Introduction

People have been received a lot of bounties from the coast and sea. On the other hand, disasters caused by high waves, storm surges, and tsunami have also suffered. Since the population and wealth have to accumulate on the lowland of coastal areas because of the terrain of our country, coastal engineering has developed as academics to protect people and living from the threat of coastal disaster. Meanwhile, maintenance for protection has hindered the use of the coast, causing a situation that deteriorates the coastal environment including living things and ecosystems. In 1999, the Coast Act was revised for the first time in 41 years, not only for the protection of the coast but also for the maintenance and conservation of the coastal “environment” and the proper “use” of the coast, for the purpose was added.

The tsunami caused by the 2011 off the Pacific coast of Tohoku earthquake of Magnitude 9.0, which occurred on March 11, 2011, brought unprecedented disaster to our country. In response to this, the Coast Act was revised, the setting of a two-level tsunami external force was proposed, and the idea was introduced that the structure should be tenacious against flooding over design outside force. In the near future, we are concerned that the Nankai Trough mega earthquake will occur with a high probability, the Cabinet Office Central Disaster Council reviewed and announced the assumption of the tsunami. In order to minimize human and asset damage, it is urgent to establish effective countermeasures against tsunami, such as improving the function of coastal structures, which is a hard measure, securing evacuation places, which are soft countermeasures, and evacuation guidance. From a new perspective not tied to the tsunami research so far, research that is useful for future tsunami countermeasures is required.

On the other hand, owing to global warming, sea surface temperature in the tropics has risen, and the intensity of strong tropical cyclones (typhoons) in the northwestern Pacific has increased since around 1970. Adaptation to emerging sea level rise and typhoon intensifying is also required for coastal engineering. The Flood Control Act was revised in 2015, and regulations for the largest class flood, domestic water and storm surge that can be assumed based on climate change were stipulated.

Aims

Our laboratory studies how to reduce human and asset damage from water disasters such as tsunami and storm surge, aiming for safe and secure coastal protection, and furthermore, to extreme weather due to global warming. We also propose effective adaptation measures against the serious water-related disasters involved.