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  • 1.
    Anderson, Leif G.
    et al.
    Univ Gothenburg, Dept Marine Sci, POB 461, S-40530 Gothenburg, Sweden..
    Björk, Göran
    Univ Gothenburg, Dept Marine Sci, POB 461, S-40530 Gothenburg, Sweden..
    Holby, Ola
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Jutterstrom, Sara
    IVL Swedish Environm Res Inst, Box 530 21, S-40014 Gothenburg, Sweden..
    Morth, Carl Magnus
    Stockholm Univ, Dept Geol Sci, S-10691 Stockholm, Sweden..
    O'Regan, Matt
    Stockholm Univ, Dept Geol Sci, S-10691 Stockholm, Sweden..
    Pearce, Christof
    Stockholm Univ, Dept Geol Sci, S-10691 Stockholm, Sweden.;Aarhus Univ, Dept Geosci, Aarhus, Denmark..
    Semiletov, Igor
    Univ Alaska Fairbanks, Int Arctic Res Ctr, Fairbanks, AK 99775 USA.;Russian Acad Sci, Far Eastern Branch, Pacific Oceanol Inst, Vladivostok 690041, Russia.;Natl Res Tomsk Polytech Univ, Tomsk, Russia..
    Stranne, Christian
    Ctr Coastal & Ocean Mapping, Joint Hydrog Ctr, Durham, NH 03824 USA..
    Stoven, Tim
    GEOMAR, Helmholtz Ctr Ocean Res Kiel, Kiel, Germany..
    Tanhua, Toste
    GEOMAR, Helmholtz Ctr Ocean Res Kiel, Kiel, Germany..
    Ulfsbo, Adam
    Univ Gothenburg, Dept Marine Sci, POB 461, S-40530 Gothenburg, Sweden.;Duke Univ, Nicholas Sch Environm, Div Earth & Ocean Sci, Durham, NC 27704 USA..
    Jakobsson, Martin
    Stockholm Univ, Dept Geol Sci, S-10691 Stockholm, Sweden..
    Shelf-Basin interaction along the East Siberian Sea2017In: Ocean Science, ISSN 1812-0784, E-ISSN 1812-0792, Vol. 13, no 2, p. 349-363Article in journal (Refereed)
    Abstract [en]

    Extensive biogeochemical transformation of organic matter takes place in the shallow continental shelf seas of Siberia. This, in combination with brine production from sea-ice formation, results in cold bottom waters with relatively high salinity and nutrient concentrations, as well as low oxygen and pH levels. Data from the SWERUS-C3 expedition with icebreaker Oden, from July to September 2014, show the distribution of such nutrient-rich, cold bottom waters along the continental margin from about 140 to 180 degrees E. The water with maximum nutrient concentration, classically named the upper halocline, is absent over the Lomonosov Ridge at 140 degrees E, while it appears in the Makarov Basin at 150 degrees E and intensifies further eastwards. At the intercept between the Mendeleev Ridge and the East Siberian continental shelf slope, the nutrient maximum is still intense, but distributed across a larger depth interval. The nutrient-rich water is found here at salinities of up to similar to 34.5, i.e. in the water classically named lower halocline. East of 170 degrees E transient tracers show significantly less ventilated waters below about 150 m water depth. This likely results from a local isolation of waters over the Chukchi Abyssal Plain as the boundary current from the west is steered away from this area by the bathymetry of the Mendeleev Ridge. The water with salinities of similar to 34.5 has high nutrients and low oxygen concentrations as well as low pH, typically indicating decay of organic matter. A deficit in nitrate relative to phosphate suggests that this process partly occurs under hypoxia. We conclude that the high nutrient water with salinity similar to 34.5 are formed on the shelf slope in the Mendeleev Ridge region from interior basin water that is trapped for enough time to attain its signature through interaction with the sediment.

