Use of Compartment Dikes as a Flood Management Strategy in Schouwen-Duiveland

Abstract

CIE4061 Multidisciplinary Project: We were tasked with determining the feasibility of dike compartments to mitigate flood risk in Schouwen-Duiveland, The Netherlands. The primary dike protecting the polder of Bruinisse is vulnerable to piping failure, leading to a high probability of flooding. In the event of a flood, the small but deep polder would fill quickly and pose disastrous consequences, both in terms of human casualties and economic loss. Compartment dikes seek to reduce the effects of flooding by strategically retaining water or protecting areas of high value. The first phase of our study aimed to find the optimal compartment dike layout for Bruinisse polder. We began with a thorough investigation into the existing site conditions and best practices for flood protection, with a particular focus on piping failures. We modelled the effect of dike breaching to determine the consequences of flooding. The results were used to calculate the tangible economic damage and potential fatalities for several different dike compartment strategies. Ultimately, we determined that reinforcing and extending an existing former sea dike near the weak primary dike section was the optimal layout. The second phase of our study sought to determine whether compartment dikes were a viable solution for flood prevention when compared to other strategies such as repairing the primary dike. Several alternative solutions were explored, including berms, cut-off walls, relief wells, temporary barriers, raising land elevations, and improving evacuation. A probabilistic approach was used to quantify uncertainty in both the strength of the dike and environmental loads acting on it. A design and cost estimate was then prepared for each alternative solution, ensuring that they complied with safety requirements for the site. We then conducted an environmental impact assessment and stakeholder analysis to ensure a balanced evaluation. Our multi-criteria analysis determined that reinforcing the weak primary dike using a berm was the optimal solution for mitigating flood risk in Bruinisse. We recommend that additional data collection and analysis take place prior to further action.