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Approaches to estimate wetland evapotranspiration and the evapotranspiration loss of groundwater from wetlands in the Liběchovka and Pšovka catchments
Pátek, Karel ; Bruthans, Jiří (advisor) ; Slavík, Martin (referee)
This work is dedicated to the study of evapotranspiration in wetlands. The theoretical part is an overview of methods that are used for estimation of evapotranspiration, especially in the wetland environment. The practical part is focused on measurement of evapotranspiration in the wetlands located in the upper part of the Pšovka and Liběchovka river watersheds. Periodical fluctuations of water table and water flow in the stream were observed there due to evapotranspiration. The role of evapotranspiration was dependent on the mean daily temperature and sunshine duration. For the warm sunny days the fluctuations indicated that in the studied wetland the maximal daily evapotranspiration can cause 32 % decrease of water flow in the stream. The evapotranspiration derived from stream flow oscilation reached 86 % of potential evapotranspiration based on Oudin method. Potential evapotranspiration in the Liběchovka wetlands in summer is capable to decrease the discharge of Liběchovka in similar way as groundwater abstraction.
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Origin of karst conduits and caves in Jizera Formation in Turnov.
Slavík, Martin ; Bruthans, Jiří (advisor) ; Schweigstillová, Jana (referee)
Aim of this study is to characterize the processes responsible for evolution of open conduits and caves in Jizera Formation near Turnov, in particular to distinguish if the main factor acting in enlargements of conduits is dissolution and the conduit system can be called karst, or if the process is caused by erosion of weakly cemented sandstone without contribution of dissolution. An important part of the study is to introduce the concept of self-organization. Based on results from accelerated simulation of dissolution of twenty rock samples, SEM analysis and drilling resistance, I have proved that rocks in Jizera Formation near Turnov dissolve in an acidic environment and their strength characteristics does not enable direct erosion by flowing water. Samples from localities of "Bartošova pec", "Slepé údolí Podhorčí", "Rozsedlinové ponory pod Drábovnou", "Šetřilovsko", "U Kačeny" and "Semikraska" dissolve, but behavior of samples from "Sudoměř - rybník" and "Sudoměř - Skalský potok" is in an acidic environment very similar to samples from Teplice Formation "Skalní pískovcový výchoz u Podhorčí" and "Valdštejn".
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Permeability of natural surfaces of Hruba Skala sandstone in rock cities for water vapour and intensity of evaporation
Slavík, Martin ; Bruthans, Jiří (advisor) ; Pavlíková, Milena (referee)
Aim of this study was to describe capillary water and vapor transport in shallow subsurface of Hrubá Skála sandstone in the Bohemian Paradise. I have quantified permeability of Hrubá Skála sandstone for water vapor using "wet cup" method and also capillary water absorption of sandstone drill cores. I have found out general rules of evaporation and rate of evaporation from several sandstone outcrops in real microclimate. Important part of my work was to determine whether surface crust plays some role in studied parameters. Based on my results, permeability of different types of sandstones for water vapor does not vary significantly and surface crust has no effect on rate of water vapor diffusion. Rate of capillary water absorption is reduced by surface crust. Hrubá Skála sandstone is classified as medium or highly absorbing material. I have proved that evaporation from porous medium can be approximated by exponential function. Rate of evaporation is strongly controlled by climatic conditions, especially by relative humidity. Powered by TCPDF (www.tcpdf.org)
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Effect of evapotranspiration from riparian zone on drying of stream Brzina and decrease in groundwater table
Knődl, Vlastimil ; Bruthans, Jiří (advisor) ; Slavík, Martin (referee)
The Brzina river drainage basin in the Sedlčany region was affleck by drought between 2015 and 2019. The Brzina river dried up repeatedly during the summer and the whole drainage basin suffered from a lack of groundwater. The aim of the bachelor thesis is to verify the influence of evapotranspiration from the river floodplain on the drying up of the Brzina river. The input data for the calculations are the historical time series provided by CHMI and the data from piezometers. The theoretical part of the bachelor thesis deals with the assessment of methods of individual calculations used in the practical part, i. e. the antecedent precipitation index, baseflow and evapotranspiration. It also deals with the influence of vegetation on the total runoff from the river drainage basin and with various calculations of evapotranspiration from groundwater level records. In the practical part of the bachelor's thesis a potential evapotranspiration is calculated using selected methods, the baseflow is separated from streamflow and the influence of components of the hydrological balance on the loss of water from the river drainage basin is verified by other methods. Recorded groundwater abstractions have an insignificant effect on the hydrological balance. The underground runoff under the Brzina riverbed is...
