National Repository of Grey Literature 45 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Changes in extremity and seasonality of floods in the Zdobnice River basin
Čermák, Daniel ; Langhammer, Jakub (advisor) ; Šobr, Miroslav (referee)
The object of the bachelor thesis is to analyze the change of extremity and seasonality of floods in the Zdobnice basin. The literary research comprehensively presents floods with description of the biggest historical floods in the Czechia and in the Zdobnice basin. The literary research also includes the physical-geographical characteristic of the studied area. The practical part is based on the daily flow data analysis, obtained from CHMI (Czech Hydrometeorological Institute). Runoff analysis is performed on the base of these data, with focus on extreme flows. To compare the seasonality change, data series is divided into two periods (1945-1969 and 1970-2014), which point of change was determined by Pettit's and Buishand's homogeneity test. Seasonality change is compared by directional statistics, polar graphs, curves of cumulative frequency and flood index. As a result of these methods, it is found that in the second period, the flood risk is greater in earlier parts of the year. It has been also found, that there are more flood events in July. Key words: Floods, discharge, hydrological extremes, historical floods, seasonality, Zdobnice
3D reconstruction of abandonned ponds using UAV photogrammetry
Stanovský, Tomáš ; Langhammer, Jakub (advisor) ; Blahůt, Jan (referee)
The main focus of the thesis is the reconstruction of 3D models and digital elevation models of five abandoned splash dams in Roklanský brook catchment using UAV photogrammetry methods. The aim of this work is to compare accuracy of the models with available conventional data sources and historical sources. Parallel topic is the research of accuracy of the models created through UAV methods and application of retention potential of small water reservoirs, in headwater areas. The images were taken with a drone-mounted camera. Modelling was done by processing images in software Agisoft PhotoScan through a workflow process, dense point cloud classification and subsequent DEM interpolation. Subsequent delineation of reservoirs retention space, altimetry correction and bathymetric analysis was performed in ArcMap over the interpolated DEM. The results and discussion point to the benefits and limitations of UAV methods, especially to altimetric accuracy of the resulting models relative to conventional DMR5G data and bathymetric characteristics derived from the models. Keywords: UAV; DEM; retention; GIS; model; pond
Impact of climate change on runoff in montane catchments of Central Europe
Lörinc, Michal ; Langhammer, Jakub (advisor) ; Jeníček, Michal (referee)
The diploma thesis "Impact of climate change on runoff in montane catchments of Central Europe" aims to assess published scientific literature on the subject and to develop projections of changes in study catchments of Upper Vydra in Czechia and Kokra in Slovenia. The thesis contains a review of selected theoretical knowledge on climate change impacts, evaluates existing methodology of impact studies and presents projection results for two study catchments in its practical part. Those were acquired using a multi-step methodology by using climate model projections, bias correction methods, usage of hydrological model and analysis of variance. Among the main conclusions is the anticipated continuation of changes in seasonal runoff, decrease of summer runoff and increase in winter runoff, as well as changes in drought characteristics. The analysis of variance revealed a substantial influence of cliamte models on the achieved results, however selection of emission scenario plays a major role as well. It is apparent that the selected catchments do and will react to climate change differently, however both can be considered to be sensitive to these changes. Kľúčové slová: climate change, hydrological cycle, montane catchments, HBV Light, ANOVA
The influence of changes of land cover on connectivity of fluvial processes in catchment
Kofroňová, Jitka ; Langhammer, Jakub (advisor) ; Kliment, Zdeněk (referee)
The connectivity of fluvial processes or hydrological connectivity are terms often used to describe internal linkages in landscape that intensify/reduce water and sediment fluxes as well as the substances they contain. It is based on the concept of landscape connectivity defined, in particular, by fragmentation of landscape and barriers that obstruct the movement of material. While researches focusing on water erosion or runoff focus on the volume of different fluxes, connectivity reveals new information on catchment functioning as well as reactions to various types of stimuli, and thus represents a more complex phenomenon. This master thesis informs about the topic as a whole, it describes the main forms of its modelling and specific influences that have major impact on presented results. Three approaches of modelling were tested. The main concept lies in evaluation of the index of connectivity, firstly, with approach proposed by Borselli et al. (2008) and implemented in software ArcGIS and secondly, in software SedInConnect 2.0. The third approach is modelling connectivity in software LAPSUS 5.0 that belongs to landscape evolution models. Modelling in LAPSUS proved that using even this indirect method for evaluation of hydrological connectivity is a suitable approach. Selected area for modelling...

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2 Langhammer, Jan
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