A certain degree of risk.Or: How great is flood risk in The Netherlands?

摘要

"One day with a sigh of relief we will give up this country to the tempestuous sea".This was theprediction made by the civil engineer Van Veen, the spiritual father of the Dutch Delta Works.Until that timewe want to be able to continue to live safely in this country protected against flooding.One hundred percentsafety is neither feasible nor affordable.Therefore the cost of water defences has to be weighed against the levelof safety they provide.For this reason a set of standards was included in the Water Defences Act (Teulings,1996).These standards are based on the probability of certain water levels being exceeded.It is also laid downin the legislation that the aim will be to work towards a set of standards based on the flood probability and theconsequences of flooding, generally referred to as the "flood risk approach".One of the steps in this process isto calculate the flood probability in the dike ring areas, and to indicate the consequences.The Flood Risks andSafety in The Netherlands (Floris) Project undertakes these calculations for a representative number of dike ringareas.The project is being carried out under the auspices of the Ministry of Transport, Public Works and WaterManagement, Rijkswaterstaat.The formal principal is the Ministry of Transport, Public Works and WaterManagement, Directorate-General for Water Affairs.The project office works closely with the Association ofWater Boards and the provincial authorities.The project was still in progress at the time this paper was drawn up.Therefore the emphasis has been placedon the theoretical principles behind the project, on the one hand, and its potential applications for governmentofficials, water boards and provincial authorities, on the other.