  • 2.
    Andrén, Hanna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
    Tillförlitligheten hos översvämningskartering: Utbredningsjämförelse med översvämningen i Hallsberg 20152016Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
  • 3.
    Bishop, Kevin
    et al.
    Uppsala University.
    Seibert, Jan
    Uppsala University, Switzerland.
    Nyberg, Lars
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Rodhe, Allan
    Uppsala University.
    Water storage in a till catchment: II: Implications of transmissivity feedback for flow paths and turnover times2011In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 25, no 25, p. 3950-3959Article in journal (Refereed)
    Abstract [en]

    This paper explores the flow paths and turnover times within a catchment characterized by the transmissivity feedback mechanism where there is a strong increase in the saturated hydraulic conductivity towards the soil surface and precipitation inputs saturate progressively more superficial layers of the soil profile. The analysis is facilitated by the correlation between catchment water storage and groundwater levels, which made it possible to model the daily spatial distribution of water storage, both vertically in different soil horizons and horizontally across a 6300-m2 till catchment. Soil properties and episodic precipitation input dynamics, combined with the influence of topographic features, concentrate flow in the horizontal, vertical, and temporal dimensions. Within the soil profile, there was a vertical concentration of lateral flow to superficial soil horizons (upper 30 cm of the soil), where much of the annual flow occurred during runoff episodes. Overland flow from a limited portion of the catchment can contribute to peak flows but is not a necessary condition for runoff episodes. The spatial concentration of flow, and the episodic nature of runoff events, resulted in a strong and spatially structured differentiation of local flow velocities within the catchment. There were large differences in the time spent by the laterally flowing water at different depths, with turnover times of lateral flow across a 1-m-wide soil pedon ranging from under 1 h at 10- to 20-cm depth to a month at 70- to 80-cm depth. In many regards, the hydrology of this catchment appears typical of the hydrology in till soils, which are widespread in Fenno-Scandia.

  • 4.
    Blumenthal, Barbara
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    När Vänern svämmade över: Händelseutveckling och konsekvenser av översvämningen 2000/20012010Report (Other academic)
    Abstract [sv]

    Mellan november 2000 och juni 2001 låg Vänerns vattennivå över sjöns dämningsgräns i nästan 6 månader. Situationen orsakades av en utdragen period med ovanligt stora nederbördsmängder över Vänerns tillrinningsområde mellan oktober och mitten av december 2000. Sjöns nivå ökade under denna period i genomsnitt med 2 cm per dygn. Översvämningsproblemen började uppstå längs den ca 2000 km långa kusten (utan öar) från mitten av november. När sjöns nivå kulminerade den 11 januari 2001 hade olika aktörer lyckats vidta omfattande åtgärder i de översvämningshotade områdena som skyddade samhällsviktiga funktioner såsom VA, transporter och elförsörjning, men även bostäder och industrianläggningar.

    I en genomgång av skador och konsekvenser i samband med översvämningen visade det sig inte oväntat att det främst är tangibla1 direkta och indirekta skador som är beskrivna i olika dokument och sammanställningar som har tagits fram inom olika sektorer. Uppföljningar av långsiktiga konsekvenser av översvämningen och beskrivningar av hur interaktionen mellan olika sektorer påverkades av Vänerns höga nivåer saknas däremot med några få undantag. Rapporten kan inte ge någon heltäckande bild av de ekonomiska konsekvenser som Väneröversvämningen 2000/2001 har lett till. För en del sektorer som lantbruk, yrkesfisket och de kommunala verksamheterna i de drabbade Vänerkommunerna kunde ekonomiska värderingar hittas medan de saknas för skogsbruket, delar av transportsektorn och industrierna. I rapporten görs en uppskattning av hushållens skador i Värmland med hjälp skadebeloppen som utbetalades av Länsförsäkringar Värmland i samband med Väneröversvämningen.

    Kommunerna utmed Vänerkusten fick omfattande skador på avlopps- och dagvattennäten och reningsverken. Kommunala, strandnära fritidsområden såsom fritidshamnar, campingplatser, badplatser och sjönära gång- och cykelvägar skadades i nästan alla berörda kommuner. Efter översvämningen gav regeringen kommunerna möjlighet att ansöka om bidrag för direkta fysiska skador och kostnader för förebyggande åtgärder, t ex temporära invallningar. 

