6.1 Integrated Water Management for Quality and Quantity
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Coming back to risk classification after WBGU, an important question concerns the
possibility of transferring one risk type (e.g., cyclops) from a certain risk area to another.
Figure 6.5 shows that the transfer of risk types within a certain areas as well as from one
area to another might be possible. Consequently, the question is: If storm surges are of
the cyclops type, what has to be done to change the risk area? While the probability of
occurrence of a storm surge cannot be influenced, it is necessary to reduce the extent of
damage (see Fig. 6.5). This can be achieved by precautionary measures that enable the
transfer to the normal risk area. But what are the consequences of this approach to coastal
protection?
Risk according to coastal protection can be defined as introduced by formula (6.1). For
the determination of the “probability of failure” the design water level and the construction of the embankment have to be considered, for example, Kortenhaus (2003). In case
of failure the vulnerability is linked to the magnitude of the damage. The magnitude of
Fig. 6.5 Risk dynamics. Source: WBGU (1999)