Assessing the performance of urban drainage systems: `general approach' applied to the city of Rotterdam

The Department of Public Works for the city of Rotterdam manages a complex urban drainage system. The system consists of 30 catchments, collects wastewater discharged by 30 pumping stations, to a total of five treatment plants (1.1 million equivalent population). At present control of all these pumping stations is being centralised. To assess the benefits of central control, a performance index (PI) was developed to classify the actual performance of the system under control, during dry weather conditions and during storm events. The PI is composed of deterministic and heuristic indicators that reflect the quality of the control with respect to different objectives set for the entire water system.

In a case study the PI was computed for several historic events and showed encouraging results in different modes of control for both dry weather and storm conditions. From the results it can be concluded that the technology described in this paper can help to identify points that need performance improvement in the urban water system in general and in the way it is controlled specifically.