    廖凯华; 徐绍辉; 吴吉春; 朱青

    2013-01-01

    以现有的4种土壤转换函数(Pedotransfer Functions,PTFs)(包括ROSETTA、RAWLS、CAMPBELL和VAUCLIN)为例,将其用于土壤水力性质数据库UNSODA中56个典型砂土样本的非饱和导水率预测,对4种PTFs的预测结果进行了误差分析,探讨了饱和导水率对非饱和导水率预测的影响.结果表明,当同种PTFs预测的饱和导水率作为输入时,在4种PTFs中VAUCLIN的预测精度最高,其次为ROSETTA和RAWLS,CAMPBELL的误差最大;当实测饱和导水率作为输入时,RAWLS、CAMPBELL和ROSETTA的预测精度有了不同程度提高,但VAUCLIN的预测误差反而有所增大;饱和导水率对非饱和导水率预测的影响较大,实测饱和导水率作为输入时CAMPBELL预测的非饱和导水率与实测值最为接近.%This study tested the ability of four published pedotransfer functions (PTFs) (including ROSETTA,RAWLS,CAMPBELL and VAUCLIN) to predict unsaturated hydraulic conductivity for 56 sandy soil samples from the UNSODA database.Different PTFs for the estimation of saturated hydraulic conductivity were also evaluated in this study.Results showed that among the four PTFs,VAUCLIN produced the best performance,followed by ROSETTA and RAWLS,and CAMPBELL gave the worst performance when saturated hydraulic conductivity predicted by the identical PTFs as input.The performance of RAWLS,CAMPBELL and ROSETTA has been improved to different extent when measured saturated hydraulic conductivity as input.However,VAUCLIN did not produce the best performance when measured saturated hydraulic conductivity as input.The influence of saturated hydraulic conductivity on the predictive accuracy of unsaturated hydraulic conductivity was significant.Overall,CAMPBELL gave the best performance when the measured saturated hydraulic conductivity was used in the functions for estimation of unsaturated hydraulic conductivity.

  13. Drought effects on hydraulic conductivity and xylem vulnerability to embolism in diverse species and provenances of Mediterranean cedars.

    Science.gov (United States)

    Ladjal, Mehdi; Huc, Roland; Ducrey, Michel

    2005-09-01

    We studied hydraulic traits of young plants of the Mediterranean cedar species Cedrus atlantica (Endl.) G. Manetti ex Carrière (Luberon, France), C. brevifolia (Hook. f.) Henry (Cyprus), C. libani A. Rich (Hadeth El Jebbe, Lebanon) and C. libani (Armut Alani, Turkey). With an optimum water supply, no major differences were observed among species or provenances in either stem hydraulic conductivity (Ks) or leaf specific conductivity (Kl) measured on the main shoot. A moderate soil drought applied for 10 weeks induced marked acclimation through a reduction in Ks, particularly in the Lebanese provenance of C. libani, and a decrease in tracheid lumen size in all species. Cedrus atlantica, which had the smallest tracheids, was the species most vulnerable to embolism: a 50% loss in hydraulic conductivity (PsiPLC50) occurred at a water potential of -4.4 MPa in the well-watered treatment, and at -6.0 MPa in the moderate drought treatment. In the other species, PsiPLC50 was unaffected by moderate soil drought, and only declined sharply at water potentials between -6.4 and -7.5 MPa in both irrigation treatments. During severe drought, Ks of twigs and stomatal conductance (g(s)) were measured simultaneously as leaf water potential declined. For all species, lower vulnerability to embolism based on loss of Ks was recorded on current-year twigs. The threshold for stomatal closure (10% of maximum g(s)) was reached at a predawn water potential (Psi(pd)) of -2.5 MPa in C. atlantica (Luberon) and at -3.1 MPa in C. libani (Lebanon), whereas the other provenance and species had intermediate Psi(pd) values. Cedrus brevifolia, with a Psi(pd) (-3.0 MPa) close to that of C. libani (Lebanon), had the highest stomatal conductance of the study species. The importance of a margin of safety between water potential causing stomatal closure and that causing xylem embolism induction is discussed.

  14. Tree level hydrodynamic approach for resolving aboveground water storage and stomatal conductance and modeling the effects of tree hydraulic strategy

    Science.gov (United States)

    Mirfenderesgi, Golnazalsadat; Bohrer, Gil; Matheny, Ashley M.; Fatichi, Simone; Moraes Frasson, Renato Prata; Schäfer, Karina V. R.

    2016-07-01

    The finite difference ecosystem-scale tree crown hydrodynamics model version 2 (FETCH2) is a tree-scale hydrodynamic model of transpiration. The FETCH2 model employs a finite difference numerical methodology and a simplified single-beam conduit system to explicitly resolve xylem water potentials throughout the vertical extent of a tree. Empirical equations relate water potential within the stem to stomatal conductance of the leaves at each height throughout the crown. While highly simplified, this approach brings additional realism to the simulation of transpiration by linking stomatal responses to stem water potential rather than directly to soil moisture, as is currently the case in the majority of land surface models. FETCH2 accounts for plant hydraulic traits, such as the degree of anisohydric/isohydric response of stomata, maximal xylem conductivity, vertical distribution of leaf area, and maximal and minimal xylem water content. We used FETCH2 along with sap flow and eddy covariance data sets collected from a mixed plot of two genera (oak/pine) in Silas Little Experimental Forest, NJ, USA, to conduct an analysis of the intergeneric variation of hydraulic strategies and their effects on diurnal and seasonal transpiration dynamics. We define these strategies through the parameters that describe the genus level transpiration and xylem conductivity responses to changes in stem water potential. Our evaluation revealed that FETCH2 considerably improved the simulation of ecosystem transpiration and latent heat flux in comparison to more conventional models. A virtual experiment showed that the model was able to capture the effect of hydraulic strategies such as isohydric/anisohydric behavior on stomatal conductance under different soil-water availability conditions.

  15. Measurement of field-saturated hydraulic conductivity on fractured rock outcrops near Altamura (Southern Italy) with an adjustable large ring infiltrometer

    Science.gov (United States)

    Caputo, M.C.; de Carlo, L.; Masciopinto, C.; Nimmo, J.R.

    2010-01-01

    Up to now, field studies set up to measure field-saturated hydraulic conductivity to evaluate contamination risks, have employed small cylinders that may not be representative of the scale of measurements in heterogeneous media. In this study, a large adjustable ring infiltrometer was designed to be installed on-site directly on rock to measure its field-saturated hydraulic conductivity. The proposed device is inexpensive and simple to implement, yet also very versatile, due to its large adjustable diameter that can be fixed on-site. It thus allows an improved representation of the natural system's heterogeneity, while also taking into consideration irregularities in the soil/rock surface. The new apparatus was tested on an outcrop of karstic fractured limestone overlying the deep Murge aquifer in the South of Italy, which has recently been affected by untreated sludge disposal, derived from municipal and industrial wastewater treatment plants. The quasi-steady vertical flow into the unsaturated fractures was investigated by measuring water levels during infiltrometer tests. Simultaneously, subsurface electrical resistivity measurements were used to visualize the infiltration of water in the subsoil, due to unsaturated water flow in the fractures. The proposed experimental apparatus works well on rock outcrops, and allows the repetition of infiltration tests at many locations in order to reduce model uncertainties in heterogeneous media. ?? 2009 Springer-Verlag.

  16. Scalable Generalization of Hydraulic Conductivity in Quaternary Strata for Use in a Regional Groundwater Model

    Science.gov (United States)

    Jatnieks, J.; Popovs, K.; Klints, I.; Timuhins, A.; Kalvans, A.; Delina, A.; Saks, T.

    2012-04-01

    The cover of Quaternary sediments especially in formerly glaciated territories usually is the most complex part of the sedimentary sequences. In regional hydro-geological models it is often assumed as a single layer with uniform or calibrated properties (Valner 2003). However, the properties and structure of Quaternary sediments control the groundwater recharge: it can either direct the groundwater flow horizontally towards discharge in topographic lows or vertically, recharging groundwater in the bedrock. This work aims to present calibration results and detail our experience while integrating a scalable generalization of hydraulic conductivity for Quaternary strata in the regional groundwater modelling system for the Baltic artesian basin - MOSYS V1. We also present a method for solving boundary transitions between spatial clusters of lithologically similar structure. In this study the main unit of generalization is the spatial cluster. Clusters are obtained from distance calculations combining the Normalized Compression Distance (NCD) metric, calculated by the CompLearn parameter-free machine learning toolkit, with normalized Euclidean distance measures for coordinates of the borehole log data. A hierarchical clustering solution is used for obtaining cluster membership identifier for each borehole. Using boreholes as generator points for Voronoi tessellation and dissolving resulting polygons according to their cluster membership attribute, allows us to obtain spatial regions representing a certain degree of similarity in lithological structure. This degree of similarity and the spatial heterogeneity of the cluster polygons can be varied by different flattening of the hierarchical cluster model into variable number of clusters. This provides a scalable generalization solution which can be adapted according to model calibration performance. Using the dissimilarity matrix of the NCD metric, a borehole most similar to all the others from the lithological structure

  17. Hydraulic Test of a Bioretention Media Carbon Amendment

    Science.gov (United States)

    Rain gardens effectively remove some stressors from stormwater, but in most cases they show much smaller removal rates of nitrate, likely due to the high sand and low organic matter content of rain garden media inhibiting denitrification. A bench-scale experiment was conducted to...

  18. Digital Measuring Devices Used for Injector Hydraulic Test

    Directory of Open Access Journals (Sweden)

    S. N. Leontiev

    2015-01-01

    Full Text Available To ensure a high specific impulse of the LRE (liquid-propellant engine chamber it is necessary to have optimally organized combustion of the fuel components. This can be ensured by choosing the optimum geometry of gas-dynamic contour of the LRE combustor, as well as by improving the sputtering processes and mixing the fuel components, for example, by selection of the optimum type, characteristics, and location of injectors on the mixing unit of the chamber.These particular reasons arise the interest in the injector characteristics in terms of science, and technological aspects determine the need for control of underlying design parameters in their manufacture.The objective of this work is to give an experimental justification on used digital measurement instrumentation and research the hydraulic characteristics of injectors.To determine injector parameters most widely were used the units with sectional collectors. A technique to control injector parameters using the sectional collectors involves spraying the liquid by injector at a given pressure drop on it for a certain time (the longer, the higher the accuracy and reliability of the results and then determining the amount of liquid in each section to calculate the required parameters of injector.In this work the liquid flow through the injector was determined by high-precision flowmeters FLONET FN2024.1 of electromagnetic type, which have very high metrological characteristics, in particular a flow rate error does not exceed 0.5% in a range of water flow from Qmin= 0.0028 l/s to Qmax Qmax = 0.28 l/s. To determine the coefficient of uneven spray were used differential pressure sensors DMD 331-ASLX of company "DB Sensors RUS", which have an error of 0.075% with a range of differential pressure 0 ... 5 kPa. Measuring complex MIC-200 of company "NPP Measure" and WinPos software for processing array information provided entry, recording, and processing of all the data of the experiment.In this

  19. Differentiation in light energy dissipation between hemiepiphytic and non-hemiepiphytic Ficus species with contrasting xylem hydraulic conductivity.