    Studien genomfördes med syfte att kunna bevara, återföra och nyttja erfarenheter från översvämningen 2000-2001 inför och under kommande översvämningssituationer med likartade eller högre nivåer. Studien är en del i Centrum för klimat och säkerhets deltagande inom EU–projektet SAWA (Strategic Alliance for integrated Water management Actions) vars målsättning bl a är att utveckla planer för hantering av översvämningsrisker. Studien är det första steget av en sårbarhetsstudie i Vänern som kommer att utföras vid Centrum för klimat och säkerhet under åren 2010/2011.

  • 5.
    Davies, Jessica
    et al.
    Lancaster University.
    Beven, Keith
    Lancaster University.
    Nyberg, Lars
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Rodhe, Allan
    Uppsala universitet.
    A discrete particle representation of hillslope hydrology: hypothesis testing in reproducing a tracer experiment at Gårdsjön, Sweden2011In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 25, no 23, p. 3602-3612Article in journal (Refereed)
    Abstract [en]

    Despite the long history of the continuum equation approach in hydrology, it is not a necessary approach to the formulation of a physically based representation of hillslope hydrology. The Multiple Interacting Pathways (MIPs) model is a discrete realization that allows hillslope response and transport to be simultaneously explored in a way that reflects the potential occurrence of preferential flows and lengths of pathways. The MIPs model uses random particle tracking methods to represent the flow of water within the subsurface alongside velocity distributions that acknowledge preferential flows and transition probability matrices, which control flow pathways. An initial realization of this model is presented here in application to a tracer experiment carried out in Gårdsjön, Sweden. The model is used as an exploratory tool, testing several hypotheses in relation to this experiment.

  • 6.
    Davies, Jessica
    et al.
    Lancaster University.
    Beven, Keith
    Lancaster University.
    Rodhe, Allan
    Uppsala universitet.
    Nyberg, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Centre for Climate and Safety.
    Bishop, Kevin
    Uppsala universitet.
    Integrated modeling of flow and residence times at the catchment scale with multiple interacting pathways2013In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 49, no 8, p. 4738-4750Article in journal (Refereed)
    Abstract [en]

    There is still a need for catchment hydrological and transport models that properly integrate the effects of preferential flows while accounting for differences in velocities and celerities. A modeling methodology is presented here which uses particle tracking methods to simulate both flow and transport in multiple pathways in a single consistent solution. Water fluxes and storages are determined by the volume and density of particles and transport is attained by labeling the particles with information that may be tracked throughout the lifetime of that particle in the catchment. The methodology allows representation of preferential flows through the use of particle velocity distributions, and mixing between pathways can be achieved with pathway transition probabilities. A transferable 3-D modeling methodology is presented for the first time and applied to a unique step-shift isotope experiment that was carried out at the 0.63 ha G1 catchment in Gårdsjön, Sweden. This application highlights the importance of combining flow and transport in hydrological representations, and the importance of pathway velocity distributions and interactions in obtaining a satisfactory representation of the observations.

  • 7.
    Evers, Mariele
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety. Bonn University.
    Participation in Flood risk Management: An introduction and recommendations for implementation2012Report (Other academic)
    Abstract [en]

    Involving interested parties in Flood Risk Management is a crucial and challenging issue. The implementation of the European Flood Directive requires the active participation of stakeholders. But how can this be achieved successfully? This publication gives a brief overview of participation issues in Flood Risk Management in order to prepare for and to assist participatory processes. It provides a synopsis of key issues, findings of literature research and project results in (public) participation in the field of water and flood risk management. 

    The focus here is on general aspects of (public) participation. This publication describes an understanding of what participation is and gives some definitions of relevant terms. Furthermore the question “why is participation important?” is considered and reasons for and against participation and potential barriers are described. Guidelines for the key questions that should be addressed before a participation process is started are offered and different working steps are explained. Finally, some examples of methods and tools for participation are described.

    However, this short description can only give an overview and orientation of this broad field. In fact, each project and process has to be adapted to the respective situation and conditions. Nevertheless, this brochure might contribute to the participatory process in Flood Risk Management and help to involve interested parties as required by the EU Floods Directive.

