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  • 201. Bjork, Goran
    et al.
    Stranne, Christian
    Borenäs, Karin
    SMHI, Core Services.
    The Sensitivity of the Arctic Ocean Sea Ice Thickness and Its Dependence on the Surface Albedo Parameterization2013In: Journal of Climate, ISSN 0894-8755, E-ISSN 1520-0442, Vol. 26, no 4, 1355-1370 p.Article in journal (Refereed)
    Abstract [en]

    In this study, the response of sea ice thickness to changes in the external forcing is investigated and particularly how this response depends on the surface albedo formulation by means of a one-dimensional coupled ocean-ice-atmosphere model. The main focus is on the thickness response to the atmospheric heat advection F-wall, solar radiation F-SW, and amount of snow precipitation S-prec. Different albedo parameterization schemes [ECHAM5, CSIRO, and Community Climate System Model, version 3 (CCSM3)] representing albedos commonly used in global climate models are compared together with more simplified schemes. Using different albedo schemes with the same external forcing produces large differences in ice thickness. The ice thickness response is similar for all realistic albedo schemes with a nearly linear decrease with increasing F-wall in the perennial ice regime and with a steplike transition into seasonal ice when F-wall exceeds a certain threshold. This transition occurs at an annual-mean ice thickness of 1.7-2.0 m. Latitudinal differences in solar insolation generally leads to increasing ice thickness toward the North Pole. The snow response varies significantly depending on which albedo scheme is used. The ECHAM5 scheme yields thinner ice with S-prec, the CSIRO scheme gives ice thickness nearly independent of S-prec, and with the CCSM3 scheme the ice thickness decreases with S-prec. A general result is that the modeled ice cover is rather sensitive to positive perturbations of the external heat supply when it is close to the transition such that just a small increase of, for example, F-wall can force the ice cover into the seasonal regime.

  • 202. Björk, G
    et al.
    Nohr, C
    Gustafsson, BG
    Lindberg, Amund E. B.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ice dynamics in the Bothnian Bay inferred from ADCP measurements2008In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 60, no 1, 178-188 p.Article in journal (Refereed)
    Abstract [en]

    A bottom mounted ADCP has monitored the ice motion and thickness in Bothnian Bay, Baltic Sea during the entire winter season 2004. The ADCP was deployed at 20 m depth at Falkensgrund well outside the land fast ice zone. The data shows that the ice motion is primarily driven by the wind but with a clear influence of internal ice stresses. The ice stresses become more dominant as the ice grow thicker with increasing number of observations with nearly stationary ice for relatively high wind speeds. A clear dependence of the ice/wind speed ratio to wind shifts is detected with higher ratio in the new wind direction. The effect of strain hardening is also seen in several events as decreasing ice speed, sometimes to zero, in spite of constant wind speed and wind direction. A rough force balance computation gives a compressive ice strength of about  9 × 104 N m−2 , which is much larger than normally used in numerical ice models. The ice thickness data show numerous ice ridges with ice draft well above 1 m passing the instrument. The ridges make up a large portion, 30–50%, of the total ice volume showing that dynamical processes are important for the total ice production in the Bothnian Bay.

  • 203. Blauw, A. N.
    et al.
    Anderson, P.
    SMHI.
    Estrada, M.
    Johansen, M.
    Laanemets, J.
    Peperzak, L.
    Purdie, D.
    Raine, R.
    Vahtera, E.
    The use of fuzzy logic for data analysis and modelling of European harmful algal blooms: results of the HABES project2006In: African Journal of Marine Science, ISSN 1814-232X, E-ISSN 1814-2338, Vol. 28, no 2, 365-369 p.Article in journal (Refereed)
    Abstract [en]

    Fuzzy logic was applied to model blooms of Nodularia spumigena, Dinophysis spp., Alexandrium minutum, Karenia mikimotoi and Phaeocystis globosa at various European sites as part of the Harmful Algal Blooms Expert System (HABES) project. This modelling approach was useful in performing integrated analyses of interacting physical and biological factors involved in HABs. A basic knowledge of HAB formation and sufficient data are a prerequisite for successful bloom prediction.

  • 204. Bloeschl, Guenter
    et al.
    Hall, Julia
    Parajka, Juraj
    Perdigao, Rui A. P.
    Merz, Bruno
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Aronica, Giuseppe T.
    Bilibashi, Ardian
    Bonacci, Ognjen
    Borga, Marco
    Canjevac, Ivan
    Castellarin, Attilio
    Chirico, Giovanni B.
    Claps, Pierluigi
    Fiala, Kayroly
    Frolova, Natalia
    Gorbachova, Liudmyla
    Gul, Ali
    Hannaford, Jamie
    Harrigan, Shaun
    Kireeva, Maria
    Kiss, Andrea
    Kjeldsen, Thomas R.
    Kohnova, Silvia
    Koskela, Jarkko J.
    Ledvinka, Ondrej
    Macdonald, Neil
    Mavrova-Guirguinova, Maria
    Mediero, Luis
    Merz, Ralf
    Molnar, Peter
    Montanari, Alberto
    Murphy, Conor
    Osuch, Marzena
    Ovcharuk, Valeryia
    Radevski, Ivan
    Rogger, Magdalena
    Salinas, Jose L.
    Sauquet, Eric
    Sraj, Mojca
    Szolgay, Jan
    Viglione, Alberto
    Volpi, Elena
    Wilson, Donna
    Zaimi, Klodian
    Zivkovic, Nenad
    Changing climate shifts timing of European floods2017In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 357, no 6351, 588-590 p.Article in journal (Refereed)
  • 205.
    Blomberg, Freddy
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Inläckage i dagbrott: En jämförelse mellan beräknade och uppmätta värden i dagbrott i norra Sverige2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Before the construction of an open pit mine is initialized it is common practice to perform hydrogeological surveys, in order to quantify the inflow of groundwater from surrounding soil and bedrock layers. As expansion of the pits progress, continuous pumping will need to be done, as groundwater will otherwise fill the pits, preventing further mining. Several quantification methods are available for these analyses, which can be either analytical or numerical in their structure. In this study, a review of established methods is performed. Then the inflow to five active mines in northern Sweden are estimated, using four analytical methods. The results from using these methods are then compared to the measured pumping rates in the mines, to evaluate the methods efficiency in estimating the correct withdrawal. One of the mines is also evaluated using a numerical model. All methods approximate the inflow rates to the same order of magnitude as the measured values. However, the same method can in some mines overestimate the inflow while in other mines make an underestimation of it. As they in most cases make an adequate approximation of the inflow, further use of the methods are recommended. Smaller adjustments might be needed based on local knowledge of the modeled area. The sensitivity analysis that was performed show a significant predisposition toward changes in hydraulic conductivity, emphasizing the importance of thorough surveys before parameterization of the models.

