Ján Szolgay

<p>When solving practical water resources management problems, situations when the amount of data is insufficient both terms of length and representativeness occur. Even the most extended observed series are short for reliable estimation and assessment long-term variability and extremes. A combination of stochastic weather generators, allowing the generation of arbitrarily long synthetic series of precipitation and air temperatures, and rainfall-runoff models, which transform them into an equally long synthetic series of river discharges, represent a feasible solution. This study aimed to develop a robust, practically oriented stochastic weather generator for rainfall-runoff modelling allowing the simulation of synthetic daily precipitation and air temperature series at multiple stations in catchments, considering seasonality, temporal dependency and spatial correlation. The design was based partly on the established methodological practices. In addition, it implements innovative components of temporal ad spatial multiscale disaggregation based process-oriented analysis of the processes involved and allows to consider the possibility of climate change. The ability of the weather generator to correctly reproduce characteristics of the observed rainfall and air temperature records was evaluated by both (temporal and spatial) statistical and hydrological process characteristics at each and across all stations.</p><p>Several case study results proved that the proposed concept of the generator is robust and practically applicable. It allows to reliably generate synthetic series of precipitation totals and air temperatures at individual stations in catchments and around simultaneously. Using a combined stochastic-deterministic rainfall-runoff modelling approach provides an infinite number of combinations of flow, including the extreme and the unobserved ones. It can be used to estimate extreme flood characteristics, determine hydrologic metrics of ecological flows, and detect changes in flow variability caused by land use and climate change.</p><p>Acknowledgements: This work was supported by the Slovak Research and Development Agency under Contract No. APVV-19-0340 and the VEGA Grant Agency No. 1/0632/19.</p>

The observations made from satellite technology enable more and more scientific communities to test and rely on this kind of product. Moreover, data acquired from satellite products is of great use regarding conceptual hydrological modeling. This study represents the process of testing the advanced scatterometer (ASCAT) remote sensing product-ASCAT SWI. In regions with little or no data, soil moisture products have significant value. They represent the relationship between surface and root zone soil moisture as a function of time. SWI represents the soil moisture content equal to a soil depth of 1 meter represented in percentage (%), with a minimum of 0% and a maximum value of soil moisture at 100% of soil capacity. In this study, the tested data in focus are soil moisture data with changing values of modeled water infiltration into the different soil layers (T). In addition to these data, the hydrometeorological data are used for hydrological modeling. These are data from water gauge stations such as runoff values (Q), precipitation (P), air temperature (T), and potential evapotranspiration (PET). All the data used in the hydrological model represent the time series from 01.01.2007 to 31.12.2019. The spatial resolution of the datasets is 500x500 meters, and the temporal resolution is one day. Calibration was performed using the lumped hydrological model developed at Technical University in Vienna-TUWdual. Areas of interest in modeling are selected catchments in Slovakia with various land use and height above sea level. Another aim of this study is to test the correlation between the measured soil moisture and the modeled one using the TUWdual model. The expected outcome of the study should point out the catchment areas that would benefit more from the additional data on satellite soil moisture in Slovakia. Acknowledgment: This study was supported by a Ph.D. student project HYDRODIAĽ.

