There are about seven meters high tide embankments surrounding Tokyo port area to prevent submergence from high tides and Tsunami. There are measures to conserve biological diversity outside of these embankments. The rise and fall of the tides bring tidal flat like effects to the embankments with biological diversity. It provides habitats to aquatic species at the same time traps floating wastes.
Tokyo Ports and Harbors Bureau or Construction Bureau is responsible and budget and sub-contract private companies to collects floating wastes on water. However, the contract excludes collection of waste once it drifts down on shore. Currently there is no local municipality, accessibility, nor collection system for the trapped wastes.
In 1997 February, SEAVERS was set up to solve those waste problems. SEAVERS has started cleanup activities accessing the shore by boat. Now cleanup activity is held every first Saturday morning of the month, which is the same day the regular monthly meeting is held. As of September 2015, total of 70 cleanups and nearly 1500 people have participated.