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  • 1.
    Bhattacharya, Prosun
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Naidu, Ravi
    Polya, David A.
    Mukherjee, Abhijit
    Bundschuh, Jochen
    Charlet, Laurent
    Arsenic in hydrological processes-Sources, speciation, bioavailability and management2014In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 518, p. 279-283Article in journal (Other academic)
  • 2.
    Cvetkovic, Vladimir
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Fiori, A.
    Dagan, G.
    Tracer travel and residence time distributions in highly heterogeneous aquifers: Coupled effect of flow variability and mass transfer2016In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707Article in journal (Refereed)
    Abstract [en]

    The driving mechanism of tracer transport in aquifers is groundwater flow which is controlled by the heterogeneity of hydraulic properties. We show how hydrodynamics and mass transfer are coupled in a general analytical manner to derive a physically-based (or process-based) residence time distribution for a given integral scale of the hydraulic conductivity; the result can be applied for a broad class of linear mass transfer processes. The derived tracer residence time distribution is a transfer function with parameters to be inferred from combined field and laboratory measurements. It is scalable relative to the correlation length and applicable for an arbitrary statistical distribution of the hydraulic conductivity. Based on the derived residence time distribution, the coefficient of variation and skewness of residence time are illustrated assuming a log-normal hydraulic conductivity field and first-order mass transfer. We show that for a low Damkohler number the coefficient of variation is more strongly influenced by mass transfer than by heterogeneity, whereas skewness is more strongly influenced by heterogeneity.

  • 3.
    Cvetkovic, Vladimir
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Soltani, Safeyeh
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Vigouroux, Guillaume
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Global sensitivity analysis of groundwater transport2015In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 531Article in journal (Refereed)
    Abstract [en]

    In this work we address the model and parametric sensitivity of groundwater transport using the Lagrangian-Stochastic Advection-Reaction (LaSAR) methodology. The 'attenuation index' is used as a relevant and convenient measure of the coupled transport mechanisms. The coefficients of variation (CV) for seven uncertain parameters are assumed to be between 0.25 and 3.5, the highest value being for the lower bound of the mass transfer coefficient k0. In almost all cases, the uncertainties in the macro-dispersion (CV = 0.35) and in the mass transfer rate k0 (CV = 3.5) are most significant. The global sensitivity analysis using Sobol and derivative-based indices yield consistent rankings on the significance of different models and/or parameter ranges. The results presented here are generic however the proposed methodology can be easily adapted to specific conditions where uncertainty ranges in models and/or parameters can be estimated from field and/or laboratory measurements.

  • 4.
    Dargahi, Bijan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Hydraulic Engineering.
    Setegn, Shimelis Gebriye
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Hydraulic Engineering.
    Combined 3D Hydrodynamic and Watershed Modelling of Lake Tana, Ethiopia2011In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 398, no 1-2, p. 44-64Article in journal (Refereed)
    Abstract [en]

     The growing high demand for lake Tana water portends a disturbing future. The main objective of this paper is to make a contribution to the development of a sustainable use of the water of Lake Tana. A fully three-dimensional hydrodynamic model was combined with a watershed model and together, these models were successfully validated for the year 2006. The flow structure is characterized by large recirculation and secondary flow regions. Secondary flows are induced by hydrodynamic instabilities occurring at the interfaces of layers with a velocity gradient and the interaction with the irregularities of the bed. The weak stratification process in Lake Tana is characterized by a classic summer profile, which is more pronounced during January-February. Mixing processes in the lake are controlled by wind, the mixing energy induced by both river inflows and the lake outlet, and convective mixing due to the negative buoyancy. An alarming fall of the water levels in Lake Tana was found in response to the planned water withdrawal. The long flushing time (19 months) will not allow a fast decay of contaminated materials released into the lake. The flow structure will not be significantly modified by the planned water withdrawal but the flushing time will decrease. The hydrodynamics of Lake Tana resemble a closed system similar to a shallow reservoir with an overflow type outlet. The implication is that the lake is vulnerable to changes in external conditions and sustainable use of the water resource of the lake will require awareness of this vulnerability. The combined watershed and hydrodynamic models would be effective tools to achieve this awareness. It is also necessary to address the impact of climate change on the fate of the lake. These are all difficult challenges that need to be addressed to safeguard the sensitive eco-system of the area.

