evaluating the hydraulic conductivity at three different scales within an unconfined sand aquifer at lachenaie quebec this paper presents the evaluation of scale effects for the hydraulic conductivity k of a sand data were obtained using several methods at a site that was densely instrumented with piezometers within an area of about 100 m 100 m the 3 1 3 6 m thick sand deposit rests on a thick nonfissured champlain sea clay deposit at the small scale local k values were obtained from the grain size curves of sand samples and also from ground penetrating radar surveys at the intermediate scale k values were obtained from field variable head tests using piezometers at the large scale k values were obtained from pumping test drawdowns in steady state conditions in this sand aquifer the careful evaluations at three scales gave similar narrow distributions for the hydraulic conductivity and therefore no scale effect is evidenced key words hydraulic conductivity sand scale effect gradation monitoring well pumping

extraction of uranium and thorium from swiss granites and their microdistribution 2 microdistribution of uranium and thorium abstract this work is concerned with the extraction at the laboratory level of uranium and thorium from swiss granites the mittagfluh bergell and rotondo granites and the giuv syenite offered a wide range of u and th concentrations 7 7 20 0 ppm u and 25 5 67 0 ppm th u and th were determined in leachates by the fission track method and by spectrophotometry respectively samples containing g u and 4 g th could be measured with an accuracy of 10 for u and 5 for th leaching experiments were performed during which the following parameters were varied granite type grain size acid type acid concentration temperature and time there were large leaching differences between the granites studied grain size caused no great variation the extracted percentages of u and th were practically the same for any particular rock with either 12 coarse or 71 fine of the grain size finer than 0 125 mm the leached fraction with h 2 so 4 was somewhat smaller than with hcl or hno 3 the difference in leaching with 2 5 and 10 m hcl was negligible temperature was the most important parameter sharp differences in extraction occurred between 20 50 and 80 c at 80 c more than 85 of the u and th were extracted the extraction curve percent extracted as a function of time of aliquots sampled after 1 2 4 8 12 and 24 hr showed a plateau after 8 hr as a general rule th was more easily extracted than u the granites investigated showed widely different u and th leachability 13 75 u 32 75 th upon treatment of rock powder in 5 m hcl at 20 c for 24 hr a separate study was devoted to relate these differences to peculiarities in the u and th microdistribution in these rocks part 2

bedform spurs a result of a trailing helical vortex wake the formative conditions for bedform spurs and their roles in bedform dynamics and associated sediment transport are described herein bedform spurs are formed by helical vortices that trail from the lee surface of oblique segments of bedform crestlines trailing helical vortices quickly route sediment away from the lee surface of their parent bedform scouring troughs and placing this bed material into the body of the spur the geometric configuration of bedform spurs to their parent bedform crests is predicted by a cross stream strouhal number when present spur bearing bedforms and their associated trailing helical wakes exert tremendous control on bedform morphology by routing enhanced sediment transport between adjacent bedforms field measurements collected at the north loup river nebraska and flume experiments described by venditti et al 2005a 2005b 2005c demonstrate that this trailing helical vortex mediated sediment transport is a mechanism for bedform deformation interactions and transitions between two dimensional and three dimensional bedforms this article is protected by copyright all rights reserved

comparison of three hydraulic property measurement methods hydraulic functions of soils may differ depending on the different measuring methods used the performance of three different methods for measuring soil hydraulic properties of a heterogeneous field were evaluated the experiments were conducted using three different sizes of undisturbed soil cores collected systematically along a 31 m long transect of a well drained sandy loam soil having three soil horizons ap 0 0 25 m c1 0 25 0 55 m c2 0 55 1 00 m the laboratory studies involved 1 detailed unsteady drainage flux experiments performed on fifteen columns of 1 m length and 0 3 m diameter 2 combined crust test and hot air methods applied to thirty columns of 0 2 m length and 0 2 m diameter and to a subset of sixty cylinders of 0 1 m length and 0 045 m diameter respectively taken from the ap horizon and 3 desorption experiments carried out on a total of one hundred eighty cores of 0 051 m length and 0 05 m diameter collected evenly from the three horizons mean soil hydraulic properties were inferred from experimental data characterizing either selected depths or the soil profile as a whole the results revealed considerable differences among estimated mean soil properties as obtained with different measuring techniques although the application of scaling theory substantially reduced variation in the measured pressure heads h and conductivities k the results revealed that scaling parameters determined from soil pressure head were not identical to scaling factors determined from hydraulic conductivity the results also show that k scaling factors in general were much more variable than h scaling factors and that the observed variability in scaling factors also depend upon the measurement technique used c 1997 elsevier science b v

morphodynamics of small scale superimposed sand waves over migrating dune bed forms 1 the kinematics and morphodynamics of low amplitude small scale sand waves developed over migrating dunes are examined using data drawn from laboratory experiments we refer to the superimposed features as sand sheets a general descriptive term for low amplitude bed waves that are not easily classified as ripples dunes or bars within the experiments the sheets formed downstream of the reattachment point at a distance that was invariant with dune size some sheets lacked slip faces composed of sand grains avalanching down a slope near the angle of repose over equilibrium dunes three to four sand sheets were observed per 100 s sheet thickness was 10 of the height of the dune upon which they were superimposed they migrated at 8 to 10 times the dune rate they had nearly constant lengths over the full range of dune lengths and flow conditions and they had aspect ratios of 0 025 dunes and sand sheets represent distinct scales of sediment transport with different migration rates however sediment transport rates calculated from the sand sheet and dune morphologies are nearly identical for transport equivalence to occur sand sheets migrating at 10 times the dune rate must be 0 1 times the size which is consistent with the morphological observations superimposed bed waves on dunes are often considered simply as additional roughness elements but these results indicate that such bed waves are the agency by which the dune bed form itself moves downstream

