National Repository of Grey Literature 102 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Fluctuations in the groundwater level in the montane peat bog Rokytka
Lencová, Kateřina ; Šobr, Miroslav (advisor) ; Doležal, Tomáš (referee)
Peatbogs are globally widespread ecosystems that have a major influence on the hydrological conditions of watersheds. Of particular importance are mountain highlands, which are characterized by their occurrence in the source areas of streams. Despite the indisputable importance of the montane peatbogs in terms of runoff conditions, their influence has not yet been conclusively clarified. Montane peatbogs are a particularly important topic for the Šumava region, where they represent a fundamental element of the landscape. The study site is therefore situated in one of the Šumava's spring areas - the Rokytka watershed. As part of this thesis, the issue of the hydrological function of the monitored peatbog has been viewed mainly through the differences in the fluctuation of the groundwater level in different parts of the peatbog. At the same time, the influence of the precipitation on the change in the groundwater level in the peatbogs and on the runoff response of the Rokytka brook has been monitored. Precipitation is the only source of water for the highlands and its influence is therefore crucial. Although several previous studies have focused on the influence of this highland on the runoff conditions of the Rokytka brook, groundwater levels from manually measured probes have not yet been analysed....
Division of the region of the Šumava/Böhmerwald Mts. in terms of heavy precipitation
Králová, Kateřina ; Müller, Miloslav (advisor) ; Šobr, Miroslav (referee)
Divison of the region of the Šumava/Böhmerwald Mts. in terms of heavy precipitation Abstract This thesis deals with the spatial and temporal distribution of heavy precipitation in the Šumava region. The first part of the work is devoted to literature review regarding precipitation conditions in mountainous areas and a brief description of the Šumava mountains. The second part is initially devoted to the analysis of a total of 683 heavy precipitation events at the 64 stations spread evenly between Czechia, Germany, and Austria. The 50 largest daily precipitation totals at individual stations in the period 1971-2018 were always selected as strong precipitation events. The analysis was focused on the seasonal division of these events into four periods, namely spring, summer, autumn, and winter. Here, a strong link between the winter period and the westerly flow and the summer period and circulation types B, Bp, SWc and C is shown, and it is also confirmed here that spring and autumn are rather transition periods between the warm and cold part of the year with regard to heavy precipitation. Furthermore, an analysis of strong precipitation events was conducted based on the location of the geographical midpoint of the Tu event in quadrants I-IV, which were defined using the created vector space. I. and IV....
Hazard evaluation from GLOFs in the Cordillera Huayhuash
Baťka, Jan ; Vilímek, Vít (advisor) ; Šobr, Miroslav (referee)
Hazard evaluation from GLOFs in the Cordillera Huayhuash Abstract: Proglacial lakes in high-mountain regions recently experienced dynamic development related to the ongoing climatic changes. Most of the mountain ranges were widely studied with respect to hazards posed by proglacial lakes. However, the Peruvian Cordillera Huayhuash was omitted by any research of this type so far. In this thesis first, the author develops and assesses the inventory of glacial lakes in the Cordillera Huayhuash, and second, evaluates the hazard from GLOFs. After a thorough discussion and comparison to other world's major mountain ranges, significant conclusions are made. Most of the characteristics of the lakes in the Cordillera Huayhuash are influenced by a local factor - fluvial erosion that has occurred since the last glacial maximum. Nevertheless, general principles such as the statistical distribution of lakes according to their elevation that are valid to other compared regions may still be identified based on the data. Lakes of the Cordillera Huayhuash generally pose minor or even no GLOF hazard, the few exceptions were further analyzed in detail. Key words: geomorphology, GLOF, lake inventory, natural hazards, Peru
Origin and evolution of proglacial lakes in the Patagonian Andes
Danišová, Dominika ; Vilímek, Vít (advisor) ; Šobr, Miroslav (referee)
Origin and evolution of proglacial lakes in the Patagonian Andes ABSTRACT: Proglacial lakes are dynamic water bodies affected by the evolution of glacier ice masses, morphology and climatic factors. Mountain glaciers are very sensitive to climate change, which has caused their continuous recession recent decades. Glacier retreat is closely linked to an increase in the volume of proglacial lakes, especially in high mountain areas. The growth of proglacial lakes can also lead to increased probability of overtopping or dam rupture, also known as GLOF. The first aims of the presented thesis are to describe how proglacial lakes are formed, what factors can influence their continuous evolution and, lastly, how the lakes can affect their surroundings. In order to perform the spatial and temporary analysis, an inventory of the proglacial lakes in the North Patagonian Icefield was made, as this area has not yet been properly studied. In the time scale from 1984 till now, 640 lakes were characterised. The results show that along with glacier retreat, proglacial lakes are increasing in both size and number. However, the correlation with the climatic data is limited because of its poor quality and inadequate distribution in this area. Keywords: glacial lakes, glaciers, lake-dams, North Patagonian Icefield, GLOF
Hydrological drought on the Lužnice River in 2018
Junková, Anna ; Šobr, Miroslav (advisor) ; Matoušková, Milada (referee)
This bachelor's thesis elaborates on hydrological draught on Lužnice river at 2018. First part is focused on literary research on draught types, causes and impacts. Following chapter evaluates hydrological draught in Czechia between 2014 and 2018. This research serves as a resource for the main part of the thesis, which deals with hydrological draught on Lužnice river at 2018. Computations are based on threshold level concept and deficit volumes methods. Analysis is performed on the basis of data series from limnigraphic stations Pilař and Bechyně. These profiles are compared for the purpose of determining differences. The results of the work show that the hydrological year 2018 on Lužnice river was very important year in modern history in terms of drought. Key words: hydrological drought 2018, deficit volumes, threshold level, Lužnice river
Reaction of surface water and groundwater to the hydrological drought in 2015-2018 in the Upper Lužnice river
