The author provides stable and safe designs of coastal and river banks using a new structural concept which stably keeps frame structure inside of the embankments, and therefore protects the backside of lowland areas, where more than ten millions of people live and social investment facilities are distributed. The projects can proceed under the framework of Public Private Partnership (PPP). This new proposal simplifies the design of multi water hazards from the probabilistic collapse risks to deterministic planning for human lives and accumulated social public facilities around coastal mega cities such as Tokyo and Nagoya in Japan. Those Metropolitan citizens experienced historical Kanto earthquake in 1923 and largest Tone-River flooding in 1947. On the other hand, heaviest storm surge in Japan by Typhoon Isewan in 1959 around Nagoya City in the Ise Bay facing Pacific Ocean. These regions distribute in flat low elevation areas for conveniences of foreign trade with port facilities, industries, and traffic infrastructures including hub airports. Mean while, those coastal districts and citizens sometimes remains in legendary collapse risks, such as gigantic fires or pandemic infection diseases nowadays along with the catastrophic destructions by M8 to M9 earthquakes, inundation and river flooding against social frameworks to keep human cultural livelihoods in the hazardous era of this modern earth of Gaia.