National Repository of Grey Literature 9 records found  Search took 0.00 seconds. 
Hydrological drought in the context of climate change: Case study of the Blšanka and Loděnice basins
Burian, Alois ; Janský, Bohumír (advisor) ; Hanel, Martin (referee)
The final thesis deals with the issue of hydrological drought in the context of climate change. The basins of the Blšanka River and the Loděnice River have been suffering from water shortages in recent years, therefore they have been selected for the purposes of this final thesis. The thesis summarizes the basic principles used to estimate climate change on the water resources with emphasis on the occurrence of hydrological drought. At the same time, individual components and processes of hydrological modelling conditioning the formation of affected time series in the near (2020-2050) and far future (2070-2100) are described. A total of sixteen simulations created from the seven global climate models (GCM) of the CMIP5 project and three climate scenarios (RCP; Representative Concentration Pathways) are used. The time series of precipitation and air temperature, which have been influenced by the climate change, were derived by an advanced delta method that counts also with the change of variability. The conceptual hydrological model BILAN is used to simulate changes, due to its availability from the T. G. M. Research Institute of Water Management and its wide use in Czech conditions. The parameters of the BILAN model are calibrated based on the observed time series of both selected river basins....
Hydrological processes and dynamics in the changing climate and environment: Lessons learned from multiple temporal and spatial scales
Su, Ye ; Langhammer, Jakub (advisor) ; Hanel, Martin (referee) ; van Meerveld, Hilda (referee)
Hydrological processes and dynamics in the changing climate and environment: Lessons learned from multiple temporal and spatial scales Ye Su ABSTRACT Climate change, along with the changes in land use and land cover (LULC), is the key factor driving the changes in hydrological processes and dynamics in a basin. This thesis emphasized on understanding the impact of both long-term climate change and abrupt anthropogenic driven agricultural intensification or natural driven insect-induced forest disturbance on hydrological processes and dynamics at varying spatial and temporal scales in two diverting terrestrial environment. Two pattern-based investigations, one case study in a forest region in Central Europe and another in a semi-arid region in Central Asia, were aimed to answer the main research question "what are the responses of hydrological dynamics and the related hydro-geochemical conditions to climate change and certain changes in LULC at a basin-scale?". The long-term hydro-climatic dataset was used for conducting statistical analyses and establishing hydro-climatic modelling at the basin scale. We further conducted process-based studies, attempting to understand how and why the specific hydrological dynamics were altered at smaller spatial and temporal scales: (i) a catchment-scale tracer-based...
Application of optimization methods in hydrological modeling
Jakubcová, Michala ; Máca, Petr (advisor) ; Hanel, Martin (referee)
Finding the optimal state of reality is the main purpose of the optimization process. The best variant from many possibilities is selected, and the effectiveness of the given system increases. Optimization has been applied in many real life engineering problems as in hydrological modelling. Within the hydrological case studies, the optimization process serves to estimate the best set of model parameters, or to train model weights in artificial neural networks. Particle swarm optimization (PSO) is relatively recent optimization technique, which has only a few parameters to adjust, and is easy to implement to the selected problem. The original algorithm was modified by many authors. They focused on changing the initialization of particles in the swarm, updating the population topology, adding new parameters into the equation, or incorporating shuffling mechanism into the algorithm. The modifications of PSO algorithm improve the performance of the optimization, prevent the premature convergence, and decrease computation time. Therefore, the main aims of the presented doctoral thesis consist of proposal of a new PSO modification with its implementation in C++ programming language. More PSO variants were compared and analysed, and the best methods based on benchmark problems were applied in two hydrological case studies. The first case study focused on utilization of PSO algorithms in inverse problem related to estimation of parameters of rainfall-runoff model Bilan. In the second case study, combination of artificial neural networks with PSO methods was introduced for forecasting the Standardized precipitation evapotranspiration drought index. It was found out, that particle swarm optimization is a suitable tool for solving problems in hydrological modelling. The most effective PSO modifications are the one with adaptive version of parameter of inertia weight, which updates the velocity of particles during searching through the multidimensional space via feedback information. The shuffling mechanism and redistribution of particles into complexes, at which the PSO runs separately, also significantly improve the performance. The contribution of this doctoral thesis lies in creation of new PSO modification, which was tested on benchmark problems, and was successfully applied in two hydrological case studies. The results of this thesis also extended the utilization of PSO methods in real life engineering optimization problems. All analysed PSO algorithms are available for later use within other research projects.
Using Weather Generators for the Assessment of the Impact of Climate Change in Catchments
Martínková, Marta ; Hanel, Martin (advisor) ; Máca, Petr (referee)
The main objective of this dissertation is to provide a novel approach to downscaling of outputs from regional climate models and to simulation of future climate. The resulting method consists of rain generator that operates in 6-hour time step. The generator performs well for the observational data. It consists of following steps: disaggregation of 6-hour cumulative precipitation into convective and stratiform types, fitting of first order 3-state discrete time Markov chain to the data and simulation of long time series of precipitation. Then the mixture of log-normal and Generalized Pareto distribution is fitted to stratiform events and the Generalized extreme value distribution is fitted to convective events. The impact of climate change on precipitation is evaluated by using change factors that are identified for precipitation occurrence (by comparing the transition matrices for the future and control period) and for precipitation amount (by comparing the scale and location parameters of distributions fitted for the future and control period). The observational data are then altered with obtained change factors. From evaluation of observational data it stems that the average volume of an convective event is higher for the western region than for eastern region of the Czech Republic. Additionally, statistically significant trends in number and volume of convective events were identified for the region. The relative portion of convective precipitation is the highest in summer for observational data. From analysis of RCMs simulations, it stems that even though the overall precipitation is projected to be lower in future, the proportion of convective events (versus stratiform ones) would be higher. The number of convective events is projected to be lower in the future, while the volume of a convective event to be bigger.
