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  • 1.
    Carstens, Christoffer
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    In the Pipe or End of Pipe?: Transport and Dispersion of Water-borne Pollutants and Feasibility of Abatement Measures2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Eutrophication is one of the key environmental problems of today, both in terms of complexity and magnitude. For the Baltic Sea (BS), eutrophication is an acute problem, leading to hypoxic conditions at the bottom; a situation that is sustained and amplified, when phosphorus is released from hypoxic sediments. Reducing nutrient loading is a top political priority but the present situation is believed to require active measures within the catchments and recipients to reduce both loading and adverse effects. Implementation of effective and cost-efficient abatement methods requires understanding of natural processes in watersheds, streams and recipients as well as technological expertise in order to compare the effects of measures of different kinds and locations. This thesis tries to combine process understanding of catchment transport behaviour, especially in coastal zones, and feasibility of certain technologies for reducing nutrient loading and effects of eutrophication in-situ. The over-arching theme is the fate of the individual contaminant, from injection to removal. Transport and dispersion in catchments are investigated, combining physically-based, distributed, numerical groundwater models with Lagrangian stochastic advective reactive solute (LaSAR) transport modelling. The approach is powerful in the sense that it incorporates catchment structural, geomorphological dispersion in the numerical model with hydrodynamic and sub-scale dispersion as well as uncertainty in the LaSAR framework. The study exemplifies the complex nature of transport time distributions in catchments in general and when varying source size and location, importance of dispersion parameters and retention due to molecular diffusion. It is shown that geomorphological control on dispersion is present even for relatively heterogeneous systems and that neither the mean residence time nor a statistical distribution may provide accurate representations of hydrological systems. To combat internal loading of P from sediments in-situ, large-scale aeration of deep waters, halocline ventilation, has been suggested. This study further investigates the feasibility of wave-powered devices to meet the energy demands for such an operation. It is shown that the required amount of oxygen needed to keep the sediments at oxic conditions could be provided, cheaply and efficiently, through the use of wave power.

  • 2.
    Carstens, Christoffer
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Hydrological dispersion in a coastal catchmentArticle in journal (Other academic)
  • 3.
    Carstens, Christoffer
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Destouni, Georgia
    Stockholm University.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Wave-power potentialfor reducing hypoxia in the Baltic SeaArticle in journal (Other academic)
  • 4.
    Cheng, Hua
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Evaluation of Colloid Transport Experiments in a Quarried Block2009In: SCIENTIFIC BASIS FOR NUCLEAR WASTE MANAGEMENT XXXII / [ed] Hyatt NC; Pickett DA; Rebak RB, 2009, Vol. 1124, p. 519-524Conference paper (Refereed)
    Abstract [en]

    Colloid tracer experiments were performed in a single, heterogeneous fracture contained in a quarried block (QB) under the configuration of dipole tracer tests. The experiments were first performed using bentonite and 100 nm latex colloids, as well as conservative tracer iodide and bromide, under conditions of different flow rates in order to identify the flow rates that favour colloid transport. The tracer experiments were later expanded to include experiments with different colloid sizes and longer transport distances. The aims of the present study are to identify the processes that affect colloid transport in the QB fracture and to estimate the retention parameters for the different sized colloids. We model the measured breakthrough curves (BTCs) using an advection-retention approach. The key feature of the advection-retention model is that advective transport and retention processes are related in a dynamic manner through the flow equation. Two Lagrangian random variables, tau and beta, that depend solely on flow conditions, control the retention processes. Here tau is the nonreactive travel time and beta is related to tau but also depends on the local aperture value. We assume the water residence time distribution g(tau) to be inverse-gaussian. The first two moments of g(tau) were obtained by calibrating the measured BTCs of conservative tracers. We then model the colloid BTCs using g(tau) and take into account the retention processes. The modelling results indicate that dominating retention processes include first-order linear kinetic attachment/detachment on the fracture surface, and mass loss (removal) by filtration/sedimentation. Diffusion into the rock matrix is of a much lesser importance.

  • 5.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    A general memory function for modeling mass transfer in groundwater transport2012In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 48, p. W04528-Article in journal (Refereed)
    Abstract [en]

    A power-law extension of the gamma distribution is proposed as a general memory function for capturing rate limitations of retention in groundwater transport. Using moments, we show how the new memory function can be reduced to most other forms available in the literature, exactly or approximately. The proposed formulation is suitable for field scale or laboratory scale transport modeling. Rate limitation effects are illustrated for solute transport by considering the fractional mass release over a given transport scale. The equilibrium and no-retention cases set bounds for contaminant attenuation, between which the impact of rate limitations is clearly exposed.

  • 6.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Diffusion-controlled tracer retention in crystalline rock on the field scale2010In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 37, p. L13401-Article in journal (Refereed)
    Abstract [en]

    Tracer retention is a key process for the barrier function of crystalline rock to any contaminant. Here we investigate the nature of retention mechanisms and their field-scale parametrization using results of a comprehensive tracer transport experiment in crystalline rock on the field scale (Aspo Hard Rock Laboratory, Sweden). A method for identifying dominant retention mechanisms and inferring key parameters on the site scale is presented. Taking advantage of multiple tracer tests with a wide range of sorption affinities, retention is shown to be diffusion-controlled. For the considered site, robust features of tracer migration can be reasonably well predicted within a rock volume on at least 200 m scale, by combining independent information with a simple model.

