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Dynamic of evolution and hazardousness of lakes in the Cordillera Blanca (Peru)
Emmer, Adam ; Vilímek, Vít (advisor) ; Šobr, Miroslav (referee) ; Haeberli, Wilfried (referee)
Adam Emmer: Dynamic of evolution and hazardousness of lakes in the Cordillera Blanca (Peru) Abstract: High mountain environment of the Cordillera Blanca (Peru) is undergoing prespicious (goe)environmantal changes such as glacier retreat and associated formation and evolution of lakes. Glacial lakes may represent a threat for the society in case of sudden release of (part of) retained water ("glacial lake outburst flood"; GLOF). Reliable identification of hazardous lakes is a key persumption of effective GLOF risk management. The fundamental part of this thesis lies in creation of new method for assessing susceptibility of lakes to outburst floods, reflecting regional specifics of these events in the study area (preconditions, causes and mechanisms) and unsuitability of existing approaches revealed in previous research. Newly created method take into account five scenarios of GLOFs, which are assessed separately, using the combination of decision trees allowing integration of qualitative and quantitative characteristics (an overall number of 17 characteristics of the dam, lake and lake surrounding enter the assessment procedure). Thus, identification of specific causes and mechanisms is enabled. The method was verified by assessing susceptibility of 20 lakes, of which 10 produced GLOFs in past (pre-flood...
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Manifestation of flood in June 2013, Upper Lužnice River
Jaček, Matouš ; Šobr, Miroslav (advisor) ; Havlíková, Petra (referee)
This thesis is about progression of chosen fluvial lakes in the upper basin of the river Lužnice. Observed changes were mainly caused by flood in spring 2013. This area is located by national border with Austria. This part of the river is very preserve and almost without human modifications. The Lužnice river is floating throw floodplain creating meanders and also many fluvial lakes. This area is very useful for research in flooding and changes they cause. First part of this thesis is focused on work with literature about fluvial lakes, their changes and characteristic, about floods and their effect on landscape and about the river Lužnice itself. The second part is about measuring and evaluating changes on four fluvial lakes. These lakes were mapped and measured and those measuring were compared to the measuring made before flood in June 2013.
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Changes of rainfall-runoff regime in the Stropnice river-basin
Volková, Alena ; Šobr, Miroslav (advisor) ; Janský, Bohumír (referee)
This paper deals with the rainfall-runoff regime in the Stropnice river-basin and its development. The aim of this paper is to answer the question of‚were there any changes in the runoff regime during the period 1945 - 2009, and if so, were these changes conditioned by climate or were they caused by human interventions' (e. g. river network modification, changes of the land cover, drainage systems development etc.). The single-mass and double- mass curves were used as the primary methodology. The homogeneity of the time series of mean discharge, precipitation and air temperature were statistically tested using Mann-Whitney-Pettit test and Mann-Whitney test. The Mann-Whitney-Pettit test was performed using the programme AnClim (v5.012), which is freely available online, the Mann-Whitney test was performed using SPSS 15.0. Non-parametric Mann-Kendall test was used for the trend detection, performed in MULTMK/PARTMK by C. Libiseller and A. Grimvall, also freely available online. Some changes in the runoff regime were uncovered in the early 80s', when the runoff decreased, which also happened after 1988. During these periods almost no annual flood occured. The first decrease of the runoff was caused by a drier season in the 80s'. The second decrease after 1988 was probably caused by a build-up of the...
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Interaction of groundwater and surface water under extreme hydrological conditions in the floodplain of the upper Lužnice river
Fialová, Petra ; Janský, Bohumír (advisor) ; Šobr, Miroslav (referee)
The object of this work is an analysis of the influence of extreme hydrological events (floods and droughts) in terms of interaction between groundwater and surface water in the river floodplain. The aim of this thesis is also the evaluation of the hydrological regime of the upper Lužnice basin and evidence of retention potential preserved natural floodplain. The selected objectives of the work were resolved on the basis of the values of groundwater levels and surface water in the area of interest. Based on data from underground wells and a digital terrain model, it was possible to create an image of the distribution of groundwater levels in river floodplains during selected hydrological situations. Data from surface flow was obtained from several habitats in the flow direction Lužnice. This has enabled graphically illustrate individual flood waves and characterize their size, speed and transformation after the passage of a preserved natural floodplain of Lužnice river. Carried out research has been confirmed retention capacity of the floodplain, which is most significant at flow rates slightly in excess of the flow capacity of the river bed. However, extreme floods or in periods with many culminations in a relatively short time leads to reduces water retention capability of the floodplain. In...
