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General Runoff Water Balance Model of a River Basin
Černý, Vojtěch ; Knoppová, Kateřina (referee) ; Marton, Daniel (advisor)
Modelling of the rainfall-runoff process is one of the basic scientific skills in hydrology. Rainfall-runoff modelling can help to improve water management, handling of the reservoir's storage volume, or also to facilitate adaptation to current climatic conditions. The aim of the diploma thesis is to create a functional rainfall-runoff model on the basis of water balance equations based on the lumped water balance principle of the hydrological model. Several modifications of the general rainfall-runoff model are approached in the diploma thesis. Four types of the daily evapotranspiration determination are used in the calculations. The rainfall-runoff model is compiled from temperature data and precipitation totals in a daily step. The practical application is carried out on a sub-basin of the river Dyje, which is located above Vranov water reservoir. The main output is a series of daily flow rates that were obtained from calibrated rainfall-runoff models. The best rainfall-runoff model takes into account the water from snow cover melting, the value of the Nash Sutcliffe calibration criterion of this model is 0.608. Finally, the hydrological simulation for the period 2021-2060 is performed in the diploma thesis.
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Amount and differences in snow accumulation in the Šumava region
Procházka, J. ; Šustková, V. ; Tesař, Miroslav
The Šumava Mts. (Bohemian Forest) represents the most extensive mountainous range of the Czech Republic and due to its area and altitude it catches the substantial portion of the winter precipitation in the snow form. Unfortunately, the more continuous information on snow characteristics from the highest and remote regions of the Šumava Mts. has been in effect missing till recently. From this reason the activities focused on the more detailed expeditionary field measurements of the snow depths and snow water equivalent. The space analysis of point snow cover measurements the appropriate tools were used: ArcGIS (ESRI), orographical interpolation, LLR methods and the methods of ClidatDEM used in the Czech Hydrometeolological Institute.
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Changes in the ratio between a new snow depth and seasonal precipitation in mountainous and submontane regions of the Czech Republic
Procházka, J. ; Lipina, P. ; Šustková, V. ; Tesař, Miroslav
Snowfall and snow cover formation is an important aspect of the colder part of the year in the Czech Republic and Central Europe. Snow cover is important from the point of view of climatology, hydrology, ecology and recreation, and therefore economic. In addition to precipitation, the amount of new snow depends mainly on the air temperature. With gradual warming, it can be assumed that with a similar total precipitation, the proportion of precipitation in the form of snow and the ability to form snow cover will decrease. In order to evaluate the mentioned changes, the ratio of the seasonal amount of new snow in cm and total precipitation in mm, Sn/P (cm/mm) was used in this paper. For the analysis, data from the CHMI database for two normal periods 1961–1990 and 1991–2020 were processed for selected mountain and foothill meteorological stations in the Czech Republic. The period from November to April was assessed as a cold part of the year for this purpose, when a new snow cover is more likely to form. The results of the study showed that the Sn/P ratio decreased in the period 1991–2020 compared to the period 1961–1990.
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Spatial analysis of snow cover using the method of electrical impedance spectrometry
Novák, Michael ; Zeleňáková, Martina (referee) ; Janál, Petr (referee) ; Pařílková, Jana (advisor)
Snow cover is an important climatic, hydrological and biological phenomenon. Especially in the empirical sciences, snow and snow cover monitoring has a long tradition, the importance of which has been reinforced in recent decades by the fact that snow cover (it is controlled by temperature and precipitation) is one of the important indicators of climate change. The dissertation thesis deals with the monitoring of snow cover in the years 2016 to 2019, mainly in the Czech Republic, in the Eagle Mountains. The characteristic properties of the snow cover and their changes, caused by changes in temperature, humidity and air flow rate or by the snow's own weight, are monitored by selected and available classical methods and non-traditional indirect method of electrical impedance spectrometry. The aim of the work was to master the measurement technique by a non-traditional method (design of measuring probes, delimitation of the space between the measuring electrodes, data collection and processing). The method is described in the work, the results of monitoring are published in graphical form and are commented. Another goal was to find a suitable mathematical description of the dependence between the measured electrical quantities and the properties of the snow cover, which can be used to determine the water value of snow and possibly also predict the avalanche danger. The technique of measurement by the indirect method of electrical impedance spectrometry was successfully mastered, including the definition of possible adverse effects affecting the measurement result. It was not possible to obtain a statistically significant set of data on the basis of which it was possible to determine the dependence between individual quantities. Classic manual methods can still be considered the standard for snow diagnostics and snow cover.