  • 7.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Significance of fracture rim zone heterogeneity for tracer transport in crystalline rock2010In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 46, no 3, p. W03504-Article in journal (Refereed)
    Abstract [en]

    Conducting fractures of crystalline rock are typically altered over long periods of time. The fracture rim zone, a result of these alterations, will as a rule have different physical and chemical properties from the unaltered ("fresh'') rock, depending on various microscopic and macroscopic factors of the alterations. In this paper, we study the impact of rim zone heterogeneity, exemplified by a decreasing porosity trend as inferred from the Aspo Hard Rock Laboratory site (Sweden), on short- and long-term tracer transport. Our main finding is that this particular rim zone structure will have a dominant effect on transport of moderately to strongly sorbing tracers on experimental time scales and a notable effect on application time scales. The findings of this work lend further support to the interpretation of the relatively strong retention reported by Cvetkovic et al. The fracture rim zone porosity structure may provide an additional safety margin for sorbing radionuclides in crystalline rock at sites where fracture alteration is prevalent.

  • 8.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    The tempered one-sided stable density: a universal model for hydrological transport?2011In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 6, no 3, p. 034008-Article in journal (Refereed)
    Abstract [en]

    A generalized distribution for the water residence time in hydrological transport is proposed in the form of the tempered one-sided stable (TOSS) density. It is shown that limiting cases of the TOSS distribution recover virtually all distributions that have been considered in the literature for hydrological transport, from plug flow to flow reactor, the advection-dispersion model, and the gamma and Levy densities. The stable property of TOSS is particularly important, enabling a seamless transition between a time-domain random walk, and the Lagrangian (trajectory) approach along hydrological transport pathways.

  • 9.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Tracer attenuation in groundwater2011In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 47, no 12, p. W12541-Article in journal (Refereed)
    Abstract [en]

    The self-purifying capacity of aquifers strongly depends on the attenuation of waterborne contaminants, i.e.,irreversible loss of contaminant mass on a given scale as a result of coupled transport and transformation processes. A general formulation of tracer attenuation in groundwater is presented. Basic sensitivities of attenuation to macrodispersion and retention are illustrated for a few typical retention mechanisms. Tracer recovery is suggested as an experimental proxy for attenuation. Unique experimental data of tracer recovery in crystalline rock compare favorably with the theoretical model that is based on diffusion-controlled retention. Non-Fickian hydrodynamic transport has potentially a large impact on field-scale attenuation of dissolved contaminants.

  • 10.
    Cvetkovic, Vladimir
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Carstens, Christoffer
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Selroos, Jan-Olof
    Destouni, Georgia
    Water and solute transport along hydrological pathways2012In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 48, no 6, p. W06537-Article in journal (Refereed)
    Abstract [en]

    A Lagrangian framework for material transport along hydrological pathways is presented and consequences of statistically stationary space-time flow velocity variations on advective transport are investigated. The two specific questions addressed in this work are: How do temporal fluctuations affect forward and backward water travel time distributions when combined with spatial variability? and Can mass transfer processes be quantified using conditional probabilities in spatially and temporally variable flow? Space-time trajectories are studied for generic conditions of flow, with fully ergodic or only spatially ergodic velocity. It is shown that forward and backward distributions of advective water travel time coincide for statistically stationary space-time variations. Temporal variability alters the statistical structure of the Lagrangian velocity fluctuations. Once this is accounted for, integration of the memory function with the travel time distribution is applicable for quantifying retention. Further work is needed to better understand the statistical structure of space-time velocity variability in hydrological transport, as well as its impact on tracer retention and attenuation.

  • 11.
    Cvetkovic, Vladimir
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Cheng, H.
    Byegard, J.
    Winberg, A.
    Tullborg, E. -L
    Widestrand, H.
    Transport and retention from single to multiple fractures in crystalline rock at Aspo (Sweden): 1. Evaluation of tracer test results and sensitivity analysis2010In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 46, p. W05505-Article in journal (Refereed)
    Abstract [en]

    We evaluate the breakthrough curves obtained within a comprehensive experimental program for investigating the retention properties of crystalline rock, referred to as Tracer Retention Understanding Experiments (TRUE). The tracer tests were conducted at the Aspo Hard Rock Laboratory (Sweden) in two phases jointly referred to as TRUE Block Scale (TBS); the TBS tests comprise a total of 17 breakthrough curves with nonsorbing and a range of sorbing tracers. The Euclidian length scales are between 10 and 30 m, compared to 5 m for the earlier tests TRUE-1. The unlimited diffusion model is consistent with measured breakthrough curves and is adopted here for evaluation. The model has four independent parameters, two of which are related to advection and dispersion, one which is related to diffusion-sorption, and one which is related to surface sorption; the individual retention parameters or properties cannot be inferred from breakthrough curves alone and require additional constraints. The mean water residence times for the TBS tests are in the range 15-250 h, whereas the coefficient of variation of the water residence times is in the range 0.4-0.6. A consistent trend is found in the calibrated retention parameters with the sorption affinities of the tracers involved. Using Bode sensitivity functions, it is shown that sensitivity increases for the retention parameter with increasing sorption affinity; for nonsorbing tracers, diffusion and hydrodynamic dispersion are shown to "compete," exhibiting similar effects; hence, their estimates are uncertain. The analysis presented here exposes a few fundamental limitations and sensitivities when evaluating diffusion-controlled retention in the subsurface; it is general and applicable to any site with comparable tracer test data. In part 2, it will be shown how discrete fracture network simulations based on the hydrostructural information available can be used for further constraining individual retention parameters, in particular, the active specific surface area (s(f)) and the rock matrix porosity (theta).

