B. Chocat

Urban flooding: one-dimensional modelling of the distribution of the discharges through cross-road intersections accounting for energy losses

Many investigations have been carried out in order to develop models which allow the understanding of complex physical processes involved in urban flooding. The modelling of the interactions between overland flows on streets and flooding flows from rivers and sewer networks is one of the main objectives of recent and current research programs in hydraulics and urban hydrology. However, the modelling of the discharge distribution in the street network with crossroad needs further research due to the complexity of the flow through junctions. This paper outlines the ability of the improved one-dimensional CANOE software to simulate the street flows through the virtual network (developed under the Hy(2)Ville French National project framework) with several cross-roads. The improvements are done by adding in CANOE the energy losses coefficients deriving from the calibration phase based on the experimental study of the flow through small scale physical model of cross-road channels. Comparisons between 1D and 2D simulated distribution of discharges through the virtual network show a good agreement for the global distribution. However, large differences are observed focusing on the individual cross-road intersections in the virtual network.

One-dimensional modelling of the interactions between heavy rainfall-runoff in an urban area and flooding flows from sewer networks and rivers

Many investigations have been carried out in order to develop models which allow the linking of complex physical processes involved in urban flooding. The modelling of the interactions between overland flows on streets and flooding flows from rivers and sewer networks is one of the main objectives of recent and current research programs in hydraulics and urban hydrology. This paper outlines the original one-dimensional linking of heavy rainfall-runoff in urban areas and flooding flows from rivers and sewer networks under the RIVES project framework (Estimation of Scenario and Risks of Urban Floods). The first part of the paper highlights the capacity of Canoe software to simulate the street flows. In the second part, we show the original method of connection which enables the modelling of interactions between processes in urban flooding. Comparisons between simulated results and the results of Despotovic et al. or Gomez & Mur show a good agreement for the calibrated one-dimensional connection model. The connection operates likes a manhole with the orifice/weir coefficients used as calibration parameters. The influence of flooding flows from river was taken into account as a variable water depth boundary condition.

Sewer system flow components identification using signal processing.

The development of a continuous model to simulate the behaviour of sewer systems requires detailed information on each component of the flows contributing to the global discharge. In this paper authors investigate a novel method based on signal processing and long time series data implemented with a 2 min time step (flow rate, conductivity, pH and turbidity) in order to identify the dry weather components in a separated stormwater sewer system draining an industrial catchment. The wavelet analysis is applied to the recorded data to identify main components in dry weather flow after the removing of the signal noise. This paper highlights also a method to detect inflow into sewer system and shows how hydrological modelling can be used to characterise the relevant components. These techniques could be used as a basis for several applications.