  • 8.
    Forsberg, Jan
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Tidsserieanalys av data från Sjöfartsverkets mätstationer i Vänern: En förstudie om seicher och uppstuvning i Vänersborgsviken2012Report (Other academic)
    Abstract [sv]

    Denna studie är finansierad av Centrum för klimat och säkerhet och har utförts vid avdelningen för Energi-, miljö- och byggteknik under 2011 - 2012. Barbara Blumenthal och Lars Nyberg vid Centrum för klimat och säkerhet har varit beställare och värdefulla diskussionspartners i studien.

    Förväntade klimatförändringar och kommunernas planer att bygga nära vatten förutsätter kunskaper om extrema nivåer i Vänern, i dess tillflöden och om extrema nivåers verkan på samhället. Sedan lång tid finns dygnsmedelvärden för nivån i Vänern, men ännu saknas kunskaper om nivåns rörelser i timskala. Fenomen som seicher och uppstuvning i Vänern uppträder i denna tidskala. Vid extrema dygnsmedelnivåer adderas riskerna från timvariationer i Vänerns nivå. Riskerna varierar från plats till plats.

    Under hösten 2011 har en av Sjöfartsverkets mätstationer i Vänern kompletterats med vindmätare. Stationen är placerad vid Dalbobron i Vänersborg och registrerar samtidig vindhastighet, vindriktning och vattennivå var tionde minut. Detta har gjort det möjligt att studera timvariationer i vattennivån i Vänersborgsviken, vars form förstärker uppträdande seicher och uppstuvningar. Studien visar att enkla bassängmodeller kan användas för att beräkna periodtiden hos möjliga seicher. Ett mindre antal tidsserieanalyser visar också på möjligheten att använda mätstationens data för att göra prognoser någon timme framåt i tiden, för den lokala nivån. Vid ett tillfälle under våren 2012 ändrades nivån 75 cm på mindre än 6 timmar vid vindstyrkor på 13 m/s, d.v.s. utan att vädret var extremt.

    Mätstationernas information tillåter enbart lokala nivåprognoser. För prognoser på en valfri plats vid Vänern krävs det förmodligen en dynamisk bassängmodell för Vänern och som utnyttjar informationen från mätstationerna.

  • 9.
    Gebrehiwot, Solomon Gebreyohannis
    et al.
    Justus Liebig University Giessen, Germany; Addis Ababa University, Ethiopia.
    Di Baldassarre, Giuliano
    Uppsala University; Centre of Natural Hazards and Disaster Science, Uppsala.
    Bishop, Kevin
    Swedish University of Agricultural Sciences, Uppsala,.
    Halldin, Sven
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Breuer, Lutz
    Justus Liebig University Giessen, Germany.
    Is observation uncertainty masking the signal of land use change impacts on hydrology?2019In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 570, p. 393-400Article in journal (Refereed)
    Abstract [en]

    Analysis of hydrological impacts of land use change raises questions about whether, and how much, such impacts are misrepresented because of errors in river flow observations. In this paper, land use change impacts (represented by changes in watershed storage) and different ranges of discharge measurement error are compared to assess how errors in discharge measurement can potentially mask a land use change impact. Using a watershed from the Ethiopian highlands to exemplify this, we simulated five different levels of land use change impacts with five levels of watershed storage reductions (from 10% to 50% change) and the associated time series of runoff. Different levels of observation error were then introduced into these artificial time series. Comparison was made between every pair, i.e. a time series derived from a certain level of land use change (storage reduction) versus a time series corresponding to a given level of observation error, using a step-change t-test. Significant step-changes between pairs define the detectability of land use change impact. The analysis was made for the entire 30-year time series as well as for the most extreme annual weather conditions. The results showed that for the average year and wettest year, 75% or more error in observed discharge masks the maximum simulated land use change impact on hydrology. In dry years, a 50% error in discharge is enough to mask the same impact. Knowing (and improving) the level of data quality contributes to a better understanding of hydrological uncertainties and improves the precision in assessing land use change impacts. Both of these are essential elements in water resources development planning.