    Science.gov (United States)

    Hao, Guang-You; Wang, Ai-Ying; Liu, Zhi-Hui; Franco, Augusto C; Goldstein, Guillermo; Cao, Kun-Fang

    2011-06-01

    Hemiepiphytic Ficus species (Hs) possess traits of more conservative water use compared with non-hemiepiphytic Ficus species (NHs) even during their terrestrial growth phase, which may result in significant differences in photosynthetic light use between these two growth forms. Stem hydraulic conductivity, leaf gas exchange and chlorophyll fluorescence were compared in adult trees of five Hs and five NHs grown in a common garden. Hs had significantly lower stem hydraulic conductivity, lower stomatal conductance and higher water use efficiency than NHs. Photorespiration played an important role in avoiding photoinhibition at high irradiance in both Hs and NHs. Under saturating irradiance levels, Hs tended to dissipate a higher proportion of excessive light energy through thermal processes than NHs, while NHs dissipated a larger proportion of electron flow than Hs through the alternative electron sinks. No significant difference in maximum net CO2 assimilation rate was found between Hs and NHs. Stem xylem hydraulic conductivity was positively correlated with maximum electron transport rate and negatively correlated with the quantum yield of non-photochemical quenching across the 10 studied Ficus species. These findings indicate that a canopy growth habit during early life stages in Hs of Ficus resulted in substantial adaptive differences from congeneric NHs not only in water relations but also in photosynthetic light use and carbon economy. The evolution of epiphytic growth habit, even for only part of their life cycle, involved profound changes in a suite of inter-correlated ecophysiological traits that persist to a large extent even during the later terrestrial growth phase.

  20. Benchmark of SIMULATE5 thermal hydraulics against the Frigg and NUPEC full bundle test experiments

    Energy Technology Data Exchange (ETDEWEB)

    Grandi, G. [Studsvik Scandpower, Inc., Idaho Falls, Idaho (United States); Lindahl, S.-O. [Studsvik Scandpower AB, Vasteras (Sweden)

    2011-07-01

    SIMULATE5 is Studsvik Scandpower's next generation nodal code. The core portion of the thermal hydraulic models of PWR and BWRs are treated as essentially identical, with each assembly having an active channel and a number of parallel water channels. In addition, the BWR assembly may be divided into four radial sub-assemblies. For natural circulation reactors, the BWR thermal hydraulic model is capable of modeling an entire vessel loop: core, chimney, upper plenum, standpipes, steam separators, downcomer, recirculation pumps, and lower plenum. This paper presents results of the validation of the BWR thermal hydraulic model against: (1) pressure drop data measured in the Frigg and NUPEC test facilities; (2) void fraction distribution measured in the Frigg and NUPEC loops; (3) quarter-assembly void fraction measured in the NUPEC experiments and (4) natural and forced circulation flow measurements in the Frigg loop. (author)

  1. Status of the art: hydraulic conductivity of acid- fractures; Condutividade hidraulica de fratura acida: estado da arte

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Valdo Ferreira [Universidade Estadual do Norte Fluminense Darcy Ribeiro (LENEP/UENF), Macae, RJ (Brazil). Centro de Ciencia e Tecnologia. Lab. de Engenharia e Exploracao de Petroleo; Campos, Wellington [PETROBRAS, RJ (Brazil). E and P Engenharia de Producao. Gerencia de Completacao e Avaliacao], e-mail: wcampos@petrobras.com.br

    2010-06-15

    This paper presents a review of the hydraulic conductivity models developed for acid fractures in almost four decades of studies in petroleum engineering. These studies have often benefited from theories and experiments carried out in areas of knowledge such as physics, geology, hydrology, fluid mechanics, rock mechanics and tribology. The review showed that the pioneer study of Nierode and Kruk (1973) is still used in commercial software and influences the current studies. There was significant evolution on the quantitative surface topography characterization of the fractures and their impact on the hydraulic conductivity. The same occurred for the effects of acid dissolution on the rock resistance. Improvements on correlations similar to the Nierode and Kruk can be applied at once on the acid fracturing project and evaluation practice for the cases of rough dissolution pattern. A method to consider the overall conductivity from heterogeneous channels and roughness pattern was recently proposed. The complexity of the theoretical fundaments, specially the range of validity of the equations in face of the simplifications assumed, the difficulty of performing representative laboratory and field experiments, the difficulty of characterizing quantitatively the fractures surface topography and its effects on the conductivity, and the large variety of rocks and acid systems keep this subject open for research. (author)

  2. Hydraulic conductivity and aquaporin transcription in roots of trembling aspen (Populus tremuloides) seedlings colonized by Laccaria bicolor.

    Science.gov (United States)

    Xu, Hao; Cooke, Janice E K; Kemppainen, Minna; Pardo, Alejandro G; Zwiazek, Janusz J

    2016-07-01

    Ectomycorrhizal fungi have been reported to increase root hydraulic conductivity (L pr) by altering apoplastic and plasma membrane intrinsic protein (PIP)-mediated cell-to-cell water transport pathways in associated roots, or to have little effect on root water transport, depending on the interacting species and imposed stresses. In this study, we investigated the water transport properties and PIP transcription in roots of aspen (Populus tremuloides) seedlings colonized by the wild-type strain of Laccaria bicolor and by strains overexpressing a major fungal water-transporting aquaporin JQ585595. Inoculation of aspen seedlings with L. bicolor resulted in about 30 % colonization rate of root tips, which developed dense mantle and the Hartig net that was restricted in the modified root epidermis. Transcript abundance of the aspen aquaporins PIP1;2, PIP2;1, and PIP2;2 decreased in colonized root tips. Root colonization by JQ585595-overexpressing strains had no significant impact on seedling shoot water potentials, gas exchange, or dry mass; however, it led to further decrease in transcript abundance of PIP1;2 and PIP2;3 and the significantly lower L pr than in non-inoculated roots. These results, taken together with our previous study that showed enhanced root water hydraulics of L. bicolor-colonized white spruce (Picea glauca), suggest that the impact of L. bicolor on root hydraulics varies by the ectomycorrhiza-associated tree species.

  3. Linking hydropedology and ecosystem services: differential controls of surface field saturated hydraulic conductivity in a volcanic setting in central Mexico

    Directory of Open Access Journals (Sweden)

    A. Gómez-Tagle

    2009-03-01

    Full Text Available In this study the variation of field saturated soil hydraulic conductivity (Kfs as key control variable and descriptor of infiltration was examined by means of a constant head single ring infiltrometer. The study took place in five coverage types and land uses in a volcanic setting in central Mexico. The tested hypothesis was that there exist a positive relationship between plant cover and surface Kfs for the study area. The examined coverage types included; Second growth pine-oak forest, pasture land, fallow land, gully and Cupresus afforestation. Results indicate that Kfs did not depend exclusively of plant cover; it was related to surface horizontal expression of the unburied soil horizons and linked to land use history. Therefore the Kfs measured at a certain location did not depend exclusively of the actual land use, it was also influenced by soil bioturbation linked to plant succession patterns and land use management practices history. The hypothesis accounts partially the variation between sites. Kfs under dense plant cover at the Cupresus afforestation was statistically equal to that measured at the fallow land or the gully sites, while second growth pine-oak forest Kfs figures were over an order of magnitude higher than the rest of the coverage types. The results suggest the relevance of unburied soil horizons in the soil hydrologic response when present at the surface. Under these conditions loosing surface soil horizons due to erosion, not only fertility is lost, but environmental services generation potential. A conceptual model within the hydropedological approach is proposed. It explains the possible controls of Kfs, for this volcanic setting. Land use history driven erosion plays a decisive role in subsurface horizon presence at the surface and soil matrix characteristic determination, while plant succession patterns seem to be strongly linked to soil bioturbation and

  4. NUMERICAL MODELING OF MULTICYLINDER ELECTRO-HYDRAULIC SYSTEM AND CONTROLLER DESIGN FOR SHOCK TEST MACHINE

    Institute of Scientific and Technical Information of China (English)

    CHU Deying; ZHANG Zhiyi; WANG Gongxian; HUA Hongxing

    2007-01-01

    A high fidelity dynamic model of a high-energy hydraulically-actuated shock test machine for heavy weight devices is presented to satisfy the newly-built shock resistance standard and simulate the actual underwater explosion environments in laboratory as well as increase the testing capability of shock test machine. In order to produce the required negative shock pulse in the given time duration, four hydraulic actuators are utilized. The model is then used to formulate an advanced feedforward controller for the system to produce the required negative waveform and to address the motion synchronization of the four cylinders. The model provides a safe and easily controllable way to perform a "virtual testing" before starting potentially destructive tests on specimen and to predict performance of the system. Simulation results have demonstrated the effectiveness of the controller.

  5. Temporal changes of hydraulic conductivity of cultivated soil studied with help of multipoint tension infiltrometer and X-ray computed tomography

    Science.gov (United States)

    Klipa, Vladimir; Zumr, David; Snehota, Michal; Dohnal, Michal

    2016-04-01

    Soil aggregates, its shape, size and spatial distribution affect the pores arrangement and thus govern the hydraulic conductivity of soil and soil moisture regime. On arable lands the soil is exposed to rapid structural changes within each growing season due to agrotechnical practices, quick crop and root growth, soil biota and climatic conditions. This contribution is mainly focused on temporal changes of unsaturated hydraulic conductivity of cultivated soil. The research is supplemented by detailed analysis of CT images of soil samples for better understanding of structural change of soil during the year and its impact on soil hydraulic conductivity. The infiltration experiments were done using automated multipoint tension infiltrometer recently developed at CTU in Prague on the plots located on the Nucice experimental catchment. The catchment is situated in a moderately hilly area in central Bohemia (Czech Republic). Fourteen regular infiltration campaigns (77 individual infiltration experiments) were conducted from October 2012 until July 2015 on a single arable plot. In general, agricultural practice captured involved complete life cycle from sowing, through harvest, to postharvest stubble breaking. Weather conditions during infiltration experiments ranged from clear-sky to light rain, with temperatures between 8 and 30°C. All measurements were consistently performed with small suction of 3 cm and hydraulic conductivities were determined using extended semiempirical estimation procedure of Zhang. Results show that unsaturated hydraulic conductivity was the lowest in early spring and did increase at beginning of summer in the years 2012 - 2014. During the summer and autumn (2012 - 2014) the unsaturated hydraulic conductivity remained relatively unchanged. On the contrary, results in the year 2015 show opposite trend - the highest hydraulic conductivity was observed in early spring and did gradually decrease until the end of July. In both cases, however, the

  6. Hydraulic Characterization of Overpressured Tuffs in Central Yucca Flat, Nevada Test Site, Nye County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    K.J. Halford; R.J. Laczniak; D.L. Galloway

    2005-10-07

    A sequence of buried, bedded, air-fall tuffs has been used extensively as a host medium for underground nuclear tests detonated in the central part of Yucca Flat at the Nevada Test Site. Water levels within these bedded tuffs have been elevated hundreds of meters in areas where underground nuclear tests were detonated below the water table. Changes in the ground-water levels within these tuffs and changes in the rate and distribution of land-surface subsidence above these tuffs indicate that pore-fluid pressures have been slowly depressurizing since the cessation of nuclear testing in 1992. Declines in ground-water levels concurrent with regional land subsidence are explained by poroelastic deformation accompanying ground-water flow as fluids pressurized by underground nuclear detonations drain from the host tuffs into the overlying water table and underlying regional carbonate aquifer. A hydraulic conductivity of about 3 x 10-6 m/d and a specific storage of 9 x 10-6 m-1 are estimated using ground-water flow models. Cross-sectional and three-dimensional ground-water flow models were calibrated to measured water levels and to land-subsidence rates measured using Interferometric Synthetic Aperture Radar. Model results are consistent and indicate that about 2 million m3 of ground water flowed from the tuffs to the carbonate rock as a result of pressurization caused by underground nuclear testing. The annual rate of inflow into the carbonate rock averaged about 0.008 m/yr between 1962 and 2005, and declined from 0.005 m/yr in 2005 to 0.0005 m/yr by 2300.

