Evacuatie voor hoogwater: Casestudie bij Callantsoog

Evacuatie voor hoogwater: Casestudie bij Callantsoog

Van Appeldoorn, M.

Van de Giesen, N.C. (mentor)
Sanders, F.M. (mentor)
Hoes, O. (mentor)
Rood, C.P.M. (mentor)

Civil Engineering and Geosciences

Transport & Planning

2008-05-01

Until recently, little attention has been given to the proper reaction of authorities and population in the case of a dike breach. It is postulated that the number of victims can be reduced if all people involved know what to do and where they have to go. No technically sound evacuation plans exist for the different polders and regions of the Netherlands. This gives rise to the question to what extent current infrastructure suffices to evacuate the complete population in time from one dike-ring to the neighboring dike-rings. The central question this report tries to answer is: Which technical information is needed to improve evacuation in case of a dike breach? First, through a literature review, it is discussed how the impact of a flood can be mitigated and how, in general, floods in the Netherlands are managed. Based on this review, the need for a better supply of technical information to government and citizen is determined. A case study (Callantsoog) was undertaken to obtain insight in the impact of a flood. The case study gives insight in inundation patterns and evacuation possibilities. A number of maps containing the necessary information for the calamity organization was defined. The case study shows that total clearance times vary depending on the clearance strategy. Clearance times vary from 135 to 225 minutes. This means that, under normal circumstances, everyone can be evacuated in the available clearance time. The case study also shows that a larger width of the dike breach causes an increase in the number of victims. The number of victims differs as a function of compartment size. The smallest compartment causes 498 victims, whereas the current single large compartment causes 36 victims. The analysis of the case study led to the creation of four maps, which can support evacuation: • Inundation map with safe areas. This map provides flight possibilities to safe places within the dike ring; • Victim map, which helps authorities decide where evacuation efforts need to be concentrated; • Golf front map, which gives insight into which areas are able to be evacuated after the dike breach; • Flee route map with the times at which dike crossings, which are normally open, need to be closed. This map helps to determine along which roads one has to evacuate and how long on has before a road will be closed. Limiting the dike opening has a positive influence on risk . It reduces the number of victims, it gives more safe areas within the compartment and the time before the compartment has overflowed is extended. The current compartment at Callantsoog has an optimum size for flood risk at one dike opening. It is recommended to build no houses on locations in the compartments where the occupants do not have the possibility to evacuate horizontal or vertically preventively.

http://resolver.tudelft.nl/uuid:3f554770-8c36-46c0-8b31-15df439eca11

Student theses

master thesis

(c) 2008 Van Appeldoorn, M.