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178 Uppsatser om Lake Mälaren catchment - Sida 9 av 12

"Fallbacks" - betydelsen av vandringstid för Atlantlax (Salmo salar L.) som faller nedströms vandringshinder

In Lake Vänern, Sweden, there is an endemic population of Atlantic salmon (Salmo salar L.) that lives its entire life in fresh water. The salmon is hindered from migrating to its natural spawning sites in the northern part of the River Klarälven by nine hydro-electric power plants. None of the hydro-electric power plants have fishways so that salmon migrating upstream or downstream may pass. In the current situation, the upward migrating salmon are caught in a fish trap at the most downstream located power plant in Forshaga. From there, the salmon are driven in a truck, past eight power plants and released a few kilometers upstream of the eighth power plant at Edsforsen.

Identifiering av områden med risk för fosforförluster genom ytavrinning : metodutveckling med GIS

The eutrophication of lakes and seas with the algal bloom and deficiency inoxygen that follow, has been given priority by the Swedish government as oneof 16 environmental objectives. The purpose of this project was to develop a toolbased on a simple model, limited amount of data and geographic informationsystem (GIS) to identify areas with risk for phosphorus losses due to surfacerunoff. This tool can act as a decision support to decide where appropriatemeasures should be applied with the aim of reducing phosphorus losses and bythat the eutrophication.The method that has been used is a combination of two models, one calculatingthe potential erosion while the other one identifies areas of erosion (net erosion)or deposition. This ability is of great importance because potential erosionshould be calculated on areas with net erosion. Areas with high potential erosionhave an increased risk for phosphorus losses due to surface runoff.The potential erosion was calculated based on factors which describe how topography(LS), land use (C), soil type (K) and precipitation (R) effect the erosion.All of them have been modified to a greater or lesser extent.

Kol-14 datering : En litteraturstudie över hur kol-14 isotopen används för datering, samt utveckling och tillämpning av djup-åldersmodeller inom naturgeografin.

This literature study concerned the use and function of the radioactive isotope carbon-14, as a dating method of organic material, within the scientific field of physical geography. In this report it is presented the need of atmospheric calibration curves and the development of these as a necessity to translate carbon-14 years to calibrated calendar years. A number of common age-depth models that is used to give an approximation of an accumulation sequence and its related dates over the actual time period in different natural archives is presented and discussed. Different problems that commonly occur when age-depth models are utilized as for instance reservoir effects, contaminations or other age deviations are addressed and analyzed. The software CLAM in presented and discussed and was also used to produce age-depth models.

Konsekvensanalys för ?worst case scenario? på Mälarhamnar AB Västerås

AbstractConsequence analysis ?worst case scenario? at Mälarhamnar AB VästeråsDavid DotzskyMälarhamnar AB is a company that handle large amounts of oil, diesel, biofuel and petrol. That result in a lot of work to prevent accidents. The risks with modern technology is very small but it can?t be eliminated.

Transporttidsmodellering vid provpumpning i heterogen jord : spårämnesförsök i en isälvsavlagring

When protection zones for wells are delineated, it is important to acquire good knowledge about possible travel time from different points in the catchment area to the well. Often, simple analytical methods are used for estimating travel times and the assumption is made that the hydraulic conductivity is relatively homogenous within the aquifer. Nevertheless, many aquifers are strongly heterogeneous which may lead to differences between estimates and actual travel times. As a part of the process to develop improved methods for delineating protection zones for groundwater supply wells, a tracer experiment was performed in a glaciofluvial esker formation in Järlåsa. On the basis of the experiment, a numerical flow model was created for the test site.The purpose of this master?s thesis was to apply the flow model to an aquifer where the hydraulic conductivity shows great variability and should be described by a stochastic distribution.

