Risk management has been established as a well-defined procedure for handling risks due to natural, environmental or manmade hazards, of which floods are representative. Schanze, et al. (2002) provided different definitions of flood risk management: ‘‘the flood risk management should be defined as holistic and continuous societal analysis, assessment and reduction of flood risk. Holistic refers to the flood risk system which should be considered as comprehensive as possible. The term ‘continuous’ expresses the need for an ongoing assessment of flood risks, and their dynamic effects of reduction activities.
Analysis, assessment and intervention for risk reduction as common elements of a development model are dedicated to the managing entity. ‘‘Flood risk management deals with a wide array of issues and tasks ranging from prediction of flood hazards, through their societal consequences to measures and instruments for risk reduction. Due to this variety of aspects, management of flood risk needs systematization and integration. Flood risk management takes place as a decision making and development process of actors.
According to potential interventions on the flood risk system, these actors represent various fields (water authority, spatial planning authority), adjacent areas (multiple municipalities) and different levels (local, regional, national, international). The decision-making and development process varies depending on the political, administrative, planning and cultural system.’’
The flood risk can be defined as the probability of negative consequences due to floods and depends on the exposure of element of risk to a flood hazard. The term of flood risk emerges from the convolution of flood hazard and flood vulnerability. The probability of the occurrence of potentially damaging flood events is called flood hazard and the damage by flood hazards depends on the vulnerability of exposed elements. Finally, the management is interpreted as decisions and actions undertaken to mitigate the remaining risk above flood protection design standards (Schanze and all, 2002).
Flood risk management is a process that has been discussed extensively from 1990 and 1999 during the International Decade of Natural Disaster Reduction (IDNDR) and it was recognized that term of ‘flood protection’ was not suitable because absolute protection is both unachievable and unsustainable because the high costs and inherent uncertainties. The risk management has been recommended as being more suitable and this paradigm is now receiving growing attention within flood research. Then, currently environmental and regional policies in many countries have shifted from flood protection to flood risk management. (Schanze and all, 2002).
Plate, E. P. and all. (2002) gave a more straightforward definition of the flood risk management:‘‘The flood risk management in a narrow sense is the process of managing an existing flood risk situation. In a wider sense, it includes the planning of a system which will reduce the flood risk management’’. Then it is more useful to interpret risk management which flood are representative as a process which involves three different set of actions depending on the operators involved (Plate, E. P., 2002):