A robust and fast model for simulating street flooding

This work is part of a long term project which aims to simulate (1) the hydrology, (2) street flows, (3) flow interception at inlets and (4) storm-sewer flows in urban areas. The present work describes the application of the model using only the first two modules. The hydrologic model (first module) transforms rainfall to runoff using the kinematic wave approximation and simulating the infiltration process with the Green-Ampt method. The street model (second module) is based on a finite volume-shock capturing scheme that solves the full conservative Saint-Venant equations and can be used to simulate subcritical and supercritical flows. The formulation of boundary conditions at the street crossings in the street model is general and can be used for any number of streets, any combination of inflowing and outflowing streets, and any flow type (e.g., supercritical flows). The model using the first two modules is fast and robust and it has several potential applications. Perhaps the most important one is that it can be used in new urban developments to identify critical zones of urban flooding (e.g., zones with high water depths and flow velocities) in order to take appropriate measures of drainage control (e.g., to increase capacity of inlets). This model can also be used in developed urban areas to locate the critical areas in case of inlet clogging. In order to illustrate the capabilities of the model (first two modules) it was applied to an urban catchment in the village of Dolton, a southern suburb of Chicago. The watershed of this village drains to the dropshaft CDS-51 in the Calumet TARP (Tunel and Reservoir Plan) system which is operated by the Metropolitan Water Reclamation District of Greater Chicago. The fact that this model is fast makes suitable its application to large urban areas.