Facility against tsunamis and green infrastructure—a case study of post-disaster reconstruction after the Great East Japan Earthquake

Abstract

The infrastructure reconstructions after the Great East Japan Earthquake (GEJE) and related attempts on biodiversity conservation were categorized and reviewed. Seawalls and wave-dissipating blocks reconstructed after the GEJE are examples of gray infrastructure. Reconstructed coastal protection forests and constructed green spaces are “green” infrastructure in the sense of using plants; however, they also seriously damage coastal ecosystems. Present states of coastal protection forests and green spaces would not sufficiently provide ecosystem services expected for a coastal environment. Attempts to conserve biodiversity and landscape, i.e., unreconstructing or downsizing seawalls, setting back seawalls, designating conservation areas, and laying coastal sand on seawalls or mounds of coastal protection forests, have been made and established. However, they were not applied with the concept of green infrastructure, were designed not to deliver ecosystem services, and were independently implemented and isolated without a strategically planned network. Therefore, the network of the sites of these attempts should be planned to deliver the expected ecosystem services. Laying coastal sands on facilities is probably useful for building a type of corridor that links isolated conservation areas. Studies on the present state of biodiversity and other environments and sociological studies are needed to improve ecological services from reconstructed coastal area.