Verification of the Stormwater Drainage System Overloads in Wrocław for an Assessment of Climate Change Effects

This paper presents a verification of the performance of the stormwater drainage system in Gaj and Tarnogaj residential developments in Wrocław with regard to climate changes, by means of a calibrated hydrodynamic model created within the SWMM software. The verification was carried out for two criterial rainfalls: the Euler model rainfall with occurrence frequency C = 3 years and an actual rainfall with C = 5 years. Two parameters: degree of flooding (DOF) and specific flood volume (SFV) were adopted to indicate potential system overloads. The simulations showed numerous outflows from the sewers, which means, that the investigated system needs adapting to climate changes. The causes of this should be sought in the too small diameters of the sewers and so in the insufficient hydraulic capacity of the sewerage system dimensioned in the past using methods which are inadequate today.