Hydrologically Enhanced Distributed Urban Drainage Model and Its Application in Beijing City

AbstractHeavy rainfall-induced inundation is becoming more serious in urban areas making it necessary to urgently appraise and redesign the infrastructure system to drain the storm water more efficiently. For the complex urban drainage systems that include street, sewer, and ditch/river networks, a sophisticated urban drainage model is required to facilitate optimal planning and management. Although most existing models simulate the runoff generation process in a simpler manner and treat the drainage connections between runoff generation cells and the corresponding drainage links in a rigid/static manner, this study proposes a new hydrologically enhanced distributed urban drainage model. In the new model, the urban area is discretized into a four-layer network, i.e., two-dimensional (2D) grid network, 1D street network, 1D sewer network, and 1D ditch/river network. Physically based equations are utilized to describe water movement along the four networks, i.e., the 1D Richards equation is used to simulate...