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Changes of physical-chemical parameters of surface water in context with hydrological extremes. Application in the Rolava River catchment.
Šajnarová, Lucie ; Matoušková, Milada (advisor) ; Havlíková, Petra (referee)
6 Abstract The diploma thesis deals with changes in the physico-chemical parameters of surface flows in response to extremes, especially increased flows due to higher precipitation totals or melting snow. The basin of the upper Rolava with peat bogs in the basin and minimal anthropogenic influence was used. The main goal of the work was the analysis of the behavior of electrical conductivity during events when there was an increase in flow rates and the categorization of individual events according to this behavior. Furthermore, the influence of the pre-condition of the watershed on the events and the subsequent behavior of the electrical conductivity was also investigated. The 10-minute electrical conductivity and flow data from the automatic stations of the ecohydrology team of the Faculty of Science, UK, or ČHMÚ were used. Among the methods are data homogenization, construction of hysteresis loops, categorization of loops, calculation of indices for hysteresis loops and PCA analysis for the pre-condition of the watershed. In most cases, a reverse relationship of electrical conductivity behavior was observed during these events, the most common types of electrical conductivity behavior during flow increases include a slow decrease in conductivity with minimum values after the peak of flow (in light...
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Extreme hydrological processes in the upper Ostravice River basin
Cermanová, Eliška ; Langhammer, Jakub (advisor) ; Matoušková, Milada (referee)
The main object of this bachelor is the assessment of rainfall-runoff processes with a primary focus on the occurrence of extreme hydrological phenomena in the upper basin of the Ostravice river. The first part of the work is devoted to literature research dealing with the issue of extreme hydrological phenomena and their assessment methods, supplemented by research about current findings regarding changes in the rainfall-runoff regime. This part ends with a description of the physical-geographical conditions of the basin, ilustrated by map outputs. In the second practical part, the available data of average daily flows and daily precipitation totals from the ČHMÚ are analyzed in the period 1970-2020. By Pettit's test of homogeneity, the period is divided into two parts (1970-1995 and 1996-2020) to analyze the change in seasonality of the runoff regime and extreme events. Attention is also paid to the change in the ratio of base and direct runoff using the baseflow index and the runoff coefficient. To detect changes in the characteristics of the frequency of occurrence, duration and intensity of extreme events, the threshold value method and the insufficient volume method were used. As a result, a shift in the seasonality of the occurrence of floods to earlier months and a significant increase in...
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Effect of climate change on hydrological extremes in montane catchments
Čermák, Daniel ; Langhammer, Jakub (advisor) ; Jeníček, Michal (referee)
This master thesis deals with the issue of low-flows in mountain catchments in the context of expected climate change. The Zdobnice, Vydra and Mumlava river basins are selected for analysis. In the first part of thesis, the meteorological and hydrological historical data are evaluated. This data are obtained from CHMI (Czech Hydrometeorological Institute). The work also focuses on estimating the possible change in flow rates in the distant future (2100). For these purposes, the conceptual model HBV is used. This model is often used for these types of analyzes due to its robustness. To evaluate the change, twelve alternative scenarios were created. These scenarious were based on the results of global and regional climate models related to each selected river basins. The model was calibrated using the automatic GAP optimization function. Based on the best results, the calibration period is set for the years 1980 - 1998. Climate models suggest increase of temperature in far future by 1.5 ř C - 4.5 ř C. At the same time, according to climate models, we can approximate a total precipitation change by 10 %. Based on climate changes, a shift in the runoff seasonality in the all river basins is evident. Seasonality change is most visible in the Zdobnice river basin. In terms of hydrological drought, an...