  • 12.
    Cvetkovic, Vladimir
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Cheng, Hua
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Evaluation of single-well injection-withdrawal tests in Swedish crystalline rock using the Lagrangian travel time approach2011In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 47, p. W02527-Article in journal (Refereed)
    Abstract [en]

    A series of 10 single-well injection-withdrawal (SWIW) tests are evaluated with two tracers each: uranine and cesium (Cs). An evaluation tool for SWIW tests in crystalline rock is presented on the basis of the Lagrangian travel time approach, whereby probabilities of tracer particle residence times are computed for key stages of the test cycle. Calibration results for three transport parameters and each breakthrough curve are presented. We show that estimates of the controlling retention parameter group psi [1/root T] are robust for Cs but highly uncertain for uranine. The estimated retention for Cs is larger for the Laxemar-Simpevarp site compared to the Forsmark site. Deviations from the -3/2 asymptotic breakthrough curve slope observed in a few of the tests at Forsmark are possibly due to a thin fracture coating that has been identified in mineralogical studies at some locations of the site.

  • 13.
    Cvetkovic, Vladimir
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Cheng, Hua
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Sorbing tracer experiments in a crystalline rock fracture at Aspo (Sweden): 3. Effect of microscale heterogeneity2008In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 44, no 12Article in journal (Refereed)
    Abstract [en]

    We study the impact of microscale (10(-3) -10(-2) m) heterogeneity in material and structural properties on sorbing tracer transport in a single crystalline fracture of the TRUE-1 tests (mesoscale, 5 m) at Aspo (Sweden). The analysis is based on the microscale characterization results as presented in part 1 of this series. Our main objective in this last part of the series is to provide an independent interpretation (or "prediction'') of the effective parameters as estimated from calibration in part 2 by combining the data presented in part 1 with analytical and numerical transport modeling. We show here that the independent information from microscopic characterization can be used for "predicting'' the effective diffusion time t(d) reasonably well; a discrepancy is to be expected given the uncertainties of microscale retention properties, in particular of the sorption coefficient.

  • 14.
    Cvetkovic, Vladimir
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Cheng, Hua
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Widestrand, H.
    Byegard, J.
    Winberg, A.
    Andersson, P.
    Sorbing tracer experiments in a crystalline rock fracture at Aspo (Sweden): 2. Transport model and effective parameter estimation2007In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 43, no 11Article in journal (Refereed)
    Abstract [en]

    [1] Transport and retention of sorbing tracers in a single, altered crystalline rock fracture on a 5 m scale is investigated. We evaluate the results of a comprehensive field study ( referred to as Tracer Retention Understanding Experiments, first phase ( TRUE- 1)), at a 400 m depth of the Aspo Hard Rock Laboratory ( Sweden). A total of 16 breakthrough curves are analyzed, from three test configurations using six radioactive tracers with a broad range of sorption properties. A transport- retention model is proposed, and its applicability is assessed based on available data. We find that the conventional model with an asymptotic power law slope of - 3/ 2 ( one- dimensional diffusion into an unlimited rock matrix) is a reasonable approximation for the conditions of the TRUE- 1 tests. Retention in the altered rock of the rim zone appears to be significantly stronger than implied by retention properties inferred from generic ( unaltered) rock samples. The effective physical parameters which control retention ( matrix porosity and retention aperture) are comparable for all three test configurations. The most plausible in situ ( rim zone) porosity is in the range 1% - 2%, which constrains the effective retention aperture to the range 0.2 - 0.7 mm. For all sorbing tracers the estimated in situ sorption coefficient appears to be larger by at least a factor of 10, compared to the value inferred from through- diffusion tests using unaltered rock samples.

  • 15.
    Dargahi, Bijan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Hydrodynamic and Transport Properties of Saltsjo Bay in the Inner Stockholm Archipelago2011In: Journal of Coastal Research, ISSN 0749-0208, E-ISSN 1551-5036, Vol. 27, no 3, p. 572-584Article in journal (Refereed)
    Abstract [en]

    DARGAHI, B. and CVETKOVIC, V., 2011. Hydrodynamic and transport properties of Saltsjo Bay in the inner Stockholm archipelago, Sweden. Journal of Coastal Research, 27(3), 572-584. West Palm Beach (Florida), ISSN 0749-0208. A three-dimensional hydrodynamic model was successfully calibrated and validated for Saltsjo Bay, located in the inner Stockholm archipelago. The work aims to obtain a scientific understanding of specific hydrodynamic characteristics of the bay. The focus is on the influence of the freshwater inflow on the hydrodynamic characteristics of the bay, which shares common features with other relatively small bays and estuaries. The model was used for investigating the flow structure, stratification, exchange process, flushing time, and oxygen content. The predicted water levels, temperature, salinity, and dissolved oxygen (DO) profiles were in good agreement with the measurements. The flow structure in the bay is characterised by the existence of large secondary flow regions and multilayer flows. The principal cause of the large secondary flow regions is the interaction of prevailing two-layer flows that have opposite directions. The stratification can be characterised by two long winter and summer stratification periods and two short overturn periods. In the absence of the freshwater, the two-layer flow changed to a three-layer flow but the flow stratification remained unaltered. The flushing time in Saltsjo Bay (2-29 days) is similar to that found in smaller water bodies. The flushing time increased to 40 days when the freshwater inflows were removed from the model boundaries. The period from 1 September to 1 November is characterised by bottom oxygen deficiency when the DO concentrations fall below 5 mg/L. At the open boundary, 3% to 25% of the total volume of the bay is exchanged daily. The work should be of interest and relevant to other bays of comparable size that have similar hydrodynamic characteristics and are subject to freshwater inflows.