  7. Hydraulic characterization of overpressured tuffs in central Yucca Flat, Nevada Test Site, Nye County, Nevada

    Science.gov (United States)

    Halford, Keith J.; Laczniak, Randell J.; Galloway, Devin L.

    2005-01-01

    A sequence of buried, bedded, air-fall tuffs has been used extensively as a host medium for underground nuclear tests detonated in the central part of Yucca Flat at the Nevada Test Site. Water levels within these bedded tuffs have been elevated hundreds of meters in areas where underground nuclear tests were detonated below the water table. Changes in the ground-water levels within these tuffs and changes in the rate and distribution of land-surface subsidence above these tuffs indicate that pore-fluid pressures have been slowly depressurizing since the cessation of nuclear testing in 1992. Declines in ground-water levels concurrent with regional land subsidence are explained by poroelastic deformation accompanying ground-water flow as fluids pressurized by underground nuclear detonations drain from the host tuffs into the overlying water table and underlying regional carbonate aquifer. A hydraulic conductivity of about 3 x 10-6 m/d and a specific storage of 9 x 10-6 m-1 are estimated using ground-water flow models. Cross-sectional and three-dimensional ground-water flow models were calibrated to measured water levels and to land-subsidence rates measured using Interferometric Synthetic Aperture Radar. Model results are consistent and indicate that about 2 million m3 of ground water flowed from the tuffs to the carbonate rock as a result of pressurization caused by underground nuclear testing. The annual rate of inflow into the carbonate rock averaged about 0.008 m/yr between 1962 and 2005, and declined from 0.005 m/yr in 2005 to 0.0005 m/yr by 2300.

  8. Hydraulic testing of helium cooled irradiation rigs of the IFMIF High Flux Test Module

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Christine, E-mail: Christine.Klein@kit.edu [Karlsruhe Institute of Technology, INR, Eggenstein-Leopoldshafen (Germany); Arbeiter, Frederik; Jackowski, Thomas; Martin, Thomas; Schlindwein, Georg [Karlsruhe Institute of Technology, INR, Eggenstein-Leopoldshafen (Germany)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Uniform perfusion of the multiple parallel minichannels of the rig model B by helium gas, which is of importance to obtain uniform and predictable temperatures, could be verified by measuring the mean velocity profiles of the rectangular jets are measured using hot-wire anemometry. Black-Right-Pointing-Pointer The pressure drop in the test section with rig model B was measured and delivers data for the validation of computational fluid dynamics (CFD) modeling approach for application in the IFMIF High Flux Test Module. The pressure drop depends significantly on the pressure level; acceleration resulting from the volumetric expansion of helium gas has to be modeled carefully in simulations. Black-Right-Pointing-Pointer Measurements with strain gage show the pressure depending deformation of the compartment container without the rig. The results agree well with simulations and approximation calculations. - Abstract: The hydraulic testing of a single 1:1 irradiation rig inside a mock-up container is part of the validation activities which support the engineering design of the High Flux Test Module. Uniform perfusion of the multiple parallel minichannels of the irradiation rigs by helium gas is of importance to obtain uniform and predictable temperatures. To evaluate the uniform distribution to the different parallel minichannels, the mean velocity profiles of the rectangular jets are measured using hot-wire anemometry. The velocity profiles show a symmetric and constant distribution of the mass flow to the parallel minichannels. The pressure drop in the test section with one of the candidate rig shapes is measured. The pressure drop depends significantly on the entrance pressure level; acceleration resulting from the volumetric expansion of helium gas has to be taken into account in simulations. Measurements with strain gage show the pressure depending deformation of the compartment container without the rig. The results agree

  9. Test Rig Design and Presentation for a Hydraulic Yaw System

    DEFF Research Database (Denmark)

    Stubkier, Søren; Pedersen, Henrik C.; Andersen, Torben Ole

    2013-01-01

    dynamics under real conditions. The behavior of the system is analyzed with regard to 20 years of operation. This is for example done by applying loads from different design load cases, e.g. normal turbulence, extreme turbulence and different fault scenarios on the turbine. The paper first presents...... an introduction with the current state of the art and problem description, followed by a system description, where the system is designed and dimensioned. Based on the design, results from the test rig are presented and analyzed. Finally a conclusion summing up the design, model and test results is given....

  10. Leaf hydraulic conductance declines in coordination with photosynthesis, transpiration and leaf water status as soybean leaves age regardless of soil moisture.

    Science.gov (United States)

    Locke, Anna M; Ort, Donald R

    2014-12-01

    Photosynthesis requires sufficient water transport through leaves for stomata to remain open as water transpires from the leaf, allowing CO2 to diffuse into the leaf. The leaf water needs of soybean change over time because of large microenvironment changes over their lifespan, as leaves mature in full sun at the top of the canopy and then become progressively shaded by younger leaves developing above. Leaf hydraulic conductance (K(leaf)), a measure of the leaf's water transport capacity, can often be linked to changes in microenvironment and transpiration demand. In this study, we tested the hypothesis that K(leaf) would decline in coordination with transpiration demand as soybean leaves matured and aged. Photosynthesis (A), stomatal conductance (g(s)) and leaf water potential (Ψ(leaf)) were also measured at various leaf ages with both field- and chamber-grown soybeans to assess transpiration demand. K(leaf) was found to decrease as soybean leaves aged from maturity to shading to senescence, and this decrease was strongly correlated with midday A. Decreases in K(leaf) were further correlated with decreases in g(s), although the relationship was not as strong as that with A. Separate experiments investigating the response of K(leaf) to drought demonstrated no acclimation of K(leaf) to drought conditions to protect against cavitation or loss of g(s) during drought and confirmed the effect of leaf age in K(leaf) observed in the field. These results suggest that the decline of leaf hydraulic conductance as leaves age keeps hydraulic supply in balance with demand without K(leaf)becoming limiting to transpiration water flux.

  11. Leaf hydraulic conductance declines in coordination with photosynthesis, transpiration and leaf water status as soybean leaves age regardless of soil moisture

    Science.gov (United States)

    Locke, Anna M.; Ort, Donald R.

    2014-01-01

    Photosynthesis requires sufficient water transport through leaves for stomata to remain open as water transpires from the leaf, allowing CO2 to diffuse into the leaf. The leaf water needs of soybean change over time because of large microenvironment changes over their lifespan, as leaves mature in full sun at the top of the canopy and then become progressively shaded by younger leaves developing above. Leaf hydraulic conductance (K leaf), a measure of the leaf’s water transport capacity, can often be linked to changes in microenvironment and transpiration demand. In this study, we tested the hypothesis that K leaf would decline in coordination with transpiration demand as soybean leaves matured and aged. Photosynthesis (A), stomatal conductance (g s) and leaf water potential (Ψleaf) were also measured at various leaf ages with both field- and chamber-grown soybeans to assess transpiration demand. K leaf was found to decrease as soybean leaves aged from maturity to shading to senescence, and this decrease was strongly correlated with midday A. Decreases in K leaf were further correlated with decreases in g s, although the relationship was not as strong as that with A. Separate experiments investigating the response of K leaf to drought demonstrated no acclimation of K leaf to drought conditions to protect against cavitation or loss of g s during drought and confirmed the effect of leaf age in K leaf observed in the field. These results suggest that the decline of leaf hydraulic conductance as leaves age keeps hydraulic supply in balance with demand without K leaf becoming limiting to transpiration water flux. PMID:25281701

  12. How to chase a tracer - combining conventional salt tracer testing and direct push electrical conductivity profiling for enhanced aquifer characterization

    Science.gov (United States)

    Vienken, Thomas; Huber, Emanuel; Kreck, Manuel; Huggenberger, Peter; Dietrich, Peter

    2017-01-01

    Tracer testing is a well-established technique in hydrogeological site characterization. However, certain a priori knowledge of the hydraulic regime is required beforehand to avoid test failure, e.g. miss of tracer. In this study, we propose a novel tracer test concept for the hydraulic characterization of shallow unconsolidated sedimentary deposits when only scarce a priori information on the hydraulic regime is available. Therefore, we combine conventional salt tracer testing with direct push vertical high resolution electrical conductivity logging. The proposed tracer test concept was successfully tested on coarse, braided river deposits of the Tagliamento River, Italy. With limited a priori information available two tracer tests were performed in three days to reliably determine ground water flow direction and velocity allowing on-site decision-making to adaptively install observation wells for reliable breakthrough curve measurements. Furthermore, direct push vertical electrical profiling provided essential information about the plume characteristics with outstanding measurement resolution and efficiency.

  13. Digital map of hydraulic conductivity for the High Plains aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set consists of hydraulic conductivity contours and polygons for the High Plains aquifer in the central United States. The High Plains aquifer...

  14. Hydraulic characterization of volcanic rocks in Pahute Mesa using an integrated analysis of 16 multiple-well aquifer tests, Nevada National Security Site, 2009–14

    Science.gov (United States)

    Garcia, C. Amanda; Jackson, Tracie R.; Halford, Keith J.; Sweetkind, Donald S.; Damar, Nancy A.; Fenelon, Joseph M.; Reiner, Steven R.

