Recycle rain to satisfy urban water needs 

Location: Japan

Sky Water Solution

A quiet, unassuming man, 53-year-old Makoto Murase looks more like the doctor of pharmacology that he is than a man with a mission. His objective — and life-passion — is to solve urban water shortages, provide water for many household uses to millions of people and change the way city planners view rainfall. In most urban centres, rainwater is seen as something to dispose of as quickly as possible, lest it interferes with traffic, floods low-lying areas and clogs sewage systems. To Murase, it is a resource we can no longer afford to waste.

With almost three decades’ service as an employee of Sumida Ward in eastern central Tokyo, Murase sprang to prominence by convincing the city fathers and the even more conservative heads of Japan’s Sumo Wrestling Federation to change plans for a new arena to include a rainwater recycling system. The success of this system, which uses rainwater collected on the roof and stored in a 1,000m³ tank for flushing toilets and as an emergency reservoir, set a new standard for construction in Tokyo. It also inspired many architects and engineers to re-evaluate rain.

An Urban Resource
While many before him have devised rainwater-recycling systems, Murase is the first to develop practical ways to use rain on such a scale in urban environments. For this original work — and for the implications it has on rainwater use globally — Murase has been selected as an Associate Laureate of the Rolex Awards. The Award should, he says, help publicise his work and convince the doubters in Japan and abroad that his ideas are not just pipe dreams.

Now head of the Rainwater Utilisation Promotion Section of Sumida City, an organization created for him, Murase has sketched out a plan that he claims could reduce household water consumption by one quarter and make most big buildings virtually self-sufficient in terms of water supply. He has persuaded Sumida City to underwrite a small Rainwater Museum and to help publish in Japanese his Rain Encyclopaedia, which is also to be translated into English with help from Murase’s Rolex Associate Laureate Award.

A Flood of Possibilities
One of his many projects is the creation of mini-dams — above-ground catch basins that already dot Tokyo neighbourhoods. Currently, they are used mainly as sources for gardening and other non-drinking applications. However he sees them becoming part of a water-utility infrastructure. "Rainwater," he says, "is ideal for drinking, and that should be its primary use, especially in places where ground water is contaminated." While using rainwater for drinking is complicated — it can need treating, and the first rainwater collected from roofs after a dry spell contains dirt — the problems can be overcome. At the same time, untreated rainwater is perfectly suited for many other household uses, such as "watering our plants, flushing our sewage and washing our clothes".

Treating rainwater to make it suitable for drinking is proving successful in pilot projects Murase is supporting in Bangladesh. Working with a local non-profit organization, he has devised a system to bottle rainwater in self-sterilising packages for use in areas where arsenic has seeped into wells. He has also been a consultant for a project in Taiwan using rainwater to flush toilets and clean cages at Taipei Zoo.

Re-using Rainwater
"Sky water" — Murase’s term for rain — can have many household uses for millions of city-dwellers worldwide. "What we need now is to make people more aware of the potential and train a new generation of application engineers who understand the how and why of recycling urban rainwater." At the moment, society is "simply throwing this incredibly valuable resource away". It is a luxury the world can no longer afford.

By the middle of this century, a greater proportion of the world’s population will be living in cities, Murase says. "Without using urban rainwater, there is no way to support the people without destroying the rural environments that provide the food."

Managing Water
The Japanese civil servant has few illusions about the task ahead. "We must change a lot of preconceptions before we can really start moving forward." He has proved he can push his ideas through local government with imagination and courage. His greatest strength, according to Sato Kiyoshi of Japan’s Techno Plan Ltd, is that "he knows how to look at things from the point of view of the ordinary person."

At the same time, Murase’s unique work makes him an extraordinary individual. The millions of mini-dams he envisions may some day dwarf the giant reservoirs that are symbolic of modern man’s quest to conquer nature instead of cooperating with it. 

Published in 2002




Links for Ballona (Watershed) Menu: 
News Article or New Content: