Flooding in urban drainage systems: coupling hyperbolic conservation laws for sewer systems and surface flow

SUMMARY In this paper, we propose a model for a sewer network coupled to surface flow and investigate it numerically. In particular, we present a new model for the manholes in storm sewer systems. It is derived using the balance of the total energy in the complete network. The resulting system of equations contains, aside from hyperbolic conservation laws for the sewer network and algebraic relations for the coupling conditions, a system of ODEs governing the flow in the manholes. The manholes provide natural points for the interaction of the sewer system and the runoff on the urban surface modeled by shallow‐water equations. Finally, a numerical method for the coupled system is presented. In several numerical tests, we study the influence of the manhole model on the sewer system and the coupling with 2D surface flow.