    2017-01-20

    An improved understanding of groundwater flow and radionuclide migration downgradient from underground nuclear-testing areas at Pahute Mesa, Nevada National Security Site, requires accurate subsurface hydraulic characterization. To improve conceptual models of flow and transport in the complex hydrogeologic system beneath Pahute Mesa, the U.S. Geological Survey characterized bulk hydraulic properties of volcanic rocks using an integrated analysis of 16 multiple-well aquifer tests. Single-well aquifer-test analyses provided transmissivity estimates at pumped wells. Transmissivity estimates ranged from less than 1 to about 100,000 square feet per day in Pahute Mesa and the vicinity. Drawdown from multiple-well aquifer testing was estimated and distinguished from natural fluctuations in more than 200 pumping and observation wells using analytical water-level models. Drawdown was detected at distances greater than 3 miles from pumping wells and propagated across hydrostratigraphic units and major structures, indicating that neither faults nor structural blocks noticeably impede or divert groundwater flow in the study area.Consistent hydraulic properties were estimated by simultaneously interpreting drawdown from the 16 multiple-well aquifer tests with an integrated groundwater-flow model composed of 11 well-site models—1 for each aquifer test site. Hydraulic properties were distributed across volcanic rocks with the Phase II Pahute Mesa-Oasis Valley Hydrostratigraphic Framework Model. Estimated hydraulic-conductivity distributions spanned more than two orders of magnitude in hydrostratigraphic units. Overlapping hydraulic conductivity ranges among units indicated that most Phase II Hydrostratigraphic Framework Model units were not hydraulically distinct. Simulated total transmissivity ranged from 1,600 to 68,000 square feet per day for all pumping wells analyzed. High-transmissivity zones exceeding 10,000 square feet per day exist near caldera margins and extend

  15. Effects of Phosphorus Nutrient on the Hydraulic Conductivity of Sorghum (Sorghum vulgare Pers.) Seedling Roots Under Water Deficiency

    Institute of Scientific and Technical Information of China (English)

    Zhou-Ping SHANGGUAN; Ting-Wu LEI; Ming-An SHAO; Qing-Wu XUE

    2005-01-01

    Hydroponic experiments were conducted in a growth chamber and changes in the hydraulic conductivity of sorghum (Sorghum vulgare Pers.) roots (Lpr) at the three-leaf stage were measured using the pressure chamber method. Water deficiency was imposed with polyethylene glycol (PEG) 6000 and the phosphorus (P) levels were controlled by complete Hoagland solution with and without P nutrient. The objective of this study was to investigate the effect of P nutrition on root Lpr under water deficiency. The results showed that the Lpr in P deficiency treatments decreased markedly, but the Lpr recovered to the same value as that of control when sufficient P was supplied for 4-24 h. Water deficiency decreased Lpr, but the hydraulic conductivity of the roots with sufficient P supply was still higher than that of plants without P supply. When resuming water supply, the Lpr of the water-deficient plants under P supply recovered faster than that of plants without P supply, which indicates that plants with sufficient P nutrient are more drought tolerant and have a greater ability to recover after drought. The treatment of HgCl2 indicated that P nutrient could regulate the Lpr by affecting the activity and the expression levels of aquaporins.

  16. Results of Hydraulic Tests in Miocene Tuffaceous Rocks at the C-Hole Complex, 1995 to 1997, Yucca Mountain, Nye County, Nevada

    Science.gov (United States)

    Geldon, Arthur L.; Umari, Amjad M.A.; Fahy, Michael F.; Earle, John D.; Gemmell, James M.; Darnell, Jon

    2002-01-01

    Four hydraulic tests were conducted by the U.S. Geological Survey at the C-hole complex at Yucca Mountain, Nevada, between May 1995 and November 1997. These tests were conducted as part of ongoing investigations to determine the hydrologic and geologic suitability of Yucca Mountain as a potential site for permanent underground storage of high-level nuclear waste. The C-hole complex consists of three 900-meter-deep boreholes that are 30.4 to 76.6 meters apart. The C-holes are completed in fractured, variably welded tuffaceous rocks of Miocene age. Six hydrogeologic intervals occur within the saturated zone in these boreholes - the Calico Hills, Prow Pass, Upper Bullfrog, Lower Bullfrog, Upper Tram, and Lower Tram intervals. The Lower Bullfrog and Upper Tram intervals contributed about 90 percent of the flow during hydraulic tests. The four hydraulic tests conducted from 1995 to 1997 lasted 4 to 553 days. Discharge from the pumping well, UE-25 c #3, ranged from 8.49 to 22.5 liters per second in different tests. Two to seven observation wells, 30 to 3,526 meters from the pumping well, were used in different tests. Observation wells included UE-25 c #1, UE-25 c #2, UE-25 ONC-1, USW H-4, UE-25 WT #14, and UE-25 WT #3 in the tuffaceous rocks and UE-25 p #1 in Paleozoic carbonate rocks. In all hydraulic tests, drawdown in the pumping well was rapid and large (2.9-11 meters). Attributable mostly to frictional head loss and borehole-skin effects, this drawdown could not be used to analyze hydraulic properties. Drawdown and recovery in intervals of UE-25 c #1 and UE-25 c #2 and in other observation wells typically was less than 51 centimeters. These data were analyzed. Hydrogeologic intervals in the C-holes have layered heterogeneity related to faults and fracture zones. Transmissivity, hydraulic conductivity, and storativity generally increase downhole. Transmissivity ranges from 4 to 1,600 meters squared per day; hydraulic conductivity ranges from 0.1 to 50 meters per day

  17. Deformation Characterization of Friction-Stir-Welded Tubes by Hydraulic Bulge Testing

    Science.gov (United States)

    Pang, Q.; Hu, Z. L.; Pan, X.; Zuo, X. Q.

    2014-10-01

    In this article, the large-diameter thin-walled aluminum alloy tubes were produced using a hybrid process combining friction-stir welding (FSW) and spinning. For this novel process, rolled aluminum alloy sheets with a thickness about 2-3 times the wall thickness of target tube, were FSW to form cylinders, and then the cylinders were subjected to spinning to get thin-walled aluminum alloy tubes. Both experimental and simulation study were conducted to investigate the deformation characterization of the FSW tube during hydraulic bulge testing, and the stress and strain states and thickness distribution of the FSW tube were investigated. It was found that the common defects of FSW tube can be significantly improved by specific welding devices. The ductility of the tube is considerably improved with nearly two times higher bulge ratio than as-spun tube after annealing treatment at 300°C. But the annealed tube still shows a high nonuniform wall thickness distribution due to the inhomogeneous deformation characteristics. With increasing deformation of the tube, the gap between the hoop and axial stress for the weld and base metal (BM) decreases. However, the hoop and axial stress of the weld are always greater than those of the BM at the same pressure.

  18. Joint Estimation of Hydraulic and Poroelastic Parameters from a Pumping Test.

    Science.gov (United States)

    Berg, Steven J; Illman, Walter A; Mok, Chin Man W

    2015-01-01

    The coupling of hydraulic and poroelastic processes is critical in predicting processes involving the deformation of the geologic medium in response to fluid extraction or injection. Numerical models that consider the coupling of hydraulic and poroelastic processes require the knowledge of relevant parameters for both aquifer and aquitard units. In this study, we jointly estimated hydraulic and poroelastic parameters from pumping test data exhibiting "reverse water level fluctuations," known as the Noordbergum effect, in aquitards adjacent to a pumped aquifer. The joint estimation was performed by coupling BIOT2, a finite element, two-dimensional, axisymmetric, groundwater model that considers poroelastic effects with the parameter estimation code PEST. We first tested our approach using a synthetic data set with known parameters. Results of the synthetic case showed that for a simple layered system, it was possible to reproduce accurately both the hydraulic and poroelastic properties for each layer. We next applied the approach to pumping test data collected at the North Campus Research Site (NCRS) on the University of Waterloo (UW) campus. Based on the detailed knowledge of stratigraphy, a five-layer system was modeled. Parameter estimation was performed by: (1) matching drawdown data individually from each observation port and (2) matching drawdown data from all ports at a single well simultaneously. The estimated hydraulic parameters were compared to those obtained by other means at the site yielding good agreement. However, the estimated shear modulus was higher than the static shear modulus, but was within the range of dynamic shear modulus reported in the literature, potentially suggesting a loading rate effect.

  19. Data report of BWR post-CHF tests. Transient core thermal-hydraulic test program. Contract research

    Energy Technology Data Exchange (ETDEWEB)

    Iguchi, Tadashi; Itoh, Hideo; Kiuchi, Toshio; Watanabe, Hironori; Kimura, Mamoru; Anoda, Yoshinari [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    JAERI has been performing transient core thermal-hydraulic test program. In the program, authors performed BWR/ABWR DBE simulation tests with a test facility, which can simulate BWR/ABWR transients. The test facility has a 4 x 4 bundle core simulator with 15-rod heaters and one non-heated rod. Through the tests, authors quantified the thermal safety margin for core cooling. In order to quantify the thermal safety margin, authors collected experimental data on post-CHF. The data are essential for the evaluation of clad temperature transient when core heat-up occurs during DBEs. In comparison with previous post-CHF tests, present experiments were performed in much wider experimental condition, covering high clad temperature, low to high pressure and low to high mass flux. Further, data at wider elevation (lower to higher elevation of core) were obtained in the present experiments, which make possible to discuss the effect of axial position on thermal-hydraulics, while previous works usually discuss the thermal-hydraulics at the position where the first heat-up occurs. This data report describes test procedure, test condition and major experimental data of post-CHF tests. (author)

  20. Thermal hydraulic similarity analysis of the integral effect test facility for main steam line break events

    Energy Technology Data Exchange (ETDEWEB)

    Choi, K.Y.; Park, H.S.; Euh, D.J.; Kwon, T.S.; Baek, W.P. [Thermal Hydraulic Safety Research Division Korea Atomic Energy Research Institute 150 Dukjin-Dong, Yusong-Gu, Daejeon 305-353 (Korea, Republic of)

    2005-07-01

    Full text of publication follows: A thermal-hydraulic integral effect test facility, ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation), is being constructed at Korea Atomic Energy Research Institute (KAERI). The ATLAS is a 1/2 reduced height and 1/288 volume scaled test facility based on the design features of the APR1400, an evolutionary pressurized water reactor developed by Korean industry. The ATLAS will be used to get more realistic understanding of the thermal hydraulic phenomena following postulated events and to carry out performance evaluation and safety analysis of the reference plants. The MSLB (Main Steam Line Break) event is one of the representative non-LOCA events and thermalhydraulic phenomena following the event are to be investigated in the ATLAS. In this paper, thermal hydraulic similarity for MSLB events between the ATLAS and the prototype plant, APR1400 is assessed by using the MARS code, which is a multi-dimensional best-estimate thermal hydraulic code being developed by KAERI. Several cases including SLBFPLOOP and SLBFP are taken into account for similarity analysis in this paper. The neutronic effects such as moderator temperature coefficients and doppler reactivity in APR1400 are not considered in this study. The same control logics for the major sequence of events such as reactor trip, turbine trip, valve opening and actuation of the emergency cooling system are applied to the ATLAS and the APR1400. The present investigation is focused on the scaling and the reduced power effects on thermal hydraulic similarity after initiation of MSLB events. It is found that the ATLAS facility has the similar thermal hydraulic responses against the MSLB events. However, the initial high secondary pressure before the MSLB initiation resulted in different primary pressure and temperature progression from the APR1400. The break flow from the main steam line is found to be one of the most dominating parameters governing the transient

  1. Water uptake by growing cells: an assessment of the controlling roles of wall relaxation, solute uptake, and hydraulic conductance

    Science.gov (United States)

    Cosgrove, D. J.