  • 5.
    Hasan, M. Aziz
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Sracek, Ondra
    Ahmed, Kazi Matin
    von Brömssen, Mattias
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Jacks, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Geological controls on groundwater chemistry and arsenic mobilization: Hydrogeochemical study along an E-W transect in the Meghna basin, Bangladesh2009In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 378, no 1-2, p. 105-118Article in journal (Refereed)
    Abstract [en]

    Hydrogeochemical investigations along an E-W transect in the middle Meghna basin show groundwater chemistry and redox condition vary considerably with the change in geology. Groundwater in the Holocene shallow (< 150 m bgl) alluvial aquifer in western part of the transect is affected by high arsenic concentration (As > 10 mu g/l) and salinity. On the other hand, groundwater from the Pliocene Dupi Tila sandy aquifer in the eastern part is fresh and low in As (< 10 mu g/l). The Holocene shallow aquifers are high in dissolved As. HCO3-, Fe and dissolved organic carbon (DOC), but generally low in SO2- and NO3-. High HCO3- concentrations (250-716 mg/l) together with high DOC concentrations (1.4-21.7 mg/l) in these aquifers reflect active sources of degradable natural organic matter that drives the biogeochemical process. There is generally de-coupling of As from other redox-sensitive elements. In contrast, the Pliocene aquifers are low in As, HCO3- and DOC. Molar ratio of HCO3-/H4SiO4 suggests that silicate weathering is dominant in the deeper Holocene aquifers and in the Pliocene aquifers. Molar ratios of Cl-/HCO3- and Na+/Cl- suggest mixing of relict seawater with the fresh water as the origin of groundwater salinity. Speciation calculations show that saturation indices for siderite and rhodochrosite vary significantly between the Holocene and Pliocene aquifers. Stable isotopes (delta H-2 and delta O-18) in groundwater indicate rapid infiltration without significant effects of evaporation. The isotopic data also indicates groundwater recharge from monsoonal precipitation with some impact of altitude effect at the base of the Tripura Hills in the east. The results of the study clearly indicate geological control (i.e. change in lithofacies) on groundwater chemistry and distribution of redox-sensitive elements such as As along the transect.

  • 6. Jonsson, K.
    et al.
    Johansson, H.
    Wörman, Anders
    Hyporheic exchange of reactive and conservative solutes in streams - tracer methodology and model interpretation2003In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 278, no 04-jan, p. 153-171Article in journal (Refereed)
    Abstract [en]

    A transient storage model is evaluated using results from a tracer experiment, where a conservative and a reactive tracer (H-3 and Cr-51(III)) were injected simultaneously and monitored in stream water and bed sediment. About 76% of the chromium was lost from the stream water on the reach 30 km downstream of the injection point directly after the passage of the pulse in the flowing water. The bed sediment hosted the main part of the retained chromium. The time to washout 75% of the maximum solute uptake in the sediment was similar to 85 times longer for chromium than for tritium (i.e. similar to 45 days). It was possible to describe the sediment-water exchange with a diffusive flux formulation that could be evaluated using tritium breakthrough curves in the stream water or the tritium inventory breakthrough curves in the sediment. This experiment revealed further that observations of chromium concentrations in the sediment were essential for the quantifying of sorption properties, as it was not possible to catch accurately the time scale of sorption within the duration of the breakthrough curves in the stream water. There was a clear need for a rate-limited description of the sorption of chromium in the sediment. We found that a first-order kinetic description of the sorption process could acceptably describe the breakthrough curves in both the stream water and the bed sediment.

  • 7.
    Lundmark, Annika
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Lindström, Riitta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Jansson, Per-Erik
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Effects of soil, vegetation and ground-water level on hydrogeological turnover timesIn: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707Article in journal (Other academic)
  • 8.
    Mahmoudzadeh, Batoul
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Liu, Longcheng
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Moreno, Luis
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Neretnieks, Ivars
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Solute transport through fractured rock: Radial diffusion into the rock matrix with several geological layers for an arbitrary length decay chain2016In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 536, p. 133-146Article in journal (Refereed)
    Abstract [sv]

    The paper presents a model development to derive a semi-analytical solution to describe reactive solute transport through a single channel in a fracture with cylindrical geometry. The model accounts for advection through the channel, radial diffusion into the adjacent heterogeneous rock matrix comprising different geological layers, adsorption on both the channel surface, and the geological layers of the rock matrix and radioactive decay chain. Not only an arbitrary-length decay chain, but also as many number of the rock matrix layers with different properties as observed in the field can be handled. The solution, which is analytical in the Laplace domain, is transformed back to the time domain numerically e.g. by use of de Hoog algorithm. The solution is verified against experimental data and analytical solutions of limiting cases of solute transport through porous media. More importantly, the relative importance and contribution of different processes on solute transport retardation in fractured rocks are investigated by simulating several cases of varying complexity. The simulation results are compared with those obtained from rectangular model with linear matrix diffusion. It is found that the impact of channel geometry on breakthrough curves increases markedly as the transport distance along the flow channel and away into the rock matrix increase. The effect of geometry is more pronounced for transport of a decay chain when the rock matrix consists of a porous altered layer.

  • 9. Mazzoleni, Maurizio
    et al.
    Brandimarte, Luigia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Amaranto, Alessandro
    Evaluating precipitation datasets for large-scale distributed hydrological modelling2019In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 578Article in journal (Refereed)
    Abstract [en]

    We are experiencing a proliferation of satellite derived precipitation datasets. Advantages and limitations of their promising application in hydrological modelling application have been broadly investigated. However, most studies have analysed only the performance of one or few datasets, were limited to selected small-scale case studies or used lumped models when investigating large-scale basins.

