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  • 1.
    Andersson, Jan-Olov
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    A GIS-based landscape analysis of dissolved organic carbon in boreal headwater streams2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In boreal catchments, stream water chemistry is influenced and controlled by several landscape factors. The influence of spatially distributed variables is in turn dependent on the hydrological scale. Headwater streams have larger variability of water chemistry, and thus together represent a large biodiversity, and therefore need to be monitored in official environmental assessments. One objective of this study was, using Geographical Information Systems (GIS), to analyse co-variation between landscape variables and water chemistry and to determine which of the landscape variables have a major influence on the concentration of dissolved organic carbon (DOC) in headwater streams. Another objective was to find a simple method for predicting sources of DOC, using official map data and publically available GIS applications.

    Totally 85 headwater catchments (0.1-4 km2) in the county of Värmland, western south Sweden, were used in the study. Water chemistry was analysed for water sampled at low, medium and high flows, and landscape variables were extracted from official map data sources: topographic maps, a digital elevation model (DEM, 50 m grid), and vegetation data. Statistical analyses showed that topography (mean slope and mean topographic wetness index (TWI)) and wetland cover often correlated well with DOC in headwater catchments. Official map data could satisfactorily extract landscape variables (mean slope, mean TWI) that were useful in predicting stream water chemistry (DOC).

    A high-resolution elevation model, which was generated by interpolation of photogrammetric data, was used to calculate and evaluate two different wetness indices and their ability to predict the occurrence of wetlands in six catchments of different sizes and topography. The SAGA (System for Automated Geoscientific Analyses) wetness index (SWI) gave substantially better results than the TWI. The effects of resolution of DEMs on calculations of the SWI were investigated using 5, 10, 25 and 50 m grids. The results showed that SWI values increased with increasing cell size. The near linear increment of mean values for resolutions 10-50 m suggests a independence of terrain type and catchment size, which supported previous findings that indicated that mean slope and mean wetness index calculated from coarse elevation models may be used for prediction of DOC in headwater streams.

     

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  • 2.
    Andersson, Jan-Olov
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    DEM resolution effects on SAGA wetness index in boreal forested catchmentsManuscript (preprint) (Other academic)
  • 3.
    Andersson, Jan-Olov
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Centre for Climate and Safety.
    Blumenthal, Barbara
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Centre for Climate and Safety.
    Nyberg, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Centre for Climate and Safety.
    Kartering av översvämningsrisker vid Vänern2013Report (Other academic)
    Abstract [sv]

    I denna studie genomfördes en översvämningskartering och -analys som utgick från fyra

    extrema vattennivåer i Vänern. Baserat på höjddata från den Nya Nationella Höjdmodellen

    (NNH) generades utbredningspolygoner med hjälp av GIS för de fyra översvämningsnivåerna.

    Överlagringsanalyser gjordes sedan med kartskikt för väg, mark och byggnader

    samt för vissa kommuner även befolkning för att urskilja vägsträckor, markområden,

    byggnader och boende inom översvämningsutbredningen vid de fyra nivåerna.

    Översvämningskartor togs fram i pdf-format och Google Earth-format. GIS-analysen har

    genererat kvantitativa data för översvämmade vägsträckor, markytor antal byggnader etc.

    Vidare har en objektsbaserad analys genomförts utifrån kartmaterial och kommunala data

    över sårbara anläggningar och funktioner. Resultaten har sammanställts kommunvis och

    för Vänerområdet i sin helhet i form av text, tabeller och diagram.

    Det som drabbas först vid en översvämning i Vänern är dels objekt som utifrån sina

    funktioner ligger vattennära t.ex. fritidsanläggningar, men även viktiga vägar som E18 och

    E45. Järnvägsträckan Göteborg-Karlstad-Stockholm översvämmas redan vid 100-årsnivån.