  • 10.
    Lund Björnås, Kristine
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Spatially explicit models: planning salmonid habitat restoration in regulated rivers2019Report (Other academic)
  • 11.
    Nyberg, Lars
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Ripemo, Tord
    Klarälvens vattenkvalitet2011In: Klarälven / [ed] Hilde Ibsen, Eva Svensson, Lars Nyberg, Karlstad: Karlstad University Press, 2011, p. 129-144Chapter in book (Other academic)
  • 12.
    Reynolds, J. E.
    et al.
    Uppsala University, Uppsala; Centre of Natural Hazards and Disaster Science (CNDS), Uppsala.
    Halldin, Sven
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Seibert, J.
    Uppsala University; Stockholm University; University of Zurich.
    Xu, C. Y.
    Uppsala University; University of Oslo.
    Grabs, T.
    Uppsala University.
    Robustness of flood-model calibration using single and multiple events2019In: Hydrological Sciences Journal, ISSN 0262-6667, E-ISSN 2150-3435, p. 1-12Article in journal (Refereed)
    Abstract [en]

    Lack of discharge data for model calibration is challenging for flood prediction in ungauged basins. Since establishment and maintenance of a permanent discharge station is resource demanding, a possible remedy could be to measure discharge only for a few events. We tested the hypothesis that a few flood-event hydrographs in a tropical basin would be sufficient to calibrate a bucket-type rainfall-runoff model, namely the HBV model, and proposed a new event-based calibration method to adequately predict floods. Parameter sets were chosen based on calibration of different scenarios of data availability, and their ability to predict floods was assessed. Compared to not having any discharge data, flood predictions improved already when one event was used for calibration. The results further suggest that two to four events for calibration may considerably improve flood predictions with regard to accuracy and uncertainty reduction, whereas adding more events beyond this resulted in small performance gains.

  • 13.
    Seibert, Jan
    et al.
    Uppsala University; Switzerland.
    Bishop, Kevin
    Uppsala University.
    Nyberg, Lars
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Rodhe, Allan
    Uppsala University.
    Water storage in a till catchment: I: Distributed modelling and relationship to runoff2011In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 25, no 25, p. 3937-3949Article in journal (Refereed)
    Abstract [en]

    Although water storage is an important variable to understand the hydrological functioning of a catchment, it is challenging to estimate the total water storage in a catchment. Catchment water storage can be estimated on the basis of water balance, but this approach is prone to errors in the different water balance terms. Here, an approach is presented to estimate the daily dynamics of catchment-wide soil water and groundwater storage on the basis of groundwater-level observations, soil properties and an assumption of hydrological equilibrium above the water table. This approach was applied to a 6300-m2 till catchment in Southwest Sweden. The predicted mean catchment water storage between April 1991 and June 1992 was 210 mm and ranged from 190 to 260 mm. The estimated water storage followed runoff rates closely especially during recession periods. On average, 79% of the water storage was held in the unsaturated zone, and the remaining 21% was groundwater, but this proportion varied strongly with runoff and total storage. During dry conditions, unsaturated storage accounted for at maximum 95% of the water storage; during wet conditions, this number dropped to 40%.

  • 14.
    Su, X.
    et al.
    Southwest University, Chongqing, China.
    Lind, L.
    Umå universitet.
    Polvi, L. E.
    Umeå universitet.
    Nilsson, C.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Variation in hydrochory among lakes and streams: Effects of channel planform, roughness, and currents2019In: Ecohydrology, ISSN 1936-0584, E-ISSN 1936-0592, article id e2091Article in journal (Refereed)
    Abstract [en]

    The configuration of channels in stream networks is vital for their connectivity, biodiversity, and metacommunity dynamics. We compared the capacity of three process domains—lakes, slow-flowing reaches, and rapids—to disperse and retain plant propagules by releasing small wooden cubes as propagule mimics during the spring flood and recording their final locations. We also measured the geomorphic characteristics (planform, longitudinal profile, cross-sectional morphology, and wood) of each process domain. The three process domains all differed in morphology and hydraulics, and those characteristics were important in shaping the transport capacity of mimics. On average, lakes retained more mimics than slow-flowing reaches but did not differ from the retainment of rapids. Living macrophytes were the most efficient element trapping mimics. In rapids and slow-flowing reaches, most trapped mimics remained floating, whereas in lakes, most mimics ended up on the banks. The decay curves of retention varied substantially among and within process domains. The results suggest that managers who rely on natural recovery of restored sites by means of plant immigration may benefit from understanding landscape patterns when deciding upon the location of restoration measures in stream networks.

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