  • 16.
    Darracq, Amélie
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Greffe, Fanny
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Hannerz, Fredrik
    Destouni, G.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water Resources Engineering.
    Nutrient transport scenarios in a changing Stockholm and Mälaren valley region, Sweden2005In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 51, no 3-4, p. 31-38Article in journal (Refereed)
    Abstract [en]

    Norrstrom catchment, west of Stockholm, covers most of the Malaren valley. Provision of drinking water from Lake Malaren is an absolute precondition for continued growth in the region. Stockholm County's population is expected to increase by 600,000 people before 2030. Current climate change predictions anticipate significant temperature and precipitation increases. We implement the PolFlow model embedded in PCRaster for quantifying water and substances fluxes on the catchment scale over a 30-year time horizon. We formulate scenarios for changes in water quality and quantity due to climate change and population development. Results indicate a mild impact from climate change on surface flow rates but substantial effects on sub-surface residence times. Population development slightly affects nutrients loads. Using source apportionment and sensitivity analysis, we identify a number of critical parameters/processes to be further studied, in order for future results to be more reliable and usable in a water resources management context.

  • 17.
    Dessirier, Benoît
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Soltani, Safeyeh
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Dynamics of internal nutrient sources in the Baltic Sea - A comparative modelling study of the Gulf of Finland.2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    For decades the Baltic Sea has been subject to eutrophication due to heavy anthropogenic nutrient loads on the aquatic ecosystem. Quantitative projections of its effects require an understanding of its driving mechanisms, i.e., the hydrodynamics that are responsible for the physical transport and mixing and the biogeochemical nutrients pathways within the algal ecosystem and between the particulate and dissolved phases in the water and in the sediments.

    A simple basin-scale hydrodynamic framework is set for the Gulf of Finland to test different descriptions of the biogeochemical transformations and determine the most robust modelling strategy. A recently developed criterion to determine the occurrence of anoxic events, based on the amount of fresh carbon detritus in the sediments is implemented in comparison with the classical criterion based on the oxygen concentration in the bottom water.

    Time-averaging of the hydrodynamics over larger than daily intervals is proved to hinder the capture of rapid mixing events jeopardizing irremediably the water quality simulation. The new carbon based criterion for anoxia shows a better dynamic response and is less sensitive to the model’s internal parameters. An internal source in the sediments correlated to the amount of fresh detritus, to represent the release of iron-bound phosphorus is confirmed as a versatile modelling assumption.

  • 18. Durdu, Oe F.
    et al.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Modeling water and nutrients fluxes in the Buyuk Menderes drainage basin, Turkey2009In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 59, no 3, p. 531-541Article in journal (Refereed)
    Abstract [en]

    Buyuk Menderes catchment, located in the southwestern part of Turkey, is one of the most populated river basins in Turkey with 2.5 millions inhabitants. Due to increasing activities in agriculture and industrial sectors, water resources management in the basin is one of the biggest matters for the future. During the past decade, it has been observed a basinwide shift to larger monocultural, intensively operated farm units. Therefore, there is land use conversion from native lands to agriculture. The threat of nutrients pollution, nitrogen and phosphorus, has become a preoccupation since many lands and rivers undergo a eutrophication process. The discharge of nutrients from Buyuk Menderes basin to the Aegean Sea through Buyuk Menderes river also needs to be reduced in order to bring the eutrophication problems under lasting control. In this paper, the PolFlow model embedded in PCraster is applied to the catchment for quantifying water and substances fluxes for the five-year period, 1999-2004. The implementation of the model in the catchment allows describing the water balance and thus nutrient transport on the landscape surface but also through the soil and aquifer's layers. Modeling process is complicated by the transfer of nutrients from diffuse and point-source emissions, managed by retention and periodic release from storages within the catchment. Modeling diffuse and point-source nutrient emissions contribution to river loads can be improved by better knowledge about spatial and temporal distribution of this retention and release in the basin.

  • 19.
    Ekwall, Jakob
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Hydraulic Engineering. KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water Resources Engineering.
    Kvalitetskontroll av Vattenförbrukningsdata: Ursprung till Fel och Osäkerheter i mätdata från Göteborgs kommun2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 20. Fiori, Aldo
    et al.
    Jankovic, Igor
    Dagan, Gedeon
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Ergodic transport through aquifers of non-Gaussian log conductivity distribution and occurrence of anomalous behavior2007In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 43, no 9Article in journal (Refereed)
    Abstract [en]

