Main Category

Utility Management

Sub Category

Watershed Management

The environment surrounding Japan's water supply is undergoing major changes, such as ashrinking population served, rising demand for water facility renewal, and an increasing risk forsource water quality. Under such circumstances, it is important to cooperate with other water
utilities for mutual water accommodation within the common water source basins and forconservation of water sources. This section introduces Japan's watershed management basedon the New Water Supply Vision (revised in 2008), which was formulated by the Ministry ofHealth, Labour and Welfare (MHLW) with the basic principle of "Let’s pass on the trust in watersupply to future generations by cooperating with the community.”
1. Watershed management in the New Water Supply Vision
In the New Water Supply Vision, an ideal future of water supply is envisaged from the threeperspectives of "safety," "resilience," and "sustainability.”○ From the perspective of "sustainability”• To ensure the stability of water sources and to secure water sources in emergencies, stablewater supply will be possible even in times of drought or accident by allowing available
water resources to be shared among water utilities on a basin-by-basin basis as well as on
an inter-basin basis.
• Ideally, the ownership and use of land within the water source basin is well managed, andwater source conservation efforts should be actively carried out.
1.1 Priority measures
Since a single measure may be related to multiple aspects of the three perspectives above,the measures to be implemented are organized into three categories, depending on who isinvolved: (a) internal measures for those concerned, (b) collaborating measures among thoseconcerned, and (c) measures to be taken with a new mindset.
(1) Internal measures for those concerned
As a countermeasure against water source accidents, it is important to plan and implement:• the development of response manuals, training drills, and the establishment of information
sharing methods among those concerned in the basin.
• the development of water safety plans based on an integrated approach, and improvementof the effectiveness of those plans.
(2) Collaborating measures among those concerned• It is important for water utilities sharing the same water source to plan and implement
coordinated water source conservation efforts.

1.2 Role of government agencies• National government should promote wide-area conservation efforts on a watershed basis
to keep water sources healthy.
• Prefectural governments should play a coordinating role with related water utilities within
their jurisdiction, while cooperating with other administrative entities on various mattersthat should be coordinated on a watershed basis. It is also necessary for prefectures to havea system that can support the promotion of water cycle and effective use of water resources
at water utilities on a watershed basis.
2. Basin management under water safety plans
The Water Safety Plan aims to create a system that ensures safe water supply by identifying
hazards that exist in the water supply system from source to tap, and continuously monitoring
and controlling them.
○ Concrete effects expected from the development of the Water Safety Plan include:
Strengthening the cooperation among related parties within the watershed in terms ofimprovement and monitoring of source water quality, and responding to abnormal waterqualities quickly.
2.1 Obtaining various information from the water source to tap
To identify hazard-causing events in the water supply system from source to tap, informationis collected on potential sources of pollution such as sewage treatment facilities, mining andindustry, and animal husbandry in the water source basin. Information on water sources andintakes is collected from relevant administrative departments, such as environmental healthrelated departments and river-related departments, as well as from neighboring water utilities
that share the same water source basin.
When collecting related information, it is desirable to share the information withneighboring water utilities that share the same basin. For small and medium-sized utilities, it isalso effective to ask large utilities having an information collection system to provide information
for them.
•Creation of water source basin maps
It is also necessary to put the collected information into a format that is easy to use. It is
desirable to create a water source basin map by entering on a map the collected water source
information, especially the location of facilities that could cause a source water pollution.
•What to do in case of deviation from the management standard
In case of deviation from the management standard, it is important to have specificmeasures in place depending on the actual situation, such as contacting related organizations,contacting people concerned in the basin when raw water quality deteriorates, and making
necessary requests.
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MHLW. “New Water Supply Vision Portal Site.”https://www.mhlw.go.jp/seisakunitsuite/bunya/topics/bukyoku/kenkou/suido/newvision/1_0_suidou_newvision.html

References

MHLW. “About the Water Safety Plan.”
https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/topics/bukyoku/kenkou/suido/suishitsu/07.html
Cabinet Office. “Secretariat of Water Cycle Policy Headquarters.”
https://www.cas.go.jp/jp/seisaku/mizu_junkan/index.html

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