  • 206.
    Blomgren, Axel
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Stockholms grundvattenkvalitet: Bidrag till övergödningen av ytvattendrag och sjöar i Stockholmsområdet2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Eutrophication is one of Sweden’s most severe environmental issues. Due to emissions through anthropogenic activity nutrients are added to aquatic systems. The latest analysis of the Stockholm municipality groundwater has examined the levels of nitrogen and phosphorus. Due to the fact that the groundwater is part of the hydrological cycle and will eventually reach the surface water, the condition of the groundwater will affect the recipient and correlating ecosystem. This report aims to analyze the levels of nitrogen and phosphorus in the groundwater of Stockholm based on current national quality standards, and to identify whether the groundwater is contributing to the eutrophication of the surface water bodies in the municipality of Stockholm. This is of significance regarding the water management in Stockholm municipality, based on the EU water framework directive, and the target of achieving good status for all water bodies. It is also of great importance regarding the Swedish environmental quality objectives.

    The groundwater quality analysis indicates high levels of phosphorus and ammonium. The nitrate and nitrite levels are only excessive in certain cases. Primarily, the levels of phosphorus and ammonium may, according to national quality standards, have eutrophic effect on surface water bodies. A cursory examination based on the flow directions of the groundwater, indicates that the municipality’s surface waters are supplied with water from the municipality’s groundwater. This correlation is represented in the analysis of groundwater quality and it is therefore concluded that the groundwater has a negative impact on the surface water bodies within the municipality. 

  • 207.
    Blomqvist (Jonsson), Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Food and Fashion: Water Management and Collective Action among Irrigation Farmers and Textile Industrialists in South India1996Doctoral thesis, monograph (Other academic)
    Abstract [en]

    In recent years, much ofthe political debate in the West, East aud South has focused on the decentralization of responsibilities from the state to private enterprises and NGOs. But what potential is there for local communities to create their own govenlance structures able to deal with issues up till recently seen as the responsibility of the state? In this thesis, answer to this question is sought by analyzing two case studies from the semi-arid Coimbatore-region in South India from an institutionai perspective. One case concerns the efforts to involve farmers in irrigation water management in the Lower Bhavani Project, while the other focuses on the pressure on textile industrialists in Tirupur city to collectively treat their polluted effluent water.

    In both cases, the new distribution ofresponsibilities required that groups ofwater users would succeed in establishing new entities for collective action among themselves strong enough to prevent free-riding on a massive scale. Overcoming three main obstacles proved crucial in this process; meeting coordination costs, re-defining the notion of free-riding among resource users, and meeting motivation costs. Factors both within and outsicte the loeal community affected the degree ofsuccess.

    The distribution and lise of economic, moral and physical power between various actors and the interconnectedness between local and external institutions proved crucial for the establishrnent oflocal govemance stmctures. Moreover, the historical relation between the respective user group and the state has to a large extent affected the goals and strategies oflocal entities of eolleetive action.

    Clearly, resource management problems at localleve1 can not be solved by simply decentralizing responsibilities from the state to groups ofresource users. Rather, the state could playan important role by initiating, supporting and directing slich local entities of collective action.

  • 208.
    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.

  • 209.
    Bockgård, N.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. LUVA.
    Niemi, A.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. LUVA.
    Role of soil-rock interaction on recharge into fractured rock2003In: Proceedings of TOUGH Symposium 2003 , May 12–14, 2003, 2003Conference paper (Refereed)
  • 210.
    Bockgård, N., Rodhe, A.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. AIR AND WATER SCIENCE.
    An experimental study of groundwater recharge to fractured bedrock2003In: Proceedings of the IAH International Conference on GROUNDWATER IN FRACTURED ROCKS, Prague 15-19 September 2003,J. Krasny, Z. Hrkal, J. Bruthans (Eds.), Prague: International Association of Hydrogeologists , 2003Conference paper (Refereed)
  • 211.
    Bockgård, Niclas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. HYDROLOGY.
    Environmental tracer methods for dating of young groundwaters2000In: XXI Nordic Hydrological Conference; T. Nilsson Ed., Uppsala: Swedish Hydrological Council , 2000, Vol. 2, 503-509 p.Conference paper (Refereed)
  • 212.
    Bockgård, Niclas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Groundwater Recharge in Crystalline Bedrock: Processes, Estimation, and Modelling2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Knowledge about the groundwater recharge is essential for the prediction of impacts of groundwater withdrawal and underground construction. Recharge in the bedrock is, however, difficult to estimate. The objectives of this thesis were to increase the understanding of groundwater recharge in crystalline bedrock, to investigate how the recharge could be estimated, and to develop new models to describe the recharge. The study was based on three approaches: groundwater dating using chlorofluorocarbons (CFCs), geohydraulic field measurements, and mathematical modelling.

    Low concentrations of CFC-11 and CFC-113 were found in the bedrock groundwater, which in combination with low dissolved-oxygen levels indicated anaerobe degradation. The CFC-12 and tritium concentrations agreed fairly well, which means that apparent ages could be true ages. The results suggest that CFC dating may not be reliable at forested, humid sites covered by fine-grained soil.

    A quick response in hydraulic head to precipitation was observed in the studied bedrock, despite the 10-m thick till cover. A substantial portion of observed head variations was found to be loading effects, involving no storage changes or water flow. The loading efficiency of the bedrock was estimated, from the air-pressure response, to be 0.95. The surface loading was calculated from measurements of air pressure, water in the soil, and snow. About 20% of the seasonal variation of the hydraulic head was estimated to be related to loading changes only. A simple conceptual model could be used to simulate the observed hydraulic heads. The loading effect had to be included to properly describe individual recharge events.

    Numerical experiments were performed with a soil–bedrock profile. When the rock was modelled as a heterogeneous continuum, unsaturated zones developed at high hydraulic gradients. The phenomenon appeared in areas where low-conductive zones were located upstream of high-conductive zones, decreasing the effective hydraulic conductivity of the material.

  • 213.
    Bockgård, Niclas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. HYDROLOGY.
    Recharge of groundwater in crystalline rock: a review2000Report (Other scientific)
  • 214.
    Bockgård, Niclas
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. LUVA.
    Niemi, Auli
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. LUVA.
    Role of rock heterogeneity on lateral diversion of water flow at the soil-rock interface2004In: Vadose Zone Journal, ISSN 1539-1663, Vol. 3, no 3, 786-795 p.Article in journal (Refereed)
  • 215.
    Bockgård, Niclas
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Air and Water Science.
    Rodhe, Allan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Air and Water Science.
    Experiences of CFC dating of groundwater in central Sweden2004Report (Other scientific)
  • 216.
    Bockgård, Niclas
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Air and Water Science.
    Rodhe, Allan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Air and Water Science.
    Olsson, K Anders
    Accuracy of CFC groundwater dating in a crystalline bedrock aquifer: Data from a site in southern Sweden2004In: Hydrogeology Journal, ISSN 1431-2174, Vol. 12, no 2, 171-183 p.Article in journal (Refereed)
    Abstract [en]

    The concentrations of chlorofluorocarbons (CFC-11, CFC-12, and CFC-113) and tritium were determined in groundwater in fractured crystalline bedrock at Finnsjon, Sweden. The specific goal was to investigate the accuracy of CFC dating in such an environment, taking potential degradation and mixing of water into consideration. The water was sampled to a depth of 42 m in three boreholes along an 800-m transect, from a recharge area to a local discharge area. The CFC-113 concentration was at the detection limit in most samples. The apparent recharge date obtained from CFC-11 was earlier than from CFC-12 for all samples, with a difference of over 20 years for some samples. The difference was probably caused by degradation of CFC-11. The CFC-12 dating of the samples ranged from before 1945 to 1975, with the exception of a sample from the water table, which had a present-day concentration. Conclusions about flow paths or groundwater velocity could not be drawn from the CFCs. The comparison between CFC-12 and tritium concentrations showed that most samples could be unmixed or mixtures of waters with different ages, and the binary mixtures that matched the measured concentrations were determined. The mixing model approach can be extended with additional tracers.

