Author(s): Karin De Bruijn; Kymo Slager; Bart Van De Hurk
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Keywords: No Keywords
Abstract: Flood-prone areas are home to societies who developed the areas, used them for agriculture, built cities and prospered. Over time, these societies have developed strategies to cope with flood hazards. Recently, however, floods seem to happen more frequently and cause more severe impacts. In recent years, floods caused by climate extremes and outliers have surprised the inhabitants of flood-prone areas, also in developed areas like western Europe. The strategies who protect them seem not adequate anymore. Whether this results from climate change, or a short memory of the citizens in the flood-prone areas, or due to land use changes is not completely clear and probably differs per case. However, it indicates that more attention for those outliers or extremes is needed (Merz, 2015). An important trigger for more attention for outliers in the Netherlands was the 2021 flood event caused by severe long-duration rainfall in summer in the Netherlands, Belgium and the Netherlands. The event was caused by unusual large-scale weather pattern which created a lot of moisture flowing in from a very large area (Kreienkamp, 2021). In the Netherlands, the consequences in the affected area were severe, but luckily no fatalities occurred. In Belgium and Germany more than 200 people were killed and many houses and infrastructure networks were damaged (ENW, 2021). This event came as a surprise: this type of large-scale rainfall event was in the Netherlands not considered in any risk approach, nor was it included in the 10.000 years of generated weather series for the Meuse River, the main river in the area, or included in procedures for response or crisis management (Asselman, 2022; ENW, 2021). In fact, the high-water/flood risk season is the winter and usually summer is used for repairs, maintenance and the warning and emergency services are then not alert. Therefore, water authorities were not well-prepared and had to challenge their experts to cope as well as possible and reduce impacts and rescue inhabitants. The event is also considered a wake-up call for other areas in the country (De Bruijn & Slager, 2022). Policy makers and other have started taking actions to improve the resilience of the Netherlands for such large-scale rainfall event by improving awareness, better preparation, land use adaptation, increasing the sponge behaviour of areas, adaptation of critical infrastructure and improving crisis management procedures (Min, I&W, 2022). To cope with flood risks the Netherlands has adopted a risk approach in which all potential events should be considered and weighed according to their probability of exceedance. However, this risk approach had a very strong focus on selecting the economic optimal design standard for water systems. Beyond-design events, with smaller probabilities, received little attention. Measures not related to adapting the water system were often found inefficient and therefore, not selected. As a consequence, strategies for adaptation of land use, or flood impact mitigation in general and for enhancing recovery are rarely implemented. This makes the country less resilient to extreme events that go beyond design standards of water systems. Understanding of what may happen if beyond-design events occur, the potential flood extent and resulting water depths and flood durations, the impacts on the functioning of critical infrastructure, on agriculture and on cities is lacking. In December 2022, the government published recommendations stating that because prevention of flooding may not always be possible, preparation and adaptation must be better taken care of.
Year: 2024