multiscale solute transport upscaling for a three dimensional hierarchical porous medium a laboratory generated hierarchical fully heterogeneous aquifer model fhm provides a reference for developing and testing an upscaling approach that integrates large scale connectivity mapping with flow and transport modeling based on the fhm three hydrostratigraphic models hsms that capture lithological static connectivity at different resolutions are created each corresponding to a sedimentary hierarchy under increasing system lnk variances 0 1 1 0 4 5 flow upscaling is first conducted to calculate equivalent hydraulic conductivity for individual connectivity or unit of the hsms given the computed flow fields an instantaneous conservative tracer test is simulated by all models for the hsms two upscaling formulations are tested based on the advection dispersion equation ade implementing space versus time dependent macrodispersivity comparing flow and transport predictions of the hsms against those of the reference model hsms capturing connectivity at increasing resolutions are more accurate although upscaling errors increase with system variance results suggest 1 by explicitly modeling connectivity an enhanced degree of freedom in representing dispersion can improve the ade based upscaled models by capturing non fickian transport of the fhm 2 when connectivity is sufficiently resolved the type of data conditioning used to model transport becomes less critical data conditioning however is influenced by the prediction goal 3 when aquifer is weakly to moderately heterogeneous the upscaled models adequately capture the transport simulation of the fhm despite the existence of hierarchical heterogeneity at smaller scales when aquifer is strongly heterogeneous the upscaled models become less accurate because lithological connectivity cannot adequately capture preferential flows 4 three dimensional transport connectivities of the hierarchical aquifer differ quantitatively from those analyzed for two dimensional systems

geometry and kinematics of dunes during steady and unsteady flows in the calamus river nebraska usa the geometry and kinematics of river dunes were studied in a reach of the calamus river nebraska during day long surveys dune height length steepness migration rate creation and destruction were measured concurrently with bedload transport rate flow depth flow velocity and bed shear stress within a survey individual dune heights lengths and migration rates were highly variable associated with their three dimensional geometry and changes in their shape through time notwithstanding this variability there were discernible changes in mean dune height length and migration rate in response to changing discharge over several days changes in mean dune height and length lagged only slightly behind changes in discharge therefore during periods of both steady and unsteady flow mean dune lengths were quite close to equilibrium values predicted by theoretical models mean dune steepnesses were also similar to predicted equilibrium values except during high falling flows when the steepness was above that predicted variations in mean dune height and length with discharge are similar to those predicted by theory under conditions of low mean dune excursion and discharge variation with a short high water period and long low water period however the calculated rates of change of height of individual dunes vary considerably from those measured rates of dune creation and destruction were unrelated to discharge variations contrary to previous results instead creations and destructions were apparently the result of local variations in bed shear stress and sediment transport rate observed changes in dune height during unsteady flows agree with theory fairly well at low bed shear stresses but not at higher bed shear stresses when suspended sediment transport is significant

morphology and flow fields of three dimensional dunes rio parana argentina results from simultaneous multibeam echo sounding and acoustic doppler current profiling 1 most past studies of river dune dynamics have concentrated on two dimensional 2 d bed forms with constant heights and straight crest lines transverse to the flow and their associated turbulent flow structure this morphological simplification imposes inherent limitations on the interpretation and understanding of dune form and flow dynamics in natural channels where dune form is predominantly three dimensional for example studies over 2 d forms neglect the significant influence that lateral flows and secondary circulation may have on the flow structure and thus dune morphology this paper details a field study of a swath of 3 d dunes in the rio parana argentina a large 0 35 km wide 1 2 km long area of dunes was surveyed using a multibeam echo sounder mbes that provided high resolution 3 d detail of the river bed simultaneous with the mbes survey 3 d flow information was obtained with an acoustic doppler current profiler adcp revealing a complicated pattern of dune morphology and associated flow structure within the swath dune three dimensionality appears intimately connected to the morphology of the upstream dune with changes in crest line curvature and crest line bifurcations junctions significantly influencing the downstream dune form dunes with lobe or saddle shaped crest lines were found to have larger more structured regions of vertical velocity with smaller separation zones than more 2 d straight crested dunes these results represent the first integrated study of 3 d dune form and mean flow structure from the field and show several similarities to recent laboratory models of flow over 3 d dunes

variability in bedform morphology and kinematics with transport stage bedform geometry is widely recognized to be a function of transport stage bedform aspect ratio height length increases with transport stage reaches a maximum then decreases as bedforms washout to a plane bed bedform migration rates are also linked to bedform geometry in so far as smaller bedforms in coarser sediment tend to migrate faster than larger bedforms in finer sediment however how bedform morphology height length and shape and kinematics translation and deformation change with transport stage and suspension have not been examined a series of experiments is presented where initial flow depth and grain size were held constant and the transport stage was varied to produce bedload dominated mixed load dominated and suspended load dominated conditions the results show that the commonly observed pattern in bedform aspect ratio occurs because bedform height increases then decreases with transport stage against a continuously increasing bedform length bedform size variability increased with transport stage leading to less uniform bedform fields at higher transport stage total translation related and deformation related sediment fluxes all increased with transport stage however the relative contribution to the total flux changed at the bedload dominated stage translation related and deformation related flux contributed equally to the total flux as the transport stage increased the fraction of the total load contributed by translation increased and the fraction contributed by deformation declined because the bedforms got bigger and moved faster at the suspended load dominated transport stage the deformation flux increased and the translation flux decreased as a fraction of the total load approaching one and zero respectively as bedforms washed out to a plane bed

flow and sediment suspension events over low angle dunes fraser estuary canada 1 the morphodynamics of large sand bedded rivers and estuaries are ultimately controlled by the way bed material is moved and the development of large subaqueous sand dunes that control hydraulic flow resistance it is widely thought that the primary mechanism for moving sandy bed material in these channels is large scale coherent flow structures that cause suspension events whose properties vary with flow especially in tidally influenced environments here we examine mean flow and sediment suspension events over low angle dunes lee face angle 30 in the unsteady flow of the fraser estuary canada at high tide flow nearly ceased and a salt wedge entered the channel forcing salt water under the downstream moving fresh water the salt wedge persisted in the channel until late in the falling tide causing stratification in the water column and instabilities along the saline fresh water interface at low tide mean velocities peaked and forced the saline water out of the channel flow over the low angle dunes displayed topographically induced patterns previously observed over high angle dunes but permanent flow separation was not observed large scale sediment suspension events dominated sediment flux during low tide and became larger scale yet less frequent as the tide began to rise the suspension events appeared to form over the lower stoss of the dunes and grew up over the bed forms and less commonly emerged downstream of the crest suspension events move 69 of the total sediment in the flow above low angle dunes when they are present