  • 217.
    Bonaglia, Stefano
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Hylén, Astrid
    Rattray, Jayne E.
    Kononets, Mikhail Y.
    Ekeroth, Nils
    Roos, Per
    Thamdrup, Bo
    Brüchert, Volker
    Hall, Per O. J.
    The fate of fixed nitrogen in marine sediments with low organic loading: an in situ study2017In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 14, no 2, 285-300 p.Article in journal (Refereed)
    Abstract [en]

    Over the last decades, the impact of human activities on the global nitrogen (N) cycle has drastically increased. Consequently, benthic N cycling has mainly been studied in anthropogenically impacted estuaries and coasts, while in oligotrophic systems its understanding is still scarce. Here we report on benthic solute fluxes and on rates of denitrification, anammox, and dissimilatory nitrate reduction to ammonium (DNRA) studied by in situ incubations with benthic chamber landers during two cruises to the Gulf of Bothnia (GOB), a cold, oligotrophic basin located in the northern part of the Baltic Sea. Rates of N burial were also inferred to investigate the fate of fixed N in these sediments. Most of the total dissolved fixed nitrogen (TDN) diffusing to the water column was composed of organic N. Average rates of dinitrogen (N-2) production by denitrification and anammox (range: 53-360 mu mol Nm(-2) day(-1)) were comparable to those from Arctic and subarctic sediments worldwide (range: 34-344 mu mol Nm(-2) day(-1)). Anammox accounted for 18-26% of the total N2 production. Absence of free hydrogen sulfide and low concentrations of dissolved iron in sediment pore water suggested that denitrification and DNRA were driven by organic matter oxidation rather than chemolithotrophy. DNRA was as important as denitrification at a shallow, coastal station situated in the northern Bothnian Bay. At this pristine and fully oxygenated site, ammonium regeneration through DNRA contributed more than one-third to the TDN efflux and accounted, on average, for 45% of total nitrate reduction. At the offshore stations, the proportion of DNRA in relation to denitrification was lower (0-16% of total nitrate reduction). Median value and range of benthic DNRA rates from the GOB were comparable to those from the southern and central eutrophic Baltic Sea and other temperate estuaries and coasts in Europe. Therefore, our results contrast with the view that DNRA is negligible in cold and well-oxygenated sediments with low organic carbon loading. However, the mechanisms behind the variability in DNRA rates between our sites were not resolved. The GOB sediments were a major source (237 kt yr(-1), which corresponds to 184% of the external N load) of fixed N to the water column through recycling mechanisms. To our knowledge, our study is the first to document the simultaneous contribution of denitrification, DNRA, anammox, and TDN recycling combined with in situ measurements.

  • 218. Bonk, Alicja
    et al.
    Kinder, Małgorzata
    Enters, Dirk
    Grosjean, Martin
    Meyer-Jacob, Carsten
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Tylmann, Wojciech
    Sedimentological and geochemical responses of Lake Żabińskie (north-eastern Poland) to erosion changes during the last millennium2016In: Journal of Paleolimnology, ISSN 0921-2728, E-ISSN 1573-0417, Vol. 56, no 2-3, 239-252 p.Article in journal (Refereed)
    Abstract [en]

    Increased erosion triggered by land-use changes is a major process that influences lake sedimentation. We explored the record of erosion intensity in annually laminated sediments of Lake Żabińskie, northeast Poland. A 1000-year-long, annually resolved suite of sedimentological (varve thickness, sediment accumulation rate) and geochemical data (scanning XRF, loss on ignition, biogenic silica) was analyzed with multivariate statistics. PCA indicated erosion was a major process responsible for changes in the chemical composition of the sediments. Analysis of sedimentary facies enabled identification of major phases of erosion that influenced lake sedimentation. These phases are consistent with the history of land use, inferred from pollen analysis. From AD 1000 to 1610, conditions around and in Lake Żabińskie were relatively stable, with low erosion intensity in the catchment and a dominance of carbonate sedimentation. Between AD 1610 and 1740, higher lake productivity and increased delivery of minerogenic material were caused by development of settlements in the region and widespread deforestation. The most prominent changes were observed between AD 1740 and 1880, when further land clearance and increased agricultural activity caused intensified soil erosion and higher lake productivity. Landscape clearance also created better conditions for water column mixing, which led to changes in redox conditions in the hypolimnion. The most recent period (AD 1880–2010) was characterized by partial reforestation and a gradual decrease in the intensity of erosional processes.

  • 219.
    Borenäs, Karin
    et al.
    SMHI, Core Services.
    Hietala, R.
    Laanearu, J.
    Lundberg, P.
    Some estimates of the Baltic deep-water transport through the Stolpe trench2007In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 59, no 2, 238-248 p.Article in journal (Refereed)
    Abstract [en]

    The subsurface flow of high-saline water masses from the Bornholm Basin through the Stolpe Channel plays an important role for the renewal of the Baltic Central Basin deep waters. In order to determine whether rotating 11/2-layer hydraulic theory is an appropriate tool for describing this process, maximal-transport estimates based on climatological data from the Bornholm and Gdansk Basins have been established. These were found to deviate considerably from observational realities, and hence similar hydraulic considerations were also applied to more-or-less synoptic field data from a Finnish field campaign carried through in the mid-1980s. Also in this case significant differences were found between calculated transport capacity and observations. Since it furthermore was demonstrated that the characteristics of the observed cross-channel hydrographic structure could be explained using a frictional-balance model of the deep-water flow, it has been concluded that a hydraulic framework, although providing an upper bound of the transport, is of limited use when dealing with the Stolpe-Channel overflow. Although it cannot be excluded that the inflow is inviscid, but submaximal, it is more likely that the transport is governed by the combined effects of friction and wind forcing.

  • 220.
    Borenäs, Karin
    et al.
    SMHI, Core Services.
    Lake, Irene
    Lundberg, P A
    On the intermediate water masses of the Faroe-Bank Channel overflow2001In: Journal of Physical Oceanography, ISSN 0022-3670, E-ISSN 1520-0485, Vol. 31, no 7, 1904-1914 p.Article in journal (Refereed)
    Abstract [en]

    A review of available hydrographic data from the Faroe-Bank Channel indicates that North Icelandic/Arctic Intermediate water masses are present in the passage to a larger extent than was previously believed. The presently compiled statistics, including results on the seasonality, are discussed in relation to previous investigations. Finally, a high quality subset of the hydrographic data is used for an analysis of the alongchannel mixing of the intermediate water masses.

