Abstract
Rainfall-runoff transformation on urban catchments involves physical processes governing runoff production in urban areas (e.g., interception, evaporation, depression, infiltration). Some previous 1D/2D coupled models do not include these processes. Adequate representation of rainfall–runoff–infiltration within a dual drainage model is still needed for practical applications. In this paper we propose a new modelling setup which includes the rainfall–runoff–infiltration process on overland flow and its interaction with a sewer network. We first investigated the performance of an outflow hydrograph generator in a 2D model domain. The effect of infiltration losses on the overland flow was evaluated through an infiltration algorithm added in a so-called Surf-2D model. Then, the surface flow from a surcharge sewer was also investigated by coupling the Surf-2D model with the SWMM 5.1 (Storm Water Management Model). An evaluation of two approaches for representing urban floods was carried out based on two 1D/2D model interactions. Two test cases were implemented to validate the model. In general, similar results in terms of peak discharge, water depths and infiltration losses against other 1D/2D models were observed. The results from two 1D/2D model interactions show significant differences in terms of flood extent, maximum flood depths and inundation volume.
Highlights
Hydrological water losses are an important issue within the spatial and temporal distribution of the runoff water in urban catchments
The influence of the sewer system in the overland flow is of recognized importance [1,2] and the interaction between surface water and the infiltration losses, in order to better estimate inundation extent and water depths [3,4,5]
Some of the current included infiltration approaches focus on: (i) hydraulic models for the simulation of flow routing in drainage canals taking into account the infiltration effect with the Green-Ampt method [6]; (ii) estimating the parameters of the Green-Ampt infiltration equation from rainfall simulation data [7]; (iii) flood routing model incorporating intensive streambed infiltration [8]; (iv) rainfall/runoff simulation with 2D full shallow water equations [9]; (v) modelling two-dimensional infiltration with constant and time-variable water depth [10] and (vi) investigation of overland flow by incorporating different infiltration methods into flood routing equations [11]
Summary
Hydrological water losses are an important issue within the spatial and temporal distribution of the runoff water in urban catchments. The influence of the sewer system in the overland flow is of recognized importance [1,2] and the interaction between surface water and the infiltration losses, in order to better estimate inundation extent and water depths [3,4,5]. The key point is to evaluate the proposed model performance when rainfall–runoff and infiltration losses are included in a dual drainage approach, crucial for proper planning and design of urban drainage systems For this purpose, we first investigated the performance of an outflow hydrograph generator in a so-called Surf-2D model and used it as an inflow boundary condition. A non-inertia model system, named subsequently in this work as Surf-2D, was implemented
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