Exchange between drainage systems and surface flows during urban flooding: Quasi-steady and dynamic modelling in unsteady flow conditions

The accurate modelling of urban flooding constitutes an integral part flood risk assessment and management in residential industrial areas. Interactions between drainage networks surface runoff flows are commonly modelled based on weir/orifice equations; however, this approach has not been satisfactorily validated unsteady flow conditions due to uncertainties estimating the discharge coefficients associated head losses. This study utilises experimental data exchange sewer floodplain through a manhole without lid develop two alternate approaches that simulate interaction describe flow. A quasi-steady model links total pipe losses manhole, whilst dynamic takes also into account evolution water level within at discrete time steps. developed numerical models subsequently against large-scale for conditions, featuring variable surface. Results confirmed both can accurately replicate with improved performance when compared existing methodologies only weir or orifice equations.