Cees Oerlemans and Robin Nicolai have developed and tested a novel API for flood risk assessment of Dutch households. For any location in the Netherlands, the API (i) calculates flood probabilities, (ii) translates these probabilities into financial impacts and (iii) quantifies how adaptation measures reduce flood risk. The Flood Risk API provides the technical foundation for flood risk labels that can make flood exposure transparent and adaptation value concrete.
Key findings from testing 320 locations:
- Flood risk concentrates in a small share of Dutch households: About 80% of Dutch properties in our sample face minimal expected annual damage (<€100/year), while 5% face substantial exposure (>€1,000/year). This concentrated risk makes household adaptation cost-effective for some properties but unnecessary for most.
- Effectiveness by measure: For properties with expected annual damage above €100/year (20% of tested locations), land-raising reduces flood risk by ~90%, dry-proofing by ~70%, and wet-proofing by ~50%. Combined measures nearly eliminate household flood risk.
- Uncertainty ranges: Flood risk estimates vary by factors of 5-10 depending on methodological choices in risk assessment and underlying data quality is insufficient for single-point risk estimates. Uncertainty mapping is essential for credible risk communication and effective risk labels.
The study is part of the risk assessment work package in the interdisciplinary research project “Encouraging Climate Change Adaptation Through Flood Risk Labels”, led by Antonia Krefeld-Schwalb (Erasmus University Rotterdam), and funded by Resilient Delta.
Links to the executive summary (~9 pages) and the full technical report.