<p>Changing climate and changes in watersheds raise questions about the safety of flood control structures. Evaluating the present safety of past designs where storage was involved requires the entire hydrograph or, at least, the flood peak-volume-shape estimates related to the present or future conditions. Therefore, studying the relationships between these quantities is exciting both from the scientific hydrological and engineering points of view. The statistical analysis of flood peaks and volumes in engineering hydrology practice was often dealt with in a multivariate frequency framework. However, examining the interplay of climatic and catchment processes in influencing the probabilities of flood wave peaks, volumes and shapes is a challenging problem for safety evaluation of flood control structures. The proposed framework for Slovakia is based on the inclusion of climatic and hydrologic controls on the flood peak-volume-wave shape relationships and their statistical models. Rather than examining the safety based on a single control flood wave, a scheme was proposed allowing us to arrive at a set of control flood waves with associated probabilistic parameters. These permit to study of several aspects of reservoir safety (hydrologic, hydraulic and geotechnical). The concept is based on flood events assigned to the prevailing flood process types in the region with discernible flood-peak-volume-shape relationships. A set of process representative flood waves is created by base-flow separation. The joint probability distribution of peaks and volumes is copula-based, which are selected by a process-based approach. Besides that, process characteristic wave shapes are scaled to a set of dimensionless shapes. These allow selecting a dimensionless control flood wave shape according to an empirical shape quantile. Finally, a set of control flood waves is constructed by combining volumes conditioned on peaks and associated with shapes of given quantiles. That provides a good variety of control waves for assessing the safety of water structures under extreme situations in a probabilistic and process-based framework in typical risks of failure scenarios.</p><p>Acknowledgements: This work was supported by the Slovak Research and Development Agency under Contract No. APVV-20-0374 and the VEGA Grant Agency No. 1/0782/21.</p>

The paper focuses on erosion processes in the Svacenický Creek catchment which is a small sub-catchment of the Myjava River basin. To simulate soil loss and sediment transport the USLE/SDR and WaTEM/SEDEM models were applied. The models were validated by comparing the simulated results with the actual bathymetry of a polder at the catchment outlet. Methods of crop management based on rotation and strip cropping were applied for the reduction of soil loss and sediment transport. The comparison shows that the greatest intensities of soil loss were achieved by the bare soil without vegetation and from the planting of maize for corn. The lowest values were achieved from the planting of winter wheat. At the end the effectiveness of row crops and strip cropping for decreasing design floods from the catchment was estimated.

In this study the authors looked at the impact of climate change on a hydrological regime and catchment runoff in selected catchments of Slovakia. Changed climate conditions, which are characterized in particular by changes in precipitation, air temperature, and potential evapotranspiration in future decades, have been predicted according to the outputs of the KNMI and MPI regional climate change models and the A1B emission scenario. Assuming these scenarios, the hydrological regime characteristics were simulated by a distributed WetSpa rainfall-runoff model parameterized for five selected river basins in a daily step by the year 2100. When compared to the current state, changes in the total runoff and its components, as well as changes in the soil moisture and the actual evapotranspiration, confirm the assumption of an increase in extremes of the runoff regime in the winter period and a decrease during the summer and autumn periods, causing possible droughts. The results of the study indicate a need for re-evaluation of the water demands and the future design of water management structures in Slovakia.

In the paper application of a methodology for analysis of flash flood events in several ungauged small basins in Slovakia was evaluated. The methodology proposed within the framework of the FP6 HYDRATE project (www.hydrate.tesaf.unipd.it) is based on the post-event surveying and hydrological modelling, using a spatially distributed hydrological model with a high spatial resolution of rainfall data and physiographical basin properties. Six large flash floods which occurred in Slovakia during the last 10 years were selected, with the emphasis on their extremity and different physical and geographical basins properties. The estimation of the maximum flood peaks and flood wave volumes was provided on the base of the post-event analysis after the flood events. The areas of channel's cross-profiles were measured for maximal water level, longitudinal slope of water level was approximated to the bottom slope and roughness was estimated according to the river banks and channel bottoms. F...

The recent extreme floods in Central Europe have resulted in scientific and societal concerns about the reliability of flood frequency estimates in the region. As a consequence, the currently used flood frequency estimation methods are being re-visited. The use of more complex climate-soil- vegetation controls in regional frequency analysis in estimating floods at regional scale instead of the traditional regional

... SILVIA KOHNOVÁ1, KAMILA HLAVCOVA1, JAN SZOLGAY1 AND JURAJ PARAJKA2 1Department of Land and Water Resources Management Faculty of Civil Engineering ... the basin area is covered by forest, 10 % by grassland, 17 % by agricultural land and 3 % by urban areas ...

