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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

Water-related disasters : An overview of landslides and floods in Sweden / Vatten relaterade naturkatastrofer : En översikt av skred och översvämningar i Sverige

Klingbjer, Josefin Wiklund January 2021 (has links)
Current research shows that water-related disasters are the most common natural disaster worldwide and these disasters are increasing in numbers. Water-related disasters cause negative consequences through damage to infrastructure and human health.  This thesis aims to provide an overview of the water-related disasters, floods, and landslides in Sweden by displaying the spatial distribution. Furthermore, the purpose is to analyze the consequences of occurred water-related disasters. By answering the following research questions:  How has landslides and floods been spatially distributed over time in Sweden?  How severe has the consequences of floods and landslides been in Sweden?  To answer these research questions a data study was conducted in ArcGIS and Excel to analyze the spatial distribution and the consequences of landslides and floods. The result shows that the three counties in Sweden with the highest number of affected areas by floods are: Västerbotten, Västernorrland and Örebro. These counties constitute 36% of the affected areas. These affected areas have occurred periodically with an increase since 1970. A detailed study over the years 2011–2017 showed that most floods in Sweden lead to consequences with a small extent and limited damages.  Furthermore, the counties Västra Götaland, Västernorrland and Värmland had the highest number of occurred landslides. In total, 83.7% of all landslides have occurred within these three counties. This means that the distribution of floods is more evenly distributed between different counties compared to landslides. Within these counties, the areas that have had notable high numbers of landslides are Ångermanälven, Norsälven, Klarälven and the areas nearby Göta älv. Overall, it has been most common that landslides have an extent in the range between 1000–10000 m2 and that an extent over 100000 m2 are rare. / Aktuell forskning visar att vattenrelaterade naturkatastrofer är de vanligaste naturkatastroferna över hela världen samt att dessa ökar i antal. Vattenrelaterade naturkatastrofer orsakar till negativa konsekvenser till följd av skador på infrastruktur och människors hälsa. Denna kandidatuppsats syftar till att ge en översikt av den geografiska utbredningen av inträffade vattenrelaterade naturkatastroferna skred och översvämningar i Sverige. Vidare, är syftet att analysera konsekvenserna av inträffade vattenrelaterade naturkatastrofer, genom att svara på följande frågeställningar:  Hur har skred och översvämningar varit utspridda över tid i Sverige? Hur allvarliga har konsekvenserna av översvämningar och jordskred varit i Sverige? För att besvara dessa frågeställningar utfördes en analys i ArcGIS och Excel för att undersöka den geografiska utbredningen och konsekvenserna av skred och översvämningar. Resultatet visar att de tre län med flest områden som blivit påverkade av översvämningar är: Västerbotten, Västernorrland and Örebro. Dessa län utgör 36% av de drabbade områdena. Antalet påverkade områden av översvämningar har inträffat periodvis med en ökning sedan 1970. En detaljerad analys över åren 2011–2017 visade att de flesta översvämningar i Sverige resulterade i konsekvenser med liten utbredning och små skador.  Vidare, hade Västra Götaland, Västernorrland och Värmlands län högst antal inträffade skred. Totalt har 83.7% av alla skred inträffat inom dessa tre län. Detta innebär att fördelningen av områden påverkade av översvämningar har varit jämnare fördelade mellan olika län jämfört med skred. Inom dessa län är de områden som har haft anmärkningsvärt högt antal skred: Ångermanälven, Norsälven, Klarälven och områdena i närheten av Göta älv. Överlag har det varit vanligast att jordskred har en utbredning mellan 1000–10000 m2 och att en utbredning över 100000 m2 är ovanlig.
152

Phreatophytes in southwest Kansas used as a tool for predicting hydrologic properties

Ahring, Trevor S. January 1900 (has links)
Master of Science / Department of Civil Engineering / David R. Steward / The Ogallala Aquifer is a supply of water for several municipalities in western Kansas, as well as an irrigation source for local farmers. Since the 1950’s, when the aquifer started to be pumped for irrigation, the region has seen steady declines of the groundwater table. These declines have reduced stream flow in the Arkansas and Cimarrron Rivers, and caused a redistribution of riparian phreatophytes. This thesis studies this redistribution of phreatophytes, and develops statistical relationships relating a phreatophyte’s location to depth to groundwater, increase in depth to groundwater, distance from a stream or river, and hydrologic soil group. Remote sensing was used to determine tree locations on predevelopment and post-development aerial photography. These locations were mapped using ArcGIS, and ArcAEM was used to model groundwater flow in six riparian regions taking root uptake into account. It was found that once the depth to groundwater becomes greater than about 3 m, tree population will decrease as depth to water increases. Trees were located within 700 m of the river. Areas with a dense tree population (>10% tree cover) occurred where the average depth to water ranged from 0.24-1.4 m. Areas with moderate tree density (5-10% tree cover) corresponded to an average depth to water ranging from 2.1-19 m. Areas with a low tree density (<5% tree cover) corresponded to an average depth to water ranging from 11-28 m. It was found that phreatophytes have a high likelihood of growing on hydrologic soil group A and a low likelihood of growing on hydrologic soil group B. The number of trees located on hydrologic soil group D was what would be statistically expected if tree location were independent of soil type. It was also found that tree locations could be used as an indicator of good hydraulic connectivity between surface water and groundwater. This information can be used to help guide future installation of monitoring networks and expand research projects from central Kansas to western Kansas.
153

Valuing Natural Space and Landscape Fragmentation in Richmond, VA

Carpenter, Lee Wyatt 01 January 2016 (has links)
Hedonic pricing methods and GIS (Geographic Information Systems) were used to evaluate relationships between sale price of single family homes and landscape fragmentation and natural land cover. Spatial regression analyses found that sale prices increase as landscapes become less fragmented and the amount of natural land cover around a home increases. The projected growth in population and employment in the Richmond, Virginia region and subsequent increases in land development and landscape fragmentation presents a challenge to sustaining intact healthy ecosystems in the Richmond region. Spatial regression analyses helped illuminate how land cover patterns influence sale prices and landscape patterns that are economically and ecologically advantageous.
154

Modelování charakteristik obyvatelstva z topografických dat / Modeling population with topographic data

Šimbera, Jan January 2016 (has links)
Accurate spatial population data are an important requirement in many applications. In this thesis, the problem of disaggregating the spatial distribution of population density and rent costs using a machine learning model is studied. An approach based on freely available ancillary data such as OpenStreetMap and Urban Atlas is proposed and implemented in the form of an automated Python toolbox for ArcGIS. The applications on the urban areas of Prague, Vienna and Ljubljana show promising results, overperforming the competing population disaggregation solutions in spatial resolution and displaying a satisfying degree of transferability. A number of further improvements is suggested. Powered by TCPDF (www.tcpdf.org)
155

Using Kriging, Cokriging, and GIS to Visualize Fe and Mn in Groundwater

Johnson, Crystal 01 May 2015 (has links)
For aesthetic, economic, and health-related reasons, allowable concentrations of iron (Fe) and manganese (Mn) found present in drinking water are 0.3 mg/L and 0.05 mg/L, respectively. Water samples taken from private drinking wells in the rural communities within Buncombe County, North Carolina contain amounts of these metals in concentrations higher than the suggested limits. This study focused on bedrock geology, elevation, saprolite thickness, and well depth to determine factors affecting Fe and Mn. Using ArcGIS 10.2, spatial trends in Fe and Mn concentrations ranges were visualized, and estimates of the metal concentrations were interpolated to unmonitored areas. Results from this analysis were used to create a map that delineates the actual spatial distribution of Fe and Mn. The study also established a statistically significant correlation between Fe and Mn concentrations, which can be attributed to bedrock geology. Additionally, higher Fe in groundwater was concentrated in shallower wells and valley areas.
156

The Impact of Tropical Cyclones on the Geomorphic Evolution of Bolivar Peninsula, TX

Hales, Billy 2012 May 1900 (has links)
Annually, tropical cyclones do tremendous damage and are agents of long-term coastal change. To test this idea of different tropical cyclones delivering consistent coastal change, a landform with such evolution is needed. One such landform is a spit. What contributions do tropical cyclones give toward the evolution of a spit, and do tropical cyclones give the same kinds of impacts? To determine if tropical cyclones have similar impacts, shoreline and volumetric change from four storms impacting Bolivar Peninsula are considered. Being a southwest-trended spit at a length of 33.5 kilometers, storm impacts are measured in the form of one dimensional shoreline and two dimensional volumetric change. These impacts are abstracted into shoreline change and volumetric change patterns. These patterns are identified and compared for differences between each storm and similarity among all storms. Results indicate that shoreline accretionary zones vary alongshore. Results from Hurricane Ike indicate an accretionary zone ten kilometers from the distal end. Shoreline change patterns for Hurricane Rita show an unstable accretionary zone at four kilometers from the distal end. Results for Tropical Storm Fay indicate an unstable accretionary zone that begins at the distal end and continues to the middle of the spit. In terms of similarity for shoreline change, all patterns from storms demonstrated erosion near Rollover Fish Pass. One dimensional volumetric change patterns were entirely erosive for Hurricanes Rita and Ike, and Tropical Storm Fay had by small zones of accretion near the distal portion of the spit. Tropical Storm Josephine demonstrated an accretion zone between the middle and distal portion of the spit. Results from two dimensional volumetric change patterns suggest a threshold for inland penetration. Tropical Storm Fay showed a ten to twenty meter wide pattern of erosion around five kilometers from the distal end and near the proximal end of the spit, and Hurricane Rita demonstrated a twenty meter wide pattern of erosion near the distal end. Hurricane Ike had erosive penetration of up to 200 meters around fifteen kilometers from the distal end. Results suggest that certain storms reinforce the standard spit growth model, and others work against it.
157