geostatistical analysis of aquifer heterogeneity from the core scale to the basin scale a case study this study examines the spatial variability of conductivity within the sandstone wabiskaw member of the lower cretaceous middle mannville in the alberta basin the wabiskaw is an important regional hydrostratigraphic unit vertical variability within the aquifer is characterized by downhole variograms of log conductivity from core measurements they are found to exhibit pseudoperiodic structures due to alternating sand and shale layers horizontal spatial variability is characterized using variograms of log transmissivity and indicator data these variograms show a steady increase in spatial variability over length scales ranging from 400 m to 100 km characteristic of self similar or fractal behavior they also reveal distinct correlation structures related to both high and low transmissivity depositional features this study also considers the upscaling of conductivity vertically from the core to the well scale and horizontally from the well to the basin scale it is shown that traditional vertical upscaling of conductivities by arithmetic averaging causes an overestimation of transmissivity in two dimensional areal flow models an alternative approach based on power averaging is proposed transmissivities derived by vertical upscaling of core measurements are compared with values derived from drill stem tests in the same well no correlation between these quantities is observed an average transmissivity for the wabiskaw in the study area is determined by geometric spatial averaging however the highly clustered spatial distribution of well locations requires a weighting of sample values using ordinary kriging

response of low angle dunes to variable flow current understanding of bedform dynamics is largely based on field and laboratory observations of bedforms in steady flow environments there are relatively few investigations of bedforms in flows dominated by unsteadiness associated with rapidly changing flows or tides as a consequence the ability to predict bedform response to variable flow is rudimentary using high resolution multibeam bathymetric data this study explores the dynamics of a dune field developed by tidally modulated fluvially dominated flow in the fraser river estuary british columbia canada the dunes were dominantly low lee angle features characteristic of large deep river channels data were collected over a field ca 1 0 km long and 0 5 km wide through a complete diurnal tidal cycle during the rising limb of the hydrograph immediately prior to peak freshet yielding the most comprehensive characterization of low angle dunes ever reported the data show that bedform height and lee angle slope respond to variable flow by declining as the tide ebbs then increasing as the tide rises and the flow velocities decrease bedform lengths do not appear to respond to the changes in velocity caused by the tides changes in the bedform height and lee angle have a counterclockwise hysteresis with mean flow velocity indicating that changes in the bedform geometry lag changes in the flow the data reveal that lee angle slope responds directly to suspended sediment concentration supporting previous speculation that low angle dune morphology is maintained by erosion of the dune stoss and crest at high flow and deposition of that material in the dune trough

relationships between the petrophysical properties density seismic velocity heat generation and mineralogical constitution the petrophysical properties density p compressional wave velocity v p and heat generation a exhibit considerable variation with rock type to characterize a given rock quantitatively a single parameter the cation fraction expressed by the k value has been found to be suited best 100 crystalline rocks have been sampled to cover the widest possible range in k value from silicic types like granophyres and granites through granodiorites tonalites diorites gabbros amphibolites hornblendites pyroxenites to ultrabasic rocks p k a and v p were determined experimentally the latter at 0 5 kbar 50 mpa the interrelations between these properties were established by regression analysis the relation k and v p k show a linear dependence whereas a k a and a v p follow exponential laws in a w m 3 12 20 230 5 k mole cm 3 in a 22 5 8 15 g cm 3 and in a 16 5 2 74 v p km s all correlation coefficients are better than 0 9

thorium and uranium contents of gneisses and trondhjemites in the western dharwar craton india widespread metasomatic addition of u has apparently occurred in archean tonalitic trondhjemitic gray gneisses in the western dharwar craton of southern india gneisses of 3200 3000 ma age near the holenarasipur schist belt contain average concentrations of about 10 ppm th and 3 5 ppm u the u is considerably more abundant than average u 1 5 ppm in archean gray gneisses of the superior province of the canadian shield and consequently the th u ratios are low in the indian gneisses comparatively massive trondhjemitic plutons associated with a 3000 ma event in the dharwar craton are very depleted in both th and u and we propose that the metasomatism of the gneisses occurred while the plutons were being emplaced and were expelling fluids from the magmas there is no evidence for metasomatism 2500 ma ago the age of extensive granulite metamorphism in southern india

bed form initiation from a flat sand bed 1 bed form initiation in unidirectional flow is examined on a flat bed composed of a homogeneous 0 5 mm sand velocity profiles taken prior to bed form development indicate that the examined flows are typical of fully turbulent uniform open channel flows under these conditions two separate modes of bed form initiation are observed defect and instantaneous initiation defect initiation occurs at lower flow stages where sediment transport is sporadic and patchy and is characterized by defect propagation associated with flow separation instantaneous initiation occurs at larger flow strengths where sediment transport is general and widespread this form of bed form initiation begins with the imprinting of a cross hatch pattern on the flat sediment bed which leads to chevron shaped forms that migrate independently of the initial pattern the chevrons eventually align to form incipient crest lines this mode of bed form initiation does not appear to be linked to turbulent structures but integral scales derived from velocity measurements prior to bed form development are similar to the initial bed form length scales

pattern analysis of dune field parameters as a basic form of pattern analysis the parameters of dune spacing defect density crest orientation and crest length are measured from remote images and treated statistically for dunes at white sands in new mexico the algodones in california the agneitir in mauritania and the namib in namibia statistical populations are identified from frequency plots of dune spacing and crest length field scale calculations of defect density and rose diagrams of crest orientation single populations characterize simple dune fields white sands whereas multiple populations characterize compound complex dunes algodones namib and complex dune fields agneitir as time increases dune fields show an increase in dune spacing and crest length a decrease in defect density more tightly clustered crest orientation and a reduction in the variance associated with measurements of these parameters the results are consistent with models of dune fields as self organizing complex systems in which a characteristic pattern emerges as a function of constructional time because pattern evolution is a function of time it may be possible to use pattern analysis to augment current methods of age determination statistically defined populations can be used in geomorphic backstripping to unstack generations of simple patterns that give rise to complex patterns and to reconstruct each generation in terms of construction time and palaeo wind regime copyright 2006 john wiley sons ltd

