Urban Flood Warning System Social Benefits

Urban Flood is one of the biggest environmental problems of the planet. It generates high negative impacts of various kinds: social, environmental and economic. These problems grow exponentially in megacities, since the disorderly occupation of land, coupled with the size of the population, make it extremely complex to control and to manage. Structural measures for flood control are not enough; the city needs to deploy a number of non-structural measures such as a flood warning system. This system aims to provide real-time occurrence and forecast of floods that may cause impacts in several areas of the city. These forecasts trigger a series of actions for civil defense, firefighter, traffic control, social support and other entities. The flood warning system of the Sao Paulo Metropolitan Region, Brazil, called SAISP system, installed a set of weather radars and telemetry networks, as well as a decision support system (SSD) operated by engineers and meteorologists, which generates a set of forecasting bulletins 24 hours a day during all year long. Several public organizations and press receive these bulletins in real time and a set of actions can be managed in order to minimize the impacts of critical hydrological events. This paper presents some analysis of a flash flood event observed in the Jaguar River small catchment on February 6th, 2016 (80 mm in one hour). In this day a set of social works could be done due to SAISP information. Therefore with this event was possible to evaluate a set of social benefits that this type of system back to town. In general is very difficult to assess the social benefits that this type of system produces in a big city, so the information obtained in this event can subsidize the planning of new systems, as overall social benefits are difficult to measure in economic values, because most of them are intangible.