Use of weather radar for combined sewer overflows monitoring and control

In the Mediterranean region, climatological factors make combined sewer overflows a major urban pollution problem that should be monitored and controlled. Some online management solutions require the use of real-time models to forecast flows at the most sensitive points of the combined sewer systems. These models need a very good time and spatial resolution of the rainfall field, which is not sufficiently reproduced by a conventional rain-gauge network. This paper presents a case study where the use of rainfall estimates from weather radar pictures is compared with the use of a rain-gauge network in terms of the ability to predict sewer flows in an urban basin in Barcelona, Spain. The results show that the use of radar data enables the combined sewer systems model to improve the reproduction of observed flows, and they provide support for the idea that the spatial description of rainfall is a key problem in modeling the events giving rise to combined sewer overflows.