The contribution is dealing with run-off conditions on the lower part of the Ondava River as the capacity of the river bed is insufficient at high flow rates. The reason for the proposed research was the flood situations when protection dikes were breached. For mathematical modeling of flood wave progress, the HEC-RAS software has been applied coupling 1D and 2D modeling procedures. Results of the mathematical model of the surface water level regime in the Ondava River were compared with measured values and afterwards it was used to design further flood protection measures utilizing the existing drainage channel system and pumping stations, as well.

This study examines the effect of drought on the discharge seasonality of the Topľa River from 1988 to 2020. Each year is classified into dry, normal, or wet years using the water-bearing coefficient as a drought index. The Seasonal and Trend decomposition using the Loess time series decomposition method was used to compare discharge patterns between these groups. The results demonstrate a significant impact of drought on the seasonal discharge of the Topľa River, with substantially lower discharge and affected seasonality during dry years. The study findings demonstrate that the impact of the drought is altering the seasonal discharge pattern of the river. This highlights the importance of considering the effects of drought in water management and resource planning, particularly in the face of climate change and increasing water scarcity. These findings provide valuable insights for informing water management policies and practices in the region and can guide future research on the impact of drought on river systems.

Consequently, to the construction and operation at water power plant Gabcíkovo came to changes in water regime in adjacent area. The power canal of the Gabcíkovo power plant cut the upper parts of the drainage system in Danube Lowlands. Groundwater level changes have occurred in the vicinity of the Hrušov reservoir what caused changes in discharge and water level regime of the drainage channels. Presented contribution deals with theoretical and practical background of the water management in agriculturally exploited regions, especially with the possibility to create and store enough water for irrigation in the channels of one part of the Rye Island. It was therefore necessary to measure and calculate the capacity of given channels as well as the volume of water stored by means of improved operation on hydraulic structures or by construction of new structures. Rye Island belongs to an area where agriculture in the growing season, especially due to the irregular distribution of precipitation, very often suffers from drought. The probability of ensuring at least 10 mm of precipitation in one decade of the growing season is only 50% and the probability of 30 mm of precipitation is only 20%. It follows that without irrigation the moisture for vegetation cover is not ensured. But there can be years with heavy rainfall and then there is no need to irrigate. Rye Island is the warmest area of the Slovakia where the vegetation period is also the longest. Most of it belongs to the area of corn production type. The irrigation economy is therefore profitable. However, the technology of implementation and the effort to introduce large-scale irrigation as soon as possible led to the conclusion that this issue should be considered from several points of view.

The creation of the adaptation strategy on impacts of the climate change in urban area comes out from assumption that the adaptation is not just a single shot but a cyclic dynamic process which has to be systematic and coordinated taking into account the necessity and effectiveness. Those cities which are or will be able to integrate the adaptation into planning process will better resist to reality which is affording the new period of climate change. One of those cities is the Trnava City in Slovakia. The analysis of the present climate change in the Trnava City and its surrounding assumes growing trend of temperature increase during the year and especially the increased extremeness. The combination of temperature and precipitation trends will affect the soil moisture and changes of run-off regimes of rivers. The main goal of proposal of water retention measures on the Trnavka River flowing through the city is the improvement of the water level by retaining the water what should attract public places and to cool down the air in the residential area of the city. The research was concentrated on evaluation of possible realisation of such water retention measures from water quantity and quality point of view. The solution consisted in design of several inflatable rubber weirs, its analysis and prognosis of water level and discharge regime in the Trnavka River using mathematical modelling connected with field measurements and updated detailed geodetic survey.

The goal of the contribution is to analyse and review the possibilities of flood protection in hydrological, morphological and geological conditions of the East Slovak Lowland, specifically the flood protection of the county city Trebišov. The flood situation is caused very often by the Trnávka stream flowing along the city. The analysis was performed by mathematical modelling using HEC-RAS software. Based on Trnávka drainage basin reconnaissance, own measurements in situ and study literature relating thereto a proposal of several technical measures for safe run-off in the Trnávka river bed has been elaborated and consequently evaluated from hydraulic point of view.