    In this study, we compared the performance of 18 different precipitation datasets when used as main forcing in a grid-based distributed hydrological model to assess streamflow in medium to large-scale river basins. These datasets are classified as Uncorrected Satellites (Class 1), Corrected Satellites (Class 2) and Reanalysis – Gauges based datasets (Class 3). To provide a broad-based analysis, 8 large-scale river basins (Amazon, Brahmaputra, Congo, Danube, Godavari, Mississippi, Rhine and Volga) having different sizes, hydrometeorological characteristics, and human influence were selected. The distributed hydrological model was recalibrated for each precipitation dataset individually.

    We found that there is not a unique best performing precipitation dataset for all basins and that results are very sensitive to the basin characteristics. However, a few datasets persistently outperform the others: SM2RAIN-ASCAT for Class 1, CHIRPS V2.0, MSWEP V2.1, and CMORPH-CRTV1.0 for Class 2, GPCC and WFEDEI GPCC for Class 3. Surprisingly, precipitation datasets showing the highest model accuracy at basin outlets do not show the same high performance in internal locations, supporting the use of distributed modelling approach rather than lumped.

  • 10.
    Meng, Shuo
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Liu, Longcheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Mahmoudzadeh, Batoul
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Neretnieks, Ivars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Moreno, Luis
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Solute transport along a single fracture with a finite extent of matrix: A new simple solution and temporal moment analysis2018In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 562, p. 290-304Article in journal (Refereed)
    Abstract [en]

    A new simple and robust solution, based on uniform steady-state flow velocity, is developed for the problem of solute transport in a fracture-matrix system with a finite penetration depth of a radioactive contaminant into the rock matrix. The solution is an extension of Liu et al. (2017) to finite penetration depth and an alternative solution strategy to the problem solved by Sudicky et al. (1982). The solution takes the form of a convolution of two functions. The first function describes the probability density function of the residence time distribution of a conservative solute resulting merely from advection and Fickian dispersion. The second function is actually the impulse response of the fracture-matrix system in the case of a plug flow without any hydrodynamic dispersion. As a result, the effects of Fickian dispersion and matrix diffusion on solute transport are decoupled, and thus the resulting breakthrough curve can be analyzed in terms of those two functions. In addition to this, the derived Péclet numbers of those two functions, based on temporal moments, are also found to be associated with the derived Péclet number of the resulting breakthrough curve. By comparing the Péclet numbers of those two functions, the contribution of Fickian dispersion and matrix diffusion to solute spreading is determined in a straightforward way. This can aid to find out the dominating mechanism on solute transport, and therefore the performance of breakthrough curve.

  • 11. Mukherjee, Abhijit
    et al.
    Verma, Swati
    Gupta, Saibal
    Henke, Kevin R.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Influence of tectonics, sedimentation and aqueous flow cycles on the origin of global groundwater arsenic: Paradigms from three continents2014In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 518, p. 284-299Article in journal (Refereed)
    Abstract [en]

    Arsenic (As) is a trace element in the Earth's crust. However, its presence in elevated concentrations in groundwaters of major aquifers around the world raises concern about its primary source(s). A close look at the global distribution of known As enriched areas reveals an intriguing systematic pattern, where most of the As enriched aquifers are parts of large sedimentary basins adjoining major orogenic belts, suggesting the existence of a large-scale geological process. Many of these sedimentary basins may be tectonically regarded as foreland basins that developed by lithospheric flexure at the time of mountain building processes (orogenesis) along convergent plate boundaries. Arsenic enrichment in the groundwater of these foreland basin aquifers may be ultimately sourced to crustal evolution processes related to plate tectonics, along with transportation of As-enriched magmatic rocks from the depth to surficial deposits, which subsequently release or mobilize the As to groundwater under conducive surficial biogeochemical processes. Circulating As-laden hydrothermal fluids may also be derived from magmas and form part of the discharge in the surficial hot springs in arc environments. These hydrothermal-genic deposits in orogenic belts may also act as the primary provenance for the As-laden sediments that are transported into foreland basins by wind, glacial erosion, and/or streams. Ultimately, the As-laden foreland sediments serve as modern-day aquifers, where the sediments release As into groundwater by water-rock interaction during various biogeochemical processes under conducive hydrogeochemical conditions. The significance of this hypothesis is that it proposes the existence of a common primary source for globally dispersed geogenic As-enriched aquifers, that have been so far mostly studied as individual occurrences. The proposed hypothesis can explain the widespread presence of As in areas as diverse as the Indus-Ganges-Brahmaputra basin (Himalayan orogen), the Chaco-Pampean basin (Andean orogen), Rocky mountain basin (Western Cordilleran orogen), New England and northeastern USA (the Applachian orogen).

