Modelling the impact of green infrastructure on potential sewer flooding in the city of Trebišov, Slovakia

The paper analyses the results of water flow modelling in the urban drainage system of the city of Trebišov, Slovakia.The purpose of the work was to assess the risk of flooding in the urban area and its reduction using Green Infrastructure (GI).The complex hydraulic and hydrological modelling software MIKE+ was used in the research.Using the model of the city's urban drainage system, water flow simulations were carried out using short-term block rainfall events of varying intensity, lasting from 15 to 120 minutes and with return periods of 2 to 10 years.For each scenario, the number of flooded manholes was determined.As a result, areas where two types of GI could be implemented were identified and included in the surface runoff hydrological model.In this study, two types of GI were used: semipermeable pavements and green roofs.The stormwater flow was modelled under four scenarios: current status, implementation of semipermeable pavements, green roofs and their combination.The model results were compared to the current conditions.It was found that the application of both types of GI could potentially reduce the number of flooded points by more than 30 % for short-term rainfall with a return period of two years.As the return period of the short-term rainfall increases, the number of flooded points decreases to an average value of 5%.