    Three-dimensional advective transport of passive solutes through isotropic porous formations of stationary non- Gaussian log conductivity distributions is investigated by using an approximate semianalytical model, which is compared with accurate numerical simulations. The study is a continuation of our previous works in which formation heterogeneity is modeled using spherical nonoverlapping inclusions and an approximate analytical model was developed. Flow is solved for average uniform velocity, and transport of an ergodic plume is quantified by mass flux ( traveltime distribution) at a control plane. The analytical model uses a self- consistent argument, and it is based on the solution for an isolated inclusion submerged in homogeneous background matrix of effective conductivity. As demonstrated in the past, this analytical model accurately predicted the entire distributions of traveltimes in formations of Gaussian log conductivity distributions, as validated by numerical simulations. The present study ( 1) extends the results to formations of non- Gaussian log conductivity structures ( the subordination model), ( 2) extends the approximate analytical model to cubical blocks that tessellate the entire domain, ( 3) identifies a condition in conductivity distribution, at the tail of low values, that renders transport anomalous with macrodispersivity growing without bounds, and ( 4) provides links of our work to continuous time random walk ( CTRW) methodology, as applied to subsurface transport. It is found that a class of CTRW solutions proposed in the past cannot be based on solution of flow in formations with conductivity distribution of finite integral scale.

  • 21.
    Frampton, Andrew
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Vladimir, Cvetkovic
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Inference of field scale fracture transmissivities in crystalline rock using flow log measurements2010In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 46, no 11, p. W11502-Article in journal (Refereed)
    Abstract [en]

    Characterization of transmissivity for crystalline rock is conducted through simulation by conditioning against borehole flow rates obtained from high-resolution, in situ field measurements during extraction pumping. Full three-dimensional discrete fracture network simulations are carried out according to specifications obtained from site characterization data in a stochastic Monte Carlo setting. A novel method of conditioning is thereby introduced and applied using nonparametric comparison tests, which provide quantifiable measures of accuracy enabling evaluation of simulated results against field measurements. The assumption of a constitutive relationship ( perfect correlation) between fracture size and transmissivity is adopted. The method is evaluated against both single and multiple realizations, various domain size, and fracture length configurations and shown to be robust for the cases considered. When the introduced method of conditioning is applied, transmissivity parameterization can be inferred to a narrow range with a quantifiable accuracy in terms of a probability value. Results indicate that elementary interpretation of transmissivity based on homogenization of a porous medium will generally underestimate transmissivity. Further implications on advective transport for natural flow conditions are briefly evaluated, indicating advective breakthrough times can be overestimated up to a factor of about 10 in the median.

  • 22.
    Gotovac, Hrvoje
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Andricevic, Roko
    Adaptive Fup multi-resolution approach to flow and advective transport in highly heterogeneous porous media: Methodology, accuracy and convergence2009In: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 32, no 6, p. 885-905Article in journal (Refereed)
    Abstract [en]

    In this paper, we present a new Monte-Carlo methodology referred to as Adaptive Fup Monte-Carlo Method (AFMCM) based on compactly supported Fup basis functions and a multi-resolution approach. We consider for illustration 2-D steady, linear and unidirectional flow and advective transport defined on a domain of size 64I(Y) * 32I(Y) with isotropic exponential correlation heterogeneity structure and sigma(2)(Y) up to 8. Accuracy and convergence issues are rigorously analyzed for each realization as well as for the ensemble. Log-conductivity is presented by continuous function at high resolution level (n(Y) = 4-32 points per integral scale) reproducing very accurately prescribed statistics. The flow problem is the most demanding Monte-Carlo step due to satisfying detailed log-conductivity properties. Presented methodology inherently gives continuous and mesh-free velocity fields, which enables the construction of a new efficient and accurate particle tracking algorithm. Results indicate that resolutions n(Y) = 8 and n(h) = 32 enable very accurate flow solutions in each realization with mass balance error less than 3% and accurate ensemble velocity statistics. Results show that the proposed AFMCM enables tracking of an unlimited number of injected particles and calculates required transport variables as continuous functions with desired relative accuracy (0.1%) in each realization. Furthermore, we show that the resolution n(Y) = 8 yields a quite accurate pdf of the transverse displacement and travel time. All required flow and transport variables require 500 Monte-Carlo realizations in order to stabilize fluctuations of the higher-order moments and the probability density functions.

  • 23.
    Levlin, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Hassan Zadeh, Reza
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water Resources Engineering.
    Soh, Raymond
    Hultman, Bengt
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    A pilot-plant research facility in Stockholm: Possibilities to test new treatment processes as magnesium salt addition to meet requirements for the future2009In: Proceedings of the IWA 2nd Specialized Conference Nutrient Management in Wastewater Treatment Processes, 2009, p. 1159-1160Conference paper (Refereed)
  • 24.
    Molin, Staffan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Microbial risk assessment in heterogeneous aquifers: 1. Pathogen transport2010In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 46, p. W05518-Article in journal (Refereed)
    Abstract [en]

    Pathogen transport in heterogeneous aquifers is investigated for microbial risk assessment. A point source with time-dependent input of pathogens is assumed, exemplified as a simple on-site sanitation installation, intermingled with water supply wells. Any pathogen transmission pathway (realization) to the receptor from a postulated infection hazard is viewed as a random event, with the hydraulic conductivity varying spatially. For aquifers where VAR[lnK] < 1 and the integral scale is finite, we provide relatively simple semianalytical expressions for pathogen transport that incorporate the colloid filtration theory. We test a wide range of Damkohler numbers in order to assess the significance of rate limitations on the aquifer barrier function. Even slow immobile inactivation may notably affect the retention of pathogens. Analytical estimators for microbial peak discharge are evaluated and are shown to be applicable using parameters representative of rotavirus and Hepatitis A with input of 10-20 days duration.