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Influence of groundwater on hydrologic drought in the Lužnice River floodplain
Korejs, Tomáš ; Šobr, Miroslav (advisor) ; Janský, Bohumír (referee)
The object of this thesis is to evaluate influence of groundwater on the period of hydrological drought in the Lužnice river floodplain, focusing on interaction between surface water and groudwater. Floodplain of the Lužnice is unique fluvial ecosystem characterized it's diversity and natural value. Especially upper stream of Lužnice represents river floodplain river and creater good conditions for water retention. Main first part of this thesis is focused on work with literature about issue interaction between surface water and groundwater in the river floodplain with examples from Czech republic and the world, including the characteristics the groundwater Work with literature is also focused at characterizing the types of drought, it's cause and consequences. The second part evaluates the basic characteristics of runoff and hydrological drought on the Lužnice. This analysis is based on statistical evaluation of longtime data series from Pilař and Bechyně stations. Both profiles are compared to identify correlations.
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Channel dynamics of the restored Sviňovický Brook
Hujslová, Jana ; Kliment, Zdeněk (advisor) ; Šobr, Miroslav (referee)
The aim of this thesis was to monitor and to evaluate development and morphological dynamics of the Sviňovický Brook channel after the restoration in 2005. Field surveying and aerial images by low-flying model planes were used to detect recent channel dynamics after the restoration in 2005. Channel changes were compared to water level measurements. The additional method was grain size analysis of bed sediments. Orthoimage and cadastral maps were utilized to document changes in channel position over the past 160 years. Field surveying detected intensive bed and bank erosion in restored channel caused by high stream velocity from the fortified upper flow. The restored channel has markedly widened and deepened. The largest changes occurred during floods in July 2006. The intensive eroding- depositing processes remodeled the channel. The changes in channel bed level were up 30 cm and bank erosion locally exceeded 1 meter. The longitudinal profile of the channel was leveled. The road bridge began to be obstacle to the longitudinal profile development. It causes deposition upstream and erosion downstream. The largest bank disruptions in the sector up the road bridge were fortified by quarried stones at the end of 2007. The channel has not shown any significant changes since 2007. With the growing density...
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Changes of rainfall-runoff conditions and anthropogenic modification in Lomnice River basin
Bažatová, Tereza ; Šobr, Miroslav (advisor) ; Langhammer, Jakub (referee)
The runoff from a landscape is a natural process which is very complicated. It's not simple to express the runoff process in general because it depends on many factors that participate more or less in its course. The main aim of this paper is the explanation of rainfall-runoff process in Lomnice River basin, the land use changes description and the evaluation of anthropogenic modifications of Lomnice River. All of these elements influence the course of hydrological extremes. Another parts of this thesis concentrate on floods (especially flood 2002) in the Lomnice River basin and on water systems of Blatensko which is the third largest of all water systems in the Czech Republic. The relationship between a rainfall and a runoff in Lomnice River basin is being assessed with the help of the simple- and double-mass curve method, regarding possible changes caused by anthropogenic impacts. This part contains the analysis of trend in development of land use, the analysis of air temperature and snow parametres as well. Great anthropogenic changes of river channels and river floodplain can evoke dramatic geomorphological effects. The methodology of research - anthropogenic modifications of Lomnice River is based on a field survey of anthropogenic transformation of a riverbed and river floodplain. Then the...
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Geographical division of the World Ocean
Kohoutková, Lucie ; Janský, Bohumír (advisor) ; Šobr, Miroslav (referee)
Geographical Division of the World Ocean Abstract Delimitation of ocean boundaries has a big importance for coastal as well as continental countries due to economical, political and other concerns. Division of the World Ocean varied a lot in the past and significant regional differences of its concept were formed. Not only the location of boundaries but even the number of identified subdivisions of the ocean varied. Some oceanographic schools which don't recpect international agreements and delimitate their own ocean boundaries still exist. Thanks to that there are still many problematic areas where neighbouring countries arque about a part of the ocean. The prefence for boundaries delimitation is very important and often also controversial. Tree main oceans - Pacific, Atlantic and Indian Ocean - are traditionally delimitate separetly for what many reasons exist. Many authorities still doubt about the independence of the Southern Ocean. The publication of 4th edition Limits of Oceans and Seas where the Southern Ocean should be officially accepted will be very significant. Keywords: Division of the World Ocean, ocean boundaries delimitation, the Southern Ocean
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