The testing of a model performance is important and is also a challenging part of scientific work. In this paper, the results of the physically-based EROSION-3D (Jürgen Schmidt, Berlin, Germany) model were compared with trapped sediments in a small reservoir. The model was applied to simulate runoff-erosion processes in the Svacenický Creek catchment in the western part of the Slovak Republic. The model is sufficient to identify the areas vulnerable to erosion and deposition within the catchment. The volume of sediments was measured by a bathymetric field survey during three terrain journeys (in 2015, 2016, and 2017). The results of the model point to an underestimation of the actual processes by 30% to 80%. The initial soil moisture played an important role, and the results also revealed that rainfall events are able to erode and contribute to a significant part of sediments.

Discharge dynamics in natural streams can be influenced by aquatic vegetation, therefore its precise evaluation is crucial for effective river management especially in lowland environments. This paper investigates the accuracy of discharge measurements in lowland natural streams with aquatic vegetation using an Acoustic Doppler Current Profiler (ADCP). The research highlights the challenges and issues of using ADCP in areas with aquatic vegetation, which cause measurement inaccuracies and deviations in the measuring sections. Field measurements carried out on the Gabčíkovo – Topoľníky canal stream during the growing seasons of 2018 and 2023 recorded differences in accuracy and calculated discharges and flow velocity attributes due to denser vegetation.

Intensities of short-term rainfalls are the basic design parameters for the dimensioning and design of urban sewerage systems. However, in connection with climate change, there is a change in rainfall characteristics, which are represented i. a. also b y increase of the short-term rainfall intensity. This means an increased hydraulic load on urban sewerage systems, which can be resolved by increase of the sewerage system capacity or by reducing the of rainwater inflow into the sewerage system. Current ly, within the framework of adaptation measures for climate change mainly the second option is preferred, i.e. reduction of the i nflow into the sewerage system. This has to be realized prioritizing the green adaptation measures (green infrastructure). The pape r deals with impact of the of green infrastructure implementation in urban sewerage system on the operational safety of the urb an sewerage system from the point of view of the floods occurrence in the urbanized area. As shown by the results of the model s tudy, the biggest effectiveness of green infrastructure in terms of preventing the occurrence of flooding is shown in case of short-term rainfalls with a lower return period (1-2 years). With increase of the return period (up to 10 years), the effectiveness of green infrastructure in terms of the occurrence of flooding decreases.

Ongoing climate change is marked by occurrence of extreme weather events (e.g., heavy rain falls and heat waves), to which reservoir ecosystems are sensitive. Despite the occurrence of heavy rains, the lack of water can increase, since such precipitation is characterized that it falls quickly, but also run s off quickly. Therefore, it is necessary to capture and use these precipitations as much as possible. On the other hand, in order to ensure suitable water quality for future use, it is necessary to take in to account the land use around water bodies, especially in locations where heavy downpours may burden water bodies with flushed nutrients. Theref ore, in the context of global warming and more extreme climatic conditions, further research should focus on the underlying ecological mechanisms of reservoirs and providing scientific support for water security and sustainable development. Water reservoirs an d water quality in them a re the subject of the project APVV – 22 – 0610 "Technological procedures for the r emoval of endocrine disruptors and the elimination of the occurrence of cyanobacteria and their undesirable effects in water sources to ensure th e quality of drinking water according to the increasing requirements of the new EU Drinking Water Directive", w ithin which water quality indicators in selected water reservoirs in Slovakia are monitored. One of them is the Turček water reservoir located in centr al Slovakia above the village of Turček in the Turčianske Teplice district at the confluence of the Turie c and Ružová streams. On July 2024, during field measurements for the purposes of this project, a storm event with intense precipitation occurred in this l ocation. Paper deals with processing and analysis of changes in the measured values of selected indicators of water quality in the reservoir - water temperature, electrical conductivity of water and dissolved oxygen concentration - before and after this storm event. Before the initial monitoring of the spatial distribution of selected water quality indica tors in the Turček water reservoir, the current bathymetry of the reservoir was measured by the AUV – EcoMapper. According to these data, a network of monitoring points was designed, in which the values of the monitored water quality indicators are measure d in the specified horizons. The values of the water quality indicators are measured with the 3630 IDS digital multimeter together with the MPP 930 IDS depth probe with housing. On July 17, 2024, a heavy rain combined with hail lasting 1 hour brought a tot al precipitation of 18 mm. After the precipitation event, water quality indicators were monitored at two monitoring points with depth s of 10 m and 37.5 m. The results show that such precipitation event did not significantly affect the values and distribution of evaluated water quality indica tors in the deep horizons of the reservoir. At the same time, however, the results point to the fa ct that area s with shallower depths located near the tributary react more sensitively to the occurrence of such a precipit ation event than area s in the central part of the reservoir. Of course, for a more detailed evaluation, or confirmation of the findings, it would be necessary to have more of these or simil ar data available. However, due to the spatial and temporal unpredictability of extreme hydrometeorological situations, obtainin g such data is very difficult.

Safe drinking water and its abundance include into among the basic attributes of a healthy environment and the basic human rights. As climate change progresses, ensuring a supply of drinking water to the population will pose increasing challenges. In this context, apart from exploiting groundwater sources, water reservoirs will assume a pivotal role in addressing this issue. On the territory of the Slovakia, there are currently 8 water reservoirs, which are used to collect water for the production of drinking water. One of them is the Turček reservoir, which was completed in May 1996 and has been in full operation since 1997. In this contribution, the hydro-meteorological data from the Turček water reservoir location, which were provided by the operator of this reservoir, are evaluated. These data contain information on daily values of basic characteristics. The period 1997-2021 was analyzed, especially the development and trends of precipitation, air temperature, occurrence of a given type of weather during this period and ice cover thickness and duration. The analysis of hydro-meteorological data showed that the average annual air temperature is rising slightly, for the period 1997-2021 it rose by 0,03 °C. The ice cover thickness (both maximum and average value) shows a decreasing trend and decreased by 7,3 cm during the observed period. The same trend is shown by the duration of the ice cover on the reservoir surface. The frequency of precipitation events has been decreasing for a long time, the annual total depth of precipitation also has a decreasing trend. Recently, this reservoir also had a problem with the occurrence of cryophilic cyanobacteria, the occurrence of which is not desirable in such types of water bodies. The performed analysis of the development of hydro-meteorological conditions is an important basis for the evaluation and understanding of processes related to water quality in this reservoir.