Decision support for active water management

Wood, Alison Powell 29 October 2013 (has links)
Active water management uses real-time information to continually respond and adjust to water management needs and situations. To support active water management, the Texas Commission on Environmental Quality (TCEQ) needs tools to access and understand data and to apply that understanding to operational decisions. The work described herein addresses two objectives in providing decision-support for the TCEQ: (1) methods for including environmental pulse flow regulations in water rights documents, and (2) improved ease of access to information needed for TCEQ watermaster operations, particularly in times of drought. A Pulse Scaling Method for calculating the trigger flow rate, volume, and duration of flow pulses, using known characteristics at a reference location A, that are appropriate at a target location B (with unknown characteristics) was developed from three key relationships found in the written environmental flow regulations for fifteen locations in the Trinity, San Jacinto, Sabine, and Neches basins. Applying the method and analyzing the results shows that the predictions are statistically consistent with original regulations. A Common Operating Picture is a layered web-map allowing simultaneous access to one or more spatially-related datasets that TCEQ watermaster staff need to consider in decision-making. By its very nature as a dynamic map with associated time series, the Common Operating Picture presents data as information in a way that can support water resource management and decision-making. The project is currently in the pilot stage, with a number of data sources included and an interface available, but with additional work planned and further testing needed before larger-scale implementation. / text
158

Remote sensing, geochemistry, geochronology, and cathodoluminescence imaging of the Egrigoz, Koyunoba, and Alacam plutons, Northern Menderes Massif, Turkey

Jacob, Lauren Rolston 15 July 2011 (has links)
The Egrigoz, Koyunoba, and Alacam plutons are located in the Northern Menderes Massif of western Turkey between the Simav normal fault to the south and the Izmir-Ankara-Erzincan suture to the north. Although much attention has focused on their geochemical and geochronological history, their relationship to each other and other major structures in the region is still debated. Some geologic maps show the Egrigoz and Koyunoba pluton bounded to the west by the low-angle Simav detachment fault. In contrast, other regional maps show no offsets between the plutons and surrounding metamorphic rocks. Yet other studies indicate thrust faults may be present near the Egrigoz pluton, between Menderes metamorphic rocks and a meta-rhyolite unit. To gain a better understanding of the history of the Egrigoz, Koyunoba, and Alacam plutons, ArcGIS digital elevation data from the region, geochronological data, geochemical analyses, and cathodoluminescence (CL) images were acquired to search for effects of micro- to macro-scales of deformation. Numerous ~E-W trending extension lineations that parallel the Simav graben and cut the plutons were observed in relief images. These lineations, likely due to large-scale ~N-S extension, continue across plutons inferring that extension continued after the exhumation of these rocks. The Simav graben and its associated high-angle fault are evident in the elevation data, but no other significant detachment-related basins or structures are shown, including the low-angle Simav detachment. U-Pb zircon ages, ranging from 29.9±3.9 Ma to 14.6±2.6 Ma, suggest the plutons crystallized over a ~15 m.y. time frame. Samples from the plutons are peraluminous S-type granite to granodiorites. The plutons were emplaced in a post-collisional volcanic-arc setting and range from magnesian to ferroan with increasing silica contents. Geochemical analyses show little difference between the three plutons, consistent with the rocks arising from a similar source. To document microstructures that might help explain these heterogeneities, CL images were obtained. CL images document a complicated tectonic history including magma mixing, multiple episodes of brittle deformation, and fluid alteration. The CL images constitute evidence of a complex multi-stage tectonic history for the region that includes water-mediated brittle deformation. / text
159

Tvorba digitálního modelu terénu pro povodí Jenínského toku a analýza drah soustředěného odtoku vod. / Cration of digital terrain model for the Jeninsky stream catchment and analysis of valley lines.