  • 221.
    Borenäs, Karin
    et al.
    SMHI, Core Services.
    Lundberg, P
    The Faroe-Bank channel deep-water overflow2004In: Deep-sea research. Part II, Topical studies in oceanography, ISSN 0967-0645, E-ISSN 1879-0100, Vol. 51, no 4-5, 335-350 p.Article in journal (Refereed)
    Abstract [en]

    In the late 1950s it was recognised that a considerable transport of water from the deeper reaches of the Norwegian Sea into the Atlantic takes place through the Faroe-Bank Channel, which thereby serves as an important source for the renewal of the North Atlantic Deep Water. Consequently, substantial efforts have, over the past decades, been dedicated towards quantifying the overflow as well as clarifying the underlying dynamics. In the present review, an attempt is made to summarise the main body of the observational results as well as some theoretical considerations regarding the dynamical mechanisms. The most prominent characteristic of the Faroe-Bank Channel overflow is that it is a persistent phenomenon with a yearly average deep-water (viz. T<5degreesC) transport of around 2 Sv. Using inviscid rotating hydraulics, the flow through the controlling section at the sill, furthermore, can be reasonably well predicted on the basis of upstream conditions in the Norwegian Sea. After passing the threshold the descending overflow plume is subject to intense mixing, a process very much in the focus of ongoing research. (C) 2004 Elsevier Ltd. All rights reserved.

  • 222.
    Bosshard, Thomas
    et al.
    SMHI, Research Department, Hydrology.
    Carambia, M.
    Goergen, K.
    Kotlarski, S.
    Krahe, P.
    Zappa, M.
    Schaer, C.
    Quantifying uncertainty sources in an ensemble of hydrological climate-impact projections2013In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 49, no 3, 1523-1536 p.Article in journal (Refereed)
    Abstract [en]

    The quantification of uncertainties in projections of climate impacts on river streamflow is highly important for climate adaptation purposes. In this study, we present a methodology to separate uncertainties arising from the climate model (CM), the statistical postprocessing (PP) scheme, and the hydrological model (HM). We analyzed ensemble projections of hydrological changes in the Alpine Rhine (Eastern Switzerland) for the near-term and far-term scenario periods 2024-2050 and 2073-2099 with respect to 1964-1990. For the latter scenario period, the model ensemble projects a decrease of daily mean runoff in summer (-32.2%, range [-45.5% to -8.1%]) and an increase in winter (+41.8%, range [+4.8% to +81.7%]). We applied an analysis of variance model combined with a subsampling procedure to assess the importance of different uncertainty sources. The CMs generally are the dominant source in summer and autumn, whereas, in winter and spring, the uncertainties due to the HMs and the statistical PP gain importance and even partly dominate. In addition, results show that the individual uncertainties from the three components are not additive. Rather, the associated interactions among the CM, the statistical PP scheme, and the HM account for about 5%-40% of the total ensemble uncertainty. The results indicate, in distinction to some previous studies, that none of the investigated uncertainty sources are negligible, and some of the uncertainty is not attributable to individual modeling chain components but rather depends upon interactions. Citation: Bosshard, T., M. Carambia, K. Goergen, S. Kotlarski, P. Krahe, M. Zappa, and C. Schar (2013), Quantifying uncertainty sources in an ensemble of hydrological climate-impact projections, Water Resour. Res., 49, 1523-1536, doi: 10.1029/2011WR011533.

  • 223.
    Bosshard, Thomas
    et al.
    SMHI, Research Department, Hydrology.
    Kotlarski, Sven
    Zappa, Massimiliano
    Schaer, Christoph
    Hydrological Climate-Impact Projections for the Rhine River: GCM-RCM Uncertainty and Separate Temperature and Precipitation Effects2014In: Journal of Hydrometeorology, ISSN 1525-755X, E-ISSN 1525-7541, Vol. 15, no 2, 697-713 p.Article in journal (Refereed)
    Abstract [en]

    Climate change is expected to affect the hydrological cycle, with considerable impacts on water resources. Climate-induced changes in the hydrology of the Rhine River (Europe) are of major importance for the riparian countries, as the Rhine River is the most important European waterway, serves as a freshwater supply source, and is prone to floods and droughts. Here regional climate model data from the Ensemble-Based Predictions of Climate Changes and their Impacts (ENSEMBLES) project is used to drive the hydrological model Precipitation-Runoff-Evapotranspiration-Hydrotope (PREVAH) and to assess the impact of climate change on the hydrology in the Rhine basin. Results suggest increases in monthly mean runoff during winter and decreases in summer. At the gauge Cologne and for the period 2070-99 under the A1B scenario of the Special Report on Emissions Scenarios, projected decreases in summer vary between -9% and -40% depending on the climate model used, while increases in winter are in the range of +4% to +51%. These projected changes in mean runoff are generally consistent with earlier studies, but the derived spread in the runoff projections appears to be larger. It is demonstrated that temperature effects (e.g., through altered snow processes) dominate in the Alpine tributaries, while precipitation effects dominate in the lower portion of the Rhine basin. Analyses are also presented for selected extreme runoff indices.

  • 224. Bots, Pieter
    et al.
    Gooch, Geoffrey
    Linköping University, Department of Management and Engineering, Political Science. Linköping University, Faculty of Arts and Sciences.
    Understanding the role of perception and valuation in the development and use of models for water management2010In: Integrated Assessment for Water Framework Directive Implementation: data, economic and Human Dimension / [ed] Vanrolleghem, P., London: IWA , 2010Chapter in book (Other academic)
    Abstract [en]

    Integrated Assessment for Water Framework Directive Implementation: Data, Economic and Human Dimension - Volume 2 is a concrete outcome from the Harmoni-CA concerted action as part of a 4-volume series of Guidance Reports that guide water professionals through the implementation process of the Water Framework Directive, with a focus on the use of ICT-tools (and in particular modelling). They are complementary to the Guidance Documents produced by the EU Directorate General for Environment.  Water resources planning and management and the development of appropriate policies require methodologies and tools that are able to support systematic, integrative and multidisciplinary assessments at various scales. It also requires the quantification of various uncertainties in both data and models, and the incorporation of stakeholders participation and institutional mechanisms into the various tools and risk assessment methodologies, to help decision makers understand and evaluate alternative measures and decisions.