calculation of in situ acoustic sediment attenuation using off the shelf horizontal adcps in low concentration settings the use of off the shelf acoustic doppler velocity profilers adcps to estimate suspended sediment concentration and grain size in rivers requires robust methods to estimate sound attenuation by suspended sediment theoretical estimates of sediment attenuation require a priori knowledge of the concentration and grain size distribution gsd making the method impractical to apply in routine monitoring programs in situ methods use acoustic backscatter profile slope to estimate sediment attenuation and are a more attractive option however the performance of in situ sediment attenuation methods has not been extensively compared to theoretical methods we used three collocated horizontally mounted adcps in the fraser river at mission british columbia and 298 observations of concentration and gsd along the acoustic beams to calculate theoretical and in situ sediment attenuation conversion of acoustic intensity from counts to decibels is influenced by the instrument noise floor which affects the backscatter profile shape and therefore in situ attenuation we develop a method that converts counts to decibels to maximize profile length which is useful in rivers where cross channel acoustic profile penetration is a fraction of total channel width nevertheless the agreement between theoretical and in situ attenuation is poor at low concentrations because cross stream gradients in concentration sediment size or gsd can develop which affect the backscatter profiles we establish threshold concentrations below which in situ attenuation is unreliable in fraser river our results call for careful examination of cross stream changes in suspended sediment characteristics and acoustic profiles across a range of flows before in situ attenuation methods are applied in river monitoring programs

comment on laboratory evaluation of a hydrodynamic inverse modeling method based on water content data by s lambot f hupet m javaux and m vanclooster

three dimensional structure characterisation and transient flow modelling of a variably saturated heterogeneous monolith in this study we investigate the possibility of modelling the transient hydraulic behaviour of an undisturbed monolithic subsoil sample of 0 5 m 3 based on a detailed characterisation of the soil structure at the larger scale the subsoil core structure is defined by the presence of discontinuous clay and a stone layer within a large sandy matrix a second structural level is characterised by the spatial distribution of hydraulic properties in the sandy matrix and described using the vogel similarity concept vogel t cislerova m hopmans j w 1991 porous media with linearly variable hydraulic properties water resources research 27 2735 2741 this exhaustive structural information is subsequently implemented into a 3 d transient and variably saturated flow model simulation results are compared with experimental observations and it is showed that the presence of a discontinuous clay and stone layer is sensitive in predicting effective outflow given the fact that no calibration is performed we consider that the outflow predictions are good the results are however disappointing for the prediction of time series of pressure head moreover the local scale kat had to be scaled based on structural and hydraulic monolith scale observations this study points out that i it would be necessary to characterise the continuity of flow and related parameters such as the hydraulic conductivity at the appropriate scale to adequately simulate variable saturated transient flow at that scale and ii a smaller spacing in the sub sampling would be needed to property predict local scale time series c 2006 elsevier b v all rights reserved

gamma ray spectrometry in the field radioactive heat production in the central slovakian volcanic zone we report 62 sets of measurements from central southern slovakia obtained using a modern portable gamma ray spectrometer which reveal the radioactive heat production in intrusive and extrusive igneous rocks of the late cenozoic central slovakian volcanic zone sites in granodiorite of the stiavnica pluton are thus shown to have heat production in the range 2 2 4 9 w m 3 this variability being primarily a reflection of variations in content of the trace element uranium sites in dioritic parts of this pluton have a lower but overlapping range of values 2 1 4 4 w m 3 sites that have been interpreted in adjoining minor dioritic intrusions of similar age have heat production in the range 1 4 3 3 w m 3 the main stiavnica pluton has zoned composition with potassium and uranium content and radioactive heat production typically increasing inward from its margins reflecting variations observed in other granodioritic plutons elsewhere it is indeed possible that the adjoining dioritic rocks hitherto assigned to other minor intrusions of similar age located around the periphery of the stiavnica pluton in reality provide further evidence for zonation of the same pluton the vicinity of this pluton is associated with surface heat flow 40 mw m 2 above the regional background on the basis of our heat production measurements we thus infer that the pluton has a substantial vertical extent our preferred estimate for the scale depth for its downward decrease in radioactive heat production being 8 km nonetheless this pluton lacks any significant negative bouguer gravity anomaly we attribute this to the effect of the surrounding volcanic caldera filled with relatively low density lavas masking the pluton s own gravity anomaly we envisage that emplacement occurred when the pluton was much hotter and thus of lower density than at present its continued uplift evident from the local geomorphology being the isostatic consequence of localized erosion the heat production in this intrusion evidently plays a significant role hitherto unrecognized in the regional geothermics

delineating hydrological response units by geographical information system analyses for regional hydrological modelling using prms mms in the drainage basin of the river brol germany a modified concept of hydrological response units hrus for regional modelling of river basins using the prms mms model is presented the hrus are delineated by geographical information system gis analysis from physiographic basin properties such as topography soils geology rainfall and land use using a thorough hydrological systems analysis the hrus once classified by gis analysis preserve the three dimensional heterogeneity of the drainage basin the river brol basin a 216km 2 rheinisches schiefergebirge germany was selected to apply the concept in total 23 hrus were delineated and tested with the prms mms model using a 20 year hydrometeorological daily database the hydrological systems analysis revealed that interflow is the dominant flow process through the basin s slopes and the major contribution to groundwater recharge and river runoff this was accounted for by parameterizing the hrus in the model control file to drain their surplus water not used for satisfying the demand of evapotranspiration to a common conceptual subsurface storage this storage was simulated by interflow drainage to the groundwater aquifer in the valley floor which in turn drained to the channel network the prms mms model simulated the observed daily discharge very well and the fit was described by a daily correlation coefficient of r 0 91 the nasim and hspf models using different means to represent the basin s physiographic heterogeneity were applied to the brol basin as well but did not achieve this correlation the hru concept was found to be a reliable method for regional hydrological basin modelling and allows spatial up and downscaling future research on this concept will focus on incorporating the variable precipitation distribution into the classification of hrus and on the hydrodynamic routing of the modelled discharge additionally satellite imagery must be used for classifying land use in macroscale drainage basins

