Dynamic flood webmapping: an operational and cost-limited tool to optimize crisis management

¹ Prolog Ingénierie – 11, rue Auguste Lacroix, 69003 Lyon France
² SyAGE (Syndicat mixte pour l'Assainissement et la Gestion des Eaux du bassin versant de l’Yerres) – 17, Rue Gustave Eiffel, 91230 Montgeron, France

^a Corresponding author: strappazzon@prolog-ingenierie.fr

Abstract

Due to strong climate variations and the multiplication of flood events, protection based strategies are no longer sufficient to handle a watershed scale crisis. Monitoring, prediction and alert procedures are required to ensure effective crisis and post-crisis management which explains the recent interest for real time predictions systems. Nevertheless, this kind of system, when fully implemented with in-situ monitoring network, meteorological forecast inputs, hydrological and hydraulic modelling and flood mapping, are often postponed or cancelled because of both their cost and time scale. That is why Prolog Ingénierie and the SyAGE have developed, as an economical and technical sustainable alternative, a tool providing shared access to a real time mapping of current and predicted flooded areas along with a dynamic listing of exposed stakes (such as public buildings, sensible infrastructures, environmental buildings, roads). The update of these maps is performed from the combination of predicted water levels in the river and a flood envelop library (based on 1D/2D hydraulic model results for a wide panel of discharges and hydraulic structures states conditions). This tool has already been implemented on the downstream part of the Yerres River, a tributary of the Seine River in France.