  • 12.
    Norrström, Ann-Catrine
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Geochemistry and Ecotechnology.
    Acid-base status of soils in groundwater discharge zones -relation to surface water acidification1995In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 170, p. 87-100Article in journal (Refereed)
  • 13.
    Prieto, Carmen
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Destouni, Georgia
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Kotronarou, Anastasia
    The influence of temporal hydrological randomness on seawater intrusion in coastal aquifers2006In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 330, no 1-2, p. 285-300Article in journal (Refereed)
    Abstract [en]

    We investigate general effects of temporal hydrological randomness on seawater intrusion in coastal aquifers, using a 2D conceptuatization and model parameterization of three coastal aquifer zones on the Mediterranean Sea. These three aquifer cases represent quite different examples of hydrogeological conditions and temporal hydrological and groundwater management variability and statistics. A general result for all aquifer cases is that the effects of temporal randomness on expected salinity in pumped groundwater are greater for spatially homogeneous than for spatially heterogeneous aquifer representations. We quantify also prediction uncertainty around expected groundwater salinity, in terms of the salinity standard deviation and coefficient of variation (CV) in the different aquifer cases. In general, the salinity CV appears to depend much more on the aquifer depth than on the input temporal fluctuation statistics of each aquifer case. Aquifer depth may thus be a main indicator for resulting prediction uncertainty in salinity of pumped groundwater due to temporal hydrological randomness.

  • 14.
    Ramos Ramos, Oswaldo Eduardo
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Rötting, Tobias S.
    French, Megan
    Stacek, Ondra
    Bundschuh, Jochen
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Quintanilla, Jorge
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Geochemical processes controlling mobilization of arsenic and trace elements in shallow aquifers and surface waters in the Antequera and Poopó mining regions, Bolivian Altiplano2014In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 518, no C, p. 421-433Article in journal (Refereed)
    Abstract [en]

    A geochemical approach was applied to understand the factors controlling the mobilization of As and trace elements (TEs) in mining areas of the Poopó and Antequera River sub-basins on the Bolivian Altiplano. A total of 52 samples (surface, groundwater and geothermal water) were collected during the rainy season (2009). Arsenic, Cd and Mn concentrations exceed World Health Organization (WHO) drinking water guidelines and Bolivian regulations for drinking water in 28 groundwater samples, but Cu, Ni, Pb and Zn do not. Arsenic, Cd, Mn, Pb and Zn concentrations exceed World Health Organization guidelines for drinking water and Bolivian regulations Class A standard for discharge to water bodies in 20 surface water samples, whereas levels of Cu do not, and Ni and Fe rarely exceed regulation and guideline values. Factor analysis was applied to 18 hydrochemical parameters of 52 samples. Five factors for groundwater (plagioclase weathering, dissolution of gypsum and halite, TEs mobilization at acidic pH, sulfide oxidation, and release of As) account for 86.5% of the total variance for Antequera and 83.9% for Poopó sub-basins. Four factors for surface water data (weathering and mobilization of TEs influenced by pH, dissolution of evaporate salts, neutralization of acid mine drainage, and As release due to dissolution of Mn and Fe oxides) account for 91% of the total variance in Antequera and 96% in Poopó sub-basins. The As and TEs mobilized in these regions could affect the local water sources, which is a prevalent concern with respect to water resource management in this semi-arid Altiplano region. Presence of both natural and anthropogenic sources of contamination requires careful monitoring of water quality.

  • 15. Raychowdhury, Nilasree
    et al.
    Mukherjee, Abhijit
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Johannesson, Karen
    Bundschuh, Jochen
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. University of Southern Queensland, Australia .
    Bejarano Sifuentes, Gabriela
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Nordberg, Erika
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Martin, Raul A.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Storniolo, Angel del Rosario
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Provenance and fate of arsenic and other solutes in the Chaco-Pampean Plain of the Andean foreland, Argentina: From perspectives of hydrogeochemical modeling and regional tectonic setting2014In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 518, p. 300-316Article in journal (Refereed)
    Abstract [en]

    Extensive arsenic (As) enriched groundwater is known to occur in the aquifers of the Chaco-Pampean Plain of Argentina. Previous studies speculated that the As mobilization in these groundwaters was a direct result of their elevated pH and oxidative conditions. The volcanic glass layers present in the aquifer matrix were hypothesized as one of the possible sources of As to the groundwaters. Here, we examine the groundwater chemistry of the Santiago del Estero province of Chaco-Pampean Plains of Argentina, and test these hypotheses by using hydrogeochemical modeling within the framework of the regional geologic-tectonic setting. The study area is located in the active foreland of the Andean orogenic belt, which forms a continental arc setting, and is dotted with several hot springs. Rhyolitic volcanic glass fragments derived from arc volcanism are abundant within the aeolian-fluvial aquifer sediments, and are related to the paleo-igneous extrusion in the vicinity. Hydrogeochemical analyses show that the groundwater is in predominantly oxidative condition. In addition, some of the groundwaters exhibit very high Na, Cl- and SO42- concentrations. It is hypothesized in this study that the groundwater chemistry has largely evolved by dissolution of rhyolitic volcanic glass fragments contained within the aquifer sediments along with mixing with saline surface waters from, adjoining salinas, which are thought to be partially evaporated remnants of a paleo inland sea. Flow path modeling, stability diagrams, and thermodynamic analyses undertaken in this study indicate that the dominant evolutionary processes include ion exchange reactions, chemical weathering of silicate and evaporites, in monosialitization-dominated weathering. Geochemical modeling predicts that plagioclase feldspar and volcanic glass are the major solids phases that contribute metal cations and dissolved silica to the local groundwaters. Co-influxed oxyanions, with similar ionic radii and structure (e.g. Mo, Si, V, PO43-), compete with As for mineral surface site, leading to As mobilization to the groundwaters (without considering the influence of microbial activities). Further, the transition of the Ca-rich groundwater to Na-rich groundwater, by mixing with water from the salinas and/or evaporative concentration, might also have led to counter-ion effects (a type of ion exchange reactions), and hence, further enrichment of groundwater by As. Some of the As may also have been contributed from mixing of meteoric water with magmatic-sourced water in the geothermal springs.

