Climate change impacts
Kumamoto City uses 100% natural groundwater for its domestic water supply and thanks to the excellent quality of this resource the city has the reputation that, ‘you can turn on the tap and get mineral water’. However, the supply of groundwater is on a downward trend over the long term; rainwater and other infiltration areas have decreased due to the progress of urbanization, and more water per person per day is used in Kumamoto than other major cities in Kyūshū. In addition, there are concerns that the demand for drinking-water will increase due to rising temperatures. The groundwater is also at risk of salinization due to rising sea levels, caused by climate change, and greater risks of land subsidence due to higher rates of groundwater consumption.
Adaptation activity
To conserve groundwater resources, Kumamoto City is working on various water-saving measures. For example, through the Water Saving Citizens' Campaign, which started in FY2005, the ‘Water Saving 210 (two one zero) Campaign’ has set a target value of 210 liters (Note 1) for daily water use per person from FY2019 to FY2024. In addition to practical water-saving ideas, the campaign offers water-saving equipment at "Water-Saving Equipment Promotion Stores (Note 2)", that is easy to install, greatly helps to protect resources and promotes an environment that is more conducive to water conservancy (Fig. 1). Throughout the year, the daily per capita water consumption is published in the City News every month, and on the Kumamoto City website to encourage the attainment of water saving targets. The months of July and August are particularly targeted as times of higher consumption, and are designated as a "Summer Water Saving Period". At this time daily per capita water consumption is updated on the Kumamoto City website every day.
In addition to using public information centers and educational facilities (such as the ‘Kumamoto City Water Science Museum’), the city is also working to create more effective media, public awareness programs, and other methods to provide people with easy-to-understand guidance. So far, the city has been conducting public awareness campaigns on the high quality of the tap water, providing background on the city’s water issues through tours of water supply and sewage facilities, on-site lectures, and the production of effective and easy-to-understand public information through collaboration with private sector professionals (Fig. 2).
The "Environmental ISO for Schools", run by the Kumamoto Prefectural Board of Education also contributes to water conservation awareness. The program aims to foster an environmentally friendly sensibility as well as a proactive attitude to environmental issues and conservation. Every year, many elementary and junior high schools take up water conservation as part of their curriculum.
Outputs / Expected benefits
As a result of the Water Saving Citizens' Campaign, per capita daily water consumption (annual average) is steadily decreasing year on year. As a result of this long-standing campaign, the city achieved its FY2012 and FY2013 target of 230 liters of water per person per day.
Footnote
（Note 1) Average daily water usage per person in major cities in Kyūshū
(Note 2) Kumamoto City's registration system for "Water-Saving Equipment Promotion Stores " to promote the use of water-saving equipment and groundwater conservation.