    1993-01-01

    Growing plant cells increase in volume principally by water uptake into the vacuole. There are only three general mechanisms by which a cell can modulate the process of water uptake: (a) by relaxing wall stress to reduce cell turgor pressure (thereby reducing cell water potential), (b) by modifying the solute content of the cell or its surroundings (likewise affecting water potential), and (c) by changing the hydraulic conductance of the water uptake pathway (this works only for cells remote from water potential equilibrium). Recent studies supporting each of these potential mechanisms are reviewed and critically assessed. The importance of solute uptake and hydraulic conductance is advocated by some recent studies, but the evidence is indirect and conclusions remain controversial. For most growing plant cells with substantial turgor pressure, it appears that reduction in cell turgor pressure, as a consequence of wall relaxation, serves as the major initiator and control point for plant cell enlargement. Two views of wall relaxation as a viscoelastic or a chemorheological process are compared and distinguished.

  2. Vertical hydraulic conductivity of a clayey-silt aquitard: accelerated fluid flow in a centrifuge permeameter compared with in situ conditions

    Directory of Open Access Journals (Sweden)

    W. A. Timms

    2014-03-01

    Full Text Available Evaluating the possibility of leakage through low permeability geological strata is critically important for sustainable water supplies, extraction of fuels from strata such as coal beds, and confinement of waste within the earth. Characterizing low or negligible flow rates and transport of solutes can require impractically long periods of field or laboratory testing, but is necessary for evaluations over regional areas and over multi-decadal timescales. The current work reports a custom designed centrifuge permeameter (CP system, which can provide relatively rapid and reliable hydraulic conductivity (K measurement compared to column permeameter tests at standard gravity (1g. Linear fluid velocity through a low K porous sample is linearly related to g-level during a CP flight unless consolidation or geochemical reactions occur. The CP module is designed to fit within a standard 2 m diameter, geotechnical centrifuge with a capacity for sample dimensions of 30 to 100 mm diameter and 30 to 200 mm in length. At maximum RPM the resultant centrifugal force is equivalent to 550g at base of sample or a total stress of ~2 MPa. K is calculated by measuring influent and effluent volumes. A custom designed mounting system allows minimal disturbance of drill core samples and a centrifugal force that represents realistic in situ stress conditions is applied. Formation fluids were used as influent to limit any shrink-swell phenomena which may alter the resultant K value. Vertical hydraulic conductivity (Kv results from CP testing of core from the sites in the same clayey silt formation varied (10−7 to 10−9 m s−1, n = 14 but higher than 1g column permeameter tests of adjacent core using deionized water (10−9 to 10−11 m s−1, n = 7. Results at one site were similar to in situ Kv values (3 × 10−9 m s−1 from pore pressure responses within a 30 m clayey sequence in a homogenous area of the formation. Kv sensitivity to sample heterogeneity was

  3. MODFLOW-2005 and PEST models used to simulate multiple-well aquifer tests and characterize hydraulic properties of volcanic rocks in Pahute Mesa, Nevada

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A three-dimensional, groundwater-flow model (MODFLOW-2005) was developed to estimate the hydraulic properties (e.g., transmissivity, hydraulic conductivity, specific...

  4. Pinhole test for identifying susceptibility of soils to piping erosion: effect water quality and hydraulic head

    Energy Technology Data Exchange (ETDEWEB)

    Nadal Romero, E.; Verachtert, E.; Poesen, J.

    2009-07-01

    Piping has been observed in both natural and soils, as well as under different types of land uses and vegetation covers. Despite its importance, no standard widely-applied methodology exists to assess susceptibility of soils to piping. This study aims at evaluating the pinhole test for assessing the susceptibility of soils to piping under different conditions. More precisely, the effects of hydraulic head and water quality are being assessed. Topsoil samples (remoulded specimens) with a small range of water contents were taken in Central Belgium (Heverlee) and the susceptibility of these soil samples are investigated under standardized laboratory conditions with a pinhole test device. Three hydraulic heads (50,180 and 380 mm) and two water qualities (tap and distilled water) were used, reflecting dominant field conditions. (Author) 6 refs.

  5. Influence of temperature and hydraulic conductivity of soil on electrokinetic decontamination

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gye-Nam; Kim, Seung-Soo; Jeong, Jung-Whan; Choi, Jong-Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    The electrokinetic process holds great promise for the decontamination of contaminated soil because it has a high removal efficiency and is time-effective for low permeability. Electrokinetic decontamination can be used to treat soil contaminated with inorganic species and radionuclides. The main mechanisms of a contaminant's movement in an electrical field involved in electrokinetic technology are the electro-migration of the ionic species and electro-osmosis. Electro-migration probably contributes significantly to the removal of contaminants, especially at high concentrations of ionic contaminants and/or a high hydraulic permeability of soil. The cathode reaction should be depolarized to avoid the generation of hydroxides and their transport in soil. The selected liquid, also known as a purging reagent, should induce favorable pH conditions in soil, and/or interact with the incorporated heavy metals so that these heavy metals are removed from the soil. The removal efficiencies of uranium from contaminated soil in manufactured laboratory electrokinetic decontamination equipment were proportional to the elapsed time. The removal efficiencies of uranium for 2 days were 77-87%. In addition, the removal efficiencies according to the elapsed time after 2 days were reduced. When 75, 80, and 85℃ electrolyte temperatures in the cathode chamber were applied, the time required for the removal efficiency of uranium to reach 92% was 6, 5 and 4 days.

  6. [Seasonal differences in the leaf hydraulic conductance of mature Acacia mangium in response to its leaf water use and photosynthesis].

    Science.gov (United States)

    Zhao, Ping; Sun, Gu-Chou; Ni, Guang-Yan; Zeng, Xiao-Ping

    2013-01-01

    In this study, measurements were made on the leaf water potential (psi1), stomatal conductance (g(s)), transpiration rate, leaf area index, and sapwood area of mature Acacia mangium, aimed to understand the relationships of the leaf hydraulic conductance (K1) with the leaf water use and photosynthetic characteristics of the A. mangium in wet season (May) and dry season (November). The ratio of sapwood area to leaf area (A(sp)/A(cl)) of the larger trees with an average height of 20 m and a diameter at breast height (DBH) of 0.26 m was 8.5% higher than that of the smaller trees with an average height of 14.5 m and a DBH of 0.19 m, suggesting that the larger trees had a higher water flux in their leaf xylem, which facilitated the water use of canopy leaf. The analysis on the vulnerability curve of the xylem showed that when the K1 decreased by 50%, the psi1 in wet season and dry season was -1.41 and -1.55 MPa, respectively, and the vulnerability of the xylem cavitation was higher in dry season than in wet season. The K1 peak value in wet season and dry season was 5.5 and 4.5 mmol x m(-2) x s(-1) x MPa(-1), and the maximum transpiration rate (T(r max)) was 3.6 and 1.8 mmol x m(-2) x s(-1), respectively. Both the K1 and T(r max), were obviously higher in wet season than in dry season. Within a day, the K1 and T(r), fluctuated many times, reflecting the reciprocated cycle of the xylem cavitation and refilling. The leaf stomatal closure occurred when the K1 declined over 50% or the psi1 reached -1.6 MPa. The g(s) would be maintained at a high level till the K1 declined over 50%. The correlation between the hydraulic conductance and photosynthetic rate was more significant in dry season than in wet season. The loss of leaf hydraulic conductance induced by seasonal change could be the causes of the decrease of T(r) and CO2 gas exchange.

  7. Out-of-pile Verifying Test for the Hydraulic Stability of the CARR Standard Fuel Assembly

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The CARR standard fuel element is a flat-plate-type assembly. A fuel plate consists of 0.6 mmthickness layer of uranium- silicon - aluminum fuel (U3Si2-Al) and 0.38 mm thickness of aluminumcladding. The fuel plates are attached to aluminum alloy side plates by a "roll swaging" technique. Thistype of fuel assembly is first used in China. The testing simulates the in-pile thermal-hydraulic operating conditions except for neutron

  8. Neutron Tomography Using Mobile Neutron Generators for Assessment of Void Distributions in Thermal Hydraulic Test Loops

    OpenAIRE

    Andersson, Peter; Bjelkenstedt, Tom; Andersson Sundén, Erik; Sjöstrand, Henrik; Jacobsson, Staffan

    2015-01-01

    Detailed knowledge of the lateral distribution of steam (void) and water in a nuclear fuel assembly is of great value for nuclear reactor operators and fuel manufacturers, with consequences for both reactor safety and economy of operation. Therefore, nuclear relevant two-phase flows are being studied at dedicated thermal-hydraulic test loop, using twophase flow systems ranging from simplified geometries such as heated circular pipes to full scale mock-ups of nuclear fuel assemblies. Neutron t...

  9. Depth-discrete specific storage in fractured sedimentary rock using steady-state and transient single-hole hydraulic tests

    Science.gov (United States)

    Quinn, Patryk M.; Cherry, John A.; Parker, Beth L.

    2016-11-01

    A method is presented for obtaining depth-discrete values of specific storage (Ss) from single-hole hydraulic tests in fractured rock boreholes using straddle packers (1.5-17 m test intervals). Low flow constant head (CH) step tests analyzed using the Thiem method provide transmissivity (T) values free from non-Darcian error. Short-term, constant-rate pumping tests (0.5-2 h) analyzed using the Cooper-Jacob approximation of the Theis method provide S from the hydraulic diffusivity using the Darcian T value from the CH step test. This synergistic use of two types of hydraulic tests avoids the common source of error when pumping tests (injection or withdrawal) are conducted at higher flow rates and thereby induce non-Darcian flow resulting in the underestimation of T. Other errors, such as well bore storage and leakage, can also substantially influence S by causing a shift in the time axis of the Cooper-Jacob semi-log plot. In this approach, the Darcian T values from the CH step tests are used in the analysis of the transient pumping test data for calculating S throughout the pumping test using the Cooper-Jacob approximation to minimize all of the aforementioned errors, resulting in more representative S values. The effect of these non-idealities on the measured drawdown is illustrated using the Theis equation with the Darcian T and S values to calculate drawdown for comparison to measured data. The Ss values for tests in sandstone obtained from this approach are more consistent with confined aquifer conditions than values derived from the traditional Cooper-Jacob method, and are within the range of field and lab values presented from a compilation of literature values for fractured sandstone. (10-7-10-5 m-1) This method for obtaining Ss values from short-interval, straddle packer tests improves the estimation of both K and Ss and provides opportunity to study their spatial distribution in fractured rock.