  • 16. Sengupta, S.
    et al.
    Sracek, O.
    Jean, J. -S
    Lu, H. -Y
    Wang, C. -H
    Palcsu, L.
    Liu, C. -C
    Jen, C. -H
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Spatial variation of groundwater arsenic distribution in the Chianan Plain, SW Taiwan: Role of local hydrogeological factors and geothermal sources2014In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 518, p. 393-409Article in journal (Refereed)
    Abstract [en]

    We present here major ion, trace element, stable and radioisotope data based on forty-six groundwater samples collected from various locations along few selected profiles across the Chianan Plain, southwestern Taiwan including the area affected by well known Blackfoot disease manifested by peripheral vascular gangrene. The objective of the study was to understand the role of local hydrogeology in terms of spatial variation of arsenic concentration in groundwater wells of the entire Chianan Plain and the foothill belt of the Central Mountain Range. An attempt has also been made to assess the contribution of nearby geothermal sources to the arsenic budget in groundwater of the Chianan Plain. Our study shows a gradual increase in all major and trace ion concentrations including total arsenic from foothill belt (arsenic: median = 4 mu g/L, range = 0-667.6 mu g/L, sample number n = 16) to coastal zones (arsenic: median = 42.74 mu g/L, range = 0.14-348.6 mu g/L, n = 15) of the plain. Inverse geochemical modeling shows that Ca may be exchanged on clays, and that the degree of the exchange increases from the foothill to the coastal zones. Inverse geochemical modeling further suggests that the oxidation of organic matter (CH2O) required in various east-west profiles across the plain to balance the total bicarbonate concentration and CO2 input from organic matters significantly increases from the foothill to the coastal zones with transfer coefficients ranging from 1.55 x 10(-2) to 1.69 x 10(-5) mol/L. High concentrations of tritium (mean = 1.33 +/- 0.11 TU; n = 4) in foothill groundwater and low concentration of tritium in groundwater of central zone suggest gradually increasing water-rock interaction from the foothill to the coastal part. Few elevated arsenic (median = 171.8 mu g/L,maximum = 667.60 mu g/L, minimum = 24 mu g/L; n = 6) hotspots are identified in the foothill belt. Available lithologs and aquifer test data suggest that the presence of impermeable clay around those pockets possibly inhibits vertical and lateral flushing of the aquifer and aids strong water-rock interactions subsequently leading to release of arsenic into groundwater. Using oxygen isotope and chloride mass balance method, we estimated that geothermal sources can recharge a maximum of 4% of groundwater in proximal aquifers and contribute <2% of average As concentration in the groundwater of Chianan Plain. Our preliminary observations thus show some arsenic enrichment in foothill aquifers, providing a necessity of detailed study of the aquifer systems in these understudied regions. Moreover, our research indicates that the contribution of arsenic from geothermal sources is insignificant, which stands in contrast to earlier studies suggesting that mud volcanoes and thermal springs in the Western Foothill Belt of the Central Mountain Range were potential sources of groundwater arsenic in the Chianan Plain aquifers.

  • 17.
    Shahkarami, Pirouz
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Liu, Longcheng
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Moreno, Luis
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Neretnieks, Ivars
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Radionuclide migration through fractured rock for arbitrary-length decay chain: Analytical solution and global sensitivity analysis: new2015In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 520, p. 448-460Article in journal (Refereed)
    Abstract [en]

