Intérêt technique et économique des radars d'investigation des précipitations en matière d'assainissement urbain

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In order to operate its sewerage system in rainy weather the operating department must make arrangements to ensure the presence of personnel when rain is falling and to enable control equipment for weirs, flood retention basins, etc. to be known and handled properly. Of this equipment, radar appears to be a popular instrument for investigation and assistance in precipitation forecasting. It sounds out the entire atmosphere to detect rainy zones and pinpoints ; - those which are near to measurement points on the ground - those which are moving towards the town. In order to specify methods of using radar the Equipment Departments of Seine Saint-Denis and Val de Marne are participating in an experiment the object of which is to improve information on rain by the RODIN radar of the Technical Equipment Centre of the National Meteorological Office (Centre Technique du Matériel de la Météorologie Nationale) which is located at Trappes between 20 and 50 km from the 500 km zone covered by their rain-gauge recording network (about twenty rain-gauges. In parallel with this experiment retransmission of the radar picture from Dammartin to the operations centre at Rosny-sous-Bois must make it possible through liaison with departments of the National Meteorological Office for rain characteristics essential to mobilisation of personnel in rainy weather and to operation of the network in terms of real time to be ensured. (Time differences in start of rainfall between critical zones, duration and intensity of the rain, surface area affected).