Fisk- och fågelpredations påverkan på den bentiska makroevertebratfaunans sammansättning under tidig vår i Tåkern

Predation is one of many factors that form the structure of the macroinvertebrate community in lakes, wetlands and watercourses. Earlier studies lack an examination concerning how fish- and waterfowl predation affect macroinvertebrates during shorter periods in the spring. I performed an exclosure study in the shallow eutrophic Lake Tåkern which is located in the western part of Östergötland County, Sweden. The experiment was performed during a three week period (1-21 April 2012) when the water temperature was low and the density of migrating diving ducks was high. The experimental cages used included three out of four different treatments; general predation (open cages), bird exclusion (net with mesh size 90*45mm) and no predation (net with mesh size 1*1mm).

I hamn : - En fallstudie av det privatoffentliga partnerskapet Vänerhamn

This study focuses upon the new societal objects that are termed public privatepartnerships where the public sector forms strategic alliances with the private sectorand the civil society to manage the wicked issues of today. An exampel of suchcooperation is Vänerhamn AB where the municipalities around the lake of Vänernand the private shipping companies got togheter to handle an economic crisis of theshipping buisiness. The partnership Vänerhamn has developed from a problematicactivity to a healthy company and the aim of this thesis is to illuminate thisdevelopment through an historical institutional approach, focusing critical junctureto discover if the governance theory can be used to understand the partnershipspositive process. This will be done through research questions about the organisation of thepartnership, about the members interests with the partnership and about eventuallycoordination problems in the partnership. The questions derive from dimensions ingovernance theory, central for the activity of partnerships. Interviews with centralinformants where held and it was complemented through a document analyses inorder to search for indications of the dimensions and that is the methodologicalapproach of the study. The conclusion of this thesis is that the governance theory can be used tounderstand Vänerhamns postive development since the members interest with thepartnership to a begining was not at all conformed and that led to obviouscoordination problems.

Biblioteksutvecklingen i Karlsborg 1907-1970 ? vägen mot ett kommunalt folkbibliotek

The purpose of this master thesis is to describe and analyse the development of the library history in the municipality of Karlsborg. This is done with a comparison to the library development in Sweden as a whole and in particular to the cities of Lidköping and Halmstad. I have worked according to the following questions: 1. How did the libraries develop before the municipality took over? 2.

Sammanvägda avrinningskoefficienter i rationella metoden : en jämförelse mellan idag och 1970-talet

Storm water is rain and melted snow that runs off, primarily from impervious surfaces.Future storm water management is facing the challenges of increased precipitation, asclimate changes, and increased areas of impervious surfaces due to the expansion anddensification of the cities. Impervious surfaces reduce the potential for water to infiltratein the ground leading to increased surface runoff and higher peak discharge.The runoff coefficient is closely related to the percentage of impervious surfaces andrepresents the maximum percentage of a catchment that can contribute to runoff. In thisstudy, the objective was to evaluate the weighted runoff coefficient for three differenturban types; apartment buildings, townhouses and residential areas and a comparisonbetween today and the 1970`s was made.The runoff coefficient was determined by manual mapping of the different surface typesin each area based on data in the form of orthophotos and aerial photographs. The surfacetypes that were mapped were asphalt, permeable areas, tiles, sand/gravel and roof.Tiles and sand/gravel were the most difficult surface types to map. In order to see towhat extent these categories influenced the weighted runoff coefficient a sensitivityanalysis was carried out and the runoff coefficient based on surface type was changed indifferent scenarios.The results of the sensitivity analysis showed that the surface types tiles and sand/gravelhad little impact on the weighted runoff coefficient which in mainly due to the fact thatthe percentage of these surfaces types of the total area is small.The result of the study showed that the largest change in the runoff coefficient occurredin residential areas where the increase in the percentage of impervious surfaces causedby new roofs in the form of porches and garages and from paved or tiled driveways.