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Modelling of runoff changes due to forest disturbances in the Šumava catchments
Švejdová, Klára ; Jeníček, Michal (advisor) ; Šípek, Václav (referee)
Runoff conditions in river basins are heavily influenced by vegetation cover. Changes in the vegetation linked to forest disturbances significantly affect the water balance of the river basin. These changes can be effectively quantified using hydrological models. Therefore, this thesis aims to describe water balance change in forests disturbed by bark beetles and storms. Three model experiments were simulated using the HBV precipitation-runoff model for Roklanský potok, Ptačí potok and Rokytka catchments in Šumava, Czechia. All these catchments underwent significant forest damage after recent disturbance. First experiment used the split sample test method. Calibration was performed separately for the period before and after disturbance, and then simulated for the whole period. The resulting simulated runoffs notably differ from one to the other, which may be caused not only by deforestation, but also by the effects of climate and the characteristics of individual catchments, which also affect their runoff response. The second model experiment was based on changes in vegetation-dependent parameters (melt factor and snowfall correction factor) and analysis of their effect on the simulated runoff. The results did not reveal significant changes in the monitored runoff characteristics. However, this is...
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Effect of selected physical-geographical factors on the snow accumulation and snow melt
Pevná, Hana ; Jeníček, Michal (advisor) ; Langhammer, Jakub (referee)
Effect of selected physical-geographical factors on the snow accumulation and snow melt Abstract: This master thesis analyzes the influence of physical-geographical factors on spatial distribution of snow water equivalent, and its evolution. In this work, emphasis is placed on describing the influence of vegetation, aspect and altitude. Measurement was carried out in experimental catchments Zlatý Brook and Bystřice River in western part of the Ore Mountains in winters 2008/2009, 2009/2010, 2010/2011 and 2011/2012. To evaluate the influence of these factors on value of snow water equivalent there was used one of the methods of multivariate statistical analysis - cluster analysis. The research shows that the greatest influence on the distribution and evolution of snow water equivalent in the experimental basins has vegetation and some dependency was proved also between the points of southern exposure. The measurement results demonstrate the suitability of cluster analysis for analyzing the data of point values of snow water equivalent. On the other hand the results showed the main limits of this method, especially the need for a large number of points with different characteristics. The results of measurements and statistical analysis are compared with results published in technical literature. Keywords: snow...
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Effect of vegetation on snow accumulation and snow melt
Pevná, Hana ; Jeníček, Michal (advisor) ; Kocum, Jan (referee)
Effect of vegetation on snow accumulation and snow melt Abstract: This bachelor thesis analyzes the impact of physical-geographic factors on the physical properties and characteristics of the development of snow cover. Results published in the literature are compared with those obtained from experimental measurements in the upper Byst ice River basin in the Ore Mountains during the winter 2009/2010. The paper compares the evolution of snow cover for the actual land cover, forest and open areas. The research of literature and research conducted in the Ore Mountains proved that vegetation significantly affects accumulation and melting of the snow. The process of accumulation in the forest is influenced by snowfall interception in the treetops. Melting snow in a forest area slowed absorption and reflection of sunlight in the treetops. The bachelor thesis demonstrates that in the open areas the snow melted faster than in the forest growth. Keywords: snow cover, snow water equivalent, vegetation, Ore Mountains
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Snow cover at the Čertova louka and the Modré sedlo sites (Krkonoše Mts) in winter 2010/2011
Tryzna, Vojtěch ; Engel, Zbyněk (advisor) ; Nyplová, Petra (referee)
Snow cover at the studied locations in the Eastern Giant Mountains in the winter of 2010/2011 were collected through periodic field measurements of snow cover height. For evaluation and interpretation of measurements was used data from the meteorological station on "Luční bouda" and published the results of previous measurements in the field. In the "Čertova louka" is located nivation hollow, which show an increase in the accumulation of snow, which melted in early June. In the "Modré sedlo" location, which is largely exposed to deflation, the snow lasted until the end of April. The distribution of snow cover at both sites in winter 2010/2011 were consistent with previous observations. Maximum height of snow cover was lowest (about 8.4 to 43.8 %) from the current observation and were recorded aproximately one month earlier (18. 2.). The main reason for the development of unusual snow was warm front with rainfall, which affected the studied area during March. Winter 2010/2011 has been in terms of power and duration of snow cover at the studied locations below average.
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