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Methods of Streamflow Measurement
Tučanová, Kamila ; Slavík, Martin (advisor) ; Datel, Josef (referee)
This bachelor thesis focuses in its review part on commonly exploited methods of discharge measurement (velocity-area methods, dilution method, volumetric method, formed constriction methods, slope-area method and rating curve). The principle of discharge measurement and calculation, advantages, disadvantages, and accuracies of individual methods, as well as the type of stream suitable for different method, are reviewed in theoretical part of the thesis based on available literature. In the practical part of the thesis, measurements with selected methods (current meter, FlowTracker, float method and dilution method) were made on 3 lower order streams equipped with Czech Hydrometeorological Institute gauging stations. Discharges collected with individual methods were compared with one another and with the discharges from the gauging stations. Resulted deviations of discharge values were confronted with the accuracies of individual methods presented in the review, and discussed. It was determined, based on 14 values of discharge, that on selected streams, the highest accuracies were reached with FlowTracker (relative deviation up to 12 %). Dilution method had lowest accuracies (relative deviation up to 25 %). The interpretation of the results is complicated due to low resolution of the gauging...
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Analysis of pitch perception depending on the spectrum
Slávik, Martin ; Indrák, Michal (referee) ; Jirásek, Ondřej (advisor)
This thesis is dealing with the research of the influence of individual harmonic components on the perception of sound height. As a part of the work has been made an internet questionnaire on a web address www.analyzavyšek.9e.cz, where individual respondents completed listening test compound of 46 samples. This experiment is based on semantic differential method. Individual samples are compound of sine wave – tone and examined sample, which respondents evaluates on three bipolar scales. The samples were either modelled by additive synthesis or modified sampled sounds of instruments. Individual samples were divided to four major groups and other minor groups for clarity. The purpose was to find which parts, combinations and harmonic components of sound and tone can affect perception of tone height.
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Permeability of sandstone surfaces and water flow in shallow zone of ruiniform sandstone landscape
Sysel, Ondřej ; Slavík, Martin (advisor) ; Tesař, Miroslav (referee)
Water in porous rocks (e.g. sandstone) plays a fundamental role in their disintegration. However, the places where water enters the sandstone rocks are somewhat overlooked. At two sites in the Český ráj region, I use Karsten tube to measure capillary water absorption (CWA) of natural sandstone exposures and, using TDR (Time Domain Reflectometry) method, I study movement of water in a shallow zone of ruiniform sandstone landscape. The CWA differed up to four orders of magnitude at a distance of tens of meters, mostly depending on the type of the surface. The highest CWA was measured at highly weathered surfaces, the second most absorbent were less weathered surfaces covered with a biologically-initiated rock crust. The horizontal surfaces on the tops of the rock formations were even less absorbent, probably due to clogging by fine particles from soil. Surfaces covered with iron crust were the least absorbent. The differences between those surfaces are significant. After simulated infiltration, the maximum rate of the propagation of the wet front in the sandstone was from 5,5.10-6 do 1,9.10-4 m.s-1 measured by TDR. The water propagated at this rate only to a certain depth (the first tens of cm), but then the propagation stopped or slowed down rapidly. From a long-term measurement of volumetric...
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Moisture characteristics of natural sandstone exposures
Slavík, Martin ; Bruthans, Jiří (advisor) ; Tesař, Miroslav (referee) ; Sněhota, Michal (referee)
Moisture in a sandstone body plays a notable role in hydrological, weathering, biological and other processes. Knowledge about presence and movement of moisture within porous medium of natural sandstone exposures is, however, rather limited. Aim of the doctoral thesis was thus to quantify selected moisture characteristics of several natural sandstone exposures in Český ráj (Czech Republic). According to long-term logging, mean annual temperature at studied areas was between 8.5 řC to 11.5 řC, mean annual relative humidity was between 73 % to 85 %. Deforested area was found warmer and drier and amplitude of the values was higher there than at the forested areas. Values of water content (more than 400 measurements) and suction (more than 150 measurements) of the exposures including their spatial-temporal changes were obtained. Mean volumetric water content in zone from the sandstone's surface to 12 cm depth was from 3 % to 10 % and mean suction in depth 2-12 cm was from 2 kPa to more than 130 kPa. Using uranine powder coloring, spatial distribution of moisture near the sandstone's surface was visualized repeatedly for the first time. The coloring divided the surficial area of the sandstone into capillary (wet) and diffusion (dry) zone. The sharp transition between the two zones was represented by...
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