Dynamical modeling in water supply and treatment and wastewater treatment helps to understand the flow in the networks. Therefore, it is important to incorporate dynamic modeling into the design and assessment processes and operation for the future of urban drainage systems. The aim of this paper was using a mathematical model to analyze the functionality of combined sewer networks during a precipitation event on 13 October 2020. The analysis was performed based on the results from the assessment of the hydraulic capacity of the sewer network using the MOUSE model in the MIKE URBAN software. This study results that the evaluated sewer network does not fulfill his purpose during heavy rainfall events.

The presented paper draws attention to the need to adapt urban areas to the negative impacts of climate change, more precisely to the solution of extreme rainfalls and long dry periods. The topic of rainwater management is popular worldwide due to the worsening situation in the field of climate change. Extreme weather fluctuations and torrential rains stress the urban hydrological cycle. Adaptation measures are proposed that mitigate the impact of climate change in cities. These also include measures to retain water in the country. The paper focuses on drainage density analysis, runoff coefficients and impermeability analysis, and the selection of appropriate measures to reduce surface runoff.

This research dealing with mathematical modeling of sewer network in urbanized area, which means creating a mathematical model in mathematical software MIKE URBAN. This software is designed to compute and create the model of surface runoff in chosen area. This model is creating because sewer system in Slovakia and also in the world is out-dated. Out-dated means, in the past sewer systems were designed for the fastest transport waste water and rain water from urbanized area. The rapid development of cities in the form of increasing urbanization has changed the original hydrological processes in cities. An increase in surface runoff with an out-dated sewage system can result in local floods in a short period of time. Therefore, it is necessary to create mathematical models to assess sewers in terms of their hydraulic capacity.

During heavy rainfalls, overflowing sewage water flows from the Combined Sewer Overflow (CSO) chambers and pollutes the Trnávka River in Trnava, Slovakia. This paper aims to propose water retention measures for the Trnávka River as a remediation technique for CSO-affected watercourses, which can contribute to the ‘flushing’ of the riverbed. During heavy rainfalls, the Trnávka River is polluted by solid, non-soluble materials, which produce unpleasant odors and are the subject of numerous complaints by citizens, particularly during low water levels. Three inflatable rubber weirs were designed, and their design was verified using a 1D numerical model of the Trnávka River. The simulations of the proposed measures performed in the HEC-RAS 5.0 software excluded the adverse effect of the backwater on the functioning of the CSO chambers in the city of Trnava during normal flow rates and confirmed that, even after installation of the weirs, the transition of the flood wave will pass in the riverbed, not causing the flooding of the adjacent area. The chemical–physical study of the Trnávka River confirmed our assumption that higher flow rates, which can be secured by the regulation of the proposed weirs, can contribute to the purity of the watercourse in the city of Trnava.

Stormwater management is an integral part of the new concept of wastewater disposal from urbanized areas, which includes all system units into a comprehensive, integrated system. This concept, based on sustainable principles, brings environmental and socio-economic benefits. The integrated stormwater management system facilities reduce the load on wastewater treatment plants and receiving water bodies while contributing to the restoration of local ecosystems. In this context, the paper focuses on the possibilities of using life cycle analysis to design specific integrated systems. The aim is to summarize the life cycle assessment studies of stormwater management facilities so that they can be applied in the future as a basis for the design of efficient and sustainable drainage systems in urban areas.

Due to the population increasing in urban settlements, the use of the territory and the surface variability of urban settlements are changing rapidly. The development of areas covered with impervious materials contributes to accelerating the runoff process, intensifying surface runoff concentration and the concentration of surface runoff pollution. Surface runoff from urban catchments can be characterized as the primary source of the receiving water's pollution during torrential rains. The aim of the paper is to obtain information about the quality of surface runoff from paved areas of roofs and roads in the urbanized area of the city of Trnava and about the of pollutants concentration by analyzing the quality parameters of the samples taken. Rainwater runoff sampling took place from 26 of November 2021 to 8 of April 2022. Ten samples were taken during the mentioned period. The number of samples is directly proportional to the current precipitation situation in the area. The aim was to capture the first flush due to the assumption of the highest pollution concentration in the initial phase of surface runoff formation. Due to low precipitation and insufficient surface runoff formation, the sampling was irregular. The analyzed qualitative parameters are pH, electrical conductivity, chemical oxygen demand, and nitrogen oxides. By comparing the quality of samples and air quality on individual days, we can state that air quality partially affects the quality of samples taken. By comparing the air quality and the daily total precipitation on separate sampling days, we can conclude that pollutants accumulate in the air and on paved areas during a more extended rainy period. The following precipitation event washes away paved areas and cleans the air. The surface runoff then contains a higher concentration of pollutants than the runoff from the precipitation event after a short rainless or multi-day precipitation event.