In the poster the possibility of using wide sense simple scaling of rainfall in Slovakia was demonstrated. It presents a case study, which focuses on application of the simple scaling theory of rainfall in the Western Carpathians, where complex rainfall generation mechanisms (intensive rainfall caused by diverse atmospheric circulation patterns, orographic effects and convection) are observed over a relatively complex

ABSTRACT A differentiation between the two basic types of precipitation, i.e. convective and stratiform, is of great importance in hydrological modeling and engineering practice. In this study we propose a methodology for the estimation of the character of precipitation events exclusively on the basis of local high resolution meteorological data (lightning strikes, precipitation), and not taking into consideration any information on the character of precipitation on the basis of remote measurements (radars, satellites). Identification of convective events is based on the hypothesis that thunderstorms with strong convective lifting are commonly associated with lightning. The study is based on precipitation depth measurements at a 10-min time step with a heated tipping-bucket gauge with tip resolution 0.1 mm from the SwissMetNet (MeteoSwiss) network at 63 stations that cover altitudes ranging from 200 up to 3300 m a.s.l. over the period 1981-2012 (32 years). Additionally, the same stations also measure the number of lightning strikes within a range of 30 km from the station. Although these data are available for the period 1987-2012 (25 years), we confine the lightning information to the period 1987-2005 (18 years) only, since changes made to the lightning observation methodology in the years 2005-2006 raise concerns about the homogeneity of the whole observation record. Independent rainfall events that occurred during the warm half-year (April to September) are first identified from this database, with the requirement that the inter-arrival time between two subsequent events is at least 2 hours. Then, for each rainfall event, the key storm characteristics (total rainfall depth R, storm duration D, and peak 10-min intensity I) are computed, and the number of lightning strikes is assigned in the case the event was accompanied by lightning activity. We found that peak rainfall intensity I during events accompanied by lightning is significantly higher than during those events where no lightning was observed. There are smaller differences in the distributions of event durations and rainfall totals. On this basis, we define a threshold of peak intensity I* that differentiates between events with and without lightning with an acceptably small probability of misclassification. This allows us to identify intense summer events with convective character as those where I > I* regardless of their duration or total rainfall depth. In a final step, the spatial variability of I* across the analyzed stations in Switzerland is examined. The results suggest that threshold intensities I* are not constant in space and vary with a strong topographic and climatological signature.

ABSTRACT The study focuses on an analysis of the controls on flood duration based on the concept of comparative hydrology. Rather than modelling a single catchment in detail we compare small groups of pilot basins with contrasting characteristics in order to understand the controls in a holistic way. We analyse flood hydrographs of 9223 events in 396 Austrian catchments ranging from 5 to about 10 000 km2 as a function of climatic controls such as storm type (synoptic and convective storms, rain-on-snow, snow melt), and catchment controls such as soils, soil moisture, geology and land form. The dependence structure of two characteristics of extreme rainfall-runoff events (i.e., flood peaks and flood volumes) is examined. Unlike the common practice where the dependence between two variables is usually described by means of linear or rank correlation coefficients, here we focus on process based analysis of residual similarity of dependence between these two variables that is expressed by the flood time scale defined as the ratio of the flood volume to the flood peak. The results indicate that, spatially, the median flood time scales range from 16 hrs in the hilly catchments where convective storms prevail to 104 hrs in the lowland catchments where substantial inundation into the floodplain occurs. The range is even larger for different flood types, from 7 hrs for flash floods in the hilly catchments to 200 hrs for snow melt floods in an Alpine area with deeply weathered rocks and deep soils. The results also indicate that catchment area is not the most important control on the flood time scales. For the range of catchments considered here, climate is very important through storm type and antecedent soil moisture, and geology is very important through soil characteristics. It is argued that the flood time scale is a rich fingerprint of the hydrological processes in a catchment because it integrates a range of climate and catchment characteristics by a time parameter.