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Changes in extremity and seasonality of floods in the Zdobnice River basin
Čermák, Daniel ; Langhammer, Jakub (advisor) ; Šobr, Miroslav (referee)
The object of the bachelor thesis is to analyze the change of extremity and seasonality of floods in the Zdobnice basin. The literary research comprehensively presents floods with description of the biggest historical floods in the Czechia and in the Zdobnice basin. The literary research also includes the physical-geographical characteristic of the studied area. The practical part is based on the daily flow data analysis, obtained from CHMI (Czech Hydrometeorological Institute). Runoff analysis is performed on the base of these data, with focus on extreme flows. To compare the seasonality change, data series is divided into two periods (1945-1969 and 1970-2014), which point of change was determined by Pettit's and Buishand's homogeneity test. Seasonality change is compared by directional statistics, polar graphs, curves of cumulative frequency and flood index. As a result of these methods, it is found that in the second period, the flood risk is greater in earlier parts of the year. It has been also found, that there are more flood events in July. Key words: Floods, discharge, hydrological extremes, historical floods, seasonality, Zdobnice
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Extreme hydrological events in the Rolava River basin
Vlach, Vojtěch ; Matoušková, Milada (advisor) ; Blahušiaková, Andrea (referee)
6 Abstract This bachelor thesis deals with characteristics of extreme hydrological events in the Rolava river basin, which is located in the Ore Mountains in northwestern part of Czech Republic. The main aim of this study is a comparison of hydrological extremes in headwater catchments of Rolava River and Slatinný brook using data from the experimental monitoring of Department of Physical Geography and Geoecology, Faculty of Science, Charles University in Prague and Czech Hydrometeorological Institute. The other object is a field survey of the impacts of hydrological extremes on fluvial-morphological dynamics of the streams, focused on river-bed forming processes. The opening part of this thesis deals with the physical geographical and hydrographical characteristics. The main part is devoted to the comparison of extreme events in the monitored catchments focusing on floods and drought. As a final result, it was found out that Slatinný brook has a greater tendency to extremity of peak discharges. Another part of the results is an analysis of the five-year flood seasonality change on upper course of the Rolava River in two periods 1967-1990 and 1991-2014. Key words: extreme events, flood, drought, fluvial dynamics, Rolava, Slatinný brook
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Streamflow dynamics in the upper Křemelná River basin
Součková, Markéta ; Kocum, Jan (advisor) ; Jeníček, Michal (referee)
Submitted thesis analyses and summarizes findings about runoff dynamics in the upper Křemelná River basin (SW Czechia, Šumava Mountains). A theoretical part of the thesis describes existing findings about hydrological extremes related to ongoing climatic change in the Central Europe region. It is also focused on water retention in headwaters, physical-geographic factors influencing runoff and runoff assessment approaches. Within the practical part of the thesis the accent was put on correct construction of discharge curves and on time series cleansing. Using basic hydrological statistics the daily, monthly and annual runoff regime in Stodůlky state profile and in chosen experimental catchments of the Department of Physical Geography and Geoecology, Faculty of Science, Charles University in Prague, were assessed. Results show slightly unbalanced runoff in the upper Křemelná River basin. The highest rate of discharge is typical for spring period during snowmelt and increased discharges are significant also within winter floods. Increased summer discharges are reflected in daily, but not in monthly mode, due to their short time of duration.
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Impact of rainwater management on mitigation of hydrological extremes
Pešková, Jitka ; Štibinger, Jakub (advisor) ; Miroslav, Miroslav (referee)
This dissertation deals with the impact of rainwater harvesting on mitigation of hydrological extremes. Due to the fact that it is a very broad topic that cannot be completely elaborated, the work targets selected aspects of this issue. The work is divided into two parts. The first part is divided into the following five chapters: The water in the landscape, Water regime, Hydrological extremes, Water regime adjustment and Legislation. These chapters summarize available worldwide knowledge about rainwater harvesting both in the landscape and in urbanized areas with a focus on mitigation of extreme hydrological phenomena (floods - drought), including legislative security of water management on national and EU level.
The second part of the thesis is compiled in the form of an annotated set of four scientific studies, whose results were presented in articles published in scientific journals. The first study targets the efficiency of torrent control (hydro-technical point of view and migration of water fauna). The second study focuses on the territory of the Morava River floodplains, where negative impacts of floods and droughts appear repetitively. The study solves the hydrological balance of the area using the WBCM-7 model. The third study focuses on computation method of the retention drainage capacity in the agricultural area drained by subsurface pipe drainage system. The last paper describes a new application of the Fourier series for detailed simulation of the runoff on a catchment in the dry periods. Within the thesis, these studies have been interconnected by explanatory comments.
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