  • 25.
    Molin, Staffan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Stenstrom, T. A.
    Microbial risk assessment in heterogeneous aquifers: 2. Infection risk sensitivity2010In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 46, p. W05519-Article in journal (Refereed)
    Abstract [en]

    The entire chain of events of human disease transmitted through contaminated water, from pathogen introduction into the source (E. coli, rotavirus, and Hepatitis A), pathogen migration through the aquifer pathway, to ingestion via a supply well, and finally, the potential infection in the human host, is investigated. The health risk calculations are based on a relevant hazardous event with safe setback distances estimated by considering the infection risk from peak exposure in compliance with an acceptable level defined by a regulatory agency. A site-specific hypothetical scenario is illustrated for an aquifer with similar characteristics as the Cape Cod site, Massachusetts (United States). Relatively large variation of safe distances for the three index pathogens is found; individually, none of the index pathogens could predict the safe distance under the wide range of conditions investigated. It is shown that colloid filtration theory (CFT) with spatially variable attachment-detachment rates yields significantly different results from the effective CFT model (i.e., assuming spatially constant parameters).

  • 26. Painter, S.
    et al.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Upscaling discrete fracture network simulations: An alternative to continuum transport models2005In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 41, no 2Article in journal (Refereed)
    Abstract [en]

    Particle tracking through stochastically generated networks of discrete fractures provides an alternative to the conventional advection-dispersion description of transport in fractured rock. However, discrete fracture network simulations are computationally intensive and usually limited to small scales. An approach for direct upscaling of discrete fracture simulations is described. Trajectories for nonreacting tracer particles are first extracted from relatively small discrete fracture network simulations. Tracer-rock interaction is represented by also calculating a cumulative reactivity parameter along each trajectory. The residence time/reactivity information is then used in a Monte Carlo simulation to construct artificial particle trajectories of any length, thereby achieving the upscaling objective. In its simplest form the procedure has the form of a random walk evolving in a two-dimensional space. Tests using site-specific and generic networks show that it is necessary to modify the random walk to produce sequential correlation along the trajectories. We achieve this by using a discrete state Markov process to direct the random walk. The procedure is computationally efficient, easily implemented, and compares well with the network simulations.

  • 27. Painter, S. L.
    et al.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water Resources Engineering.
    Effect of kinetic limitations on colloid-facilitated radionuclide transport at the field scale2006In: Proceedings of the 11th International High Level Radioactive Waste Management Conference, IHLRWM, 2006, p. 323-329Conference paper (Refereed)
    Abstract [en]

    Sorption onto natural groundwater colloids, a process that may enhance field-scale transport of radionuclides in the subsurface, is typically modeled in studies of potential high-level waste repositories using equilibrium partitioning assumptions. A new streamline-based model suggests that kinetic limitations on radionuclide sorption/desoption may significantly enhance field-scale radionuclide transport in some situations. Specifically, the leading edge of mass breakthrough curves may be enhanced if the kinetic rate constants are in a critical range as quantified by a Damkohler-type number. Application of the model to plutonium transport in the alluvial aquifer near Yucca Mountain, Nevada indicates that the bulk of the uncertain parameter space is in the equilibrium range. However, a small parameter region is in the kinetic regime. Monte Carlo simulations suggest that this kinetic region of the parameter space may cause early breakthrough for a small fraction of migrating plutonium, but the effect on peak breakthrough is minimal.

  • 28. Painter, S. L.
    et al.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water Resources Engineering.
    Pensado, O.
    Time-domain random walk algorithms for simulating radionuclide transport in fractured porous rock2006In: Proceedings of the 11th International High Level Radioactive Waste Management Conference, 2006, p. 293-300Conference paper (Refereed)
    Abstract [en]

    Time-domain random walk (TDRW) algorithms are efficient methods for simulating solute transport along one-dimensional pathways. New extensions of the TDRW algorithm accommodate decay and in-growth of radionuclides in a decay chain and time-dependent transport velocities. Validation tests using equilibrium sorption and matrix diffusion retention models demonstrate that the extended TDRW algorithm is accurate and computationally efficient. When combined with stochastic simulation of transport properties, the resulting algorithm, Particle On Random Streamline Segment (PORSS), also captures the effects of random spatial variations in transport velocities, including the effects of very broad velocity distributions. When used in combination with discrete fracture network simulations, the PORSS algorithm provides an accurate and practical method for simulating radionuclide transport at the geosphere scale without invoking the advection-dispersion equation.

  • 29. Painter, Scott
    et al.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Mancillas, James
    Pensado, Osvaldo
    Time domain particle tracking methods for simulating transport with retention and first-order transformation2008In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 44, no 1Article in journal (Refereed)
    Abstract [en]

    Particle tracking in the time domain has received increasing attention as a technique for robustly simulating transport along one-dimensional subsurface pathways. Using a stochastic Lagrangian perspective, integral representations of transport including the effects of advection, longitudinal dispersion, and a broad class of retention models are derived; Monte Carlo sampling of that integral leads directly to new time domain particle tracking algorithms that represent a wide range of physical phenomena. Retention-time distributions are compiled for key retention models. An extension to accommodate linear transformations such as decay chains is also introduced. Detailed testing using first-order decay chains and four retention models (equilibrium sorption, limited diffusion, unlimited diffusion, and first-order kinetic sorption) demonstrate that the method is highly accurate. Simulations using flow fields produced by large-scale discrete-fracture network simulations, a transport problem that is difficult for conventional algorithms, demonstrate that the new algorithms are robust and highly efficient.

