Stormwater Management in Congested Urban Areas in Tokyo

The sewerage systems in Tokyo play an important role in draining stormwater in urban areas. To prevent inundation, various measures have been introduced, including the construction of new and additional trunk sewers and pumping stations to increase the capacity to drain stormwater. Furthermore, new sewerage systems and facilities recently introduced include stormwater detention basins, storage in sewers and a new type of sewerage system which infiltrates stormwater positively into the earth. This report describes the facilities for draining stormwater in the urban district together with examples of the technologies applied in Tokyo.