  10. Lead Coolant Test Facility Systems Design, Thermal Hydraulic Analysis and Cost Estimate

    Energy Technology Data Exchange (ETDEWEB)

    Soli Khericha; Edwin Harvego; John Svoboda; Ryan Dalling

    2012-01-01

    The Idaho National Laboratory prepared a preliminary technical and functional requirements (T&FR), thermal hydraulic design and cost estimate for a lead coolant test facility. The purpose of this small scale facility is to simulate lead coolant fast reactor (LFR) coolant flow in an open lattice geometry core using seven electrical rods and liquid lead or lead-bismuth eutectic coolant. Based on review of current world lead or lead-bismuth test facilities and research needs listed in the Generation IV Roadmap, five broad areas of requirements were identified as listed: (1) Develop and Demonstrate Feasibility of Submerged Heat Exchanger; (2) Develop and Demonstrate Open-lattice Flow in Electrically Heated Core; (3) Develop and Demonstrate Chemistry Control; (4) Demonstrate Safe Operation; and (5) Provision for Future Testing. This paper discusses the preliminary design of systems, thermal hydraulic analysis, and simplified cost estimate. The facility thermal hydraulic design is based on the maximum simulated core power using seven electrical heater rods of 420 kW; average linear heat generation rate of 300 W/cm. The core inlet temperature for liquid lead or Pb/Bi eutectic is 4200 C. The design includes approximately seventy-five data measurements such as pressure, temperature, and flow rates. The preliminary estimated cost of construction of the facility is $3.7M (in 2006 $). It is also estimated that the facility will require two years to be constructed and ready for operation.

  11. Development of scaling laws on thermal-hydraulic effect test facility for CANDU-6 moderator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. Y.; Jung, Y. S.; Kim, N. S. [Handong University, Pohang (Korea, Republic of); Kim, M. W.; Kim, H. J. [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    2004-07-01

    The scaling laws on thermal-hydraulic effect test facility for CANDU-6 moderator (HGU-KINS) have been investigated and manufactured. The basic laws are the satisfaction of energy conservation and dimensionless number, Ar and Re, for the similarities of thermal-hydraulic properties. And then the thermal-hydraulic scaling analyses of test facilities, SPEL(1/10 scale) and STERN(1/4 scale), have been identified by the present method. As a result, in the case of SPEL, the energy conservation is confirmed, but the similarities of Ar and the heat density are not considered. In the case of STERN, the energy conservation and the characteristics of Ar were well defined. But the similarity of the heat density is unsatisfied, either. Therefore the present method was applied with 1/8 length scale. For the performance test, CFD analysis has been accomplished by CFX5. The results of flow pattern certifications and variation of axial properties with CANDU show that the present scaling method is acceptable.

  12. Lead coolant test facility systems design, thermal hydraulic analysis and cost estimate

    Energy Technology Data Exchange (ETDEWEB)

    Khericha, Soli, E-mail: slk2@inel.gov [Battelle Energy Alliance, LLC, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Harvego, Edwin; Svoboda, John; Evans, Robert [Battelle Energy Alliance, LLC, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Dalling, Ryan [ExxonMobil Gas and Power Marketing, Houston, TX 77069 (United States)

    2012-01-15

    The Idaho National Laboratory prepared a preliminary technical and functional requirements (T and FR), thermal hydraulic design and cost estimate for a lead coolant test facility. The purpose of this small scale facility is to simulate lead coolant fast reactor (LFR) coolant flow in an open lattice geometry core using seven electrical rods and liquid lead or lead-bismuth eutectic coolant. Based on review of current world lead or lead-bismuth test facilities and research needs listed in the Generation IV Roadmap, five broad areas of requirements were identified as listed below: Bullet Develop and demonstrate feasibility of submerged heat exchanger. Bullet Develop and demonstrate open-lattice flow in electrically heated core. Bullet Develop and demonstrate chemistry control. Bullet Demonstrate safe operation. Bullet Provision for future testing. This paper discusses the preliminary design of systems, thermal hydraulic analysis, and simplified cost estimated. The facility thermal hydraulic design is based on the maximum simulated core power using seven electrical heater rods of 420 kW; average linear heat generation rate of 300 W/cm. The core inlet temperature for liquid lead or Pb/Bi eutectic is 4200 Degree-Sign C. The design includes approximately seventy-five data measurements such as pressure, temperature, and flow rates. The preliminary estimated cost of construction of the facility is $3.7M (in 2006 $). It is also estimated that the facility will require two years to be constructed and ready for operation.

  13. Kinetics of recovery of leaf hydraulic conductance and vein functionality from cavitation-induced embolism in sunflower.

    Science.gov (United States)

    Trifilò, Patrizia; Gascó, Antonio; Raimondo, Fabio; Nardini, Andrea; Salleo, Sebastiano

    2003-10-01

    The kinetics of leaf vein recovery from cavitation-induced embolism was studied in plants of sunflower cv. Margot, together with the impact of vein embolism on the overall leaf hydraulic conductance (Kleaf). During the air-dehydration of leaves to leaf water potentials (Psi L) of -1.25 MPa, Kleaf was found to decrease by about 46% with respect to values recorded in well-hydrated leaves. When leaves, previously dehydrated to Psi L= -1.1 MPa (corresponding to the turgor loss point), were put in contact with water, Kleaf recovered completely in 10 min and so did leaf water potential. Functional vein density was estimated in both dehydrating and rehydrating leaves in terms of total length of red-stained veins infiltrated with a Phloxine B solution per unit leaf surface area. Veins were found to embolize (unstained) with kinetics showing a linear relationship with Kleaf so that about a 70% loss of functional veins corresponded with a Kleaf loss of 46%. Cavitated veins recovered from embolism within 10 min from the beginning of leaf rehydration. These data indicate that: (a) leaves of sunflower underwent substantial vein embolism during dehydration; (b) vein embolism and leaf hydraulic efficiency apparently recovered from dehydration completely and rapidly upon rehydration; (c) vein refilling occurred while conduits were still at more negative xylem pressures than those required for spontaneous bubble dissolution on the basis of Henry's law. The possible consistent contribution of vital mechanisms for vein refilling is discussed.

  14. Comparison of Three Methods for Determination of Root Hydraulic Conductivity of Maize (Zea mays L.) Root System

    Institute of Scientific and Technical Information of China (English)

    LI Qing-ming; LIU Bin-bin

    2010-01-01

    Three techniques of root pressure probe,pressure chamber and high pressure flow meter were used to measure the hydraulic conduetivities (Lp,) of whole root systems of young maize (Zea mays L.) seedlings grown hydroponically under either drought or normal water conditions.Compared to normal water conditions,drought stress simulated by polyethylene glycol 6 000 (osmotic potential=-0.2 MPa) reduced Lp,in the root system by over 50%.It indicated that water permeability in the roots decreased significantly when plants suffered from water shortages.Moreover,there was no significant difference (P<0.05) on the Lpr values in the root systems developed under a given water stress regime among the three techniques used.Therefore,all three methods are acceptable to study the hydraulic conductivity of maize seedling root systems.We have also highlighted some of the technical limitations of each method.It can be inferred that the root pressure probe is preferable for young maize seedlings because it is subtle and has the additional ability to determine solute transport properties,but the method is time consuming.Other advantages and disadvantages of each technique are discussed in order to acquaint researchers with basic information that could contribute to their choice of an appropriate technique for future studies.

  15. Estimation of groundwater flow directions and the tensor of hydraulic conductivity in crystalline massif rocks using information from surface structural geology and mining exploration boreholes

    Science.gov (United States)

    Florez, C.; Romero, M. A.; Ramirez, M. I.; Monsalve, G.

    2013-05-01

    In the elaboration of a hydrogeological conceptual model in regions of mining exploration where there is significant presence of crystalline massif rocks., the influence of physical and geometrical properties of rock discontinuities must be evaluated. We present the results of a structural analysis of rock discontinuities in a region of the Central Cordillera of Colombia (The upper and middle Bermellon Basin) in order to establish its hydrogeological characteristics for the improvement of the conceptual hydrogeological model for the region. The geology of the study area consists of schists with quartz and mica and porphyritic rocks, in a region of high slopes with a nearly 10 m thick weathered layer. The main objective of this research is to infer the preferential flow directions of groundwater and to estimate the tensor of potential hydraulic conductivity by using surface information and avoiding the use of wells and packer tests. The first step of our methodology is an analysis of drainage directions to detect patterns of structural controls in the run-off; after a field campaign of structural data recollection, where we compile information of strike, dip, continuity, spacing, roughness, aperture and frequency, we built equal area hydro-structural polar diagrams that indicate the potential directions for groundwater flow. These results are confronted with records of Rock Quality Designation (RQD) that have been systematically taken from several mining exploration boreholes in the area of study. By using all this information we estimate the potential tensor of hydraulic conductivity from a cubic law, obtaining the three principal directions with conductivities of the order of 10-5 and 10-6 m/s; the more conductive joint family has a NE strike with a nearly vertical dip.

  16. Agricultural use of soil, consequences in soil organic matter and hydraulic conductivity compared with natural vegetation in central Spain

    Science.gov (United States)

    Vega, Verónica; Carral, Pilar; Alvarez, Ana Maria; Marques, Maria Jose

    2014-05-01

    When ecosystems are under pressure due to high temperatures and water scarcity, the use of land for agriculture can be a handicap for soil and water conservation. The interactions between plants and soils are site-specific. This study provides information about the influence of the preence vs. The absence of vegetation on soil in a semi-arid area of the sout-east of Madrid (Spain, in the Tagus River basin. In this area soil materials are developed over a calcareous-evaporitic lithology. Soils can be classified as Calcisols, having horizons of accumulation with powdered limestone and irregular nodules of calcium carbonate. They can be defined as Haplic Cambisols and Leptic Calcisols (WRB 2006-FAO). The area is mainly used for rainfed agriculture, olive groves, vineyards and cereals. There are some patches of bushes (Quercus sp.) and grasses (Stipa tenacissima L.) although only found on the top of the hills. This study analyses the differences found in soils having three different covers: Quercus coccifera, Stipa tenacissima and lack of vegetation. This last condition was found in the areas between cultivated olive trees. Soil organic matter, porosity and hydraulic conductivity are key properties of soil to understand its ability to adapt to climate or land use changes. In order to measure the influence of different soil covers, four replicates of soil were sampled in each condition at two soil depth, (0-10 cm and 10-20 cm). Hydraulic conductivity was measured in each soil condition and replicate using a Mini-disk® infiltrometer. There were no differences between the two depths sampled. Similarly, there were no changes in electric conductivity (average 0.1±0.03 dS m-1); pH (8.7±0.2) or calcium carbonate content (43±20 %). Nevertheless, significant differences (p>0.001) were found in soil organic matter. The maximum was found in soils under Quercus (4.7±0.5 %), followed by Stipa (2.2±1.1 %). The soil without vegetation in the areas between olive trees had only 0

  17. Changes in hydraulic conductance cause the difference in growth response to short-term salt stress between salt-tolerant and -sensitive black gram (Vigna mungo) varieties.

