National Repository of Grey Literature 59 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Methods to characterize the intensity of recharge via riverbed due to groundwater abstraction
Bašus, Jan ; Bruthans, Jiří (advisor) ; Kůrková, Iva (referee)
EN There is an intense exchange of water between the quaternary fluvial sediments and river. Although the precise amount of seepage flow is needed for various hydrogeological models and calculations, the systematic measurements of the seepage flux in our country are lacking. This Batchelor thesis describes 4 methods that can be used to measure the intensity of water exchange between quaternary sediments and river flows. These are manual and automatic seepage meters, which isolate a small part of the river bed and measure the amount of water that is lost or gained. These two approaches differ by frequency of measuremens. Secondly, there are methods that measure the temperature distribution in the river bed with heat-sensitive electric sensors (point measurements) and light distraction in an optic fiber. The measured temperatures are used to simulate the water and heat flow in the river bad. At each of these methods, I described the method principle, the equipment used for measurement, the measurement methodology as well as examples of where were these methods already used. Discussion in the final part of the thesis contains comparison of the practical use of the mentioned methods. Key words: Seepage, Seepage meter, riverbed infiltration, water flow in riverbed.
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...
Selected issues in karst hydrogeology in Czech Republic
Belokopytov, Daniil ; Bruthans, Jiří (advisor) ; Vysoká, Helena (referee)
- Albeřický brook, Dyleň karst and Javoříčko - Mladeč of Čerlinka eastern edge of the Javoříčko - Mladeč karst. In Javoříčko - Mkadeč karst, the method was supplemented with several potential springs of karst origin in Albeřice valley and Dyleň karst. In spite of expectations, there were low water levels found in the region of Javoříčko_Mladeč kars
Possibilities of karstification of calcareous sandstones in the Jizera segment of the Bohemian Cretaceous Basin and evolution of conduits in the thick-bedded sandstones
Vojtíšek, Jan ; Bruthans, Jiří (advisor) ; Vysoká, Helena (referee)
Features typical for karst, such as fast groundwater flow and existence of open conduits were observed in various parts of Bohemian Cretaceous Basin (BCB). So far, vertical and areal extent of karst rocks is not known. In case of concerning conduits in quartz sandstones the observation of their evolution in profiles perpendicular to flow is missing. The thesis deals with above mentioned issues. Concerning potential to karstification it is limited to Jizera facial area of BCB. For this purpose, leaching of samples in hydrochloric acid were carried out. The hydrochloric acid was used as an accelerated simulation of natural processes of dissolution of rock by acidic solutions. The reaction of samples on leaching in acid, disintegration and content of the CaCO3 component were evaluated. CaCO3 content was determined also by calcimetry. Rocks which disintegrated can be a suitable for the evolution of karst conduits. According to the lithostratigraphic sections, the examined profiles belong to the TUR5 and TUR6 units - thus these units contain rocks suitable for the evolution of karst conduits. In Předměřice site about 23 % of samples disintegrated, in Kosmonosy site 8 % and in Turnov site 36 % disintegrated. Thus about 1/10 to 1/3 of tested profiles is prone to karstification and evolution of karst...
Using environmental tracers and other methods to estimate mean residence time and water flow in karst areas, Czech Republic
Bruthans, Jiří ; Krásný, Jiří (advisor) ; Bosák, Pavel (referee) ; Buzek, František (referee) ; Grmela, Arnošt (referee)
5. CONCLUSTON -Springs in 9 se|ected areas Were studied. Areas difÍer in geo|ogy (|itho|ogy, tectonics, intensity of metamorphism), recharge intensity (móuntainous coniřa lowland areas) and intensity of karst development differing by climatic conditions, geology -Concentrated recharge is only minor importance in most of areas compared to diffuse recharge -Most of the springs (90%) show predominant infiltration during last two decades with minor content (0-30%) of water infi|trated in sixties and sevénties of the twentieth century (based on tritium content). Analysis of lBO variations in spring water indicate that contribution of short residence time component (MRT in weekš to months) is about 5-20o/o of the spring yield -These numbers are similar or somewhat lower to results of MRT studies in other karst areas in the world (mostly vast carbonate bodies), which show mean residence time of water in karst aquifers to be from several years to hundreds of years -Volume of water in catchments of particular springs based on mean yield of spring and mean residence time is in orders of units to tens of millions m3 -|n studied karst areas SFo and CFCs can give re|iab|e resu|ts. |f no data from trítium are available the residence time must be considered as a minimum age. -Mean residence time of water percolating...

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4 Bruthans, J.
3 Bruthans, Jan
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