HSRR02: Flood risk in unembanked areas

Climate change impacts such as sea level rise and a higher river discharge have an effect on the flood risk in the region of Rotterdam. Within this project, the unembanked areas located within the Hotspot region were addressed. The research comprised the following steps:

    1. Flood risk in unprotected areas: climate scenarios were translated to flood maps. Furthermore, maps were developed based on potential adaptation strategies
    2. Vulnerability analysis of direct damages: based on the flood maps potential direct damages in the unprotected areas were determined
    3. Vulnerability of harbor infrastructure: the vulnerability of the harbor infrastructure was analyzed, with a focus on the chemical sector

The project provided insights in the consequences of climate change for flood safety in unprotected areas using flood maps, damage predictions and predictions for specific effects in the harbor infrastructure. The methodology also enabled the researchers to visualize the effectiveness of a number of adaptation strategies. This provided an input for the adaptation strategy for the region of Rotterdam. The results of this research also were an input to the projects HSRR07 – Perception and HSRR09 – Construction.

Currently the vulnerability to floods for the unembanked areas is limited, because they are at a relatively high level of elevation. Because of the relatively low flood velocities, structural damages nor high casualty rates are expected. This is confirmed by historical data since no major flood events have been recorded in the area. Yet, the area is susceptible to ‘extreme events’. Flood impacts can be considerable, which demands a sound flood management strategy. The unembanked area comprises locations with different characteristics (e.g. in elevation and asset concentration) which provides a multitude of opportunities for adaptation. With the high level of detail used in this study local hotspots for adaptation were identified. Special attention is needed for the cultural heritage in the area, as many historic buildings are prone to future flooding.

The Rotterdam port area provides a special case in the flood risk assessment. While on individual property level the flood risk seems limited, more research has to be performed on the scale effects of flooding; when multiple installations and plants are affected by flooding the consequences might be more substantial than currently estimated. Research is also needed to better assess flood vulnerability of the lower areas. The port area can develop many feasible responses that increase flood resilience without major efforts. An example of this is flood proofing the electricity supply to the area.

Project Results

Veerbeek, W., Huizinga J., Asselman, N., Lansen, A.J., Jonkman, S.N., Meer, R.A.E. van der, Barneveld, N. van (2010). Flood risk in unembanked areas. Synthesis. Report number: KfC 022/2010; ISBN 978-94-90070-21-2.

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