JURÁNEK, Stanislav January 2008 (has links)
The aim of the thesis is localization and interpretation of paths of concentration runoff in digital terrain model. Digital terrain model(DTM) is processed for the catchment of the Jenín stream, where The Faculty of Agriculture has held the research since the year 2004. For creation of DTM following software programs were used for comparison: Erdas and ArcGIS. Digitalized maps of contour lines for this catchment were the backgrounds for creation of the DTM. Localization of paths of concentration runoff and natural thalwegs was made on created DTM. Then was the comparison of models and the real topography of the catchment realized. Possible reasons of differences were discussed in discussion. Different (in colours and resolution) variations of DTM with localized paths of concentration runoff are the result, with the view of better legibility and more truly representation of real topography of the landscape.
160

Utredning av lakvattnets ursprung på Brista deponi

Nordin, Joel January 2018 (has links)
Utredning av lakvattnets ursprung på Brista deponiJoel NordinBrista deponi har uppvisat oväntat höga lakvattenflöden trots att deponin har sluttäckts. Före sluttäckning var genomförd förväntades flödena reduceras till 700 m3 per år från flöden på några tusen m3. Brista deponi är belägen utanför Märsta i Mellansverige.Söder om deponikroppen finns lakvattendammar som är nyrenoverade med täta dukar från vilka förorenat vatten pumpas upp underifrån dammarna. Pumpningen sker då dammduken annars bucklar upp på grund av för högt grundvattentryck. Vattnet som pumpas upp är för påverkat, av främst närsalter, för att direkt släppas ut till recipienten vilket gör att det pumpas in i de befintliga dammarna. Syftet med detta arbete har varit att utreda ursprunget till de höga lakvattenflöden som fortsätter att rinna ut från deponin samt att utreda ursprunget till de föroreningar som pumpas upp underifrån lakvattendammarna.Marken under deponikroppen har undersökts genom att geologin från flera olika befintliga undersökningar och flygfoton har bearbetats i ArcMap och lagts in i programvaran Rockworks. I programvaran har en modell byggts upp och tvärsektioner över marken tagits ut och tolkats tillsammans med grundvattenytor. Utifrån modellen i Rockworks framkommer det att huvuddräneringen under deponikroppen ligger lågt i förhållande till dräneringen runt deponikroppen. Denna information tillsammans med att deponin inte har någon tät botten har lett till en slutsats att den huvudsakliga anledningen till de höga lakvattenflödena är inträngande grundvatten.Det påverkade vattnet under lakvattendammarna har undersökts med hjälp av programvarorna SIMCA, Rockworks och genom att studera analysserier av provtagningar på vattnet som pumpas upp och vatten från provpunkter på anläggningen. I SIMCA har analysserier lagts in från olika provpunkter i området t.ex. grundvattenrör, och en principalanalys genomfördes för att hitta mönster i föroreningsnivåer. Rockworks användes för att se relationen mellan dammarna, grundvattnet och geologin. Efter sammanställning av kemin, där närsalter varit den kraftigaste föroreningen, tillsammans med analys av redoxförändring, har de olika delarna från SIMCA och Rockworks vägts ihop med kemin. Sammanvägningen gav slutsatsen att det påverkade vattnet under lakvattendammarna härstammar ifrån tiden före lakvattendammarna renoverats och belagts med täta dukar. / Investigation of leachate water origin at the Brista landfillJoel NordinBrista landfill has showed unexpectedly high volumes of leachate out from the landfill even though it has been covered. Before the cover over the landfill was done, leachate volumes were expected to be 700 m3 after the cover would be finished compared to leachate volumes of a couple of thousand m3. Brista landfill is situated south of the city Märsta, in the middle part of Sweden.South of the landfill are newly renovated leachate ponds where polluted water is pumped up from beneath the ponds. The water is pumped up due to high pressure from the groundwater which makes the liner to buckle up if the water is not removed. The water is too polluted, mostly by nutrients, to be released to the recipient directly and is therefore pumped in to the ponds. The purpose of this project has been to investigate the origin of the high volumes leachate water from the landfill and to find an answer to the origin of the polluted water under the leachate ponds.The ground beneath the landfill has been investigated by putting the geology from several old investigations and aerial photos together in ArcMap and exported that information to Rockworks. With the help of Rockworks a model was build and cross sections of the soil could be produced with levels of the groundwater. From the cross sections, it can be seen that the main drainage under the landfill body is lower than the drainage that is around the landfill body. This information together with the information that the landfill doesn’t have any liner in the bottom, have concluded in the conclusion that the main reason of the high volumes of leachate water is due to groundwater intrusion.The polluted water beneath the leachate ponds have been investigated with the software SIMCA, Rockworks and by studying the test results from analyses of the water from different sample points on the facility, compared to the water that is pumped up. In the software SIMCA the test results from the different sample points, as groundwater wells, was imported and a principal component analysis was done to find patterns in the pollutants. Rockworks was used to see the relation between the ponds, geology and the groundwater. After revision of the chemistry, where nutrients were the biggest problem, together with studies of the redox change, the different parts from SIMCA and Rockworks has been weighted together with the chemistry. The parts combined led to a conclusion that the polluted water beneath the leachate ponds is derived from the time before the ponds was renovated and installed with liners.

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