  • 225.
    Bouwman, Henk
    et al.
    Northwest University, South Africa.
    Choong Kwe Yive, Nee Sun
    University of MAuritius.
    Kylin, Henrik
    Linköping University, The Tema Institute, Department of Water and Environmental Studies.
    Polder, Anushka
    Veterinary Institute, Norway.
    Organic pollutants in term eggs from Rodrigues Island – Indian Ocean.2012Conference paper (Other academic)
  • 226.
    Bouwman, Henk
    et al.
    Nort-West University, South Africa.
    Krátká, M
    Masaryk University, Czech Republic.
    Choong Kwet Yive, Nee Sun
    University of Mauritius, Mauritius.
    Kylin, Henrik
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Klanova, Jana
    Masaryk University, Czech Republic.
    Do POPs Transfer from Plastic Marine Debris to Coral on Tropical Islands?2014In: Organohalogen Compounds, ISSN 1026-4892, Vol. 76, 1352-1355 p.Article in journal (Refereed)
  • 227.
    Bouwman, Hindrik
    et al.
    North-West Uniersity, South AFrica.
    Evans, Steven
    University of Venda, South Africa.
    Cole, Nik
    Durrell Wildlife Conservation Trust, Jersey, Channel Isles, UK.
    Choong Kwer Yive, Nee Sun
    University of Mauritius, Mauritius.
    Kylin, Henrik
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    The flip-or-flop boutique: Marine debris on the shores of St Brandon’s Rock, an isolated tropical atoll in the Indian Ocean2016In: Marine Environmental Research, ISSN 0141-1136, E-ISSN 1879-0291, Vol. 114, 58-64 p.Article in journal (Refereed)
    Abstract [en]

    Isolated coral atolls are not immune from marine debris accumulation. We identified Southeast Asia, the Indian sub-continent, and the countries on the Arabian Sea as most probable source areas of 50 000 items on the shores of St. Brandon’s Rock (SBR), Indian Ocean. 79% of the debris was plastics. Flip-flops, energy drink bottles, and compact fluorescent lights (CFLs) were notable item types. The density of debris (0.74 m-1 shore length) is comparable to similar islands but less than mainland sites. Intact CFLs suggests product-facilitated long-range transport of mercury. We suspect that aggregated marine debris, scavenged by the islands from currents and gyres, could re-concentrate pollutants. SBR islets accumulated debris types in different proportions suggesting that many factors act variably on different debris types. Regular cleaning of selected islets will take care of most of the accumulated debris and may improve the ecology and tourism potential. However, arrangements and logistics require more study.

    The full text will be freely available from 2018-01-04 04:57
  • 228.
    Bouwman, Hindrik
    et al.
    North West University, South Africa .
    Kylin, Henrik
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Sun Choong Kwet Yive, Nee
    Mauritian Wildlife Fdn, Mauritius .
    Loken, Katharina
    Norwegian School Vet Science, Norway .
    Utne Skaare, Janneche
    Norwegian School Vet Science, Norway .
    Polder, Anuschka
    Norwegian School Vet Science, Norway .
    First report of chlorinated and brominated hydrocarbon pollutants in marine bird eggs from an oceanic Indian Ocean island2012In: Environmental Research, ISSN 0013-9351, E-ISSN 1096-0953, Vol. 118, 53-64 p.Article in journal (Refereed)
    Abstract [en]

    We report for the first time levels of persistent organic pollutants in marine bird eggs from an oceanic island in the Indian Ocean, the worlds third largest ocean. Ten eggs each of the Common Noddy, also known as the Brown Noddy (Anous stolidus), and Sooty Tern (Sterna fuscata) were collected from Ile Cocos off the coast of the island of Rodrigues, located 560 km east of the island of Mauritius. Sigma PCBs had the highest levels (2.2 and 2.6 ng/g wm, wet mass; 20 and 19 ng/g lm, lipid mass) for common Noddy and Sooty Tern, respectively (and following), then Sigma DDT (1.9 and 3.1 ng/g wm; 17 and 23 ng/g lm), and mirex (0.96 and 0.69 ng/g wm; 8.7 and 5.0 ng/g lm). Sigma Chlordanes (0.094 and 0.15 ng/g wm; 0.48 and 0.73 ng/g lm) and Sigma toxaphenes (0.26 and 0.61 ng/g wm; 2.4 and 5.9 ng/g lm) are rare data for these compounds from this ocean. Brominated flame retardants were low (0.08 and 0.07 ng/g wm; 0.7 and 0.7 ng/g lm). Multivariate analyses indicated different contamination patterns in the prey items as Sooty Terns had significantly higher levels of mean Sigma chlordanes and Sigma toxaphenes, as well as CB105, -108 and -157. p,p-DDE had an association with thinner eggshells in the Sooty Tern. Although the contaminant levels were in all respects low, industrialisation, development on the periphery, commercial exploitation of the marine environment, and pollutants transferred over long distances by marine debris is likely to add to chemical pressure in this region. Monitoring changes in background levels of pollutants in remote regions will indicate such trends, and marine bird eggs from Rodrigues would be an excellent site.

  • 229.
    Brage, Markus
    Executive, Länsstyrelser, Länsstyrelsen Gävleborg.
    Svartån och dess omgivning: En beskrivning och sammanställning av befintligt material2008Report (Other academic)
    Abstract [sv]

    Svartån och dess omgivning- En beskrivning och sammanställning av befintligt material

  • 230. BRANDIMARTE, L
    et al.
    BRATH, A
    CASTELLARIN, A
    Di Baldassarre, Giuliano
    School of Civil Engineering (Dept. DISTART), University of Bologna, Italy Viale Risorgimento, 2, Bologna I-40136, Italy.
    Isla Hispaniola: A trans-boundary flood risk mitigation plan2009In: Physics and chemistry of the earth. Part A: Solid earth and geodesy, ISSN 1464-1895, E-ISSN 1873-4642, Vol. 34, no 4-5, 209-218 p.Article in journal (Refereed)
  • 231. Brandimarte, L
    et al.
    Di Baldassarre, Giuliano
    UNESCO-IHE Institute for Water Education, Westvest 7, P.O. Box 3015, 2601, DA, Delft, The Netherlands .
    Bruni, G
    D’Odorico, P
    Montanari, A
    Relation Between the North-Atlantic Oscillation and Hydroclimatic Conditions in Mediterranean Areas2011In: Water Resources Management, Vol. 25, no 5, 1269-1279 p.Article in journal (Refereed)
    Abstract [en]

    Mediterranean basins are known for their susceptibility to water stress conditions resulting from a reduction in winter-season precipitation. This region is also prone to the effects of the North Atlantic Oscillation (NAO), a large-scale climatic pattern associated with a displacement of air mass between the arctic and the subtropical Atlantic. Even though previous studies have demonstrated the impact of the NAO on winter climate conditions in Europe and Northern Africa, it is still unclear to what extent the NAO is related to hydroclimatic patterns in Mediterranean areas and whether it can explain its recent drought history. To this end, this study investigates the interdependence between the NAO and winter precipitation, river flow and temperature in two Mediterranean regions: Southern Italy and Nile Delta (Egypt). The outcomes show the presence of significant connections between the NAO, winter rainfall and river discharge.

  • 232. Brandimarte, Luigia
    et al.
    Di Baldassarre, Giuliano
    UNESCO-IHE, Institute for Water Education, Delft, The Netherlands .
    Uncertainty in design flood profiles derived by hydraulic modelling2012In: Hydrology Research, ISSN 1998-9563, Vol. 43, no 6, 753-761 p.Article in journal (Refereed)
    Abstract [en]

    The scientific literature has widely shown that hydraulic modelling is affected by many sources of uncertainty (e.g. model structure, input data, model parameters). However, when hydraulic models are used for engineering purposes (e.g. flood defense design), there is still a tendency to make a deterministic use of them. More specifically, the prediction of flood design profiles is often based on the outcomes of a calibrated hydraulic model. Despite the good results in model calibration, this prediction is affected by significant uncertainty, which is commonly considered by adding a freeboard to the simulated flood profile. A more accurate approach would require an explicit analysis of the sources of uncertainty affecting hydraulic modelling and design flood estimation. This paper proposes an alternative approach, which is based on the use of uncertain flood profiles, where the most significant sources of uncertainty are explicitly analyzed. An application to the Po river reach between Cremona and Borgoforte (Italy) is used to illustrate the proposed framework and compare it to the traditional approach. This paper shows that the deterministic approach underestimates the design flood profile and questions whether the freeboard, often arbitrarily defined, might lead to a false perception of additional safety levels.

