Radar-based alert system to operate a sewerage network: relevance and operational effectiveness after several years of use.

Since January 2000, the sewerage network of a very urbanised catchment area in the Greater Nancy Urban Community has been operated according to the alarms generated in real time by a storm alert system using weather radar data. This alert system is based on an automatic identification of intense rain cells in the radar images. This paper presents the characteristics of this alert system and synthesises the main results of two complementary studies realised in 2002 in order to estimate the relevance and the operational effectiveness of the alert system. The first study consisted in an off-line analysis of almost 50,000 intense rain cells detected in four years of historical radar data. The second study was an analysis of the experience feedback after two years of operational use of this alert system. The results of these studies are discussed in function of the initial operational objectives.

Management of a detention-settling basin using radar data and risk notion.

This paper presents a practical application of sewage network management strategy using radar data to control a detention-settling basin. This practical application, used in operational mode since January 2000, is based on three main notions. Firstly, the use of radar data without rainfall estimation. Secondly, the definition of some gradual risk levels for the sewage network by a detailed modelling of the sewage system functioning. Thirdly the definition of relations between risk levels for the sewage network and types of rain events defined from radar data. The operational application produces gradual alarms for decision-making assistance: no risk, potential risk and confirmed risk.