    This study presents an analytical approach to simulate nuclide migration through a channel in a fracture accounting for an arbitrary-length decay chain. The nuclides are retarded as they diffuse in the porous rock matrix and stagnant zones in the fracture. The Laplace transform and similarity transform techniques are applied to solve the model. The analytical solution to the nuclide concentrations at the fracture outlet is governed by nine parameters representing different mechanisms acting on nuclide transport through a fracture, including diffusion into the rock matrices, diffusion into the stagnant water zone, chain decay and hydrodynamic dispersion. Furthermore, to assess how sensitive the results are to parameter uncertainties, the Sobol method is applied in variance-based global sensitivity analyses of the model output. The Sobol indices show how uncertainty in the model output is apportioned to the uncertainty in the model input. This method takes into account both direct effects and interaction effects between input parameters. The simulation results suggest that in the case of pulse injections, ignoring the effect of a stagnant water zone can lead to significant errors in the time of first arrival and the peak value of the nuclides. Likewise, neglecting the parent and modeling its daughter as a single stable species can result in a significant overestimation of the peak value of the daughter nuclide. It is also found that as the dispersion increases, the early arrival time and the peak time of the daughter decrease while the peak value increases. More importantly, the global sensitivity analysis reveals that for time periods greater than a few thousand years, the uncertainty of the model output is more sensitive to the values of the individual parameters than to the interaction between them. Moreover, if one tries to evaluate the true values of the input parameters at the same cost and effort, the determination of priorities should follow a certain sequence.

  • 18.
    Shahkarami, Pirouz
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Liu, Longcheng
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Moreno, Luis
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Neretnieks, Ivars
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    The effect of stagnant water zones on retarding radionuclide transport in fractured rocks: An extension to the Channel Network Model2016In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 540, p. 1122-1135Article in journal (Refereed)
    Abstract [en]

    An essential task of performance assessment of radioactive waste repositories is to predict radionuclide release into the environment. For such a quantitative assessment, the Channel Network Model and the corresponding computer program, CHAN3D, have been used to simulate radionuclide transport in crystalline bedrocks. Recent studies suggest, however, that the model may tend to underestimate the rock retarding capability, because it ignores the presence of stagnant water zones, STWZs, situated in the fracture plane. Once considered, the STWZ can provide additional surface area over which radionuclides diffuse into the rock matrix and thereby contribute to their retardation.

    The main objective of this paper is to extend the Channel Network Model and its computer implementation to account for diffusion into STWZs and their adjacent rock matrices.

    In the first part of the paper, the overall impact of STWZs in retarding radionuclide transport is investigated through a deterministic calculation of far-field releases at Forsmark, Sweden. Over the time-scale of the repository safety assessments, radionuclide breakthrough curves are calculated for increasing STWZ width. It is shown that the presence of STWZs enhances the retardation of most long-lived radionuclides except for 36Cl and 129I.

    The rest of the paper is devoted to the probabilistic calculation of radionuclide transport in fractured rocks. The model that is developed for transport through a single channel is embedded into the Channel Network Model and new computer codes are provided for the CHAN3D. The program is used to (I) simulate the tracer test experiment performed at Äspö HRL, STT-1 and (II) investigate the short- and long-term effect of diffusion into STWZs. The required data for the model are obtained from detailed hydraulic tests in boreholes intersecting the rock mass where the tracer tests were made.

    The simulation results fairly well predict the release of the sorbing tracer 137Cs. It is found that over the short time-scale of the tracer experiment, the effect of diffusion into STWZs is not as pronounced as that of matrix diffusion directly from the flow channel, and the latter remains the main retarding mechanism. Predictions for longer time-scale, tens of years and more, show that the effect of STWZs becomes strong and tends to increase with transport time. It is shown that over the long times of interest for safety assessment of radioactive waste repositories, STWZs can substantially contribute to radionuclide retardation, though for the short time-scales the impact is not very strong and is not expected to affect the results of short-term field experiments.

  • 19.
    Sokrut, Nikolay
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Thunvik, Roger
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Motovilov, Juri
    Örsundaån case: an example of multiple-scale hydrological modelling2005In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707Article in journal (Other academic)
  • 20. Talei, Amin
    et al.
    Chua, Lloyd Hock Chye
    Quek, Chai
    Jansson, Per-Erik
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Runoff forecasting using a Takagi-Sugeno neuro-fuzzy model with online learning2013In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 488, p. 17-32Article in journal (Refereed)
    Abstract [en]

    A study using local learning Neuro-Fuzzy System (NFS) was undertaken for a rainfall-runoff modeling application. The local learning model was first tested on three different catchments: an outdoor experimental catchment measuring 25 m(2) (Catchment 1), a small urban catchment 5.6 km(2) in size (Catchment 2), and a large rural watershed with area of 241.3 km(2) (Catchment 3). The results obtained from the local learning model were comparable or better than results obtained from physically-based, i.e. Kinematic Wave Model (KWM), Storm Water Management Model (SWMM), and Hydrologiska Byrans Vattenbalan-savdelning (HBV) model. The local learning algorithm also required a shorter training time compared to a global learning NFS model. The local learning model was next tested in real-time mode, where the model was continuously adapted when presented with current information in real time. The real-time implementation of the local learning model gave better results, without the need for retraining, when compared to a batch NFS model, where it was found that the batch model had to be retrained periodically in order to achieve similar results.