  • 233. Brandimarte, Luigia
    et al.
    Paron, Paolo
    Di Baldassarre, Giuliano
    UNESCO IHE, Inst Water Educ, Westvest 7, NL-2601 DA Delft, Netherlands.
    Bridge pier scour: A review of processes, measurements and estimates2012In: Environmental Engineering and Management Journal, ISSN 1582-9596, E-ISSN 1843-3707, Vol. 11, no 5, 975-989 p.Article in journal (Refereed)
  • 234.
    Brandt, Maja
    SMHI, Core Services.
    Areella snöstudier1986Report (Other academic)
    Abstract [sv]

    Den areella variationen hos ett snötäcke påverkas av mångafaktorer. De meteorologiska förhållandena - främst temperaturoch fuktighet - när snön faller, styr snöns ursprungligadensitet och djup. Vind under och efter snötillfället förflyttarsnön. Den ansamlas i svackor och längs hinder, texlängs skogsgränser, och eroderas på utsatta platser, såsomryggar. Snöförluster orsakade av smältning och avdunstningpåverkar även snöackumulationen.

  • 235.
    Brandt, Maja
    SMHI, Core Services.
    Bestämning av optimalt klimatstationsnät för hydrologiska prognoser1987Report (Other academic)
    Abstract [sv]

    Det är lätt att avfärda dåliga prognosresultat med att klimatstationsnätet är för glest för att man skall kunna bestämma vinternederbörden korrekt. För att testa antalet behövliga temperatur- och nederbördsstationer för olika typer av områden har vi därför prövat att ändra antalet temperatur- resp. nederbördsstationer och studerat hur det påverkar simuleringarnas precision.Studien har finansierats av Vattenregleringsföretagens samarbetsorgan(VASO).

  • 236.
    Brandt, Maja
    SMHI, Core Services.
    GENERATION, TRANSPORT AND DEPOSITION OF SUSPENDED AND DISSOLVED MATERIAL - EXAMPLES FROM SWEDISH RIVERS1990In: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 72, no 3-4, 273-283 p.Article in journal (Refereed)
    Abstract [en]

    Soil erosion, sediment transport and deposition in river systems in Sweden are discussed. The database consists of observations from a research project and from the Swedish network for the measurement of sediment transport. Examples are given from measurements in small plots, and from river basins of different sizes and characteristics. Effects of hydrological regime, of deposition in lakes, and of geology and human impact are illustrated. It was found that observations of erosion losses in index plots cannot easily be extrapolated to large areas, and that trends of transport most likely reflect trends in runoff.

  • 237.
    Brandt, Maja
    SMHI, Core Services.
    SIMULATION OF RUNOFF AND NITRATE TRANSPORT FROM MIXED BASINS IN SWEDEN1990In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 21, no 1, 13-34 p.Article in journal (Refereed)
  • 238.
    Brandt, Maja
    et al.
    SMHI, Core Services.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    INTEGRATION OF FIELD DATA INTO OPERATIONAL SNOWMELT-RUNOFF MODELS1994In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 25, no 1-2, 101-112 p.Article in journal (Refereed)
    Abstract [en]

    Conceptual runoff models have become standard tools for operational hydrological forecasting in Scandinavia. These models are normally based on observations from the national climatological networks, but in mountainous areas the stations are few and sometimes not representative. Due to the great economic importance of good hydrological forecasts for the hydro-power industry attempts have been made to improve the model simulations by support from field observations of the snowpack. The snowpack has been mapped by several methods; airborne gamma-spectrometry, airborne georadars, satellites and by conventional snow courses. The studies cover more than ten years of work in Sweden. The conclusion is that field observations of the snow cover have a potential for improvement of the forecasts of inflow to the reservoirs in the mountainous part of the country, where the climatological data coverages is poor. This is pronounced during years with unusual snow distribution. The potential for model improvement is smaller in the climatologically more homogeneous forested lowlands, where the climatological network is denser. The costs of introduction of airborne observations into the modelling procedure are high and can only be justified in areas of great hydropower potential.

  • 239.
    Brandt, Maja
    et al.
    SMHI, Core Services.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    Gardelin, Marie
    SMHI, Professional Services.
    MODELING THE EFFECTS OF CLEARCUTTING ON RUNOFF - EXAMPLES FROM CENTRAL SWEDEN1988In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 17, no 5, 307-313 p.Article in journal (Refereed)
  • 240.
    Brandt, Maja
    et al.
    SMHI, Core Services.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    Gardelin, Marie
    SMHI, Professional Services.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Modellberäkning av extrem effektiv nederbörd1987Report (Other academic)
    Abstract [sv]

    Följande analys av vattenbalansen vid extrema situationer är ett led i Flödeskommittens arbete med att ta fram nya riktlinjer för dimensioneringsberäkningar för dammar och utskov, som inleddes våren 1985 (Ehlin, 1986). Frågan fick förnyad aktualitet i samband med höstflöden 1985 och 1986, som orsakade översvämningar och ett antal mindre dammras.De viktigaste faktorerna för beräkning av dimensionerande flöden är arealnederbörd, snösmältning, markfuktighet samt flödessituationen före flödet. En analys av extrem nederbörd har utförts (Vedin och Eriksson, 1986). För beräkning av effekten av den extrema nederbörden på flödet behöver även kombinationer av eventuell snösmältning och markfuktighetsunderskott i marken vara kända. Hur stor snösmältning kan tänkas ske i ett avrinningsområde? Kan vi räkna med att marken är helt mättad? Ett sätt att analysera detta är att med HBV-modellen ta fram extrema arealnederbörds- och snösmältningsvärden samt lägsta  markfuktighetsunderskott. I denna rapport redovisas en analys, som bygger på HBV-modellberäkningar i tjugofem avrinningsområden. Sammanlagt täcker områdena 79 000 km2 av Sveriges totala yta på449 000 km2. Den sammantagna tidsperioden för beräkningarna är475 år.

