Abstract
Flood risks can be evaluated from two points of view, the economic and the process one. The economic approach parts from consequences of the causal event when the risk is defined as the function of probability of occurrence of a certain phenomenon and of potential damage.
The process approach evaluates the risk via main processes and factors involved in the risk development. The risk is then defined on the basis of three factors - hazard, exposure, vulnerability (Barredo et al. 2005, Crichton 1999, Kron 2003).
Anthropogenous changes in the landscape represent, according to the process approach to risks, one of the vulnerability factors. Vulnerability of environment in relation to values exposed to the hazard represents their susceptibility to damage occurrence and is decisive for the extent of damage.
Large changes in intensity, character and structure of land-use occurring in the cultural landscape during these last centuries, affect changes in outflow conditions of the catchment and can thus influence the course of floods. Vulnerability is a risk element which can be, differently from the other risk components, at least partly influenced and controlled.
While natural processes representing a source of hazard cannot be influenced and accumulation of property in flood areas can be only hardly reduced, it is possible to purposefully reduce vulnerability both of natural environment and of social links in a way to minimize consequences of natural elements activities, to increase the efficiency of flood control measures and to limit damages to a strict minimum corresponding to the extremity of the phenomenon.