Column 14. Developing into a Water-Efficient City
During the latter part of January, various areas of Kyushu faced a series of problems such as suspension of water services because of a cold snap. Thirty-eight years earlier in 1978, Fukuoka City was forced to implement water use restrictions that continued for 287 days. At that time, the population of Fukuoka City was 1.05 million, and its system could supply 478,000 m3 of water daily, which was obtained from the Egawa Dam, four other dams within the city’s administrative area, and rivers, but extremely little rainfall (70% of a typical year) had a major impact on the lives of residents of not only Fukuoka City but also surrounding cities.
In order to resolve this precarious situation, the General Plan for Measures Related to Water Use in a Water-efficient Fukuoka was created in 1979, and fundamental measures to resolve the problem were launched. Up until the present, the city has implemented numerous measures, which have been based on the idea of a stable supply of water and water-efficient urban development.
First of all, dams were constructed on and water obtained from the Tatara River and Naka River systems within the city’s administrative area, and the long-awaited aqueduct from the Chikugo River, the largest river in Kyushu, was completed in 1983. The benefits from this were shared throughout the city by the Fukuoka District Waterworks Agency. For Fukuoka City, if one includes the increased volume from the Egawa Dam and Oyama Dam (competed in 2013), 32% of the city’s current capacity, 777,700 m3, comes from the Chikugo River system. This was possible precisely because of the understanding and cooperation of various parties, including local governments and residents of the watershed.
At the same time, efforts have been launched to employ new technologies, such as using a seawater desalination plant (MAMIZU PIA) that was completed in 2005 and makes a stable supply of water possible regardless of the weather.
On the other hand, progress has been made in creating a water-efficient city through cooperation with residents, and this has involved greater awareness of water conservation among residents, the spread of water-efficient faucets and other equipment, and the use of recycled water (a first for Japan), and for FY2013, Fukuoka’s water demand was 400,000 m3 per day, giving it the lowest per capita water demand among major cities in Japan. Incidentally, Fukuoka City was hit by a heat wave in the summer of FY2013, and the monthly average temperature was 30°C, the highest in Japan, and there were seventeen consecutive days that the daytime high temperature was 35°C or more, a historically long streak, but even so, the water use volume was the lowest among major Japanese cities.
Furthermore, by installing a water supply coordination system (water management center) to provide a fair and smooth supply of water to all areas of the city and investigating water leaks, the city is working to not only make the most effective use of water as possible but also maintain water quality and safety .
Between 1994 and 1995, water restrictions were implemented 295 days on account of unusual little rainfall, less than the previous time, and for the total period, rainfall was only 60% that of the previous time. In 2005, there was another period of little rainfall, the third smallest recorded amount, but water restrictions were not implemented. This is probably because of water resource development (expansion from those within the watershed to those outside the watershed and the use of sea water), the water supply coordination system, and above all the cooperation of residents.
The water level at the eight related dams is more than 90% on account of the large amount of rainfall since last year, but there have still been years when restrictions have been placed on the amount of water that can be taken from these reservoirs on account of the recent high volatility in the weather.
The Gokayama Dam, which will be the largest dam in the prefecture with an effective storage capacity of 39.70 million m3 is being constructed upstream from the Minamihata Dam on the Naka River system, is expected to come into use in 2018. The dam is unique in that part of its capacity is allocated for drought countermeasures, and of the overall 16.60 million m3, 13.10 million m3 is for Fukuoka City, and will serve as water in the case a once-in-a-decade of more severe drought. It will probably be necessary to continue to develop a water-efficient city as a reassuring backstop for future crisis.
Waterworks are indispensable lifelines, and efforts to secure water resources and get communities to work together to conserve water on account of the harsh local water resource environment are probably some of the reasons that Fukuoka City continues to grow.