The assessment of change in the water balance of Hačka catchment due to the climate change
Moravec, Vojtěch ; Hanel, Martin (advisor) ; Ladislav, Ladislav (referee)
In the presented paper the changes in mean runoff, temperature and precipitation totals in an observed period 1962-2015 in the catchment river Hačka are assessed. The paper further presents the analysis of climate change impact on mean runoff between the periods 1984-2014 (control period) and 2035-2065 and 2068-2098 (scenario periods) using the projections of three regional climate model simulations. Thin Plate Spline interpolation was used to estimate basin precipitation and temperature. Modified hydrological analogy was used for precise quantification of naturalized runoff (i.e. not affected by water use). Climate change scenarios were derived using simple delta change approach, i.e. observed series of precipitation and temperature were adjusted in order to give the same changes between the control and scenario period as regional climate model simulations. Hydrological balance was modelled with a conceptual hydrological model Bilan. The parameters of the hydrological model were estimated using observed data. These parameters were subsequently used to derive discharge series under climate change conditions for each regional climate model simulation. Results showed a 1.7 °C average increase in mean annual temperature in the scenario period 2035-2065 and a 2.8 °C average increase in the scenario period 2068-2098. The seasonal cycle of precipitation in the scenario conditions is shifted, although mean annual precipitation totals remain practically unchanged (max changes -8.1 %; +9.3 %). The mean annual discharge decreases by 5.7% in average (most 20.3 %) in period 2035-2065 and a significant decrease of 25.5% in average (most 45.9 %) in annual mean discharge is expected in the period 2068-2098. Frequency of minimal runoff is expected to increase up to two times. Precipitation increase is expected from the beginning of the fall to the beginning of the summer, with a slight decrease in spring. Increase in precipitation is followed by evapotranspiration increase, caused by increase in temperature. Summer precipitation is expected to decrease as well as summer runoff. Due to the temperature increase, time shift of the snowmelt is expected from the periods between March-April to January-February. This will also affect the increase of the discharge in this period. This knowledge can be applied in water management planning in the future.
Short duration precipitation extremes in the Czech Republic
Roub, Tomáš ; Hanel, Martin (advisor) ; Máca, Petr (referee)
The aim of this paper is to assess precipitation records from 182 monitoring stations. For every station intensities of short duration rain events are evaluated and compare with intensities presented in the work of Josef Trupl Intensity krátkodobých dešťů v povodích Labe, Odry a Moravy. For comparison always nearest monitoring station with an appropriate altitude was selected. The comparison is done for 3 data groups based on quality code of the records. Furthermore, stations with overlapping records are compared. The review part deals with rainfall and the methods of assessment of short duration rainfall intensities. The following part describes the selected historical rainfall series, which serve as a basis for estimation of design rainfall.
Relation between basin and runoff characteristics
Svoboda, Marek ; Hanel, Martin (advisor) ; Vlnas, Radek (referee)
Bachelor thesis describes the hydrological modeling, hydrological models and model Bilan in a literary review. Subsequent practical part deals with the characteristics of processing datsets basin in a programming environment R. The introduction defines the notion basin and put foreword to the hydrological modeling. The aim is to describe the hydrological modeling and datasets basin to try to determine whether there is a dependence of parameters on the percentage of overlap basin. The literature review describes the concepts related to hydrological modeling, such as hydrological balance, or what is a hydrological model. Subsequently hydrological models describe according to various divisions. Specifically, there is described a model Bilan. In the practical part solves the dependence of the parameters on the size of the catchment overlap. These analyzes are used in the programming environment R.
Water retention and flood protection measures in Plzeň district
Šrámek, Martin ; Hanel, Martin (advisor) ; Kožín, Roman (referee)
This work is about water reservoirs planed in Pilsen region in addiction to Generel LAPV and it generally introduces this document. In more detail there is specified problematics of Střela river basin and planed reservoir Strážiště. Work includes calculation of water balance in this reservoir following the different scenarios of flow in Střela river and consumption of water, indicating sustainibility of reservoir to the future. There are also evaluated long term trends of flow and basic characteristics of the bigest flood waves between years 1960 and 2000. Discussion summarize pozitives and negatives of dam construction at Strážiště locality and genarally also at other localities in Pilsen region. There are also outlined options of other adaptive measures.
Manipulation of hydrological data in R
Ficaj, Václav ; Hanel, Martin (advisor) ; Stanislav, Stanislav (referee)
This thesis deals with the creation package in R language. This package should facilitate the work of European river basins. It should serve to derive the river basins in Europe. Package can be also used for extract value from the database of daily precipitation and temperature E-OBS for these derived river basins. This package is designed to work with standardized data. The basis of this package is to work with a Europe-wide database of rivers and catchment. This work also contain description of the all organisations, which has developed used data. There is also discusses the basic rules of production packages.

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