| Publication date | January 5, 2021 |
|---|---|
| Sector | Life of Citizenry and Urban Life |
| Region name | Kyushu (Kumamoto City, Kumamoto Prefecture) |
In the Kumamoto region, precipitation is following a rising trend in the summer months, and it is particularly concentrated in the rainy season, which accounts for more than 40% of total annual precipitation. Especially, the end of the rainy season is characterized by frequent torrential downpours, and property damage due to the resulting hazards of sediment collapse, inundation, and river flooding are a cause of concern.
The water supply for the city of Kumamoto (with a population of about 740,000 people) is relatively unusual in that its tap water is collected from groundwater. Unlike most other urban centers there are no dams or water treatment plants. Residential tap water, which is treated by adding the minimum amount of chlorine prescribed by law to purify groundwater from wells, is stored in distribution and treatment reservoirs.
Kumamoto municipal wells are privately managed and provide emergency drinking water or a stopgap auxiliary water supply in the event of regional disruption to the regular supply from natural disasters. The Kumamoto municipal government has agreements with private contractors to provide well water in the case of emergencies. As of March 9, 2020, 92 emergency wells have been registered. The Kumamoto City Information Service Map allows people to check the location of the emergency wells (Fig. 1).
Signage indicating domestic and drinking water have been installed at locations where well water is available (Fig. 2). When certain conditions are met, the Water Conservation Section of the Kumamoto municipal government informs contractors to allow well water to be used for the non-potable domestic water supply. In the case of drinking-water, well samples are taken by the Water Conservation Section and then tested by the Kumamoto Environmental Research Center. If test results do not show any abnormalities, the availability of potable water from that source is posted on the city web page. At the discretion of individual contractors, a source may be put into service for non-potable household water before inspection, however, the company managing the well is responsible for making it clear to end users that the water is not considered safe to drink. (Fig. 3).
The provision of emergency wells by private businesses is expected to be widely useful as a water supply in the event of emergencies.
Fig. 1 Location of Emergency Wells
(Source: Kumamoto City, "The Provision of Wells during Emergencies")
Fig. 2 Emergency Well Signage for Non-potable Domestic Water (left) and Potable Water (right)
(Source: Kumamoto City Website, "The Provision of Wells during Emergencies")
Fig. 3: How Wells will be Used in the Event of Emergencies
(Source: Kumamoto City, "The Provision of Wells during Emergencies")