    Med stigande vattennivå drabbas allt fler objekt och samhällsviktiga funktioner. De städer

    som påverkas mest är Karlstad, Kristinehamn, Mariestad, Lidköping och Vänersborg.

    De direkta skadekostnaderna för en 100-årsnivå i Vänern har beräknats till 100-240 Mkr,

    där en möjlig vindeffekt kan ge ytterligare upp till 120 Mkr i skadekostnader. För en

    dimensionerande nivå skulle skadekostnaderna bli av en helt annan storleksordning och

    uppgå till ca 9,8 miljarder kr. Vid denna nivå skulle stora indirekta skador uppstå som vi

    inte har haft möjlighet att värdera ekonomiskt. De största kostnaderna kan kopplas till

    översvämmade byggnader.

    I en absolut jämförelse med Mälaren av kvantitativa data för översvämmade vägar,

    markområden och antal byggnader är konsekvenserna vid Vänern något lägre.

    Studien genomfördes på uppdrag av och i samarbete med

    Vänerkommunerna i samverkan om

    Vänerns reglering.

     

  • 4.
    Andersson, Jan-Olov
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Nyberg, Lars
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Spatial variation of wetlands and flux of dissolved organic carbon in boreal headwater streams2008In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, no 22, p. 1965-1975Article in journal (Refereed)
    Abstract [en]

    In order to investigate the relation between water chemistry and functional landscape elements, spatial data sets of characteristics for 68 small (0·2–1·5 km2) boreal forest catchments in western central Sweden were analysed in a geographical information system (GIS). The geographic data used were extracted from official topographic maps. Water sampled four times at different flow situations was analysed chemically. This paper focuses on one phenomenon that has an important influence on headwater quality in boreal, coniferous forest streams: generation and export of dissolved organic carbon (DOC). It is known that wetland cover (bogs and fens) in the catchment is a major source of DOC. In this study, a comparison was made between a large number of headwater catchments with varying spatial locations and areas of wetlands. How this variation, together with a number of other spatial variables, influences the DOC flux in the streamwater was analysed by statistical methods. There were significant, but not strong, correlations between the total percentages of wetland area and DOC flux measured at a medium flow situation, but not at high flow. Neither were there any significant correlations between the percentage of wetland area connected to streams, nor the percentage of wetland area within a zone 50 m from the stream and the DOC flux. There were, however, correlations between catchment mean slope and the DOC flux in all but one flow situations. This study showed that, considering geographical data retrieved from official sources, the topography of a catchment better explains the variation in DOC flux than the percentage and locations of distinct wetland areas. This emphasizes the need for high-resolution elevation models accurate enough to reveal the sources of DOC found in headwater streams.

  • 5.
    Andersson, Jan-Olov
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Nyberg, Lars
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Using official map data on topography, wetlands and vegetation cover for prediction of stream water chemistry in boreal headwater catchments2009In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 13, p. 537-549Article in journal (Refereed)
  • 6.
    Andersson, Jan-Olov
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Nyberg, Lars
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Wetness indices as predictors of boreal wetlandsManuscript (preprint) (Other academic)
  • 7.
    Blumenthal, Barbara
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Centre for Climate and Safety (from 2013). Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Haas, Jan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Andersson, Jan-Olov
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Centre for Climate and Safety (from 2013).
    A GIS-based multivariate approach to identify flood damage affecting factorsManuscript (preprint) (Other academic)
    Abstract [en]

    This paper investigates causal factors leading to pluvial flood damages, beside rainfall amount and intensity, in two Swedish cities. Observed flood damage data from a Swedish insurance database, collected under 13 years, and a set of spatial data, describing topography, demography, land cover and building type were analyzed through principal component analysis (PCA). The topographic wetness index (TWI) is the only investigated variable that indicates a significant relationship with to the number and amount of insurance damage. The Pearson correlation coefficient is 0.68 for the number of insurance damages and 0.63 for amount of insurance damages. With a linear regression model TWI explained 41% of the variance of the number of insurance flood damages and 34% of variance of amount of insurance flood damage.