  • 30. Painter, Scott L.
    et al.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Pensado, Osvaldo
    Time-domain random-walk algorithms for simulating radionuclide transport in fractured porous rock2008In: Nuclear Technology, ISSN 0029-5450, E-ISSN 1943-7471, Vol. 163, no 1, p. 129-136Article in journal (Refereed)
    Abstract [en]

    Time-domain random-walk (TDRW) algorithms are efficient methods for simulating solute transport along one-dimensional pathways. New extensions of the TDRW algorithm accommodate decay and ingrowth of radionuclides in a decay chain and time-dependent transport velocities. Tests using equilibrium sorption and matrix diffusion retention models demonstrate that the extended TDRW algorithm is accurate and computationally efficient. When combined with stochastic simulation of transport properties, the resulting algorithm, Particle on Random Streamline Segment (PORSS), also captures the effects of random spatial variations in transport velocities, including the effects of very broad velocity distributions. When used in combination with discrete fracture network simulations, the PORSS algorithm provides an accurate and practical method for simulating radionuclide transport at the geosphere scale without invoking the advection-dispersion equation.

  • 31. Severino, G.
    et al.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Coppola, A.
    On the velocity covariance for steady flows in heterogeneous porous formations and its application to contaminants transport2005In: Computational Geosciences, ISSN 1420-0597, E-ISSN 1573-1499, Vol. 9, no 4, p. 155-177Article in journal (Refereed)
    Abstract [en]

    We consider groundwater steady flow in a heterogeneous porous formation of random and stationary log-conductivity Y = ln K, characterized by the mean < Y >, and the two point correlation function C (Y) which in turn has finite, and different horizontal and vertical integral scales I and I (v) , respectively. The fluid velocity V, driven by a given head drop applied at the boundary, has constant mean value U equivalent to (U, 0, 0). Approximate explicit analytical expressions for transverse velocity covariances are derived. The adopted methodology follows the approach developed by Dagan and Cvetkovic (Spatial moments of kinetically sorbing plume in a heterogeneous aquifers, Water Resour. Res. 29 (1993) 4053) to obtain a similar result for the longitudinal velocity covariance. Indeed, the approximate covariances of transverse velocities are determined by requiring that they have the exact first order variances as well as zero integral scale (G. Dagan, Flow and Transport in Porous Formations (Springer, 1989)) , and provide the exact asymptotic limits of the displacement covariance of the fluid particles obtained by Russo (On the velocity covariance and transport modeling in heterogeneous anisotropic porous formations 1. Saturated flow, Water Resour. Res., 31 (1995) 129). Comparisons with numerical results show that the proposed expressions compare quite well in the early time regime, and for Ut/I > 100. Since most of the applications, like assessing the effective mobility of contaminants or quantifying the potential hazards of nuclear repositories, require predictions over higher times the proposed approximate expressions provide acceptable results. The main advantage related to such expressions is that they allow obtaining closed analytical forms of spatial moments pertaining to kinetically sorbing contaminant plumes avoiding the very heavy computational effort which is generally demanded. For illustration purposes, we consider the movement of one contaminant species, and show how our approximate spatial moments compare with the numerical simulations.

  • 32. Severino, Gerardo
    et al.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Coppola, Antonio
    Spatial moments for colloid-enhanced radionuclide transport in heterogeneous aquifers2007In: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 30, no 1, p. 101-112Article in journal (Refereed)
    Abstract [en]

    We consider colloid facilitated radionuclide transport by steady groundwater flow in a heterogeneous porous formation. Radionuclide binding on colloids and soil-matrix is assumed to be kinetically/equilibrium controlled. All reactive parameters are regarded as uniform, whereas the hydraulic log-conductivity is modelled as a stationary random space function (RSF). Colloid-enhanced radionuclide transport is studied by means of spatial moments pertaining to both the dissolved and colloid-bounded concentration. The general expressions of spatial moments for a colloid-bounded plume are presented for the first time, and are discussed in order to show the combined impact of sorption processes as well as aquifer heterogeneity upon the plume migration. For the general case, spatial moments are defined by the aid of two characteristic reaction functions which cannot be expressed analytically. By adopting the approximation for the longitudinal fluid trajectory covariance valid for a flow parallel to the formation bedding suggested by Dagan and Cvetkovic [Dagan G, Cvetkovic V. Spatial Moments of Kinetically Sorbing Plume in a Heterogeneous Aquifers. Water Resour Res 1993;29:4053], we obtain closed form solutions. For illustrative purposes, we consider the case when sorption/desorption between solution and moving colloids is a linear non-equilibrium process, whereas sorption onto the soil-matrix is a linear equilibrium process. Based on the flow and transport parameters pertaining to the alluvial aquifer at the Yucca Mountain Site (Nevada), we investigate the potential enhancing role of colloidal particles by comparing radionuclide spatial moments with and without colloids, and mainly investigate the sensitivity to the reverse rate parameter. The most potentially significant effects are obtained when radionuclide attachment to colloidal particles is irreversible. The simplicity of our results makes them suitable for quick assessments of the potential impact of colloids on contaminant transport in heterogeneous aquifers.