  • 21. Viglione, A.
    et al.
    Di Baldassarre, G.
    Brandimarte, Luigia
    Department of Integrated Water Systems and Governance, UNESCO-IHE, Delft, Netherlands.
    Kuil, L.
    Carr, G.
    Salinas, J. L.
    Scolobig, A.
    Blöschl, G.
    Insights from socio-hydrology modelling on dealing with flood risk - Roles of collective memory, risk-taking attitude and trust2014In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 518, no A, p. 71-82Article in journal (Refereed)
    Abstract [en]

    The risk coping culture of a community plays a major role in the development of urban floodplains. In this paper we analyse, in a conceptual way, the interplay of community risk coping culture, flooding damage and economic growth. We particularly focus on three aspects: (i) collective memory, i.e., the capacity of the community to keep risk awareness high; (ii) risk-taking attitude, i.e., the amount of risk the community is collectively willing to be exposed to; and (iii) trust of the community in risk reduction measures. To this end, we use a dynamic model that represents the feedback between the hydrological and social system components. Model results indicate that, on the one hand, by under perceiving the risk of flooding (because of short collective memory and too much trust in flood protection structures) in combination with a high risk-taking attitude, community development is severely limited because of high damages caused by flooding. On the other hand, overestimation of risk (long memory and lack of trust in flood protection structures) leads to lost economic opportunities and recession. There are many scenarios of favourable development resulting from a trade-off between collective memory and trust in risk reduction measures combined with a low to moderate risk-taking attitude. Interestingly, the model gives rise to situations in which the development of the community in the floodplain is path dependent, i.e., the history of flooding may lead to community growth or recession.

  • 22.
    von Brömssen, Martin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Markussen, Lars
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Ahmed, Kazi Matin
    Hossain, Mohammed
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Jacks, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Sracek, Ondra
    Thunvik, Roger
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Hasan, Md Aziz
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Islam, M. Mainul
    Rahman, M. Mokhlesur
    Hydrogeological investigation for assessment of the sustainability of low-arsenic aquifers as a safe drinking water source in regions with high-arsenic groundwater in Matlab, southeastern Bangladesh2014In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 518, no C, p. 373-392Article in journal (Refereed)
    Abstract [en]

    Exploitation of groundwater from shallow, high prolific Holocene sedimentary aquifers has been a main element for achieving safe drinking water and food security in Bangladesh. However, the presence of elevated levels of geogenic arsenic (As) in these aquifers has undermined this success. Except for targeting safe aquifers through installations of tubewells to greater depth, no mitigation option has been successfully implemented on a larger scale. The objective of this study has been to characterise the hydrostratigraphy, groundwater flow patterns, the hydraulic properties to assess the sustainability of the low-arsenic aquifers at Matlab, in south-eastern Bangladesh, one of the worst arsenic-affected areas of Bangladesh. Combining groundwater modelling with monitoring hydraulic heads in multi-level piezometer tests, 14C-dating of groundwater, conventional hydraulic testing and assessment of groundwater abstraction rate proved to be a useful strategy. A model comprising of three aquifers covering the top 250 m of the model domain showed to best fit the evaluation criteria for calibration. Matlab is a recharge area, even though it is adjacent to the great Meghna River. Irrigation wells are placed in clusters and account for most of the groundwater abstraction. Even though the hydraulic heads are affected locally by seasonal pumping, the aquifer system is fully recharged during and after the monsoon period. Groundwater simulations demonstrated the presence of deep regional and horizontal flow systems with recharge areas in the eastern, hilly part of Bangladesh and shallow small local flow systems driven by local topography. Based on modelling and 14C groundwater data, it can be concluded that the natural local flow systems reach a depth of 30 m b.g.l. in the study area. A downwardvertical gradient of roughly 0.01 down to 200 m b.g.l. was observed and reproduced bycalibrated models. The vertical gradient is mainly the result of the aquifer system and-properties rather than abstraction rate, which is too limited at depth to make an imprint. Although irrigation wells substantially change local flow pattern, targeting low-As aquifers seems to be a suitable mitigation option for providing people with safe drinkingwater. However, installing new irrigation- or high capacity production wells at the same depth is strongly discouraged as these substantially change the groundwater flow pattern. The results from the present study and other similar studies can further contribute to develop a rational management and mitigation policy for the future use of the groundwater resources for drinking water supplies.

  • 23.
    Wu, Mousong
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Experimental study on evaporation from seasonally frozen soils under various water, solute and groundwater conditions in Inner Mongolia, China2016In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 535, p. 46-53Article in journal (Refereed)
  • 24. Wörman, Anders
    et al.
    Kronnas, V.
    Effect of pond shape and vegetation heterogeneity on flow and treatment performance of constructed wetlands2005In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 301, no 04-jan, p. 123-138Article in journal (Refereed)
    Abstract [en]

    A model framework is developed for nitrogen transformations in a constructed wetland by combining both hydraulics and chemical transformation of nitrogen species. The nitrogen concentration of the effluent water is represented in terms of a convolution between the probability density function of the hydraulic residence Limes and a chemical transformation function describing the rate of mass-removal of total nitrogen with time in the water as a first-order reaction. Closed-form solutions to the treatment efficiency is derived and related to the nitrogen reduction in wetland Alhagen in Nynashamn, Sweden. Further. the model coefficients are explored by numerical simulations and expressed in terms of heterogeneity of the flow resistance. i.e. in vegetation, and the aspect ratio of the wetland. Heterogeneity in vegetation contributes to increasing the variance of the water residence time and this increases the effluent concentration of nitrogen. Based on the theory and the data from Alhagen. the residence time probability density function for water can have a significant influence, on the treatment, and particularly the aspect ratio markedly affects the active water volume and the treatment efficiency.

