Vízügyi Közlemények, 2003 (85. évfolyam)

3. füzet - Nagy L.: Differenciált védelmi szintek az árvízvédelemben

452 Rákóczi László One needs to change the paradigm and reformulate the safety-policy. The leading principle must be the development of such a system in which the acquired rights are not violated, and this should be done by a step-forward towards the improvement of risk-calculation. In any era of flood-levee construction the population, the decision makers and the engineers have all relied on a certain formulation of the level of safety. This helped them to assign technical parameters to the designed structures (Figure I). Depending on the era and on the technical knowledge the main effort was made for the providing an identical level of safety. In the calculation of risk (which is the best method to be applied) one considers not only the technical safety but also the damages that might be caused to the protected valuables. With this the formulation of safety can better follow the social-economic needs and can even be the driving force of development in certain cases. In developing the protection-capacity of flood control structures of flood-prone areas (flood-basins) and in constructing the system of levees one must not forget about the damage that could be caused on the protected area. In the case of flood-basins of higher value (where a Hooding will eventually cause higher damages) the level of safety must follow the higher economic needs. Although the procedure of risk-calculation cannot be easily followed by the lay public, the principle is clear and can be controlled by the society. This is expressed by the "Best Practices of Flood Control" of the European Union. The number of people living in a flood basin varies in wide ranges ( Table II, Figure 2). Similarly high is the variation in the protected economic values (Table III, Figure 4) and in the damage, which can be caused by a single inundation (Table IV). This provides a good basis for differentiation and for setting the identical risk levels (see Figures 3 and 5). Those flood-basins where the assuring of higher safety level can be justified on the basis of both the number of people living there and of the economic values concerned are listed in Table V on the basis of the above mentioned investigations and calculations. In Table V the flood-basins where large cities are located have eventually an advantage but the protection levels can be further refined with a more accurate mapping of risks and by considering the probabilities of failure of the flood-control structures and also by the estimation of the inundation probabilities of these basins. * * * Differenzierte Schiitzniveans im Hochwasserschutz von Dipl.-Ing László NAGY Ein bedeutender Teil der mit dem Wasser bzw. mit dem Hochwasser zusammenhängenden Aufgaben steht in Beziehung zur sozialen Versorgung und Existenzsicherheit. Deshalb muß auch eine wirtschaftliche Annäherung die strengen ethischen und politische Kompromissen, die wirtschaftlichen Erwartungen der Gesellschaft verfolgen. Bei der Formulierung der Sicherheit darf nie vergessen werden, daß es immer um außerordentliche wirtschaftliche Entscheidungen, um den Schutz des staatlichen und privaten Vermögens geht. Die Verantwortlichkeit wird dadurch nur erhöht, daß die Interessenten i.a. nicht im Bewubtsein des Ausmaßes ihrer Gefährdung sind. Das Mab der Sicherheit ist von der Tragfähigkeit des jeweiligen Landes abhängig (Tabelle 1). Ein Paradigmenwechsel ist an der Tagesordnung: bei der Formulierung einer neuen Sicherheitspolitik soll eine solche Entwicklung des bestehenden Systems angestrebt werden, bei welcher die erworbenen Rechte ungeschmälert bleiben. Man soll in der Richtung der Entwicklung, der Risikoberechnung vorwärts schreiten.