  • 33.
    Singh, Nandita
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Socio-cultural norms, human rights and access to water and sanitation2012In: The Right to Water: Theory, Practice & Prospects / [ed] Malcolm Langford & Anna Russell, Cambridge: Cambridge University Press, 2012Conference paper (Refereed)
    Abstract [en]

    The human right to water and sanitation has been most commonly approached from the perspective of the machinery and mechanisms for its implementation. Perhaps the underlying assumption is that once action for implementation is undertaken, access to water and sanitation and hence realization of the right will be spontaneously achieved. Little attention has been drawn to the processes at the micro-level where such action for implementing the right takes place. This paper aims to propose a framework for understanding the micro-level processes at the ‘interface’ where the duty-bearing agents implementing action come face-to-face with the right-holders in the community who interpret the action within the context of their socio-cultural norms. This framework proposes that the actions for implementation are influenced by factors located in the ‘implementation context’ that is external to the right-holders’ community, while actual ‘realization’ of the right is ultimately influenced by factors situated in their ‘socio-cultural context’. The two contexts can in turn be understood as constituted of distinct ‘norm-triads’ comprising knowledge, will, and systemic conditions and possibilities. The framework is validated through an inter-disciplinary study in India where the respective norm-triads have been analysed.

  • 34.
    Trönnberg, Linda
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Hawksworth, David
    Hansen, Anette
    Archer, Colleen
    Stenstrom, Thor Axel
    Household-based prevalence of helminths and parasitic protozoa in rural KwaZulu-Natal, South Africa, assessed from faecal vault sampling2010In: Transactions of the Royal Society of Tropical Medicine and Hygiene, ISSN 0035-9203, E-ISSN 1878-3503, Vol. 104, no 10, p. 646-652Article in journal (Refereed)
    Abstract [en]

    This study was undertaken to examine the family-based prevalence of environmentally persistent parasites in two rural communities of KwaZulu-Natal, South Africa. Samples were collected from 120 urine-diversion family toilets and screened for selected protozoa and helminths with immunomagnetic separation and the ammonium bicarbonate (AMBIC) protocol respectively. The parasites found were Ascaris lumbricoides (59%), Giardia intestinalis (54%), Trichuris trichiura (48%), Cryptosporidium spp. (21%) and Taenia spp. (18%). Only 14% of the household toilets were negative for these pathogens. The occurrence of A. lumbricoides and T. trichiura was lower (P<0.001) in the area with better hygiene behaviour, whereas G. intestinalis was more common (P<0.05) in families with at least one child aged five years or less and in families with more than four persons. Quantification of the parasites per gram was done for each sample and this provided realistic risk assessment data for the reuse of material from urine-diversion toilets. The high occurrence of parasites found in the two communities, in spite of sanitation and hygiene interventions in the areas, suggests an endemicity that will not be reduced without de-worming campaigns. Finally, the study showed that sampling directly from the deposited faecal material may be useful for parasitic prevalence estimations.

  • 35.
    Vladimir, Cvetkovic
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Molin, Staffan
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Combining numerical simulations with time-domain random walk for pathogen risk assessment in groundwater2011In: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 36, no SI, p. 98-107Article in journal (Refereed)
    Abstract [en]

    We present a methodology that combines numerical simulations of groundwater flow and advective transport in heterogeneous porous media with analytical retention models for computing the infection risk probability from pathogens in aquifers. The methodology is based on the analytical results presented in [1,2] for utilising the colloid filtration theory in a time-domain random walk framework. It is shown that in uniform flow, the results from the numerical simulations of advection yield comparable results as the analytical TDRW model for generating advection segments. It is shown that spatial variability of the attachment rate may be significant, however, it appears to affect risk in a different manner depending on if the flow is uniform or radially converging. In spite of the fact that numerous issues remain open regarding pathogen transport in aquifers on the field scale, the methodology presented here may be useful for screening purposes, and may also serve as a basis for future studies that would include greater complexity.

  • 36. Widestrand, H.
    et al.
    Byegard, J.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Tullborg, E. L.
    Winberg, A.
    Andersson, P.
    Siitari-Kauppi, M.
    Sorbing tracer experiments in a crystalline rock fracture at Aspo (Sweden): 1. Experimental setup and microscale characterization of retention properties2007In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 43, no 10Article in journal (Refereed)
    Abstract [en]

    [ 1] Mineralogical and retardation properties of rock materials responsible for water-rock interaction in in situ migration experiments with sorbing radioactive tracers were studied in laboratory experiments. The porosity was studied by water saturation measurements and the PMMA method was used for detailed porosity characterization of heterogeneity distributions and porosity profiles toward the fracture surface. Mylonite and altered diorite sampled in the rim zone of the fracture and representative bulk rock types were investigated by batch sorption measurements with crushed materials and through-diffusion and in-diffusion experiments in intact rock pieces. Autoradiography was used for visualization of in-diffusion profiles of sorbing tracers. The use of detailed porosity information and quantitative data on heterogeneity in porosity is shown to significantly improve the interpretation and evaluation of laboratory-scale diffusion experiments. We show through the combined approach of detailed porosity characterization and laboratory sorption and diffusion investigations that we can distinguish retention properties of bulk rock and altered rock and provide qualitative and quantitative data of heterogeneous rock properties that expand the possibility for including relevant processes in the interpretation of the results of in situ tracer tests.

1 - 36 of 36
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