National Repository of Grey Literature 86 records found  previous11 - 20nextend  jump to record: Search took 0.01 seconds. 
Hydrological drought in the context of climatic change in the world and in the Czech part of Elbe River basin
Šachová, Barbora ; Kocum, Jan (advisor) ; Janský, Bohumír (referee)
Hydrological drought in the context of climatic changes in the world and in the Czech part of Elbe River basin Abstract The submitted thesis deals with the hydrological drought as one of extreme runoff situations in relation to climate change. Part of this work is a comprehensive research sources to Czech and foreign literature defining the concepts and the development of hydrological drought due to the physical- geographic and anthropogenic factors. Low flow characteristics and methods for defining the drought events are described. Attention is paid to the possibilities of prevention and compensation of negative impacts of drought. Within the second part the presence of low flow in Elbe River subbasins, Blšanka River, Rakovnický Brook and Vydra River, is analyzed. Water deficit is evaluated with regard to the physical-geographic characteristics and the specifics of water resources use. Outline of possibilities to increase the retention capacity of study catchments is given. Key words: hydrological drought, low flow, runoff regime, retention potential, Blšanka River, Rakovnický Brook, Vydra River
Water quality analysis in the Mastník catchment area
Mrkva, Luboš ; Janský, Bohumír (advisor) ; Chalupová, Dagmar (referee)
The quality of surface water in the Czech Republic has changed distinctly in two last decades. The pollution of important rivers has been reduced radically. Small rivers in agricultural areas, however, remain problematic. There is a long-term absence of information about such rivers concerning the purity of water. Mastník, which flows through the agricultural area of Central Bohemian Uplands and as a right-hand side tributary flow into the Vltava River, is one of those rivers. Quality circumstances in catchment area were analysed on the basis of data about the concentration of selected indicators, which come from three monitored profiles of the State public enterprise Povodí Vltavy. The present state of surface water quality was specified by means of ČSN 75 7221. Further, the development of quality was observed since 1995 and the reliance of the concentration on the flow or the season of the year was rated. All the data, which were acquired about anthropogenic and natural pollution of the river, are very important for precautions, which lead towards the improvement of quality of water in rivers. It was discovered that the precautions, which are made in catchment area lead to the improvement of the quality of water in Mastník. If the present state should be retained, the remediation of waste water must be...
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...
Runoff regime in the basin of Hamerský brook with respect on pH reaction in selected flood episodes
Prokš, Milan ; Janský, Bohumír (advisor) ; Bubeníčková, Libuše (referee)
Odtokový režim v povodí Hamerského potoka se zaměřením na reakci pH vody ve vybraných povodňových Abstrakt Práce se zabývá analýzou odtokového režimu v povodí Hamerského potoka. Zájem je soustředěn především na posouzení vlivu Hamerského potoka na tok řeky Vydry v souvislosti s odpojením Vchýnicko-tetovského kanálu. Problémem spojeným s touto problematikou je dodržování minimálních zůstatkových průtoků v korytě Vydry po tomto odpojení. V práci je dále posuzována reakce pH vody na změnu průtoků při vybraných povodňových epizodách. Tento vztah naznačuje možnost hodnocení hydrologické funkce rašelinišť právě pomocí parametru pH vody. Klíčová slova: minimální zůstatkové průtoky, pH vody, rašelinišťě, Hamerský potok, Vydra, Šumava Runoff regime in the basin of Hamerský brook with a view to pH reaction on selected flood episodes Abstract This paper deals with an analysis runoff regime in the basin of Hamerský brook. Interest is primarily focused on assessment of the impact Hamerský brook of the Vydra river. There is a connection with the disconnection of Vchynicko-tetovský water port. An associated problem with this issue is keeping the minimum residual flow in Vydra river after the disconnection of water port. The work is further considering response of water pH reaction to change flows at selected flood...
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...
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.
Tropical rainforest: dynamics of development and human impact (material for learning of geography at the highschools and universities)
Bartošová, Martina ; Janský, Bohumír (advisor) ; Matějček, Tomáš (referee)
The submitted thesis deals with the tropical rainforests as one of the most threatened biomes of the world. The work is a comprehensive research sources to Czech and foreign literature dealing with characteristics of tropical rainforests. The main causes of the disappearance of tropical rainforests are described. Particular attention is devoted to Amazon forests. Conclusion of this work is devoted to the treatment of a worksheet.

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