influence of defects on sorted bedform dynamics 1 bedforms with plan view patterns consisting of long crests interrupted by defects occur ubiquitously in subaqueous and subaerial environments where they strongly influence flows and sediment transport we explore how such patterns adjust to changes in the external forcing we utilize a numerical model of a wide spread large scale seabed pattern sorted bedforms examining their response to changes in wave forcing numerical experiments show that the pattern adjustment progresses through two stages characterized by defect propagation and defect creation respectively and that the rates of the initial stage and therefore overall pattern adjustment are determined by the initial defect density all characteristics of the sorted bedforms are similarly influenced by the presence of defects although the processes of growth are likely to be different for other types of bedforms it is reasonable to expect they will be similarly influenced by defects in pre existing patterns

hydrological and hydrochemical processes observed during a large scale infiltration experiment at the super sauze mudslide france rainfall is one of the major triggering factors of landslides and its pattern controls their temporal behaviour characterization of the groundwater processes and possible preferential infiltration of rainfall is necessary challenging and very relevant for landslide hazard analysis the objective of this paper is to identify the groundwater dynamics matrix flow and preferential flow within highly heterogeneous and fissured reworked black marl material using a large scale infiltration test the artificial rainfall experiment over a 100 m2 infiltration plot monitored with several hydrological hydrochemical and geophysical equipments was carried out on the super sauze mudslide south french alps high resolution groundwater and water quality measurements were collected artificial rainfall was applied over a period of 14 days conservative tracers br and cl were used successively during the infiltration period the mean rainfall intensity was 8 5 mm h 1 with a mean tracer concentration of 100 mg l 1 the hydrodynamic and hydrochemical responses of the tracing experiments allowed us to get a new insight into 1 the horizontal and vertical variability of the rain infiltration in unstable black marl hillslopes 2 the effect of shallow fissuration on the groundwater recharge 3 the role of piston flow on the rate of water level changes and the increase of pore water pressures and 4 the effect of material heterogeneity in the development of preferential water flows and local perched water tables copyright 2011 john wiley sons ltd

saturated hydraulic conductivity and soil water retention properties across a soil slope transition the hydraulic properties of soil and their spatial structures are important for understanding soil moisture dynamics land surface and subsurface hydrology and contaminant transport we investigated whether landscape features including relative position on a slope contribute to the variability of soil hydraulic properties in a complex terrain of a glacial till material using 396 undisturbed soil cores collected along two orthogonal transects we measured saturated hydraulic conductivity ksat and soil water retention functions at two 15 and 30 cm depths across a glacial till landscape in central iowa that encompassed two soil types nicollet loam with 1 3 slope on the hilltop position and clarion loam with 2 5 slope on the shoulder position the van genuchten mualem model was fitted to the experimental data using the retc optimization computer code at the 15 cm depth a statistical comparison indicated significant differences in ksat saturated water content us water content at permanent wilting point u15 000 and van genuchten fitting parameters a and n between soil types and landscape positions at the 30 cm depth us u15 000 and residual water content ur were found to be significantly different across the soil slope transition available water content u333 15 000 did not show any significant difference across the soil slope transition for either depth no clear directional trend was observed with some exceptions for k sat us and a on specific transect limbs and depths drifts in the soil hydraulic parameters due to soil slope transition were removed using a mean polishing approach geostatistical analyses of these parameters showed several important characteristics including the following 1 the spatial correlation lengths and semivariogram patterns of the independently measured or estimated loge ksat and us at 30 cm depth matched extremely well 2 better spatial structures with large correlation lengths were observed for macro and micro porosity related loge ksat us and loge a than for texture related loge u333 15 000 loge u15 000 ur and loge n at 30 cm depth and 3 a higher nugget effect at 15 cm depth was evident for most soil hydraulic parameters indicating tillage and other surface disturbances these novel findings may prove to be critical for modeling and interpreting field scale or larger scale soil moisture dynamics surface and subsurface flow and solute transport

upscaling capillary pressure saturation curves in heterogeneous porous media numerical models of flow in the vadose zone require capillary pressure saturation relationships for the grid blocks discretizing the medium however the scale of these grid blocks is generally much larger than the sample scale at which capillary pressure saturation relationships are measured this study investigates the upscaling of capillary curves under static conditions of capillary gravity equilibrium the averaging regions are horizontal layers parallel to the phreatic surface as in one dimensional models of infiltration at the point or sample scale it is assumed that all capillary curves can be normalized using the leverett 1941 approach to a common dimensionless form described by the corey brooks model static water saturation at any point in the medium is then expressed as a parametric function of three regionalized variables permeability porosity and irreducible water saturation water saturations at the layer scale are obtained by spatial averaging of point scale values with certain assumptions it is shown that the nondimensional relationship between capillary pressure and saturation at the layer scale is the same as at the sample scale in general the nondimensional scaling of layer averaged capillary pressure requires exhaustive knowledge of the spatial distribution of the permeability porosity ratio within the averaging region however when permeability and porosity are jointly lognormal this spatial distribution may be approximated by a lognormal model requiring only two parameters for each averaging region the developments are illustrated using published field data from the apache leap tuff site exact and estimated upscaled capillary curves are compared in simulated coregionalized fields of permeability porosity and irreducible water saturations results show that the upscaled capillary pressure saturation curves accurately reproduce the vertical saturation profile obtained by exhaustive spatial averaging of point scale water saturations