Článok sa zaoberá hodnotením vplyvu zmeny klímy na využívanie hydroenergetického potenciálu vo vybraných povodiach na území Slovenska. Z.kladným ukazovateľom potenciálu využitia vodnej energie je výpočet tzv. hydroenergetického potenciálu (HEP). Zmenené klimatické podmienky charakterizované najmä zmenami zrážok, potenciálnou evapotranspiráciou a teplotou vzduchu v budúcich desaťročiach boli predpovedané podľa najnovších výstupov z dvoch regionálnych modelov klimatických zmien KNMI a MPI a podľa emisného scenára A1B. Na určenie zmien dlhodobého priemerného mesačného odtoku v porovnaní medzi referenčným obdobím 1981-2010 a budúcimi časovými horizontami sme použili fyzikálne založený zrážkovo-odtokový model WetSpa. Na základe prognóz klimatických zmien podľa dvoch spom.naných scenárov výsledky naznačujú, že vplyvy zmeny klímy v budúcnosti môžu viesť k poklesu hydroenergetického potenciálu.

<p>Climate change challenges policymakers and river basin authorities to find sustainable management solutions and optimal strategies to avoid undesirable impacts on water resources and the environment. Our study aimed to evaluate the possible impacts of future climate change on water resources in Slovakia. Eight pilot river basins spread throughout the whole territory of Slovakia were selected in this study. To draw more general conclusions, basins were delineated into two different groups, i.e. basins with a mean elevation < 435 m a.s.l. (four basins) and basins with a mean elevation > 435 m a.s.l. (four basins). An HBV bucket-type hydrological model (the TUW model) was used to provide runoff projections. For the model parametrization, we used a cross-calibration strategy based on selecting the most suitable decade in the observation period. The model was calibrated and validated over four periods (1981–1990, 1991–2000, 2001–2010, and 2011–2019) with rainfall, air temperature and potential evapotranspiration as inputs. Then, the parameters that best reflect the current climate (mainly in terms of the mean daily air temperatures) were used to simulate runoff over the baseline (1981–2010) and three future time horizons (2011–2040, 2041–2070, and 2071–2100). For the future runoff projections, the model was driven by the precipitation and air temperatures projected by the KNMI and MPI regional climate models under the A1B (moderate) emission scenario. The model performance during the calibration and validation was assessed using four metrics (the objective function, the logarithmic Nash–Sutcliffe efficiency, the Nash–Sutcliffe efficiency, and the volume error). All model performance metrics and visual inspection of hydrographs indicated that the simulated runoff has a good agreement with the observed values.</p><p>Our results indicate that the change in climate variables is expected to be more or less the same for both groups of the river basins. Precipitation shows an increasing pattern during spring, autumn, and winter periods. The regional climate model data suggest that the long-term mean monthly air temperatures will rise with the future time horizons. Compared to the baseline (1981–2010), winter runoff (December–February) is projected to increase, with a maximum increase in the period 2071–2100. In the summer season (June–August), the runoff will react in reverse. The values of maximum annual daily runoff are more prominent in lower elevations (i.e., basins < 435 m a.s.l.) than at higher elevations (i.e., basins > 435 m a.s.l.). Our analysis could help develop optimal strategies for water resources management and flood control in the studied basins.</p><p> </p><p>Acknowledgments</p><p>This work was supported by the Slovak Research and Development Agency under Contract No. APVV-18-0347, No. APVV-19-0340, No. APVV-20-0374 and the VEGA Grant Agency No. 1/0632/19 and No. 2/0065/19. The financial support by the Stefan Schwarz grant of the Slovak Academy of Sciences is also gratefully acknowledged.</p>

In the paper 10-day maximum precipitation totals from 23 rain gauges from the period 1961 to 2000 in the upper Hron River basin in Slovakia were analysed. A combined method, based on statistical criteria and on the evaluation of evaporation and runoff conditions during long precipitation events, has been used for the selection of the 10day precipitation totals. N-year values of the 10-day annual maximum precipitation totals were estimated separately in the summer and winter seasons using a methodology developed by Hosking and Wallis (1997). The regional distribution function was selected using a L-moments diagram. Finally, a comparison of the resulting N-year maximum precipitation totals estimated from these regional distributions with the at–site analyses was performed.

