Risk management, questions and answers

The development of urbanisation has leaded, concerning urban storm drainage control, to the concept of risk management. This concept is considered, classically as the conjonction of a hazard and a vulnerability. The analysis of the flooding risk and of the pollution risk show a lack of knowledge for the estimation of the hazard and some difficulties to define the vulnerability. Nevertherless the management of risk must deal with the present level of knowledge, the regulation context, and decision making process between the different institutions and between the different geographic levels. To achieve this management, a panel of approaches can be used: scientific and technic, formation and sensibilisation of elected people, cultural, regulational and application of the precautionary principle. But it seems, in the end, that the risk management is essentially a political affair.