  • 241.
    Brandt, Maja
    et al.
    SMHI, Core Services.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    Sandén, Per
    SMHI, Research Department, Hydrology.
    ENVIRONMENTAL IMPACTS OF AN OLD MINE TAILINGS DEPOSIT - MODELING OF WATER-BALANCE, ALKALINITY AND PH1987In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 18, no 4-5, 291-300 p.Article in journal (Refereed)
  • 242.
    Brandt, S. Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Betydelse av höjdmodellers kvalitet vid översvämningsmodellering2009In: ULI aktuellt, ISSN 1654-6016, no 1, 8-9 p.Article in journal (Other (popular science, discussion, etc.))
  • 243.
    Brandt, S. Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Conceptualization of hydraulic and sedimentary processes in downstream reaches during flushing of reservoirs2005In: Proceedings of the XXXI IAHR Congress [Elektronisk resurs]: Water engineering for the future : choices and challenges : COEX Seoul September 11-16, 2005, Seoul: Korea Water Resources Association , 2005, 2577-2588 p.Conference paper (Refereed)
    Abstract [en]

    The main focus of this paper is to describe the active hydraulic and sedimentary processes in downstream river reaches during flushing of sediments from reservoirs. During flushing extreme amounts of sediment may be released. Therefore, these processes are different than those downstream from dams and reservoirs not subjected to flushing. Hence, also the effects differ, which knowledge of may be of value for biologists, etc. During flushing of a reservoir a wave will be released to the downstream reaches. This wave can be divided into one water part and one sediment part. Initially they are in phase with each other, but with increased distance downstream from the dam, the transported sediment lags behind the water due to different traveling velocities. The paper treats when and where sedimentation occurs, and how this is related to the different traveling velocities of water and sediment. Also included are discussions on how the downstream effects during flushing differ from non-flushing effects, how visualization of effects can enhance both the analysis and communication with planners, politicians, etc., as well as discussions on how the studies of these effects can benefit from improved field-work methods.

  • 244.
    Brandt, S. Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Resolution issues of elevation data during inundation modeling of river floods2005In: Proceedings of the XXXI IAHR Congress [Elektronisk resurs]: Water engineering for the future: choices and challenges. COEX Seoul September 11-16, 2005, Seoul: Korea Water Resources Association , 2005, 3573-3581 p.Conference paper (Refereed)
    Abstract [en]

    A case study of the Eskilstuna River in Sweden is presented. This study is carried out within the project KRIS-GIS®, a Swedish initiative of handling crisis situations, including flooding. The purpose is to show how different resolutions in input elevation data affect the resulting inundation maps. Terrain elevation points at the sides of the river were gathered from an airborne laser altimetry survey, and river bed elevations were gathered from an echosounding survey. The terrain model was constructed in ArcView GIS as a triangulated irregular network (TIN), which served as the base for all later modeling. The hydraulic modeling was done as one-dimensional steady flow in HEC-RAS flow routing software. High-resolution elevation data resulted in better inundation delineation than did lowresolution elevation data. If the mean water discharge was used in the modeling and if the river is narrow, a low resolution could even lead to that the river itself would not be marked as inundated. At high water discharges, the river was usually inundated, but there was great uncertainty if the riparian areas really would be flooded or not. With steep side slopes, the delineation of inundation becomes more certain, while at gentler side slopes, the flow is distributed on a larger surface with a risk that the raster cells will be incorrectly marked regarding inundation. Finally, the use of high-resolution elevation data compared with lowresolution data, makes estimates of friction factor, Manning’s n, relatively more important for correct results in inundation studies.

  • 245.
    Brandt, S. Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Översvämningsmodellering i GIS: betydelse av höjdmodellers upplösning applicerat på Eskilstunaån - ett delprojekt i KRIS-GIS®2005Report (Other academic)
    Abstract [sv]

    Under senare tid har översvämningar alltmer uppmärksammats av allmänhet, politiker, myndigheter och organisationer. Samtidigt har allt fler insett att det inte är en fråga om en översvämning kommer att ske utan när och hur stor den blir. Detta innebär att översvämningsrisker ständigt måste vara en närvarande del i politikers, planerares och krisberedskapsorganisationers arbete. Ett sätt att vara väl förberedd inför översvämningar är att ta fram översvämningsområden för olika stora vattenflöden. Därför har det inom projektet KRIS-GIS®, beställt och finansierat av Krisberedskapsmyndigheten, gjorts en mer detaljerad specialstudie över översvämningar kring Eskilstunaån. Tillförlitligheten hos framtagna översvämningsområden beror framför allt av två faktorer: korrekt vattenflödessimulering och korrekt beskrivning av terrängen. I denna studie har den endimensionella modellen HEC-RAS använts för flödessimuleringen och för beskrivning av terrängen har en flygburen 3D-laserskanning över området kring Eskilstunaån utförts. Dessutom har ekolodning utförts för att möjliggöra beskrivning av bottentopografin i Eskilstunaån. Samtliga höjddatapunkter kopplades ihop i ett GIS till ett triangulärt oregelbundet nätverk, TIN. Därefter lades sektioner tvärs över vattendraget och omgivande terräng. Dessa tvärsektioner tilldelades höjdvärden från TIN-modellen innan de exporterades till HEC-RAS. Fyra olika vattenföringar simulerades i HEC-RAS: medelvattenföringen på 23,7 m3/s, årsfloden på 70 m3/s, 100-årsflödet på 123 m3/s samt högsta beräknade flödet på 198 m3/s. Dessutom har det gjorts några alternativa körningar med varierande värden på Mannings n, dvs. markfriktion. Efter körningar i HEC-RAS, exporterades resulterande vattennivåer tillbaka till GISet där ett resultatraster skapades, där varje rastercell visades som översvämmad eller ej, och i förekommande fall översvämmat djup. Resultaten av översvämningsanalyserna visar att betydligt säkrare översvämningsprognoser nu kan göras när tillgång till terrängmodeller av hög kvalitet finns. Vid tidigare studier har Lantmäteriets höjddatabas använts, där höjder finns representerade med ett värde per 50-metersruta. Från att terrängmodellen har varit den begränsande faktorn övergår i stället en korrekt beskrivning av markens råhet eller friktion, uttryckt som Mannings n, till att vara den begränsande faktorn. Det rekommenderas därför att differentiera råhetsvärdena beroende på vilken markanvändningstyp som finns längs med vattendraget. Speciellt viktigt är detta i flacka områden. För Eskilstunaåns nordligaste delar är det viktigt att vattennivån i Mälaren bedöms korrekt. För att sprida och kunna dra nytta av resultaten framtagna i KRIS-GIS®-projektet rekommenderas det att färdiga översvämningspolygoner kan användas av kommuner, räddningstjänst osv. i deras arbete. De kan ringa eller automatiskt få information, från t.ex. SMHI eller vattenregleringsföretag, som innehåller upplysningar om förväntade flöden. Motsvarande polygon för förväntat flöde visas i ett GIS och direkt har man lägesbilden klart för sig. Utöver detta har även visualiseringsaspekter behandlats.

  • 246.
    Brandt, S. Anders
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Bergquist, Arne
    Lantmäteriet.
    Översvämningskarteringars tillförlitlighet2009In: Kart & Bildteknik (Mapping and Image Science), ISSN 1651-792X, no 4, 33-35 p.Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    I ett tidigare nummer av Kart & Bildteknik beskrevs ett pågående forskningsprojekt som försökte ta reda på om det finns en optimal kvalitet på geografisk information som underlag för detaljerad översvämningskartering (Bergquist, Brandt & Klang, 2008). Projektet är nu avslutat och avrapporterat i Brandt (2009) och Klang och Klang (2009). Av resultaten framgår bland annat hur mycket tillförlitligheten av en översvämningskartering minskar med graden av försämrad höjdmodell, vilken utgör ett av de viktigaste underlagen för en översvämningsanalys. I samband med EUs översvämningsdirektiv (Europaparlamentets och rådets direktiv, 2007) föranleder detta en diskussion om vilka översvämningskarteringar som krävs för att uppfylla direktivet.