Monthly discharges can be modelled and predicted by the decomposition of the runoff process model into two components – deterministic and stochastic. For such approach the term hybrid was often adopted. In this study a hybrid (deterministic-stochastic) modelling approach for one step ahead forecasting of mean monthly discharges at the gauging stations Banska Bystrica and Brehy on the Hron River in Slovakia was developed. The aim was to join the conceptual monthly rainfall runoff model KVHK and several time series models of the forecasting error time series of the conceptual model into a hybrid framework. Since these rainfall-runoff model error series may exhibit nonstationarity and heteroscedasticity, beside traditional ARMA models, GARCH type nonlinear time series models were also considered.

Research gaps in understanding flood changes at the catchment scale caused by changes in forest management, agricultural practices, artificial drainage, and terracing are identified. Potential strategies in addressing these gaps are proposed, such as complex systems approaches to link processes across time scales, long‐term experiments on physical‐chemical‐biological process interactions, and a focus on connectivity and patterns across spatial scales. It is suggested that these strategies will stimulate new research that coherently addresses the issues across hydrology, soil and agricultural sciences, forest engineering, forest ecology, and geomorphology.

The discrete state space representation of the Kalinin-Miljukov model was used as the basis for a multilinear discrete cascade flood routing model. The time distribution scheme of model inputs was employed in the setup of the multilinear model and the travel-time parameter of the model was allowed to vary with discharge. The relationship between travel-time and discharge for a reach of the Hron River between Brezno and Banska Bystrica was studied. Empirical models of that relation have been considered that would fit the data and would be consistent with the physical interpretation of the factors determining the relation. Seven such fitted empirical models were used to model the variability of the time parameter in the discrete state space representation of the Kalinin and Miljukov model. The performance of the multilinear model was verified on five flood waves. The modelling results showed that the inclusion of empirical information on the variability of the travel-time with discharge enables satisfactory accuracy of the prediction of the flood propagation process without needing to calibrate the model on pairs of input-output hydrographs. The choice of an appropriate travel-time discharge relationship was briefly discussed.

The use of rainfall-runoff models in the flood frequency analysis of flows often faces problems with the model calibration on maximum flows. Calibration techniques that are traditionally used usually use objective functions such as Nash-Sutcliffe criterion. These techniques are usually not able to satisfactorily simulate extreme flows which are crucial in the flood frequency analysis. This paper deals with the improvement of the calibration of rainfall-runoff model to simulate extreme flows. Two improvements are suggested: 1) using of a new optimization function comparing only values that are higher than 95th percentile of observed flows and 2) changing of a structure of the model HRON, so various sets of parameters are used to simulate low and high flows. The combination of both of these measures we have managed to substantially improve the simulation of extreme flows, which is demonstrated on the empirical cumulative distribution function curves calculated for both observed and si...

Nous proposons ici une méthode permettant drqintégrer des débits de crues extrêmes ayant touché des bassins versants non jaugés dans une analyse statistique régionale des crues. Lrqapproche proposée est basée sur une technique standard de régionalisation des crues reposant sur une hypothèse de "< simple scaling ">: dans une région hydrologiquement homogène, les distributions statistiques de débits de crues ne diffèrent que par leur moyenne. Une méthode bayesienne de maximisation de vraisemblance couplée à un algorithme de type Monte Carlo Marcov Chain (MCMC) est utilisée pour caler les paramètres de la loi statistique régionale. Cette approche a été utilisée pour sa rigueur -- explicitation des hypothèses statistiques, sa flexibilité -- des données de nature très variées peuvent être intégrées, mais aussi et surtout parce qurqelle permet une estimation fiable des intervalles de confiance sur les paramètres de la loi de probabilité et les quantiles de crues estimés. L...

