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How Has Flooding & Coastal Erosion Affected Housing?

Two-thirds of the world's population lives in coastal environments. The combined hazards of flooding and coastal erosion have, in extreme cases, eradicated whole towns. In better circumstances, the hazards have forced coastal towns to strengthen building regulations, build seawalls, and in some cases, ban building on the beach.

  1. Flooding

    • Coastal flooding caused by tsunamis, hurricanes and severe storms spreads debris, spurs erosion and inundates normally dry lands. Major flood events can occur over a short- or long-term basis causing loss of life, water damage and mold development, and can level homes. The most dangerous natural hazard, floods have killed millions with the deadliest occurring in 1931 in China. When the Yellow and Yangtze Rivers flooded, nearly four million people died from drowning, disease and starvation.

    Coastal Erosion

    • Coastal erosion caused by wave action, tidal currents, wave currents, rain events, drainage and high winds leads to loss of rocks and sediment and sediment redistribution. Major erosion events can occur over a short- or long-term basis causing damage to or leveling homes. A massive erosion event in Hallsands, Devon, England, washed away the entire village overnight. Natural erosion had been worsened by dredging shingle (small, rounded stones) from the bay.

    Building Codes

    • One technique cities use to combat possible losses, building codes, require property owners to use specific materials, building to base flood elevations, and may require special features, such as stilts.

    Seawalls

    • Seawalls provide temporary protection from erosion, but the sand used to form them eventually wears away and must be replaced. Their construction, however, allows building on the shore to continue.

    Building Ban

    • Although banning construction along the shores is the only way to guarantee that coastal properties and lives are not lost to flood and erosion, bans are rarely implemented. Most municipalities lack the political will to enact such a ban since it would impact personal property rights. Some areas make the ban more palatable by purchasing the coastal land and using it as open space or parks.

    Flood Insurance

    • The U.S. government requires homeowners in coastal flood zones to buy flood insurance through the National Flood Insurance Program.

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