In this study, the FRIER rainfall-runoff model with distributed parameters was developed to assess changes in runoff and water balance due to changes in land use and climate. The water balance was calculated at 3 levels: on the surface and in unsaturated and saturated zones. Six basins from the central and eastern parts of Slovakia were selected on the basis of their similar size, but different topography, land use, soil texture and climate: the upper Hornád, the upper Hron, the Poprad, the Rimava, the Slaná and the Torysa River basins. Model parameters were estimated using data from the period from June 1998 to May 2000 in daily time steps. The differences and similarities of the hydrologic processes in individual basins were investigated during the calibration period. Several scenarios of changes in land use and two simple scenarios of changes in climate were developed to estimate the impact of these changes on water balance and runoff. The changes in the hydrological regime were compared and discussed. and V posledných rokoch sa veľmi často hodnotia a diskutujú vplyvy zmien využitia krajiny a klímy na procesy hydrologickej bilancie, aj keď miera ich vplyvu na hydrologický režim sa najmä pre komplexnosť týchto procesov veľmi ťažko kvantifikuje. Na odhad vplyvu zmien využitia krajiny a klímy na odtok a zložky hydrologickej bilancie bol vyvinutý zrážkovo-odtokový model FRIER s rozčlenenými parametrami. Na základe podobnej veľkosti, ale rôznej topografie, využitia krajiny a pôdnej štruktúry bolo vybraných šesť pilotných povodí: povodie horného Hornádu, horného Hrona, Popradu, Rimavy, Slanej a Torysy. Parametre modelu boli kalibrované pre obdobie jún 1998 - máj 2000 v dennom časovom kroku. Na základe simulácií hydrologickej bilancie pre súčasný stav sa hodnotili rozdiely a podobnosti procesov tvorby odtoku v jednotlivých povodiach. Odtok a zložky hydrologickej bilancie boli následne simulované pre sedem scenárov zmien využitia krajiny a dva jednoduché scenáre zmeny zrážok a teploty vzduchu. Zmeny odtoku a hydrologickej bilancie boli porovnané a diskutované.
This work examines the main features of the flash flood regime in Central Europe as revealed by an analysis of flash floods that have occurred in Slovakia. The work is organized into the following two parts: The first part focuses on estimating the rainfall-runoff relationships for 3 major flash flood events, which were among the most severe events since 1998 and caused a loss of lives and a large amount of damage. The selected flash floods occurred on the 20th of July, 1998, in the Malá Svinka and Dubovický Creek basins; the 24th of July, 2001, at Štrbský Creek; and the 19th of June, 2004, at Turniansky Creek. The analysis aims to assess the flash flood peaks and rainfall-runoff properties by combining post-flood surveys and the application of hydrological and hydraulic post-event analyses. Next, a spatially-distributed hydrological model based on the availability of the raster information of the landscape’s topography, soil and vegetation properties, and rainfall data was used to simulate the runoff. The results from the application of the distributed hydrological model were used to analyse the consistency of the surveyed peak discharges with respect to the estimated rainfall properties and drainage basins. In the second part these data were combined with observations from flash flood events which were observed during the last 100 years and are focused on an analysis of the relationship between the flood peaks and the catchment area. The envelope curve was shown to exhibit a more pronounced decrease with the catchment size with respect to other flash flood relationships found in the Mediterranean region. The differences between the two relationships mainly reflect changes in the coverage of the storm sizes and hydrological characteristics between the two regions.