Projects

Motivation and practical challenge

My contribution both as engineer and researcher is to understand the middle ground between man and nature. Flood defences protect us from the water but are also integrated with many other functions such as housing and nature. Depending on the location, some functions are more common than other ones (see photo). This shared-use of the flood defences often comes with conservative estimates for a robust design that guarantees the flood safety. While having multi-functional flood defences generally impose restrictions on the design, some elements in the natural foreshores or flooded areas near the dike can contribute to reducing flood risk. For example, vegetated foreshores in coastal areas can damp the amount of wave energy that reaches the dikes. Aside from natural values, coastal salt marshes can also capture clay over time which may be used in future dike reinforcements. With the new probabilistic risk approach recently adopted in the Netherlands, we may be able to quantify the effects on flood safety of both standard and nature-based reinforcement measures. Yet, an integrated risk assessment framework is required.

Innovative components

My research integrates already existing work in flood protection, risk management and nature-based engineering into a risk assessment framework. To develop this framework, I used existing assessment procedures to estimate the probabilities of dike failure for typical mechanisms (top-left figure). Under presence or absence scenarios of housing and trees, I compared the effects of multiple reinforcement measures such as broadening or heightening the dike for a more robust design (top-centre figure). I further extended the framework to assess the effects of dike reinforcements that include salt marsh development as nature-based adaptation measure for sea-level rise (top-right figure).

I am applying the concepts of this framework into two innovative case studies (bottom figures): the Wide Green Dike, and the Double Dike. How are the dike designs adapted for additional functions such as clay mining and salt marsh development? Moreover, what are the synergies and risks that these functions provide to dike safety? In the final step, insights from developing the extended framework, as well as the application cases are synthesised. Thereby, I can provide some recommendations for assessing the effects of other (nature-based) functions within the new flood risk standards.