    Future studies on this topic should consider implementing TWI as a potential measure in urban flood risk analyses.

  • 8.
    Nyberg, Lars
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Andersson, Jan-Olov
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Mörth, Carl-Magnus
    Dept of Geology and Chemistry, Stockholm University.
    Malmström, Maria
    Karlstad University, Faculty of Social and Life Sciences.
    Influence of wetland restoration on hydrology and water chemistry in a Swedish boreal catchmentManuscript (preprint) (Other academic)
  • 9.
    Svensson, Torbjörn
    et al.
    Karlstad University.
    Andersson, Jan-Olov
    Karlstad University.
    Blumenthal, Barbara
    Karlstad University.
    Forsberg, Jan
    Karlstad University.
    Hedelin, Beatrice
    Karlstad University.
    Projekt Byälven: Översvämningsrisker, förebyggande åtgärder och konsekvenser2002Report (Other academic)
  • 10. Swantesson, Jan O. H.
    et al.
    Andersson, Jan-Olov
    Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Älvens betydelse för landskapet och människan2011In: Klarälven / [ed] Ibsen, H., Svensson, E. & Nyberg, L., Karlstad: Karlstad University Press, 2011, p. 13-26Chapter in book (Other academic)
  • 11.
    Temnerud, J.
    et al.
    Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, Uppsala, Sweden.;Swedish Meteorol & Hydrol Inst, Res Dept, S-60176 Norrkoping, Sweden..
    von Bromssen, C.
    Swedish Univ Agr Sci, Dept Econ, Unit Appl Stat & Math, Uppsala, Sweden..
    Folster, J.
    Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, Uppsala, Sweden..
    Buffam, I.
    Univ Cincinnati, Dept Biol Sci, Cincinnati, OH USA.;Univ Cincinnati, Dept Geog, Cincinnati, OH USA..
    Andersson, Jan-Olov
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Department of Geography, Media and Communication (from 2013).
    Nyberg, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Centre for Climate and Safety (from 2013).
    Bishop, K.
    Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, Uppsala, Sweden.;Uppsala Univ, Dept Earth Sci, Uppsala, Sweden..
    Map-based prediction of organic carbon in headwater streams improved by downstream observations from the river outlet2016In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 13, no 2, p. 399-413Article in journal (Refereed)
    Abstract [en]

    In spite of the great abundance and ecological importance of headwater streams, managers are usually limited by a lack of information about water chemistry in these headwaters. In this study we test whether river outlet chemistry can be used as an additional source of information to improve the prediction of the chemistry of upstream headwaters (size < 2 km(2)), relative to models based on map information alone. We use the concentration of total organic carbon (TOC), an important stream ecosystem parameter, as the target for our study. Between 2000 and 2008, we carried out 17 synoptic surveys in 9 mesoscale catchments (size 32-235 km(2)). Over 900 water samples were collected in total, primarily from headwater streams but also including each catchment's river outlet during every survey. First we used partial least square regression (PLS) to model the distribution (median, interquartile range (IQR)) of headwater stream TOC for a given catchment, based on a large number of candidate variables including sub-catchment characteristics from GIS, and measured river chemistry at the catchment outlet. The best candidate variables from the PLS models were then used in hierarchical linear mixed models (MM) to model TOC in individual headwater streams. Three predictor variables were consistently selected for the MM calibration sets: (1) proportion of forested wetlands in the sub-catchment (positively correlated with headwater stream TOC), (2) proportion of lake surface cover in the sub-catchment (negatively correlated with headwater stream TOC), and (3) river outlet TOC (positively correlated with headwater stream TOC). Including river outlet TOC improved predictions, with 5-15% lower prediction errors than when using map information alone. Thus, data on water chemistry measured at river outlets offer information which can complement GIS-based modelling of headwater stream chemistry.

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1 - 11 of 11
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