dunes and associated sand transport in a tidally influenced sand bed channel fraser river british columbia dunes form annually on the sand bed of the tidally influenced south arm of fraser river british columbia bathymetric surveys along the center of the main channel throughout a snow melt freshet provided measurements of dune geometry and migration dune length height and steepness all increase with river discharge however lag between the highest flow conditions and development of the largest steepest dunes reflects the influence of antecedent flow conditions on dune geometry population averages of dune height and steepness ratio change more rapidly than dune length whilst coefficients of variation of dune height length and steepness ratio indicate high variability in dune geometry within the estuarine reach during periods of dune growth and decay unlike dune geometry dune migration rates display little lag with flow conditions the largest coefficients of variation for dune migration occur during periods of rapid change in discharge and tidal fall corresponding to the onset of rapid change in

scale dependency of the hydraulic properties of a variably saturated heterogeneous sandy subsoil the effective hydraulic behaviour of heterogeneous sand was experimentally investigated at two scales under transient flow upper boundary conditions at the monoliths scale one dimensional inverse modelling was performed from a transient infiltration experiment by implementing in the objective function the outflow and pressure head time series at four depths notwithstanding the important heterogeneity of the subsoil principally due to the presence of discontinuous clay and a stone layer we observed that the effective behaviour was surprisingly well reproduced it was also observed that the structural features mainly induced a kind of hysteresis between the saturation and drainage cycles of the outflow time series subsequently 104 kopecky cores 100 cm 3 were sub sampled throughout the monolith mainly in the sandy matrix the variability of local hydraulic parameters was investigated by optimising the local hydraulic parameters from mufti step outflow experiments and measured retention points the comparison between 1 d optimised measured and kopecky averaged retention curves showed relatively similar shape near saturation in contrast to this important discrepancies existed between averaged local scale hydraulic conductivity and effective hydraulic conductivity close to saturation different experimental designs at different scales may explain the observed discrepancies it is further suggested that the monolith scale effective hydraulic functions are more representative for wet soil conditions this case study illustrates the complexity of finding validated scaling relationships for the hydraulic properties of heterogeneous soils at scales larger than the usual small column scale c 2005 elsevier b v all rights reserved

spatial variability of soil hydraulic conductivity along a tropical rainforest catena abstract we investigate the spatial variability of saturated hydraulic conductivity ksat along a tropical rainforest catena which consists of a typic kandiudult latossolo vermelho distrofico argissolico and plinthic hapludox latossolo amarelo distrofico tipico the former soil type extends from midslope to interfluve and has a high clay content throughout the profile whereas the latter soil type extends from the midslope to valley bottom and only has a high clay content at depths 90 cm we measured ksat along a transect at depths of 20 30 50 and 90 cm with a compact constant head permeameter ksat is not significantly different 0 10 between these soil types at any depth except for 90 cm ordinary and robust linear regression models with distance from the interfluve as in the independent variable showed no significant change in ksat as a function of topography loess regression showed some dependency of ksat on topography only at the 90 cm depth semivariograms showed no apparent spatial structure in ksat at distances 25 m for all depths we conclude that the strong topography dependence of soil types along this catena and hence primary soil attributes is not reflected in a similar dependence of ksat and tentatively attribute this lack of dependence to the overriding influence of bioturbation controlled macroporosity we outline a framework for detecting possible ksat topography relationships based on the distinction between bioturbation controlled nonstructural macroporosity and mineralogy controlled structural macroporosity

case study bed resistance of rhine river during 1998 flood detailed field measurements during the 1998 flood of the rhine river in the netherlands show that both manning in and darcy weisbach friction factor if increase with discharge the changes in bedform roughness height and friction factors are attributed to the increased dune height during floods there is a near peak hysteresis in the dune height measurements at a given discharge dunes are significantly larger after than before the peak discharge the trend is most apparent for the bovenrijn with weaker variations for the waal the methods of engelund and vanoni hwang provide similar estimates of form drag when combined with van rijn s method to estimate grain resistance both methods tend to overpredict the measured bed friction factor after the peak discharge these methods perform best when field bedform measurements are available to estimate form drag the composite effect of primary and secondary dunes should be considered in the analysis of resistance to flow

heat generating radioelements in granitic magmas abstract spatial variation trends of the radioelements u th and k in granitic units show distinct regularities zonation patterns of u and th at fairly constant k contents are common in individual granitic bodies it is shown that radioelement abundance and distribution result from a combined migration diffusion process in the fluid phase during and after solidification of the granite magma the process is mainly governed by pressure and temperature gradients as well as by chemical potentials model calculations yield numerical values for the intrinsic diffusion coefficient 10 4 cm 2 s and migration velocity 0 2 2 cm s which are in agreement with laboratory experiments on comparable systems the process distributing the radioelements is of limited duration it is also clearly related to the cooling history of the granite analogies to the overall distribution of crustal radioactivity are discussed

scale dependency in spatial patterns of saturated hydraulic conductivity this study investigates spatial patterns of ks and tests the hypothesis of whether structural variance emerges from noise with increasing sampling precision we analyzed point measurements of ks along independent transects at sampling intervals of 25 10 1 and 0 25 m the field area is a tropical rainforest catena i e toposequence characterized by systematic downslope changes in soil properties including color red to yellow mineralogy kaolinite illite to kaolinite and texture sandy clay to sand independent transects spanning the entire catena at lag intervals of 25 and 10 m reveal little to no spatial patterns in ks i e scatter plots are noisy and lack apparent spatial trends and semivariograms suggest little to no autocorrelation in ks as sampling precision is increased h 1 and 0 25 m spatial patterns emerge in ks for the downslope areas in which distinctive hydraulic boundaries in ks correlate with relatively small scale topography controlled soils with coarse textures 80 sand for these areas semivariograms of ks and those of sand and clay exhibit similar spatial structure characterized by small nugget variances and large ranges and nugget variance is reduced as sampling precision increases from 1 to 0 25 m in the upslope clay rich locations along this toposequence ks exhibits few spatial patterns irrespective of sampling scale for these locations scatter plots are noisy without apparent spatial trends and semivariograms show almost complete nugget variance suggesting little to no correlation in this hydraulic parameter at any scale this study suggests that in the absence of coarse textures 80 sand there is little predictability in ks even at sampling intervals of 0 25 m we believe this lack of spatial structure is due to a predominance of small scale processes such as biological activity that largely control ks in this forested setting

