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Small water reservoirs in the Krkonoše Mountains: What would their regeneration bring?
Šádková, Eva ; Janský, Bohumír (advisor) ; Daňhelka, Jan (referee)
This thesis deals with the evaluation of influence of small water reservoirs on the extreme runoff events (floods and drought) in the upper Úpa River basin. It summarizes knowledge about both hydrological extremes and their manifestations in the basin of interest as well as about small water reservoirs in the sense of water retention measures and their possible importance during the periods of low flows or floods. In this thesis two localities of possible reservoirs at place of former splash dams in Obří důl and on the Lysečinský Brook were chosen. To assess the influence of small water reservoirs on runoff during two chosen flood events and two periods of drought, the hydrological model HEC-HMS was applied. The results of model simulation proved a positive influence of reservoirs on the reduction of flood peaks (except for a concurrence of transformed flood waves in the outlet that occurred during one flood event), but the effect was decreasing with the increasing catchment area and the intensity of precipitation and with smaller storage capacity of a reservoir. During the low flows, a positive influence of reservoirs was observed as well, relating to the release of stored water. However, the ability of a reservoir to reduce deficit volume and to balance the flow was decreasing with smaller...
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Hydrological drought in the upper Mže catchment area
Lukášová, Karolína ; Janský, Bohumír (advisor) ; Šobr, Miroslav (referee)
Nowadays drought is a very actual topic. Hydrological drought is most often caused by a deficit of precipitation and it has been missing almost one year of rain in some areas in Czechia. This bachelor thesis focuses on the analysis of this type of drought in the upper Mže River basin, which is located in West Bohemia. In the basin there are these five gauging stations: VD Lučina and Stříbro on the Mže River, Planá on Hamerský brook, Třebel on Kosový brook and Stříbro on the Úhlavka River. The theoretical part defines the area of interest in terms of physiographic and runoff conditions. Furthermore, a research of the current knowledge about drought, its causes and impacts is performed. The practical part follows with the analysis, using data of the average daily discharges from gauging stations and two methods - threshold limit method and deficit volumes. Results are based on a mutual comparison of the stations and hydrological years. The biggest drought on the Mže River was registred in the period 1934-1935, since 1970s natural discharges were improved due to the built dam. The period 2018-2019 can be considered as driest years for the whole river basin. Key words: upper Mže River basin, hydrological drought, runoff, precipitation, physiographic conditions
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Hydrological drought in the Loděnice basin
Burian, Alois ; Janský, Bohumír (advisor) ; Skála, Vít (referee)
The aim of the bachelor thesis is to analyse of the current situation of the selected basin of Loděnice which has suffered a significant drought in recent years. The first part of the thesis is a literary research which presents drought as a complex phenomenon. The literary research is based on domestic and foreign literature. The thesis describes its genesis, connections with other types of drought, indicators of drought and possible consequences. The research includes physical-geographical characteristics of the area. The practical part is based on the data obtained from the CHMI (Czech Hydrometeorological Institute) and introduces the runoff regime of Loděnice river with a focus on the period of drought in the past and now. Hydrological drought is evaluated using the threshold limit method and deficit volumes. It has been detected that the basin of Loděnice is still under the larger impact of hydrological drought, especially in August and September. Keywords: hydrological drought; runoff regime; deficit volumes; threshold limit method, Loděnice river
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Hydrological drought in headwater areas of the Ore Mountains
Vlach, Vojtěch ; Matoušková, Milada (advisor) ; Kliment, Zdeněk (referee)
Changes in the hydrological cycle are one of the expected impacts of climate change. Until recently, Central European mountain ranges have not been considered to be affected by water scarcity. Nevertheless, recent years have suggested an increasing risk of drought occurrence also in these regions, which have a major impact on the water supply to rivers that drain them. The master thesis deals with the evaluation of hydrological drought in the headwater areas of three catchments in the Ore Mountains for the period from 1967 to 2018. The main aim is to compare the of hydrological drought characteristics in the catchment areas of upper Svatava River, upper Rolava River and Načetínský brook based on available hydrological and climatic data. In connection with this, the work aims to detect the long-term trends of drought occurrence in selected basins. Furthermore, the emphasis is given on the evaluation of natural conditions, especially the historical and current land cover changes in the study catchments. The results point to a significant change in the seasonality of the occurrence of hydrological drought in the second half of the studied period, when the streamflow deficits concentrate between August and October. Furthermore, increasing trends in deficit volumes were found in the catchment areas of...