Husarik, Pavel ; Burian, Alois (advisor) ; Šobr, Miroslav (referee)
The Bachelor's thesis focuses on the examination of drought as an extreme and complex phenomenon. It provides a clear overview of its types, causes, and impacts on the landscape and society. Furthermore, it discusses the response of surface and groundwater to dry periods. The theoretical conclusion specifically analyzes the period of hydrological drought in the Czech Republic between 2015 and 2018. In the practical part, the characteristics of monthly and annual discharges are evaluated, and the response of surface and groundwater is assessed using data. Data from both surface and groundwater, as well as precipitation totals from the ČHMÚ (Czech Hydrometeorological Institute) observation network, were utilized. Average precipitation totals were also taken into account. The evaluation of time series was performed in terms of precipitation-runoff regime, including exceedance lines and monthly flow distributions. The results indicated that the lowest average flows were recorded in 2018, which also saw the lowest average groundwater level. Conversely, the highest number of dry days occurred in the studied period in 2015. Keywords: surface water, groundwater, hydrological drought, the upper Lužnice river
Supraglacial lakes detection and volume estimation from remote sensing data
Rusnák, Samo ; Brodský, Lukáš (advisor) ; Šobr, Miroslav (referee)
Supraglacial lakes detection and volume estimation from remote sensing data Abstract Supraglacial lakes play an important role in understanding glacier dynamics, including their response to climate change. This thesis explores the problematics of estimating lake depth and volume using a physical model. This brings challenges in considering the influence of various factors, such as cryoconite on glacier surface and suspended particular matter, which influences physical model, which is in research mostly neglected. Regression analysis of the g parameter of a physical model, representing light attenuation coefficient, and supervised classification of supraglacial lakes is applied in this thesis. The results reveal the variability of parameter Ad, representing lake bottom albedo reflectance, and its impact on predicted supraglacial lakes depth and volume. The results highlight the problem of global parameterisation of the physical model of supraglacial lakes and the need for further research to improve its accuracy and explore future possibilities in this field. Keywords: supraglacial lake, remote sensing, machine learning, physical model, depth estimation, regression analysis
Restoration and renaturation in the Klíšský Brook catchment
Holík, Jan ; Matoušková, Milada (advisor) ; Šobr, Miroslav (referee)
This bachelor's thesis presents a revitalization and renaturation study of a small watercourse in rural area. Specifically, it is the Klíšský stream, which is a tributary of the Bílina River. Among the main goals of the bachelor thesis is the development of possible proposals for possible revitalization and renaturation measures with the aim of improving the hydromorphological quality of a small watercourse. During the development of the revitalization plans, a total of 18 cross-section profiles and one longitudinal profile were surveyed within the geodetic survey, in which specific revitalization measures were proposed. Within the evaluation of the characteristics of the study area, analyses of the granular composition of the sediment of the bottom were carried out, an evaluation of the property conditions was carried out and also flow monitoring was carried out during the periods of field surveys. In the revitalization modification proposals, the existing capacity in the targeted transverse profiles was also calculated. By synthesis of all the obtained and available information, proposals for measures to improve the overall condition of the water course were carried out, in the section the water surface in the form of a pool and wetlands in the area of the non-functional hydromelioration network...
Hydrological drought in 2022: Case study of the Lužnice River and Bouřlivec River Basins
Hajný, Vojtěch ; Šobr, Miroslav (advisor) ; Burian, Alois (referee)
This bachelor thesis is focused on evaluating the issue of hydrological drought on Lužnice River and Bouřlivec River Basins in 2022. The first part of the thesis is focused on solving the topic of drought, its classification and causes. The next part of the work deals with a general assessment of the hydrological drought in Europe in 2022, its impacts in specific countries and the indicators used to measure it. The practical part is a key part, dealing with the evaluation of hydrological drought in the areas of interest in 2022 using the threshold level concept, deficit volumes and drought indices. The analysis is carried out on the basis of the provided flow data from the Pilař and Bechyně profiles in Lužnice River and Lahošť and Duchcov in the Bouřlivec basin. Based on the resulting values, the year 2022 is compared with previous years and placed in the context of long-term drought observation. The results show that the drought in 2022 was severe but not very ignificant in the long-term monitoring. In terms of the number of dry days and insufficient volumes, the hydrological drought in the Bouřlivec basin was more pronounced than in Lužnice River, where it was accompanied by lower flows. Key words: hydrological drought, Lužnice River, Bouřlivec River
Evolution of proglacial lakes in the South Patagonian Icefield
Schreiner, Vojtěch ; Vilímek, Vít (advisor) ; Šobr, Miroslav (referee)
Today, as our planet warms, the dangers posed by proglacial lakes are becoming increasingly apparent. Often, due to faster glacial retreat, these lakes are enlarged and the risk of lake dam failure is consequently increased. This can lead to a phenomenon known as GLOF (Glacial Lake Outburst Flood), i.e. the breaching or overflowing of a lake dam and subsequent flooding of downstream areas. The key to limiting the damage caused by these events is to increase our knowledge of this phenomenon and to be able to anticipate these events in time. The basis for this must be an analysis of glacial lakes in the area. This should include a time element, which will allow us to keep track of changes in the amount of water retained in the lake. This is the focus of this paper. The South Patagonian Icefield was chosen as the research area and proglacial lakes were mapped from images taken in 1985 which are available on Google Earth Pro. In this way, 93 lakes were found and their evolution was followed up to the present day. From these observations an inventory table with spatial and temporal elements was created. It was confirmed that most of the proglacial lakes in this region are also experiencing an increase in area.

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