    Science.gov (United States)

    Win, Khin Thuzar; Oo, Aung Zaw; Ookawa, Taiichiro; Kanekatsu, Motoki; Hirasawa, Tadashii

    2016-04-01

    Black gram (Vigna mungo) is an important crop in Asia, However, most black gram varieties are salt-sensitive. The causes of varietal differences in salt-induced growth reduction between two black gram varieties, 'U-Taung-2' (salt-tolerant; BT) and 'Mut Pe Khaing To' (salt-sensitive; BS), were examined the potential for the first step toward the genetic improvement of salt tolerance. Seedlings grown in vermiculite irrigated with full-strength Hoagland solution were treated with 0mM NaCl (control) or 225 mM NaCl for up to 10 days. In the 225 mM NaCl treatment, plant growth rate, net assimilation rate, mean leaf area, leaf water potential, and leaf photosynthesis were reduced more in BS than in BT plants. Leaf water potential was closely related to leaf photosynthesis, net assimilation rate, and increase in leaf area. In response to salinity stress, hydraulic conductance of the root, stem, and petiole decreased more strongly in BS than in BT plants. The reduction in stem and petiole hydraulic conductance was caused by cavitation, whereas the reduction in root hydraulic conductance in BS plants was caused by a reduction in root surface area and hydraulic conductivity. We conclude that the different reduction in hydraulic conductance is a cause of the differences in the growth response between the two black gram varieties under short-term salt stress.

  18. Laboratory-Measured and Property-Transfer Modeled Saturated Hydraulic Conductivity of Snake River Plain Aquifer Sediments at the Idaho National Laboratory, Idaho

    Science.gov (United States)

    Perkins, Kim S.

    2008-01-01

    Sediments are believed to comprise as much as 50 percent of the Snake River Plain aquifer thickness in some locations within the Idaho National Laboratory. However, the hydraulic properties of these deep sediments have not been well characterized and they are not represented explicitly in the current conceptual model of subregional scale ground-water flow. The purpose of this study is to evaluate the nature of the sedimentary material within the aquifer and to test the applicability of a site-specific property-transfer model developed for the sedimentary interbeds of the unsaturated zone. Saturated hydraulic conductivity (Ksat) was measured for 10 core samples from sedimentary interbeds within the Snake River Plain aquifer and also estimated using the property-transfer model. The property-transfer model for predicting Ksat was previously developed using a multiple linear-regression technique with bulk physical-property measurements (bulk density [pbulk], the median particle diameter, and the uniformity coefficient) as the explanatory variables. The model systematically underestimates Ksat,typically by about a factor of 10, which likely is due to higher bulk-density values for the aquifer samples compared to the samples from the unsaturated zone upon which the model was developed. Linear relations between the logarithm of Ksat and pbulk also were explored for comparison.

  19. Air China conducts first biofuel test flight

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Air China became the first Chinese carrier to conduct a demonstration flight powered in part by biofuel, indicating the alternative energy's possible use in future commercial flights in China. The Beijing-based airline company, also China's flag carrier,

  20. Dynamic effects of wet-dry cycles and crust formation on the saturated hydraulic conductivity of surface soils in the constructed Hühnerwasser ("Chicken Creek") catchment

    Science.gov (United States)

    Hinz, Christoph; Schümberg, Sabine; Kubitz, Anita; Frank, Franzi; Cheng, Zhang; Nanu Frechen, Tobias; Pohle, Ina

    2016-04-01

    Highly disturbed soils and substrates used in land rehabilitation undergo rapid changes after the first wetting events which in turn can lead to ecosystem degradation. Such changes were detected during the early development of the constructed Hühnerwasser ("Chicken Creek") catchment in Lusatia, Germany. Surface substrates consisting of quaternary sandy sediments formed surface seals during the first rainfall events leading to reduced infiltration and substantially increased surface runoff. Subsequently biological soil crusts formed and stabilised the surface. The aim of this study is to investigate the factors that cause the hydraulic conductivity to decrease using undisturbed and disturbed soil samples. Based on the hypothesis that physical and biological crusts lower the hydraulic conductivity, the first set of experiments with undisturbed soil cores from the Hühnerwasser catchment were carried out to measure the saturated hydraulic conductivity using the constant head method. Measurements were done with intact cores and repeated after the surface crust was removed. As the quaternary glacial sediments tend to display hard setting behaviour, we further hypothesised that the mobilisation of fine particles within the cores lead to pore clogging and that wet-dry cycles will therefore decrease hydraulic conductivity. A second set of experiments using the same methodology consisted of five repeated measurements of hydraulic conductivity after each drying cycle. These measurements were done with undisturbed core samples as well as repacked cores in order to assess how dry packing affects the dynamics of the hydraulic conductivity somewhat similar to the situation during the first wetting after completion of the catchment construction. For all experiments, the temporal evolution of hydraulic conductivity was measured and the turbidity of the effluent was recorded. The results clearly demonstrated that the substrate is highly unstable. The first set of experiments

  1. Scaling analysis of the thermal-hydraulic test facility for the large break LOCA of KNGR

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Byong Jo; Kwon, Tae Soon; Song, Chul Hwa; Euh, Dong Jin; Chu, In Cheol; Cho, Hyoung Kyu; Park, Jong Kyun

    2001-03-01

    Korea Next Generation Reactor(KNGR) adopts a Direct Vessel Injection (DVI) system instead of conventional Cold Leg Injection (CLI) system. In this report, a scaling analysis for the steam-water test facility of KNGR with DVI under reflood phase of Loss of Coolant Accident(LBLOCA) is carried out. The major objectives of the test facility are to clarify the thermal hydraulics phenomena in the upper downcomer region and to provide experimental data for evaluating or validating relevant thermal hydraulic models and correlations of the best estimate codes. The test facility should be designed based on the appropriate scaling law so that the same thermal hydraulics phenomena is happened as in the case of prototype. For these, the investigations of previous scaling laws are carried out. And, in the present study, a new scaling approach, named the modified linear scaling, is developed for the design of a scaled-down experimental facility. Its velocity is scaled by a Wallis-type parameter and an aspect ratio of experimental facility is preserved with that of a prototype. The test facility is designed primarily by a volume scaling law and the area ratio of test facility is set to be 1/24.3. However, additional DVI nozzles are also installed at the elevation which is determined by the modified linear scaling law. It is for the scaling analysis of ECC bypass fraction. The cold leg, hot leg and DVI nozzles are additionally attached in the upper annulus downcomer region so that the UPTF counterpart test is possible.

  2. TRAC-PF1/MOD1 thermal-hydraulic predictions of JAERI Slab Core Test Facility gravity-feed tests

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, J.S.; Lin, J.C.

    1985-12-01

    The Transient Reactor Analysis Code, TRAC-PF1/MOD1, was used to analyze the Slab Core Test Facility gravity-feed tests (Runs 604, 605, 611, and 613) performed by the Japan Atomic Energy Research Institute. The objectives of the TRAC analysis are to compare the TRAC predictions with the test results and to assess the TRAC capability for simulating the core thermal-hydraulic behavior during the reflood phase of a large loss-of-coolant accident. In general, the TRAC-calculated results agree well with the data.

  3. Measurement of leaf hydraulic conductance and stomatal conductance and their responses to irradiance and dehydration using the Evaporative Flux Method (EFM).

    Science.gov (United States)

    Sack, Lawren; Scoffoni, Christine

    2012-12-31

    Water is a key resource, and the plant water transport system sets limits on maximum growth and drought tolerance. When plants open their stomata to achieve a high stomatal conductance (gs) to capture CO2 for photosynthesis, water is lost by transpiration(1,2). Water evaporating from the airspaces is replaced from cell walls, in turn drawing water from the xylem of leaf veins, in turn drawing from xylem in the stems and roots. As water is pulled through the system, it experiences hydraulic resistance, creating tension throughout the system and a low leaf water potential (Ψ(leaf)). The leaf itself is a critical bottleneck in the whole plant system, accounting for on average 30% of the plant hydraulic resistance(3). Leaf hydraulic conductance (K(leaf) = 1/ leaf hydraulic resistance) is the ratio of the water flow rate to the water potential gradient across the leaf, and summarizes the behavior of a complex system: water moves through the petiole and through several orders of veins, exits into the bundle sheath and passes through or around mesophyll cells before evaporating into the airspace and being transpired from the stomata. K(leaf) is of strong interest as an important physiological trait to compare species, quantifying the effectiveness of the leaf structure and physiology for water transport, and a key variable to investigate for its relationship to variation in structure (e.g., in leaf venation architecture) and its impacts on photosynthetic gas exchange. Further, K(leaf) responds strongly to the internal and external leaf environment(3). K(leaf) can increase dramatically with irradiance apparently due to changes in the expression and activation of aquaporins, the proteins involved in water transport through membranes(4), and K(leaf) declines strongly during drought, due to cavitation and/or collapse of xylem conduits, and/or loss of permeability in the extra-xylem tissues due to mesophyll and bundle sheath cell shrinkage or aquaporin deactivation(5

  4. A safety vs efficiency trade-off identified in the hydraulic pathway of grass leaves is decoupled from photosynthesis, stomatal conductance and precipitation.

    Science.gov (United States)

    Ocheltree, Troy W; Nippert, Jesse B; Prasad, P V Vara

    2016-04-01

    A common theme in plant physiological research is the trade-off between stress tolerance and growth; an example of this trade-off at the tissue level is the safety vs efficiency hypothesis, which suggests that plants with the greatest resistance to hydraulic failure should have low maximum hydraulic conductance. Here, we quantified the leaf-level drought tolerance of nine C4 grasses as the leaf water potential at which plants lost 50% (P50 × RR ) of maximum leaf hydraulic conductance (Ksat ), and compared this trait with other leaf-level and whole-plant functions. We found a clear trade-off between Ksat and P50 × RR when Ksat was normalized by leaf area and mass (P = 0.05 and 0.01, respectively). However, no trade-off existed between P50 × RR and gas-exchange rates; rather, there was a positive relationship between P50 × RR and photosynthesis (P = 0.08). P50 × RR was not correlated with species distributions based on precipitation (P = 0.70), but was correlated with temperature during the wettest quarter of the year (P hydraulic system of grass leaves, which can be decoupled from other leaf-level functions. The unique physiology of C4 plants and adaptations to pulse-driven systems may provide mechanisms that could decouple hydraulic conductance from other plant functions.

  5. An Analytical Solution of Hydraulic Head due to an Oscillatory Pumping Test in a Confined, Unconfined or Leaky Aquifer

    Science.gov (United States)

    Huang, C. S.; Yeh, H. D.

