Disaster Management of Yokohama Waterworks Bureau

A. Case Study Overview

1. Activity/ Project Title:
Disaster Management of Yokohama Waterworks Bureau
2. Themes:
3. Summary:  

Based on the purpose of the Yokohama City Disaster Prevention Plan, Yokohama Waterworks Bureau carry out various projects for disaster countermeasure from the perspectives of “self-help,” “mutual help,” and “public help”, aiming to build a safe and secure lifeline under the cooperation with water utilities in other local governments.

4. Sector:
City : Yokohama Waterworks Bureau
5. Implementation Period:

Since 1979
In 1979, the Large-Scale Earthquake Countermeasures Law was enforced in the wake of the M7 earthquake near Izu Oshima. In response to this, Yokohama City established disaster countermeasures that are the basis of the current policies of YWWB: such as the water supply in emergencies, storage of drinking water, and strengthening of earthquake-resistant facilities.

Since 1995
After the Great Hanshin-Awaji Earthquake (1995), YWWB strengthened the countermeasures against earthquakes and established the current system.

6. Project Site :
Yokohama City
7. Stakeholders&Partners:
・Relevant bureaus and ward offices of City of Yokohama
・Water utilities of other local governments
・Corporations and organizations of waterworks industry
・Japan Waterworks Association (JWWA)

B. Objective:

8. Objectives:
・Stable water supply in case of emergencies
・Prevention and reduction of damages by disasters based on the concepts of “Self-help”, “Mutual Help” and “Public Help”.

C. Activities

9. /Activities:

“Self-help”: Encourage citizens to stock water in case of water suspension in emergencies.

“Mutual Help”: Cooperation in communities and in workplaces

“Public Help”: Improvement of main facilities of YWWB

Based on these concepts, YWWB makes main facilities such as water purification plants, distribution reservoirs and pipelines more earthquake-resistant.  Also in preparation for heavy rainfall, we make efforts to simulate damages in intake facilities and make a plan for earlier recovery.

Self-help at home and mutual help in the community are promoted.  Emergency aids in collaboration with other cities are also enhanced as well.

Thus, YWWB has been challenging in both tangible and intangible aspects, to minimize the damages and accelerate recovery.

D. Challenges and solutions:

10. Challenges and solutions:
  • We need to systematically replace and take anti-seismic processes to aging facilities and pipelines.
  • We also have to strengthen the countermeasures against not only big earthquakes, and also heavy rain or volcano eruption.

E. Outcomes and Impacts:

11. Outcomes&Impacts:

As of the end of March, 2020


Promotional activities to encourage citizens to have stocks of water of 3 liters per day, a total of 9 liters per person, minimum of 3 days’ worth.
(Information is carried in the payment slip for users, website, events etc.)

Mutual Help

Emergency Water Supply Stations

Underground water supply tanks for emergencies  134 tanks
Distribution Reservoirs  22 locations
Emergency Water Taps 358 taps
Earthquake Resistant Water Taps 32 taps

Disaster Drills for Citizens
Approx. 200 times of emergency water supply drills are yearly implemented.

Public Help

Reinforcement of Water Facilities and Communication System
Rate of anti-seismic measures taken:51% of water purification facilities, 69% of conveyance facilities, 96% of distribution reservoirs
Installment of emergency power generators: 29 spots Cooperation with other water utilities , corporations & JWWA

  • With Nagoya City: Joint disaster drills and technical information sharing under the Agreement
  • With JWWA: Joint disaster drill of the Kanto Regional Branch, where YWWB serves as a leader city

F. Budget:

12. Budget:

Approx. 29.8 billion JPY (2020 budget)

*Total budget of all projects related to countermeasures for disasters

13. Source:
Revenue from water tariff, public enterprise bond and national subsidy