Mathematical Modelling of the Dynamics of Snow Cover in a Mountain Watershed for Operational Purposes

Import 22/10/2012Cieľom tejto dizertačnej práce je overiť vhodnosť modelov a metód, ktorými disponujú k modelovaniu odtoku vody zo snehovej pokrývky pre operatívne účely. V tejto štúdii bol hodnotený jednak model HYDROG, ktorý sa využíva v operatívnej praxi v ČR a model HEC-HMS poskytujúci sofistikovanejšie riešenie danej problematiky. Pre porovnanie prístupu k modelovaniu odtoku vody zo snehu bol využitý aj model SWAT. Vyššie spomenuté modely využívajú k stanoveniu množstva vody uvoľnenej zo snehu metódu teplotného indexu, resp. ju rozširujú o ďalšie parametre, s cieľom lepšie napodobniť skúmaný proces. Ako záujmová oblasť bola vybraná horná časť povodia rieky Ostravice po profil Staré Hamry. Na základe výsledkov modelovania bolo zistené, že pomocou modelov HEC-HMS a HYDROG je možné pri kvalitných vstupných dátach a vhodnej parametrizácii dosiahnuť vo väčšine prípadoch vyhovujúce výsledky, čo sa týka simulácie prietoku k záverovému profilu povodia. Sofistikovanejšie prevedenie metódy teplotného indexu v modeli HEC-HMS sa prejavilo aj na celkových výsledkoch. Takmer vo všetkých epizódach sa prostredníctvom tohto modelu na danom území podarilo dosiahnuť väčšiu presnosť v zhode medzi simulovaným a meraným prietokom ako v modeli HYDROG. Využitie modelu SWAT, pri simulácii v dennom časovom kroku, sa na danom povodí a pri dostupných vstupných údajoch neosvedčilo. Samotná práca je rozdelená do štyroch častí. Prvá časť sa venuje súčasnému stavu danej problematiky so zameraním sa na modelovanie odtoku vody zo snehovej pokrývky pre potreby operatívnej hydrológie. V ďalšej časti sú definované ciele práce spoločne s vymedzením skúmaného územia a špecifikovaním použitých vstupných údajov. V tretej časti je priestor venovaný aplikácii vybraných modelov k modelovaniu odtoku vody zo snehovej pokrývky. Poslednú časť práce tvorí záver, v ktorom sú uvedené jednotlivé poznatky a prínosy dizertačnej práce a možnosti jej ďalšieho smerovania.The aim of this dissertation is to verify the suitability of models and its methods, which are used to simulate runoff from snowmelt for operational purposes. Three models have been investigated, first HYDROG used within the application sphere in the Czech Republic, then HEC-HMS providing more sophisticated solution of the problem and finally SWAT model for a better result comparison. All mentioned models utilise temperature index method or a modification of it to compute the amount of water released from snow. Method modification differs in parameters which can be added in the equation. Ostravice upper river-basin (upstream the profile Staré Hamry) was selected as the research area. According to HEC-HMS and HYDROG results it is possible to model suitable stream flow outputs by using precise input data and appropriate values of parameters in most cases. The more sophisticated implementation of temperature index method in HEC – HMS is also significant in model results, where better results were achieved in comparing simulated and observed discharge values in HEC – HMS compared to HYDROG. The result of SWAT model did not fit the nature of the process at all. The dissertation is divided into four parts. First part deals with theoretical background of the problem with emphasis on runoff from snowmelt for operational purposes. Second part includes dissertation objectives, research area allocation, and input data specification. Third part contains application of models for runoff from snowmelt modelling. The last part is a summary, which is made of knowledge, conclusions, results and contribution of the dissertation to solving the problem. A part of it is a possibility of next extension of the research.Prezenční548 - Institut geoinformatikyvyhově

Analýza zrážkoodtokových vzťahov a fluviálnej erózie na povodí Ipľa s pomocou hydrologických modelov a GIS

Import 10/11/2008Prezenční548 - Institut geoinformatikyNeuveden

Modelování transportu sedimentů v povodí pomocí dynamického erozního modelu ArcSWAT 2005 na příkladu povodí Ostravice

