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Sources of nitrate in lower reach of Jizera alluvium: unsaturated zone and other sources
Hronec, Lukáš ; Bruthans, Jiří (advisor) ; Šanda, Martin (referee)
The water supply system Káraný (WSSK), which is using the water from Quaternary fluvial aquifer and induced recharge from Jizera River, is affected by increase of nitrate content in recent years. No tension lysimeters were emplaced into the soil at locality north of Sojovice and sampled roughly with monthly frequency. Samples were analyzed on isotopic content ( 2 H and 18 O of H2O) and chemistry. Volume of water collected in lysimeters was recalculated to mm/year. Infiltration tests demonstrated that infiltration rate at surface of agricultural land is low and therefore Horton surface flow is generated after heavy rains and during watering periods. Horton surface flow is disappearing into open desiccation cracks. This concentrated recharge may via preferential pathways transport nitrates via unsaturated zone. Using selected environmental tracers (Ca2+ a SO4 2- ) the portion of water from Jizera River in individual wells of WSSK was calculated. For Sojovice part of WSSK the water from Jizera River accounts for 71 - 80% of pumped groundwater and for Skorkov part of WSSK this is only 38 - 41%. The remaining part of water is either water from infiltration to Quaternary fluvial aquifer and/or water from Cretaceous Jizera Formation Aquifer. It is not possible to distinguish these two sources by means of...
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Hydrology of Amateur cave and sinking streams focused on tracer tests
Gregorová, Anita ; Bruthans, Jiří (advisor) ; Vojtěchová, Anna (referee)
This study briefly summarizes methodology of tracer studies in karst areas (the way how they were carried out and their evaluation). Second part of the study specifies geological, hydrogeological and hydrological situation of the area of interest - northern part of the Moravian Karst, surroundings of Sloup - using available literature on that topic. Description of the area was completed with field measurements done by the author. Their results can be used as a basis for possible future surveys.
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Repeated tracer tests under different hydraulic conditions
Paděra, Martin ; Bruthans, Jiří (advisor) ; Kůrková, Iva (referee)
The thesis deals with tracer tests conducted repeatedly at several sites under different flow rates. Number of parameters vary depending on flow rates, such as mean residence time, tracer concentration and recovery, the character of breakthrough curve. I compared results from various sites, including the results of my own measurements to see if it is some general pattern. As it turned out, generalization is not possible. Mean residence time can decrease with increasing discharge in one system, while it increases in the other one. The same can be said about tracer recovery. Both parameters are controlled mainly by geometry of karst conduits, especialy by volume of phreatic and vadose spaces in individual levels above and below the lowest water table in the system Breakthrough curve plays essential role in the description of the karst system. It's character varies depending on the flow rate and allows to characterize the karst system. By it's interpretation, it is possible to detect or locate bifurcation and describe the water distribution into discrete conduits.
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Flow, chemical and isotopic composition of water in unsaturated zone of the castellated sandstone at Klokočské skály area
Mikuš, Petr ; Bruthans, Jiří (advisor) ; Jiráková, Hana (referee)
The study is focused on character of flow, permeability, mean residence of water, chemical composition of water and chemical fluxes in unsaturated zone of castellated sandstone at Klokočské Skály area. Soil water as well as the water seeping from up to 15 m thick sandstone unsaturated zone consists of mixture of: A) Component with mean residence time 2-4 months (50-75% of mixture) and B) Component with mean residence time exceeding 4 years (25-50% of mixture). In winter the component A is missing in K3 drip place probably because of freezing conditions, which prevent infiltration of the fast component. Sulfates are the most abundant anion in studied waters with chemical flux in sandstone unsaturated zone (SUZ) 7-10 g/m2/year, which exceeds several times the influx from total (wet and dry) atmospheric deposition (1.2 g/m2/year). On the other hand nitrates flux is decreasing with depth (atmospheric deposition 1.7 g/m2/year; flux in SUZ 0.2-0.4 g/m2/year). Aluminum is the most abundant cation in SUZ (average concentration 6.3 mg/l, max. 35 mg/l). Flux of aluminum in SUZ is 2.5 g/m2/year, which is 80 times more that atmospheric deposition. Surprisingly the forest vegetation does not seem to suffer any directly visible damage. Silica is another substance which is intensively leached from SUZ. The most prominent...
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Frost weathering of sandstones: mechanisms and laboratory experiments
Dvořák, Matěj ; Bruthans, Jiří (advisor) ; Schweigstillová, Jana (referee)
Frost weathering of sandstones: mechanisms and laboratory experiments This thesis studies and compares different mechanisms of frost weathering, and further describes the characteristics of the rock material and the external environment, which affect this process. The effects of frost action were related to sandstones. The thesis consists of a literature review and practical experiments. The literature review indicates, that frost weathering of sandstones is due to their characteristics (higher porosity, grain structure) rather influenced by mechanisms based on water migration through the pore space of freezing rock. Beside the properties of the sandstone material, also the water content, the final temperature of freezing and the rate of the temperature fall are important. The experiments were performed on samples of Cretaceous sandstones (thick-bedded and argillaceous sandstones of Bohemian Paradise) and Carboniferous arkoses of Syřenov formation. Samples were subjected to repeated cycles of freezing at - 20 řC and thawing in distilled water. The weathering progress was monitored by measuring the weight loss and damage description. Selected samples were further compared to samples weathered under the influence of tensile stress (3 kPa). Based on the experiments, the frost resistance (from the most...
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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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Sapping- its field features and studies focused on detail description of the process
Soukup, Jan ; Bruthans, Jiří (advisor) ; Schweigstillová, Jana (referee)
The study discuss about groundwater sapping erosion, whereas is upon process looked from various points of view. In small scale it observes difference between sapping drainage network and network formed by surface runoff. Further forms of the sapping weathering are described and are mentioned examples of sapping valleys from different places around the world. Partially are mentioned actual knowledge in evolution of deep incised valleys on the Mars surface, which are obviously also formed partly by sapping. In the second part, study describes some experiments focused on evolution of sapping valleys in laboratory environment.
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Study of water flow and geochemical processes in the unsaturated zone of carbonate and salt karst
Kamas, Jiří ; Bruthans, Jiří (advisor) ; Tesař, Miroslav (referee) ; Buzek, František (referee)
Water flow and geochemical processes within the unsaturated zone (UZ) in two distinct types of karst environment were investigated using natural tracers (chemistry, stable isotopes 13 C, 18 O, 2 H, and 3 H, 14 C, 87 Sr/86 Sr). The extent of horizontal flow component and the response of drip water chemistry to recharge events were examined in the Moravian Karst (Czech Republic), while the character of water flow and its chemistry were studied in salt diapirs in southeastern part of the Zagros mountains (Iran). Under the conditions of well-developed epikarst, the horizontal flow component, defined as Hmax/T (Hmax = horizontal migration component, T - thickness of VZ) typically reaches values of 0.1 - 0.6 (Moravian and Slovenian Karst). However, in areas where epikarst was stripped off by glacial or human activity, the proportion of horizontal flow component is far greater (Hmax/T 1.6 - 24). This parameter is vital for the design of water source protection zones above caves. Nitrate mean residence time in 120 m thick VZ of the Moravian karst exceeded 16 years. The VZ above the Ochoz Cave (Moravian Karst) represents a semi-open to open system with respect to soil CO2. Under a high drip rate (high flow), the event water only made 5% of the total. During the year, water degassing and so called prior...
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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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