bed form development based upon the results of a series of 47 bed development experiments the evolution of bed features subsequent to their initial generation from flat bed conditions is examined for each such experiment bed profiles were measured at frequent time intervals as sand wave configurations developed under the action of open channel water flow the two sediments used for these experiments were of geometric mean size 0 20 mm and 0 82 mm respectively in line with the bed form unification model of bed development postulated by saudkivi and witte in 1990 the principle of bed form propagation speed decreasing with increasing bed form height and the mechanisms of bed form coalescence and bed form throughpassing are all found to be central to bed evolution processes a quantitative relation between bed form speed and bed form height is presented bed development predictions based upon bed form unification models can be seen to clearly parallel the present experimental results stability analyses based upon potential

moving through scales of flow and transport in soil flow and transport in soil is governed by the binary geometry of solid and void this may be described at typical length scales of some millimeters and even less in contrast the problems which are supposed to be solved in soil physics are related to a scale of some meters the typical distance between soil surface and groundwater a quantitative understanding of flow and transport based on measurements of hydraulic properties and transport parameter at a given scale requires the transfer of information in space time and across scales this is the major challenge in heterogeneous soils and this has motivated many concepts for the organization of heterogeneities including macroscopic homogeneity discrete hierarchy and fractal geometry we propose a conceptual approach termed the scaleway to predict flow and transport in structured materials whatever the scale and whatever the specific type of structural organization this is based on the explicit consideration of structure that is assumed to be present at the scale of interest while the microscopic heterogeneities are replaced by averaged effective descriptions the three ingredients needed are a representation of the structure a process model at the scale of interest and corresponding effective material properties we demonstrate the scaleway for one example of solute transport in a soil column and discuss implications for future research

bedform migration and bed load transport in some rivers and tidal environments reliable field data obtained by directly measuring bed load transport of fine to coarse grained bed material are extremely scarce mainly because of the difficulty of sampling accurately therefore the verification of bed load transport formulae is largely based on flume experiments which refer to unrealistic shallow water conditions in this study some bed load transport formulae were tested against data from natural environments as an alternative to ascertaining the bed load transport rate by sampling the bed load the transport rate was deduced from data on bedform height and bedform celerity for this purpose 43 sets of data from rivers representing a wide range of bed material bedform dimensions and hydraulic conditions were collected as were some sets of data from tidal settings two formulae were used for the prediction of the bed load transport the formula of van rijn 1981 and the kalinske 1947 formula as approximated by elzerman frijlink 1951 and in the present study slightly modified for application to tidal waters both the bed load function of van rijn and the modified formula of kalinske frijlink require data which are easily obtained and that can be measured accurately at those stages of the flow when bed load transport was high the van rijn function tended to overestimate that transport for flow stages when bed load transport was low the opposite was true the modified kalinske frijlink function gave consistently good results 86 of the transport rates predicted using the river data were within 0 5 2 0 times the values actually measured

bar and dune development during a freshet fraser river estuary british columbia canada bi weekly multi track sonar surveys collected along a 2 km reach of the estuarine south arm of the fraser river british columbia canada during seasonal high flows document the initiation development and interaction of dune and bar morphologies bedforms of several scales developed in well delineated fields bedforms that appear to fit accepted equilibrium depth scaling developed in the main channel during rising discharge when there was little local aggradation during the rising stage a bar also formed along the tidal shelf of the channel migrated downstream and expanded into the main channel dunes that formed along the bar crest a region of rapid deposition lagged flow conditions and were larger than expected based on depth scaling relations the larger dunes developed simultaneously although bar growth lagged dune development and was initially partially obscured by the more rapidly developing dune field it appears that rapid deposition enhances dune development along the channel tidal shelf to dimensions larger than would be expected by simple depth scaling rules smaller dunes that fit equilibrium depth scaling relations re established themselves throughout the study area during falling discharge when there was again little or no aggradation bed material transport rates estimated from the migration rates of the large dunes suggest that at high flows the dunes transport the majority of the material found within the bar

a comparative review of upscaling methods for solute transport in heterogeneous porous media the classical fickian model for solute transport in porous media cannot correctly predict the spreading the dispersion of contaminant plumes in a heterogeneous subsurface unless its structure is completely characterized although the required precision is outside the reach of current field characterization methods the advection dispersion model remains the most widely used model among practitioners two approaches can be adopted to solve the effect of physical heterogeneity on transport first based on a given characterization of the spatial structure of the subsurface upscaling methods allow the computation of apparent scale dependent parameters especially longitudinal dispersivity to be used in the classical fickian model in the second approach upscaled non fickian transport equations with scale independent parameters are used in this paper efforts are made to classify and review upscaling methods for fickian transport parameters and non fickian upscaled transport equations for solute transport with an emphasis on their mathematical properties and their one dimensional analytical formulations in particular their capacity to mode scale effects in apparent longitudinal dispersion is investigated upscaling methods and upscaled models are illustrated in the case of two three dimensional synthetic aquifers with lognormal hydraulic conductivity distributions characterized by variance values of 2 and 8 c 2008 etsevier b v all rights reserved

on the transition between 2d and 3d dunes sediment transport in sand bedded alluvial channels is strongly conditioned by bedforms the planimetric morphology of which can be either two or threedimensional experiments were undertaken to examine the processes that transform the bed configuration from two dimensional 2d dunes to threedimensional 3d dunes a narrowly graded 500 lm size sand was subjected to a 0ae15 m deep non varying mean flow ranging from 0ae30 to 0ae55 m sec 1 in a 1 m wide flume changes in the planimetric configuration of the bed were monitored using a high resolution video camera that produced a series of 10 sec time lapsed digital images image analysis was used to define a critical value of the non dimensional span sinuosity of the bedform crestlines that divides 2d forms from 3d forms significant variation in the non dimensional span is observed that cannot be linked to properties of the flow or bedforms and thus appears random images also reveal that once 2d bedforms are established minor transient excesses or deficiencies of sand are passed from one bedform to another the bedform field appears capable of absorbing a small number of such defects but as the number grows with time the resulting morphological perturbations produce a transition in bed state to 3d forms that continue to evolve but are pattern stable the 3d pattern is maintained by the constant rearrangement of crestlines through lobe extension and starving downstream bedforms of sediment which leads to bifurcation the experiments demonstrate that 2d bedforms are not stable in this calibre sand and call into question the reliability of bedform phase diagrams that use crestline shape as a discriminator