Soil is one of the most important natural sources on earth. The same way as all parts of the environment, and the global ecosystem generally, it suffers from several kinds of human activities in the landscape. One of the most serious environmental problems of our present days is accelerated soil erosion and related processes. In the past, the most of soil erosion studies and researches took place in the field, on experimental plots or in laboratories. The problem of these studies is the fact that they take quite a long time and are expensive. Nowadays, in the age of computers and information technologies, the soil erosion and sediment transport studies can be managed by new effective tools – numerical models. There are lots of numerical models being able to solve several tasks in the field of soil erosion and sediments. One of the most complex numerical models is the SWAT model (Soil and Water Assessment Tool). This physically based semi-distributed model can be used to analyze the complex watershed management and soil erosion, and sediment transport is only a fraction of the tools offered by the model. The main goal of this contribution is to introduce the basic abilities of the model as a tool of soil erosion analyses and sediment transport in watersheds.Eroze půdy, zejména ve své akcelerované podobě, patří mezi nejzávaţnější problémy spojené s aktivitou člověka v krajině a v souvislosti s tempem růstu světové civilizace a nerovnoměrným rozmístěním zdrojů na Zemi je tato hrozba čím dál naléhavější. Člověk se o půdu, jakoţto základní zdoj, zajímal jiţ od samotného vzniku zemědělské společnosti, tedy i poznání v oblasti eroze půdy si prošlo dlouhým obdobím bádání. V dnešní době tak v návaznosti na prudký rozvoj jiných oborů, zejména IT, disponujeme pestrou paletou numerických modelů řešících erozi půdy. Jedním takovým je i právě model SWAT (Soil and Water Assesment Tool). Jedná se o fyzikálně podloţený semidistribuovaný kontinuální dynamický model poskytující řadu nástrojů pro řešení poměrně obsáhlé problematiky managementu povodí, zejména pak s ohledem na vodní sloţku, erozi půdy a rostlinnou produkci. Nápní tohoto příspěvku je pak testování nabídky modelu v oblasti eroze půdy a transportu sedimentů a na ně vázaných látek v povodí. Model byl testován na schematizovaném povodí Ostravice

Mathematical modelling of the dynamics of mountain basin snow cover in Moravian-Silesian Beskydy for operational purposes

The objective of this paper is to evaluate the applicability of models and methods available for research to simulate runoff from snowmelt for operational purposes. Both the HYDROG model exclusively used in operational practice in the Czech Republic and the HEC-HMS model were evaluated in this study. In both models has been implemented the temperature index method to meet the given purpose of usage. While the HYDROG model is in fact basic implementation of the temperature index method, the HEC-HMS allows inclusion of other factors into the calculation, which are affecting the studied process, such as the cold content of snow cover, snowmelt above the active surface, thermal deficiency of snow cover, variability of thermal factor. HEC-HMS allows the division of the research area or river sub-basins into altitudinal zones. The upper stream of the Ostravice River was selected as the area of interest. Simulation was carried out on episodes occurring in 2006 and 2009. Although the temperature index method is not widely recommended for simulating the runoff for a time period shorter than one day, the results from both models in the given area proved that using appropriate input data, as well as parameterisation, can result in the values which are accurate enough even in one hour time periods. The value of the Nash-Sutcliff coefficient is larger than 0.5 in almost all cases, which generally indicates a satisfactory behaviour of the models during the simulation. Similarly, the satisfactory results were achieved with other criteria used for assessing the accuracy of modelling. Complementing additional parameters into the temperature index method using HEC-HMS enabled better simulation of snow-melt conditions than the simulation with HYDROG.Web of Science42331230

Analysis of the impact of land cover spatial structure change on the erosion processes in the catchment

Soil erosion is one of the main environmental problems of this time. Erosion in its recent accelerated form is the reflection of the human activities in the landscape. Soil erosion is a complicated process. Its behaviour and final rate are results of an interaction of whole group of factors. One of these factors is the character of land cover whose main role in the erosion process consists in its protective function. Intensive land use do not dispense with the land cover change and the change of its spatial distribution thus the main content of this contribution is the study of the influence of the land cover change on the erosion processes in the catchment. To quantify that the dynamic erosion SWAT model was used together with the GIS tools. As a study area the Stonavka river catchment was chosen and the erosion processes were analysed using the three CORINE Land Cover layers (specifically CORINE Land Cover of the years 1990, 2000 and 2006) as a model input. The outputs of the analyses in the form of average annual specific sediment loss from the catchment were relativized to the reference years 1990 and following 2000 and were cartographically visualized in the form of cartograms.Web of Science15427626