    2014-12-01

    This study builds a mathematical model for three-dimensional (3D) transient hydraulic head induced by an oscillatory pumping test in a confined, unconfined or leaky aquifer. The aquifers are of a rectangular shape where the four sides are under the Robin conditions. The 3D flow governing equation with a line sink term representing a vertical well is employed. The sink term has a cosine function for the oscillatory pumping. A general equation describing the head on the top of the three kinds of aquifers is considered. The analytical head solution of the model is derived by the direct Fourier method and the double-integral transform and in terms of a double series with fast convergence. With the aid of the solution, we have found that the vertical component of flow vanishes when Kv d2/(KhD2) > 1 where Kh and Kv are aquifer's hydraulic conductivities, respectively, D is aquifer's thickness, and d is a distance measured from the pumping well. Under the condition, temporal head distributions predicted by the present solution agree with those predicted by solutions developed based on two-dimensional flow by most previous researches.

  6. Thermal-hydraulic analysis of the semiscale Mod-1 blowdown heat transfer test series. [PWR

    Energy Technology Data Exchange (ETDEWEB)

    Cozzuol, J.M.

    1976-06-01

    Selected experimental thermal-hydraulic data from the recent Semiscale Mod-1 blowdown heat transfer test series are analyzed from an experimental viewpoint with emphasis on explaining those phenomena which influence core fluid behavior. Comparisons are made between the trends measured by the system instrumentation and the trends predicted by the RELAP4 computer code to aid in obtaining an understanding of the interactions between phenomena occurring in different parts of the system. The analyses presented in this report are valuable for evaluating the adequacy and improving the predictive capability of analytical models developed to predict the system response of a pressurized water reactor during a postulated loss-of-coolant accident (LOCA).

  7. Comparison of Hydraulic Conductivity Determinations in Co-located Conventional and Direct-Push Monitoring Wells

    Science.gov (United States)

    2011-03-08

    was redeveloped in an attempt to obtain use- able slug-test data. Development was done by manually surging and purg- ing the well in a manner that...was consistent with industry practices as giv- en by ASTM D5521 and by Kraemer et al. (2006). An inertial-lift pump was used to surge and purge the...sediments were deposited during the presence of a glacial lake (Lake Hitchcock) that formed when melt water from a retreating glacier was dammed by a mo

  8. Specifications for a coupled neutronics thermal-hydraulics SFR test case

    Science.gov (United States)

    Tassone, A.; Smirnov, A. D.; Tikhomirov, G. V.

    2017-01-01

    Coupling neutronics/thermal-hydraulics calculations for the design of nuclear reactors are a growing trend in the scientific community. This approach allows to properly represent the mutual feedbacks between the neutronic distribution and the thermal-hydraulics properties of the materials composing the reactor, details which are often lost when separate analysis are performed. In this work, a test case for a generation IV sodium-cooled fast reactor (SFR), based on the ASTRID concept developed by CEA, is proposed. Two sub-assemblies (SA) characterized by different fuel enrichment and layout are considered. Specifications for the test case are provided including geometrical data, material compositions, thermo-physical properties and coupling scheme details. Serpent and ANSYS-CFX are used as reference in the description of suitable inputs for the performing of the benchmark, but the use of other code combinations for the purpose of validation of the results is encouraged. The expected outcome of the test case are the axial distribution of volumetric power generation term (q‴), density and temperature for the fuel, the cladding and the coolant.

  9. Use of Ground-water Temperature Patterns to Determine the Hydraulic Conductance of the Streambed Along the Middle Reaches of the Russian River, CA

    Science.gov (United States)

    Su, G. W.; Constantz, J.; Jasperse, J.; Seymour, D.

    2002-12-01

    Along the Russian River in Sonoma County, the alluvial aquifer is the preferred source of drinking water because sediments and other constituents in the river water would require additional treatment. From late spring to early winter, an inflatable dam is erected to raise the river stage and passively recharge the alluvial aquifer. The raised stage also permits diversion of river water to a series of recharge ponds located near the dam along the river. Improved understanding of stream exchanges with ground water is needed to better manage available water resources. Heat is used as a tracer of shallow ground-water movement for detailed hydraulic parameter estimation along the middle reaches of the river. Water-levels and ground-water temperatures were measured in a series of observations wells and compared to the river stage and surface-water temperatures. Hydraulic conductivities were predicted by optimizing simulated ground-water temperatures using VS2DHI, a heat and water transport model, to observed temperatures in the aquifer. These conductivity values will be used in a stream/ground-water model of this region being developed using MODFLOW. Temperature-based estimates of streambed conductance will be inserted in the STREAM package of the model to constrain this parameter. Although temperature-based predictions of hydraulic conductivity vary significantly along the reach, the results generally suggest that an anisotropy of 5 to 1 (horizontal to vertical) provides the best hydraulic conductivity matches for predicted versus observed ground-water temperatures.

  10. Effects of branch height on leaf gas exchange, branch hydraulic conductance and branch sap flux in open-grown ponderosa pine.

    Science.gov (United States)

    Hubbard, Robert M; Bond, Barbara J; Senock, Randy S; Ryan, Michael G

    2002-06-01

    Recent studies have shown that stomata respond to changes in hydraulic conductance of the flow path from soil to leaf. In open-grown tall trees, branches of different heights may have different hydraulic conductances because of differences in path length and growth. We determined if leaf gas exchange, branch sap flux, leaf specific hydraulic conductance, foliar carbon isotope composition (delta13C) and ratios of leaf area to sapwood area within branches were dependent on branch height (10 and 25 m) within the crowns of four open-grown ponderosa pine (Pinus ponderosa Laws.) trees. We found no difference in leaf gas exchange or leaf specific hydraulic conductance from soil to leaf between the upper and lower canopy of our study trees. Branch sap flux per unit leaf area and per unit sapwood area did not differ between the 10- and 25-m canopy positions; however, branch sap flux per unit sapwood area at the 25-m position had consistently lower values. Branches at the 25-m canopy position had lower leaf to sapwood area ratios (0.17 m2 cm-2) compared with branches at the 10-m position (0.27 m2 cm-2) (P = 0.03). Leaf specific conductance of branches in the upper crown did not differ from that in the lower crown. Other studies at our site indicate lower hydraulic conductance, sap flux, whole-tree canopy conductance and photosynthesis in old trees compared with young trees. This study suggests that height alone may not explain these differences.

  11. Stochastic inverse modelling of hydraulic conductivity fields taking into account independent stochastic structures: A 3D case study

    Science.gov (United States)

    Llopis-Albert, C.; Capilla, J. E.

    2010-09-01

    SummaryMajor factors affecting groundwater flow through fractured rocks include the geometry of each fracture, its properties and the fracture-network connectivity together with the porosity and conductivity of the rock matrix. When modelling fractured rocks this is translated into attaining a characterization of the hydraulic conductivity ( K) as adequately as possible, despite its high heterogeneity. This links with the main goal of this paper, which is to present an improvement of a stochastic inverse model, named as Gradual Conditioning (GC) method, to better characterise K in a fractured rock medium by considering different K stochastic structures, belonging to independent K statistical populations (SP) of fracture families and the rock matrix, each one with its own statistical properties. The new methodology is carried out by applying independent deformations to each SP during the conditioning process for constraining stochastic simulations to data. This allows that the statistical properties of each SPs tend to be preserved during the iterative optimization process. It is worthwhile mentioning that so far, no other stochastic inverse modelling technique, with the whole capabilities implemented in the GC method, is able to work with a domain covered by several different stochastic structures taking into account the independence of different populations. The GC method is based on a procedure that gradually changes an initial K field, which is conditioned only to K data, to approximate the reproduction of other types of information, i.e., piezometric head and solute concentration data. The approach is applied to the Äspö Hard Rock Laboratory (HRL) in Sweden, where, since the middle nineties, many experiments have been carried out to increase confidence in alternative radionuclide transport modelling approaches. Because the description of fracture locations and the distribution of hydrodynamic parameters within them are not accurate enough, we address the

  12. Research on Simulation and Test of the Nonlinear Responses for the Hydraulic Shock Absorber

    Institute of Scientific and Technical Information of China (English)

    张建武; 刘延庆

    2003-01-01

    Basically on the multi-body system dynamics,the virtual prototype of the hydraulic shock absorber for the bench test is developed in the ADAMS environment.Dynamic behaviors of the absorber are studied by both computer simulation and real test.Numerical predictions of dynamic responses are produced by the established virtual prototype of the absorber and compared with experimental results.It has been shown from the comparison that the vibration behaviors of the prototype with hysteretic damping characteristics are considered to be more identical with the bench test results than those of the same prototype with piecewise linear damping properties are.The current virtual prototype of the shock absorber is correct and can be a developing terrace for the optimizing design of the absorber and matching capability of the whole car.

  13. Geological and hydrogeological conditions of the Aigion seismic active fault zone (Deep Geodynamic Laboratory Corinth) based on borehole data and hydraulic tests

    Science.gov (United States)

    Rettenmaier, D.; Giurgea, V.; Pizzino, L.; Unkel, I.; Hoetzl, H.; Foerster, A.; Quattrocchi, F.; Nikas, K.

    2003-04-01

    The Gulf of Corinth and the northern part of the Peloponnesus/Greece, an area of asymmetric graben structure, step faults and tilted blocks, is one of the most active seismic zones in the world. Six major faults are known to be most responsible for the historic and present seismic activities in the area of Aigion. Our study focuses preliminarily on the area around the Aigion fault, whose trace runs E-W through the harbour of Aigion. Investigations of the stratigraphic sequence, tectonic structure and hydrogeologic conditions of the southern Corinth graben shoulder and first drilling activities there, have started in summer 2001. From July until September 2002 the International Continental Deep Drilling Project (ICDP) and the EU Project DGLab-Gulf of Corinth drilled the AIG10 borehole in the harbour of Aigion to a total depth of 1001 m. Our investigations in this ICDP/EU framework are aimed at studying the thermal-hydraulic conditions on the southern graben shoulder. Here we report the first results on sampling and hydraulic testing. The deep AIG10 borehole has successfully cored in approx. 760 m depth the fault plane, which separates fractured radiolarite in the hanging wall from highly fractured and karstified platy, micritic limestone (Olonos-Pindos Unit) in the footwall. A complete lithologic section is now available through the monitoring of cuttings and cores, which built a major cornerstone for defining an integrated regional tectonic and geologic model. Several pumping tests and hydrochemical investigations made in the region of Aigion and especially in the AIG10 borehole deliver together with geophysical borehole logging the database for a thermo-hydraulic heat flow model. The pumping test AIG10C in the conglomerates of the graben sediments show a hydraulic conductivity of about 2 x 10E-5 m/s - 3 x 10E-4 m/s at a depth of approximately 211 m. The result was a residual drawdown, which indicates a closed hydraulic system between the semi-permeable Aigion

  14. Thermal-Hydraulic Issues in the ITER Toroidal Field Model Coil (TFMC) Test and Analysis

    Science.gov (United States)

    Zanino, R.; Bagnasco, M.; Fillunger, H.; Heller, R.; Savoldi Richard, L.; Suesser, M.; Zahn, G.

    2004-06-01

    The International Thermonuclear Experimental Reactor (ITER) Toroidal Field Model Coil (TFMC) was tested in the Toska facility of Forschungszentrum Karlsruhe during 2001 (standalone) and 2002 (in the background magnetic field of