Inundation simulation for urban drainage basin with storm sewer system

An urban inundation model, combining a storm sewer model SWMM, two-dimensio nal (2D) diffusive overland-flow model and operations of pumping stations, has been developed to simulate inundation in urban areas caused by the surc harge of storm sewers and outlet pumping stations. The movement of water in the studied urban watershed is characterized by two components, namely, th e storm sewer flow component and the surcharge-induced inundation component . SWMM is employed to solve the storm sewer flow component and to provide t he surcharged flow hydrographs for surface runoff exceeding the capacity of the storm sewers. The 2D diffusive overland-flow model considering the non -inertia equation with Alternative Direction Explicit numerical scheme is t hen used to calculate the detailed inundation zones and depths due to the s urcharged water on overland surface. Drainage by pumping stations at outlet s of the storm sewer system has also been taken into consideration. The par ameters of the model are calibrated and verified for discrete storms. The c ombined model is suitable for analysis of inundation on urban areas due to overflow of storm sewers and flooding caused by failure of pumping stations . Simulated results can be applied to establish flood-mitigation measures. (C) 2000 Elsevier Science B.V. All rights reserved.