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Interaction of groundwater and surface water under period of hydrological drought in the floodplain of the upper Lužnice River
Korejs, Tomáš ; Šobr, Miroslav (advisor) ; Janský, Bohumír (referee)
The object of this thesis si to evaluate the interaction of groundwater and surface water under the period of hydrological drought in the floodplain of the upper Lužnice river. The thesis tries to show the influence of the groudwater in the river floodplain during the period of hydrological drought and its correlation with the surface water state. The area of interst of the upper Lužnice is characterized by a unique ecosystem of unique natural value. It is a preserved river floodplain, which plays an irreplaceable role in fluvial processes, especially in water retention. The objectives were solved based on the monitoring of groudwater and surface water states from data obtained from the PřF UK profiles, which are represented by boreholes aross the floodplain and level meters in the watercourse. From the data obtained, it was possible to create a final analysis and to determine the behaviour and the mutual interaction between the surface water and groundwater in this natural floodplain. A detailed analysis has confirmed, that the interaction between watercourse and the floodplain and its retention potential. It can be said that during the hydrological drought, the water state or discharge in the watercourse is improved by water from the floodplain. The subsidy is only evident in certain stretches of...
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Signs and impacts of hydrological drought in the Rakovnicky stream basin
Maroušková, Kateřina ; Matoušková, Milada (advisor) ; Hrdinka, Tomáš (referee)
This thesis deals with the signs and impacts of the hydrological drought in the Rakovnicky stream basin. Its aim is to evaluate trends of the selected hydroclimatic variables, to analyze drought periods and land cover changes as one of the factors influencing a runoff regime in the catchment. The main methods used for the long-term and seasonal trends are Man-Kendall test, IHA analysis, flow duration curves and mass curves. Dry periods are evaluated based on Streamflow drought index (SDI), Low Flow index and runoff Q95 exeedance. Land use changes are analyzed using historical maps and index of change. Basic indices of ecological stability are calculated. According to the results the frequency and intensity of the hydrological drought in the Rakovnicky stream basin is increasing. Although the amount of a rainfall is consistent, its distribution throughout the year is changing. In addition the constantly increasing temperature and land use changes cause a significant runoff decreasing. To improve a water retention capacity in the cathment, it would be convenient to apply adaptation measures in the river channels and floodplains. Key words: rainfall, runoff, drought, ecological status, Rakovnicky stream
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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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Climatic change effect on hydrological drought in the Otava River headwaters
Šachová, Barbora ; Kocum, Jan (advisor) ; Fiala, Theodor (referee)
CLIMATIC CHANGE EFFECT ON HYDROLOGICAL DROUGHT IN THE OTAVA RIVER HEADWATERS Abstract The submitted thesis deals with hydrological drought in condition of climate change in Otava River headwaters. The topic is discussed from four different aspects that together create a complex view on the hydrological drought issues in the catchment. The first aspect, the hydrological drought analysis in daily series, is done by threshold level method and SPA. Second aspect studies the impact of climate change on the hydrological drought by using the BILAN model. Following aspect determines a prediction of low flows and deficit volumes during drought by the recession analysis. Final aspect suggests relating process of management, planning and adaptation measures on drought. Key words: hydrological drought, minimal discharges, deficit volumes, BILAN model, climatic change, recession analysis, Otava River, Modrava, Rejštejn, Sušice, adaptation measures
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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
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Accumulation and retention reservoirs in Czechia
Leipeltová, Petra ; Kocum, Jan (advisor) ; Česák, Julius (referee)
This bachelor thesis is aimed in detail on small water reservoirs, on their distribution and function. Brief history of reservoirs is mentioned as well as their water management and technical solution. The part of the thesis is represented by the assessment of their influence and integration within an environment. In the second part, historical use and potential renovation of former accumulation reservoirs in Šumava Mts., situated in Vydra River basin and used for wood floating in the past, is solved. These water bodies are no more in function but their system could be an effective part of measures within an integrated flood protection and hydrological drought elimination. Geomorphologically suitable relief of Vydra River basin, source area of extreme runoff situations formation, also provides optimum conditions for realization of small retention reservoirs that could, in connection with other measures for headstream areas retention potential enhancement, reduce extreme runoff episodes in future. Keywords: small water reservoir, accumulation reservoir, retention reservoir, integrated flood protection, hydrological drought, Vydra River basin
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