|
|
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.
|
|
|
Chemical composition of water from the unsaturated zone of selected sandstone outcrops
Paděra, Martin ; Bruthans, Jiří (advisor) ; Kamas, Jiří (referee)
The thesis is focused on the chemical composition of water from the unsaturated zone of sandstones on six localities in the Bohemian Cretaceous Basin and one site in the permocarbon basin. The subject of the study is mainly capillary water from several cm depth of sandstone exposure. Soil lysimeters, called rhizons, were tested to sample this water. Although rhizons are primarily designed for soil moisture sampling, under suitable conditions water abstraction has been successful. Vadose waters have low pH of 3.7-6.2, mainly caused by the infiltration of acid atmospheric precipitations, rich on sulphates and nitrates and other components, which are subsequently involved in the formation and crystallization of salts. Higher pH 5.7-6.2 show sites where rise in pH and different water chemistry are due to different geological conditions. Waters contain high concentrations of sulphates (4.9-763 mg/l), nitrates (2.2-109 mg/l), calcium (1.8-167 mg/l) and aluminium (0.1-4.7 mg/l) and compared to atmospheric precipitation are enriched for all dissolved ions. However, vadose waters sampled with rhizons do not differ from sandstone seeping waters. According to the results of geochemical modelling, waters are supersaturated with respect to quartz and chalcedony. The precipitation of main salts, such as gypsum...
|
|
|
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.
|
guest ::
