Analysis of Major Flood Events: Collapse of the Malpasset Dam, December 1959
Résumé
Major floods are a relatively rare occurrence, but the socioeconomic consequences are disastrous, making them a core focus of flood risk management. Authorities are particularly concerned about the possibility of major events taking place, notably due to previously affected areas becoming more vulnerable, linked with increased urbanization of flood plains and the inability to fully recall the impact of past events. For example, the potential recurrence of floods similar to those affecting capital cities Paris and London, respectively, in January 1910 and January 1928 is of much concern. The recurrence of such events could cause unprecedented economic damage (the Seine flood of 1910 cost an estimated 30 billion euros) and would paralyze key political and financial decision-making centers, seriously affecting proper functioning of the affected countries. In order to prepare for possible recurrence of such events, the European Floods Directive has recommended for a census to be carried out on past historical floods. The analysis of these floods has brought a number of questions to light. Is there a particular methodology that we should to adopt in order to select and document them? What lessons can we learn, and how can the information in fine help improve future management of major floods? In order to answer these questions, we will review core studies linked to major floods. We will then look closely at the collapse of the Malpasset Dam in December 1959. While this event did not occur due to overflowing waterways, it was one of the most serious events of the 20th Century in France in terms of the number of lives lost, and became a key point of reference for important decisions regarding dam safety.