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Changes in the fluvial valley network at NW Šumava foothills
Hošek, Roman ; Hartvich, Filip (advisor) ; Borská, Jana (referee)
This bachelor thesis is focused on the processes causing the changes of the river network. Among the most important processes are tectonics, landslides, headward and lateral erosion, anthropogenic activities, lithology of a stream bed, changes of the erosion base and climate, as a factor influencing the morphology of valleys. The information from the literature search is applied on finding potential valley network changes localities based on indicators of changes of the river network, which were analysed in the GIS environment. Each potential locality was chosen for a presence of an indicator, which may signify changes of the river network: sudden direction changes of a stream, wind gap, streams which flow through topographic barrier, captured stream. The main criterion for finding potential localities was elevation above the valley-floor interpolated surface, where low values indicate low water divide between valleys. These selected localities were compared with the position of the anomalies on the longitudinal profiles of the rivers. The longitudinal profiles with sudden changes of inclination (knickpoint) indicate possible changes of the river network. Key words: changes of the river network, headward erosion, lateral erosion, river piracy, landslides, tectonics, anthropogenic activities, Šumava...
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Debris flows as a result of environmental changes in midmountains of the Cenral Europe, case study in the Hrubý Jeseník Mts.
Raschová, Tereza ; Křížek, Marek (advisor) ; Hartvich, Filip (referee)
This work determines on the basis of literature according to its objectives the definition of the debris flows, an overview of their types and description of the genesis and morphology. Debris flows are mass movements with high rate of speed, caused by atmospheric conditions (intense precipitation, melting snow) or geomorphological events (sudden burst of water pockets, burst of moraine or ice dammed lakes) in mountainous areas that move down the valley along torrential chanels or along slopes and pull down everything in their path. We distinguish between structural and turbulent debris flows. In case of structural ones the water is creating an envelope of the debris. Their genesis is conditioned by supersaturation of weathered soil with water and the movement is created by gravity. The turbulent debris flow are formed by water which is not able to be absorbed and the water pulls down the debris on slopes and in the channels. Material is transported in suspension. I compared some debris flows from different mountains and it is quite complex to define specific values of parameters that cause debris flows. Structural debris flow in this study originated on rocks with a high content of micas or on sandstones. Turbulent debris flows originated on granitoids. Precipitation should have higher intensity...
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Biomechanické vlivy stromů na půdu v přirozených temperátních lesích
Senecká, Anna
Biomechanical effects of trees (BETs) on soil have not yet been sufficiently evaluated. In this study, we aim to (i) develop a widely applicable methodology for measuring the BETs, and (ii) to analyze structure of these processes. The research took place in the Boubínský Primeval Forest where Fagus sylvatica L. and Picea abies (L.) Karst occur predominantly. Manifestations of the 11 different BETs were evaluated with 4,000 standing or lying trees on an area of 10.2 hectares. We recorded specific biomechanical effect (of trees) in 59% standing and in 51% of the lying trees. There were significant differences in the structure of BETs among trees of different species and dimensions. While the bioprotective function of tree was the most frequent effect, from the viewpoint of areas and soil volumes affected the treethrow were the most important. The total area affected by the processes was 342 m2 ha-1 and the total volume was 322 m3 ha-1.
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Debris flows as a result of environmental changes in midmountains of the Cenral Europe, case study in the Hrubý Jeseník Mts.
Raschová, Tereza ; Křížek, Marek (advisor) ; Hartvich, Filip (referee)
This work determines on the basis of literature according to its objectives the definition of the debris flows, an overview of their types and description of the genesis and morphology. Debris flows are mass movements with high rate of speed, caused by atmospheric conditions (intense precipitation, melting snow) or geomorphological events (sudden burst of water pockets, burst of moraine or ice dammed lakes) in mountainous areas that move down the valley along torrential chanels or along slopes and pull down everything in their path. We distinguish between structural and turbulent debris flows. In case of structural ones the water is creating an envelope of the debris. Their genesis is conditioned by supersaturation of weathered soil with water and the movement is created by gravity. The turbulent debris flow are formed by water which is not able to be absorbed and the water pulls down the debris on slopes and in the channels. Material is transported in suspension. I compared some debris flows from different mountains and it is quite complex to define specific values of parameters that cause debris flows. Structural debris flow in this study originated on rocks with a high content of micas or on sandstones. Turbulent debris flows originated on granitoids. Precipitation should have higher intensity...
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Changes in the fluvial valley network at NW Šumava foothills
Hošek, Roman ; Hartvich, Filip (advisor) ; Borská, Jana (referee)
This bachelor thesis is focused on the processes causing the changes of the river network. Among the most important processes are tectonics, landslides, headward and lateral erosion, anthropogenic activities, lithology of a stream bed, changes of the erosion base and climate, as a factor influencing the morphology of valleys. The information from the literature search is applied on finding potential valley network changes localities based on indicators of changes of the river network, which were analysed in the GIS environment. Each potential locality was chosen for a presence of an indicator, which may signify changes of the river network: sudden direction changes of a stream, wind gap, streams which flow through topographic barrier, captured stream. The main criterion for finding potential localities was elevation above the valley-floor interpolated surface, where low values indicate low water divide between valleys. These selected localities were compared with the position of the anomalies on the longitudinal profiles of the rivers. The longitudinal profiles with sudden changes of inclination (knickpoint) indicate possible changes of the river network. Key words: changes of the river network, headward erosion, lateral erosion, river piracy, landslides, tectonics, anthropogenic activities, Šumava...
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