The recent extreme floods in Central Europe have resulted in scientific and societal concerns about the reliability of flood mitigation measures, design flood estimates and design criteria in the region. The August floods have not caused extensive damage in Slovakia, however the meteorological conditions and the atmospheric circulation patterns have led to severe flooding in the past. In order to

The HYDRATE project (Hydrometeorological Data Resources and Technologies for Effective Flash Flood Forecasting) objective is to improve the scientific basis of flash flood forecasting by extending the understanding of past flash flood events and developing a coherent set of technologies and tools for effective early warning systems. To understand rainfall-runoff processes during selected extreme flash floods occurred in the past

Flows of the Váh River and its tributaries are predominantly fed by snowmelt in the spring and convective precipitation in the summer. Therefore their regime properties exhibit seasonal patterns. Moreover the left and right side tributaries of the Váh River spring in different physiographic conditions in the High and Low Tatry Mountains. This provided justification for the application of nonlinear

The estimation of design floods in ungauged small and medium basins in Slovakia was often performed by simple regional flood formulae derived for various geographical regions. Envelope curves were also applied in order to get an acceptable regional safety factor for design purposes. Usually the 100-year flood was estimated from the basin area; correction factors were used to account for deviations from the average of local runoff forming conditions in the region. Floods with shorter return periods were computed by regional frequency factors. Comparisons of design floods derived from such formulae with at site values in 260 small and mid-sized basins [1,2] showed a case-sensitive, highly variable safety factor in these schemes. They are not generally applicable for river training and restoration since they tend to overestimate the design discharges in almost all basins of a particular region. For these tasks other regional approaches, which do not include the regional safety introduced by the envelope curve concept, but allow for site specific over-and under-estimation resulting from the regional average concept, seem to be more appropriate. Some of the recently introduced concepts of regional homogeneity as e.g. in [3,4,5,6,7] were suggested to be used together with regional flood formulae composed of catchment characteristics other than the basin area only. To eliminate the heterogeneity in the annual flood data series due to the diverse genetic origin of flood events, it was proposed to consider annual maximum peak discharges separately for two seasons - the summer season with rainfall-induced discharges and the winter season with floods originating from snowmelt and mixed events.

The impact of the planned future operation rules of the Gabcikovo diversion type peak hydropower station on the runoff regime of the River Danube downstream from the weir in Hrusov has been studied. A multilinear flow routing model based on the state space representation of the Kalinin-Miljukov cascade was developed and calibrated. A model of the operation rules of the

ABSTRACT Štúdia sa zaoberá analýzou dlhých časových radov koncentrácie dusičnanov v rieke Ouse vo Východnom Anglicku. Časový rad priemerných mesačných koncentrácií dusičnanov bol rozložený na trendovú, sezónnu a cyklickú zložku a reziduá, ktoré boli k sebe pripočítané aby vytvorili jednoduchý aditívny model. Reziduá boli ďalej modelované zložitejšími lineárnymi modelmi reprezentovanými modelmi triedy ARMA a nelineárnym modelom SETAR. Výsledky analýzy ukázali, že dvoj a trojrežimové modely SETAR nedokázali výrazne lepšie opísať daný časový rad ako modely triedy ARMA, keď modely SETAR dokázali jednoduchý AR(1) model zlepšiť len o 4% resp. 1%. Najnižšie hodnoty sumy štvorcov odchýliek (SSR) modelovaných a meraných hodnôt boli získané jednoduchými AR modelmi nízkeho rádu. Vizuálne posúdenie výsledkov modelov ukázalo, že modely AR ani modely SETAR nedokázali zachytiť extrémne hodnoty. V tomto ohľade boli najlepšie modely ARMA, ktoré aj napriek vyšším hodnotám SSR dokázali zachytiť väčšinu extrémnych hodnôt. Výsledky práce môžu byť použité v budúcnosti pri konštrukcii iných opisných alebo predpovedných modelov koncentrácií dusičnanov.