  • 25.
    Wörman, Anders
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Hydraulic Engineering.
    Lindstrom, G.
    Riml, Joakim
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Hydraulic Engineering.
    The power of runoff2017In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 548, p. 784-793Article in journal (Refereed)
    Abstract [en]

    Although the potential energy of surface water is a small part of Earth's energy budget, this highly variable physical property is a key component in the terrestrial hydrologic cycle empowering geomorphological and hydrological processes throughout the hydrosphere. By downscaling of the daily hydrometeorological data acquired in Sweden over the last half-century this study quantifies the spatial and temporal distribution of the dominating energy components in terrestrial hydrology, including the frictional resistance in surface water and groundwater as well as hydropower. The energy consumed in groundwater circulation was found to be 34.6 TWh/fy or a heat production of approximately 13% of the geothermal heat flux. Significant climate driven, periodic fluctuations in the power of runoff, stream flows and groundwater circulation were revealed that have not previously been documented. We found that the runoff power ranged from 173 to 260 TWh/y even when averaged over the entire surface of Sweden in a five-year moving window. We separated short-term fluctuations in runoff due to precipitation filtered through the watershed from longer-term seasonal and climate driven modes. Strong climate driven correlations between the power of runoff and climate indices, wind and solar intensity were found over periods of 3.6 and 8 years. The high covariance that we found between the potential energy of surface water and wind energy implies significant challenges for the combination of these renewable energy sources.

  • 26. Xu, Shulan
    et al.
    Wörman, Anders
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Hydraulic Engineering.
    Dverstorp, Bjorn
    Criteria for resolution-scales and parameterisation of compartmental models of hydrological and ecological mass flows2007In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 335, no 04-mar, p. 364-373Article in journal (Refereed)
    Abstract [en]

    The effect of compartment resolution-scale, i.e. number of compartments and compartment size, on prediction of transport of water and solute mass in watersheds is analysed by using numerical discretisation and temporal moments methods. The one-dimensional advection-diffusion model is used as a theoretical frame of reference for representing transport along a single series of compartments along a pathway in the surface water or ecosystem. Criteria for parameterisation of compartment models and error estimates are derived for two cases: (1) requiring an exact match with the advection-diffusion model; and (2) requiring as good match as possible with a simplified compartment model using a small number of compartments. The matching criteria are based on a comparison of numerical discretisation and temporal moments of the compartmental backflow model with those of the one-dimensional advection-diffusion equation. We derived solutions in terms of temporal moments of both the advection-diffusion equation and compartmental backflow model. with arbitrary input concentration vs. time boundary condition. This approach can be used to translate parameters between the models and analyse the error caused by any arbitrary structure of the compartmental model as a function of boundary conditions and the physical parameters of the advective-diffusive equation. Data from tracer experiments were compared with model predictions to provide a practical frame of reference.

  • 27.
    Åkesson, Anna
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Hydraulic Engineering.
    Wörman, Anders
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Hydraulic Engineering.
    Stage-dependent hydraulic and hydromorphologic properties in stream networks translated into response functions of compartmental models2012In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 420-421, p. 25-36Article in journal (Refereed)
    Abstract [en]

    A distributed non-uniform routing model was constructed and applied to two stream networks in southern Sweden to investigate the effects of stage, topology and morphology on advective travel times within the stream networks.Using particle-tracking, we found markedly non-linear relationships between travel time distributions and discharge for both catchments under a range of hydraulic conditions, represented by discharges comprising percentiles between 30 and 99.9 extracted from the discharge data set for the two catchments in this study.The travel time distributions from the particle tracking were used to numerically parameterise the response function of a lumped hydrological model, which resulted in improvements, particularly in the prediction of high flows. A sensitivity analysis was performed on the routing procedure, particularly regarding the choice of Manning's friction coefficient and the choice of generic cross-sectional areas along the two stream networks showing that the uncertainty in routing parameters did not have a major effect on the final hydrograph. The new parameterisation performed better than the conventional model in every modelled case.A theoretical demonstration shows that correct descriptions of streamflow processes becomes more important with increased watershed scale, because the travel time within the stream network relative to the travel time on hillslopes increases with the watershed scale. The topology and topography of the stream network were shown to be the major factors influencing the network averaged travel time. These results demonstrate that physically based response functions (and model parameters) can be superior to compartmental model parameters that are based on numerical calibration and that are extrapolated to account for conditions during hydrological extremes.

1 - 27 of 27
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