  • 247.
    Brandt, S. Anders
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Jiang, Bin
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    3D geovisualization as a communication and analysis tool in fluvial geomorphology2004In: Geoinformatics 2004: proceedings of the 12th International Conference on Geoinformatics - Geospatial Information Research: Bridging the Pacific and Atlantic, University of Gävle, Sweden, 7-9 June 2004, Gävle: Gävle University Press , 2004, 339-346 p.Conference paper (Refereed)
    Abstract [en]

    The fields of hydrology and fluvial geomorphology get more and more attention in the general public. The reason for this is changed climate patterns with increased frequencies of storms and river flooding and as a result changed geomorphology and living conditions for the inhabitants of the area. With the development of 3D geovisualization, hydrological and geomorphological processes can be better simulated and visualized. Thus not only the domain specialists, but also the general public can appreciate very complex hydrological processes and resulting geomorphology. This is of great value since a high frequency of storms and flooding has been a big issue for politicians, planners, and the general public. It is in this sense that 3D geovisualization can be an important tool for analysis and communication. Complex hydrological and geomorphological processes can be effectively simulated and analyzed by the domain specialists while efficient and effective visualization provides a common platform for communication among domain specialists and the general public. This paper will discuss and illustrate these issues using a case study of geomorphology along the Reventazón River, downstream from the Cachí Reservoir in Costa Rica, due to the release of extreme amounts of sediment during flushing of the reservoir.

  • 248.
    Brandt, S. Anders
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Lim, Nancy J.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Visualising DEM-related flood-map uncertainties using a disparity-distance equation algorithm2016In: The spatial dimensions of water management: Redistribution of benefits and risks / [ed] A. H. Schumann, G. Blöschl, A. Castellarin, J. Dietrich, S. Grimaldi, U. Haberlandt, A. Montanari, D. Rosbjerg, A. Viglione, and S. Vorogushyn, Göttingen: Copernicus Publications on behalf of International Association of Hydrological Sciences (IAHS) , 2016, 153-159 p.Conference paper (Refereed)
    Abstract [en]

    The apparent absoluteness of information presented by crisp-delineated flood boundaries can lead tomisconceptions among planners about the inherent uncertainties associated in generated flood maps. Even mapsbased on hydraulic modelling using the highest-resolution digital elevation models (DEMs), and calibrated withthe most optimal Manning’s roughness (n) coefficients, are susceptible to errors when compared to actual floodboundaries, specifically in flat areas. Therefore, the inaccuracies in inundation extents, brought about by thecharacteristics of the slope perpendicular to the flow direction of the river, have to be accounted for. Instead ofusing the typical Monte Carlo simulation and probabilistic methods for uncertainty quantification, an empiricalbaseddisparity-distance equation that considers the effects of both the DEM resolution and slope was used tocreate prediction-uncertainty zones around the resulting inundation extents of a one-dimensional (1-D) hydraulicmodel. The equation was originally derived for the Eskilstuna River where flood maps, based on DEM dataof different resolutions, were evaluated for the slope-disparity relationship. To assess whether the equation isapplicable to another river with different characteristics, modelled inundation extents from the Testebo Riverwere utilised and tested with the equation. By using the cross-sectional locations, water surface elevations, andDEM, uncertainty zones around the original inundation boundary line can be produced for different confidences.The results show that (1) the proposed method is useful both for estimating and directly visualising modelinaccuracies caused by the combined effects of slope and DEM resolution, and (2) the DEM-related uncertaintiesalone do not account for the total inaccuracy of the derived flood map. Decision-makers can apply it to alreadyexisting flood maps, thereby recapitulating and re-analysing the inundation boundaries and the areas that areuncertain. Hence, more comprehensive flood information can be provided when determining locations whereextra precautions are needed. Yet, when applied, users must also be aware that there are other factors that caninfluence the extent of the delineated flood boundary.

  • 249.
    Brandt, S. Anders
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Lim, Nancy Joy
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Importance of river bank and floodplain slopes on the accuracy of flood inundation mapping2012In: River Flow 2012: Volume 2 / [ed] Rafael Murillo Muñoz, Leiden, The Netherlands: CRC Press / Balkema (Taylor & Francis) , 2012, 1015-1020 p.Conference paper (Refereed)
    Abstract [en]

    Effective flood assessment and management depend on accurate models of flood events, which in turn are strongly affected by the quality of digital elevation models (DEMs). In this study, HEC-RAS was used to route one specificwater discharge through the main channel of the Eskilstuna River, Sweden. DEMs with various resolutions and accuracies were used to model the inundation. The results showed a strong positive relationship between the quality of theDEMand the extent of the inundation. However, evenDEMswith the highest resolution produced inaccuracies. In another case study, the Testebo River, the model settings could be calibrated, thanks to a surveyed old inundation event. However, even with the calibration efforts, the resulting inundation extents showed varying degrees of deviation from the surveyed flood boundaries. Therefore, it becomes clear that not only does the resolution of the DEM impact the quality of the results; also, the floodplain slope perpendicular to the river flow will impact the modelling accuracy. Flatter areas exhibited the greatest predictive uncertainties regardless of the DEM’s resolution. For perfectly flat areas, uncertainty becomes infinite.

  • 250.
    Brandt, Sven Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Modeling and visualizing uncertainties of flood boundary delineation: algorithm for slope and DEM resolution dependencies of 1D hydraulic models2016In: Stochastic environmental research and risk assessment (Print), ISSN 1436-3240, E-ISSN 1436-3259, Vol. 30, no 6, 1677-1690 p.Article in journal (Refereed)
    Abstract [en]

    As flood inundation risk maps have become a central piece of information for both urban and risk management planning, also a need to assess the accuracies and uncertainties of these maps has emerged. Most maps show the inundation boundaries as crisp lines on visually appealing maps, whereby many planners and decision makers, among others, automatically believe the boundaries are both accurate and reliable. However, as this study shows, probably all such maps, even those that are based on high-resolution digital elevation models (DEMs), have immanent uncertainties which can be directly related to both DEM resolution and the steepness of terrain slopes perpendicular to the river flow direction. Based on a number of degenerated DEMs, covering areas along the Eskilstuna River, Sweden, these uncertainties have been quantified into an empirically-derived disparity distance equation, yielding values of distance between true and modeled inundation boundary location. Using the inundation polygon, the DEM, a value representing the DEM resolution, and the desired level of confidence as inputs in a new-developed algorithm that utilizes the disparity distance equation, the slope and DEM dependent uncertainties can be directly visualized on a map. The implications of this strategy should benefit planning and help reduce high costs of floods where infrastructure, etc., have been placed in flood-prone areas without enough consideration of map uncertainties.

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