On the flood risk in the Netherlands

Abstract

The Netherlands are protected from storm surges and river floods by the Deltaworks: a reinforcement of the primary flood defence system consisting of coastal dunes, dikes and storm-surge barriers. These were implemented in response to the dramatic flooding disaster in 1953. Over the last 50 years, billions of euros have been invested in this scheme creating a feeling of safety in society. However, in this paper we argue that the current sense of safety may be inappropriate. Scientific evidence is growing, which shows that the hydraulic baseline conditions like storm wave properties and maximum river discharges may be different and more severe than recently thought. Climate change and sea-level rise may aggravate this situation. Moreover, the number of people and the value of properties behind the dikes have increased significantly since the coastal protection schemes were designed. In the present situation the flood risk appears to be disproportionately large compared to other daily risks. We conclude that on the short term the existing coastal and river flood protection should be reinforced to accommodate the more extreme hydraulic conditions and protect these valuables. Alternatively, protection levels of different areas should be reconsidered and perhaps reduced. The latter would in fact mean retreat from particular areas.