Modelling of Retention Reservoirs Network Running to Optimize the Storm Water Management

In urban environments, or in the areas where storms are frequent and violent, it is advisable to temporarily store rainfall in balancing reservoir before slackening them with flow controlled in the sewer system or in the natural environment, which limits the risks of flood and the environmental impact. The dimension of these reservoirs can be sizeable and their establishment on saturated site may be complicated and expensive. The solution suggested in this study is to distribute the retention on several reservoirs connected to each other by pipes and controlled by nozzles, and to exploit their respective capacity and the conditions of transfer to optimize the downstream flow in the network or in the natural environment. A numerical model named tank type was developed, which represents with a good level of precision the heights in the reservoirs and the flows transferred according to time as well as intensity and duration of the rain. This simplified model incremented according to a step of time adjusted with the intensity of the rain works in volumes and flow. The hydraulic conditions of flow are not considered. The model is validated by several studies of sensitivity on meshes or series of 2 or 3 reservoirs and opens up the way for a fast and reliable tool of pre dimensioning.