Human-centred design approaches to tsunami mitigation under sea level rise in Kesennuma, Japan

Abstract

Abstract. Human-centred design (HCD) is increasingly prioritised as studies show human experience is critical in infrastructure use, and recent policies call for more socially responsive design. Tsunami impacts intensify as sea level rise (SLR) raises baseline water levels and reduces existing defence effectiveness, yet HCD informed approaches are rarely tested under projected SLR. Based on identified infrastructure preferences in Kesennuma City, Japan, we develop three multi-layered defence configurations: an environmentally integrated eco hybrid system (Design 1), a discreet open feeling barrier system (Design 2), and a reinforced high-performance system (Design 3). Using TUNAMI-N2 numerical modelling, 150 simulations combine three tsunami sources, five SLR conditions, and five defence states. Results for inundation extent, fatality rates, and economic loss show a consistent hierarchy: Design 3 achieves the strongest containment, while Design 2, which more closely aligns with residents’ preferences for openness and access, delivers near equivalent reductions typically within 10–15 percent. Design 1 provides only limited hazard reduction and is unsuitable as a standalone mitigation system. We show that HCD informed configurations can deliver strong technical performance and support a shift toward socially integrated, multi-layered tsunami protection under rising sea levels.