ABSTRACT Copula-based estimation methods of hydro-climatological extremes have increasingly been gaining attention of researchers and practitioners in the last decade. Unlike the traditional estimation methods which are based on bivariate cumulative distribution functions, copulas are a relatively flexible tool which allows for modelling dependencies between two or more variables without making strict assumptions on their marginal distributions. This study focuses on the analysis of the interdependence of critical storm properties (such as rainfall duration, intensity and total rainfall amount) in Switzerland. The data base for the analysis consists of rainfall records with 10 minute resolution, which are available at about 70 SwissMetNet stations and span the period of observations of 26 years. The storm characteristics are estimated from this data both on an annual and seasonal basis. First, the storm variable combinations are analyzed in terms of their distribution functions. Then, the choice of the copula functions that best fit the data is carried out. The cornerstone of the study is an analysis of seasonal and spatial differences that appear in the patterns of the copula parameters and the dependence models. It is attempted to relate the dependence characteristics to the dominant generating mechanisms of precipitation as well as to climatological factors. The aim of the study is to contribute to our understanding of the spatial and seasonal variability of dependence characteristics of storm properties in an orographically complex environment.

... the Medal of Merit for Development of Hydrology and Meteorology 1993 from the Slovak Hydrometeorological Institute, Bratislava; Medal of Merit from Civil Engineering Faculty of the Slovak Technical University in Bratislava; International Suvarna Parisara Rathna Award 1998 ...

A regional frequency analysis including reconstructed major flash flood events on ungauged catchments that occurred in Slovakia during the past few decades is carried out. These events are characterized by extremely high discharge values, largely exceeding the highest the values recorded on the gauged catchments (e.g., the Strba Creek event, June 24, 2001, had a peak discharge of 65 m3/s

A warming climate is expected to have an impact on the magnitude and timing of river floods; however, no consistent large-scale climate change signal in observed flood magnitudes has been identified so far. We analyzed the timing of river floods in Europe over the past five decades, using a pan-European database from 4262 observational hydrometric stations, and found clear patterns of change in flood timing. Warmer temperatures have led to earlier spring snowmelt floods throughout northeastern Europe; delayed winter storms associated with polar warming have led to later winter floods around the North Sea and some sectors of the Mediterranean coast; and earlier soil moisture maxima have led to earlier winter floods in western Europe. Our results highlight the existence of a clear climate signal in flood observations at the continental scale.

The paper is dealing with possibilities of application of rainfall-runoff modelling in integrated water basin management. Two physically based rainfall-runoff models with distributed parameters , WetSpa and WaSiM, were compared in the study. The models were used for estimation of the land-use changes impact on runoff regime in the upper Hron river basin, with emphasis on parameterization of land cover properties in runoff simulations. The basin was divided into a number of grid cells for which the water and energy balance were maintained and hydrological processes were simulated continuously both in time and space. Land use changes connected to forest management were expressed by several scenarios and changes in surface runoff, interflow, base flow and total runoff in the basin's outlet were compared. Differences in simulated runoff by both models were analyzed and discussed. KAMILA HLAVČOVÁ, JÁN SZOLGAY, SILVIA KOHNOVÁ, ZDENĚK KOSTKA Doc. Ing. Kamila Hlavčová, PhD., Katedra vod...

The main goal of this study was to compare the precipitation and runoff seasonalities in Austria and Slovakia, in order to understand the differences in the climatic conditions and long term catchment characteristics using mean monthly seasonality indices and to explore the differences in the flood processes at the short term event scale. The seasonality of mean monthly precipitation and runoff was quantified by the Pardé coefficient and the seasonality of the maximum annual floods and annual maximum daily precipitation by applying the Burn’s index. Altogether 555 climate stations located in Austria and 202 climate stations in Slovakia were selected for analysis of mean monthly precipitation. Annual maximum daily precipitation was available at 520 and 56 climate stations, res-pectively. Mean monthly runoff values and maximum annual flood records were available at 258 and 85 gauging stations in Austria and Slovakia. Even though some of the selected stations have an incomplete series ...