ABSTRACT
Alternatively, in order to determine the number of storm overflow discharges one can use numerical programmes (SWMM, PCSWMM, MIKE URBAN MOUSE) as well as simplified
1 INTRODUCTION
The fundamental function of the stormwater drainage system is draining away precipitation water from the surface of an area to a stormwater treatment plant. When the plant’s capacity is exceeded, the excess stormwater is discharged directly into the receiving water via the emergency overflow weir, which leads to an abruptly increased watercourse flow and may contribute to scouring and the disturbance of biological-chemical balance (Martino et al. 2011, Szeląg et al. 2013, Bąk et al. 2012). Therefore, in order to limit a potential threat for the receiving water, it is necessary to know the number and volume of discharges and the quality of the effluent discharged directly into the receiving water bodies. The above considerations resulted in the development of computational methods (Mantegazza et al. 2010, ATV-A 128, Zabel et al. 2001, Dąbrowski 2007) for modelling the storm overflow performance. The methods of determining the number of storm overflow discharges in the combined sewer system can be divided into: empirical ones (Shigorin’s equations, equations derived by Fidala-Szope et.al (1999) based on many years of research), deterministic ones (Kuiper’s (Dąbrowski 2007, Mrozik et al. 2015) methods of routing drain retention above overflow weirs) and stochastic ones.