Utlakning av tungmetaller från Skörby deponi

The purpose of this thesis has been to assess whether leaching from one particular Swedishlandfill site, Skörbytippen, is contributing to elevated levels of heavy metals in a ditch runningfrom the landfill site to the lake Mälaren in the communal region of Håbo kommun. Since theditch is stretching approximately five km downstream from the landfill site, in situ observationsand maps with known points of inflow was utilized to determine appropriate test points for thecollection of samples.Soil, water and sediment samples were collected and analyzed for content of organic material, pHand conductivity. Data on plant-available elements and total amounts of heavy metals wasacquired through ICP-analysis.The results show that the Skörby landfill is currently in the methane-forming anaerobedevelopment phase, which indicates that the concentration of free and complex-bound metals inthe leachate water should be low due to chemical binding with other landfill compounds. The pHof the sediment samples was generally one unit higher than the soil samples and some of themeasured data, such as pH and conductivity, show that an environmentally disturbing dischargeof some kind of strongly alkaline chemical(s) has been made from Benders? takpanneindustri inclose proximity to the landfill.

Insect communities inhabiting Inonotus radiatus growing on Alnus glutinosa trees at northern and southern shores of boreal lakes

This is a study of the insect community associated to the wood-decaying fungus Inonotus radiatus found on Alnus glutinosa trees growing in riparian forests at the northern and southern shores of boreal lakes in the province Uppland. Little is known about this particular bracket fungus and its inhabitants. Insects were reared out at the laboratory from samples of fruiting bodies of the fungus taken at five lakes. During the fieldwork in 2009, data about several environmental variables was also taken. After the rearing period, these variables and their effects over the insects were analyzed.

Muntliga källor från Rystad : Intervjumetoden som historiebruk

AbstractHow do we remember? What do we remember? How does the memory change over time? These are the main questions in this essay.Five persons, who have lived or are still living in the old parish Rystad, situated seven kilometers from the town Linkoping south of Lake Roxen, have participated in interviews. They have been given the possibility to present their oral history which has been recorded and later transmitted to texture. The participants represent different social backgrounds and professions and they were born between the years 1920 ? 1936.

Vegetationsutveckling och brandhistorik i Tyresta under 9000 år : en pollenanalytisk studie av en skvattramtallmyr i Tyresta nationalpark, Södermanland

Analyses of pollen and charcoal in peat cores, together with age-structure data of Pinus sylvestris from a Ledum-Pinus-mire in the Tyresta National Park (south-east Sweden) show the regional vegetation succession and fire history over the last 9000 years. Five major stages of mire development are identified: 1. Lake (c 7000-6400 cal BC); 2. Wet fen (c 6400-6000 cal BC); 3. Deciduous fen (c 6000 cal BC to c cal AD 700); 4.

Vegetationsförändringar i Hornborgasjöns naturreservat : med fokus på restaureringems följder

Den här studien undersöker hur vegetationen förändras mellan 1979 och 2010 i området som idag är Hornborgasjöns naturreservat. Sjösänkningar i området ledde till att ett igenväxt träskområde ersatte en viktig vattenreservoar och närsaltfälla. Restaureringsarbetet under 80-talet var banbrytande och antagligen ett av vår tids mest omfattande naturvårdsarbete. Studien svarar också på om restaureringen uppnådde sitt mål och om resultatet blev som man tänkt sig.I arbetet skapades en aktuell vegetationskarta för 2010, denna jämfördes med en i arbetet digitaliserad vegetationskarta från 1979. Kartbilder skapades och justerades i ArcGIS och vegetationsytornas area framtogs för att möjliggöra en vegetationsanalys mellan kartorna.

Tillämpning av GIS-analyser i MKB

The reason for performing an Environmental Impact Assessment (EIA) is to incorporate environmental concern in different kinds of plans and projects. The purpose of such an assessment is to identify and describe direct, indirect and cumulative environmental impacts.Geographical Information System (GIS) is a tool that can be used to combine spatial extension of both sensitive areas and different environmental impacts in a quick and easy way. Because of that, descriptions of environmental impacts and motivation of different standpoints on a specific issue can be more correct and easier to make if GIS is used as a tool.Hence, GIS can contribute to improve the quality of Environmental Impact Assessments. If the benefits of using GIS are to out weight the costs, geographical information of satisfactory detail, actuality and accuracy need to be available at reasonable prices.In this paper, case studies are carried out for three different geographical analyses to investigate the use of GIS as a tool in EIA. From these case studies, more general conclusions about the benefits and limitations of using GIS for Environmental Impact Assessments are also drawn.

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