Makoto MURASE

Solution / Tokyo’s Rainwater Recycling System

With 12.9 million inhabitants, Tokyo is a megacity composed of 23 wards. Unfortunately, this population density means a city covered with concrete, impeding the natural drainage of rainwater. In a country where torrential rains are often synonymous with catastrophe, finding a way of handling the overflow from storm sewer systems was desperately needed to avoid recurrent and devastating floods. The sheer volumes are staggering: 2.5 million tons of water fall on Tokyo alone every year!

Makoto Murase, an employee in the public health department for the Sumida ward, came up with a sustainable solution: a rainwater recycling system. Rainwater is collected from rooftops, filtered and sent to underground cement reservoirs. It can then be used to irrigate parks, flush toilets and supply electrical equipment, or simply be stockpiled for later use.