large scale natural gradient tracer test in sand and gravel cape cod massachusetts 3 hydraulic conductivity variability and calculated macrodispersivities hydraulic conductivity k variability in a sand and gravel aquifer on cape cod massachusetts was measured and subsequently used in stochastic transport theories to estimate macrodispersivities nearly 1500 k measurements were obtained by borehole flowmeter tests and permeameter analyses of cores the geometric mean for the flowmeter tests 0 11 cm s is similar to that estimated from other field tests the mean for the permeameter tests 0 035 cm s is significantly lower possibly because of compaction of the cores the variance for the flowmeter 0 24 is also greater than that for the permeameter 0 14 geostatistical analyses applying negative exponential models with and without nuggets reveal similar spatial correlation structures for the two data sets estimated correlation scales range from 2 9 to 8 m in the horizontal and from 0 18 to 0 38 m in the vertical estimates of asymptotic longitudinal dispersivity b 35 0 78 m are similar in magnitude to that observed in the natural gradient tracer test 0 96 m previously conducted at this site

eolian dunes computer simulations and attractor interpretation a simple computer simulation algorithm for the transport of sand by wind produces forms resembling barchan crescentic ridge linear and star natural dune classes sand is moved as slabs composed of many grains that are picked up at random transported in a specified direction and deposited 1 with a probability that depends on the local presence or absence of sand or 2 in shadow zones in the lee of dunes the simulated dune fields are interpreted as complex systems with sand dune classes being dynamical attractors of these systems the evolution of dunes once formed becomes decoupled from the details of eolian sand transport

radioelement distribution in the tertiary lundy granite bristol channel uk the radioelement distribution and content of the lundy granite a coarse grained megacrystic granite of tertiary age has been measured using a portable gamma ray spectrometer in order to assess fractionation and alteration processes in the granite results indicate a systematic variation of k th and u with a few notable exceptions that follows a partially concentric distribution to lower concentrations inland the plateau region of the island particularly the southern half is relatively depleted in all radioelements over the island measurements of k vary from 1 3 4 9 wt th varies from 5 0 20 3 ppm and u varies from 2 0 12 5 ppm a petrographic electron microprobe and autoradiography examination of the granite indicates that the radioelements mainly reside in discrete major and accessory minerals of which k feldspar k biotite k monazite th xenotime u tungsteniferous columbite u and uraninite u are the most important uraninite is rare being preserved only in fresh samples which come mainly from abandoned quarries mass balance modelling indicates that up to 76 6 of uranium could reside in uraninite and where this has been leached by secondary processes such as hydrothermal alteration or weathering then the present radioelement content no longer reflects the original rock composition fission track evidence is presented to show the pathways along which uranium has been mobilized from or within the granite secondary sites of radioelements include fractures cross cutting all major minerals but especially quartz grain boundaries altered cores of plagioclase feldspar and occasionally yellowy brown mixed chlorite smectite replacement product after biotite biotite itself may exhibit secondary tracks along cleavage traces combined effects of crystal fractionation primary variation and secondary alteration best explain the distribution of radioelements with k controlled by fractionation of the major phases k feldspar and biotite th by fractionation of the accessory mineral monazite xenotime and uraninite and u contents by uraninite and tungsteniferous columbite secondary processes have removed much of the uraninite leaving behind indeterminate fe u material along fractures and residual u and th enrichment within altered major minerals there is some evidence to suggest that late radioelement bearing fluids precipitated monazite and uraniferous zircon along fractures during the waning stages of magmatic activity

on the entrainment of sediment and initiation of bed defects insights from recent developments within turbulent boundary layer research sediment entrainment and the initiation of bed defects has commonly been ascribed to the impact of high velocity sweeps upon mobile sand beds results of visualization experiments suggest that these sweep impacts are grouped and may define patches of entrainment upon a mobile bed that may be wider than an individual sweep impact additionally the presence of longitudinal ribs of sediment generated by sweep impacts may stabilize the position of sweeps and low speed streaks these observations are interpreted in the light of recent boundary layer research which suggests the formation of multiple hairpin shaped vortices within turbulent flows these are postulated to generate multiple sweeps that manifest themselves as entrainment patches on a mobile bed these features of the turbulent boundary layer and its modification by sweep generated sediment ridges can be used to propose a model for bed defect formation and the subsequent development of current ripples

nature of deformation of sandy bed forms 1 we explore a stochastic component of topographic evolution of sandy river beds and its relationship to bed material flux the behavior of trains of mobile bed forms can be decomposed into two independent constituents translation and deformation translation is the mean downstream migration of the bed at velocity that defines the lagrangian reference frame of the bed deformation is the sum of all changes to the bed s topographic profile measured from within the bed s moving reference frame the occurrence of deformation leads to exponential decorrelation of bed topography that is in dynamic equilibrium with flow conditions for the field and laboratory data sets used correlation decays to 0 5 by the time the bed translates 40 and 360 of the mean bed form length respectively proportions of bed material flux responsible for translation and deformation can be straightforwardly calculated translation flux is measured using the traditional bed form bed load equation deformation flux is determined by excess topographic change scaled by the ratio of horizontal sediment velocity to fall velocity deformation represents the sediment exchanged between bed load and suspended load because deformation is a stochastic process with zero mean the apparent rate of deformation decreases as a function of time interval between bed surveys for the field case deformation accounts for 40 of bed material flux while it is only 1 of the flux in the laboratory