Understanding Why Residents Remain in Japan's Flood Zones

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Why do residents in flood-prone areas of Japan choose to stay despite the risks? This question drives two recent studies exploring how cultural ties, economic realities, and policy gaps shape decisions in high-risk zones. For planners worldwide, these findings reveal practical lessons for crafting disaster resilience strategies that resonate with communities.

Japan (Google Earth image © 2025)

Cultural Ties Drive Risk Acceptance

In Japan, land carries deep cultural weight. Terms like senzo daidai no tochi (ancestral land) and chien (local community networks) highlight the emotional and social bonds tying residents to their homes. These ties often outweigh flood risks.

In a study by Kazunori Sugiyama and Ryoga Ishihara, only 15 percent of commercial store owners in Wakayama prefecture were willing to relocate from flood-prone areas. For the rest, their location is a multi-generational legacy, often tied to inherited businesses and customer relationships.

In traditional Wakayama communities like Maejima-cho and Gejo-higashi-cho, over half of the residents pointed to ancestral land as a reason to stay. Similarly, in Toyohashi City, research by Asano Junichiro and Uda Tomoya found that 41.2 percent of households opted to raise ground levels rather than relocate, reflecting a preference for adaptation rooted in place attachment. For planners, this suggests that cultural values must inform land use and relocation strategies.

Economic Trade-Offs Shape Decisions

Economic factors add another layer of complexity. In Wakayama, business owners face steep relocation costs, moving both homes and businesses, often inadequately covered by government support. Many operate in a mixed-use model that cuts costs but is hard to replicate elsewhere.

The study by Sugiyama and Ishihara notes that 31.9 percent of owners fear losing their customer base, while urban property owners worry about asset devaluation post-relocation. In Toyohashi, economic barriers vary by demographic: young families (37.9 percent aged 40-60) grapple with mortgages, while elderly residents (31.7 percent over 70) face fixed-income constraints.

As a result, 35.8 percent of residents raise ground levels, and 28.3 percent build multi-story homes — adaptations that, while practical, may falter in severe floods. Planners need to account for these economic trade-offs when designing support systems.

Awareness Lags Behind Risk

Awareness of planning policies lags behind flood risk recognition. In Toyohashi, Junichiro and Tomoya found that only 24.4 percent of residents grasp basic zoning distinctions, and just two percent know about residential guidance zones.

In areas excluded from these zones, 97.2 percent were unaware of the policy shift. This disconnect shows in development patterns: building permit applications barely differ between designated and non-designated areas.

In Wakayama, business owners lean on personal experience and economic priorities over policy guidance. Traditional communication methods — official publications and website updates — often fail to reach residents effectively. This gap challenges planners to rethink how policies are shared and understood.

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